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  • richardmitnick 4:07 pm on January 20, 2022 Permalink | Reply
    Tags: "Going beyond the exascale", , , Classical computers have been central to physics research for decades., , , , Fermilab has used classical computing to simulate lattice quantum chromodynamics., , , , Planning for a future that is still decades out., Quantum computers could enable physicists to tackle questions even the most powerful computers cannot handle., , Quantum computing is here—sort of., , Solving equations on a quantum computer requires completely new ways of thinking about programming and algorithms., , Symmetry Magazine, The biggest place where quantum simulators will have an impact is in discovery science.   

    From Symmetry: “Going beyond the exascale” 

    Symmetry Mag

    From Symmetry

    01/20/22
    Emily Ayshford

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    Quantum computers could enable physicists to tackle questions even the most powerful computers cannot handle.

    After years of speculation, quantum computing is here—sort of.

    Physicists are beginning to consider how quantum computing could provide answers to the deepest questions in the field. But most aren’t getting caught up in the hype. Instead, they are taking what for them is a familiar tack—planning for a future that is still decades out, while making room for pivots, turns and potential breakthroughs along the way.

    “When we’re working on building a new particle collider, that sort of project can take 40 years,” says Hank Lamm, an associate scientist at The DOE’s Fermi National Accelerator Laboratory (US). “This is on the same timeline. I hope to start seeing quantum computing provide big answers for particle physics before I die. But that doesn’t mean there isn’t interesting physics to do along the way.”

    Equations that overpower even supercomputers.

    Classical computers have been central to physics research for decades, and simulations that run on classical computers have guided many breakthroughs. Fermilab, for example, has used classical computing to simulate lattice quantum chromodynamics. Lattice QCD is a set of equations that describe the interactions of quarks and gluons via the strong force.

    Theorists developed lattice QCD in the 1970s. But applying its equations proved extremely difficult. “Even back in the 1980s, many people said that even if they had an exascale computer [a computer that can perform a billion billion calculations per second], they still couldn’t calculate lattice QCD,” Lamm says.

    Depiction of ANL ALCF Cray Intel SC18 Shasta Aurora exascale supercomputer, to be built at DOE’s Argonne National Laboratory (US).

    Depiction of ORNL Cray Frontier Shasta based Exascale supercomputer with Slingshot interconnect featuring high-performance AMD EPYC CPU and AMD Radeon Instinct GPU technology , being built at DOE’s Oak Ridge National Laboratory (US).

    But that turned out not to be true.

    Within the past 10 to 15 years, researchers have discovered the algorithms needed to make their calculations more manageable, while learning to understand theoretical errors and how to ameliorate them. These advances have allowed them to use a lattice simulation, a simulation that uses a volume of a specified grid of points in space and time as a substitute for the continuous vastness of reality.

    Lattice simulations have allowed physicists to calculate the mass of the proton—a particle made up of quarks and gluons all interacting via the strong force—and find that the theoretical prediction lines up well with the experimental result. The simulations have also allowed them to accurately predict the temperature at which quarks should detach from one another in a quark-gluon plasma.

    Quark-Gluon Plasma from BNL Relative Heavy Ion Collider (US).

    DOE’s Brookhaven National Laboratory(US) RHIC Campus

    The limit of these calculations? Along with being approximate, or based on a confined, hypothetical area of space, only certain properties can be computed efficiently. Try to look at more than that, and even the biggest high-performance computer cannot handle all of the possibilities.

    Enter quantum computers.

    Quantum computers are all about possibilities. Classical computers don’t have the memory to compute the many possible outcomes of lattice QCD problems, but quantum computers take advantage of quantum mechanics to calculate differently.

    Quantum computing isn’t an easy answer, though. Solving equations on a quantum computer requires completely new ways of thinking about programming and algorithms.

    Using a classical computer, when you program code, you can look at its state at all times. You can check a classical computer’s work before it’s done and trouble-shoot if things go wrong. But under the laws of quantum mechanics, you cannot observe any intermediate step of a quantum computation without corrupting the computation; you can observe only the final state.

    That means you can’t store any information in an intermediate state and bring it back later, and you cannot clone information from one set of qubits into another, making error correction difficult.

    “It can be a nightmare designing an algorithm for quantum computation,” says Lamm, who spends his days trying to figure out how to do quantum simulations for high-energy physics. “Everything has to be redesigned from the ground up. We are right at the beginning of understanding how to do this.”

    Just getting started

    Quantum computers have already proved useful in basic research. Condensed matter physicists—whose research relates to phases of matter—have spent much more time than particle physicists thinking about how quantum computers and simulators can help them. They have used quantum simulators to explore quantum spin liquid states [Science] and to observe a previously unobserved phase of matter called a prethermal time crystal [Science].

    “The biggest place where quantum simulators will have an impact is in discovery science, in discovering new phenomena like this that exist in nature,” says Norman Yao, an assistant professor at The University of California-Berkeley (US) and co-author on the time crystal paper.

    Quantum computers are showing promise in particle physics and astrophysics. Many physics and astrophysics researchers are using quantum computers to simulate “toy problems”—small, simple versions of much more complicated problems. They have, for example, used quantum computing to test parts of theories of quantum gravity [npj Quantum Information] or create proof-of-principle models, like models of the parton showers that emit from particle colliders [Physical Review Letters] such as the Large Hadron Collider.

    The European Organization for Nuclear Research [Organización Europea para la Investigación Nuclear][Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN].

    The European Organization for Nuclear Research [Organización Europea para la Investigación Nuclear][Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH)[CERN] map.

    CERN LHC tube in the tunnel. Credit: Maximilien Brice and Julien Marius Ordan.

    SixTRack CERN LHC particles.

    “Physicists are taking on the small problems, ones that they can solve with other ways, to try to understand how quantum computing can have an advantage,” says Roni Harnik, a scientist at Fermilab. “Learning from this, they can build a ladder of simulations, through trial and error, to more difficult problems.”

    But just which approaches will succeed, and which will lead to dead ends, remains to be seen. Estimates of how many qubits will be needed to simulate big enough problems in physics to get breakthroughs range from thousands to (more likely) millions. Many in the field expect this to be possible in the 2030s or 2040s.

    “In high-energy physics, problems like these are clearly a regime in which quantum computers will have an advantage,” says Ning Bao, associate computational scientist at DOE’s Brookhaven National Laboratory (US). “The problem is that quantum computers are still too limited in what they can do.”

    Starting with physics

    Some physicists are coming at things from a different perspective: They’re looking to physics to better understand quantum computing.

    John Preskill is a physics professor at The California Institute of Technology (US) and an early leader in the field of quantum computing. A few years ago, he and Patrick Hayden, professor of physics at Stanford University (US), showed that if you entangled two photons and threw one into a black hole, decoding the information that eventually came back out via Hawking radiation would be significantly easier than if you had used non-entangled particles. Physicists Beni Yoshida and Alexei Kitaev then came up with an explicit protocol for such decoding, and Yao went a step further, showing that protocol could also be a powerful tool in characterizing quantum computers.

    “We took something that was thought about in terms of high-energy physics and quantum information science, then thought of it as a tool that could be used in quantum computing,” Yao says.

    That sort of cross-disciplinary thinking will be key to moving the field forward, physicists say.

    “Everyone is coming into this field with different expertise,” Bao says. “From computing, or physics, or quantum information theory—everyone gets together to bring different perspectives and figure out problems. There are probably many ways of using quantum computing to study physics that we can’t predict right now, and it will just be a matter of getting the right two people in a room together.”

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:57 am on January 19, 2022 Permalink | Reply
    Tags: "More than one way to make a qubit", A qubit is essentially a quantum state of matter that allows you to store more information and process more information than a traditional bit., Another approach employs flaws in diamonds., Another drawback is that superconducting circuits must stay frigid., Another upside of trapped ions is that they are stalwart defenders against a qubit’s greatest nemesis: loss of information., Because ions are electrically charged they are easily held in place by electromagnetic fields., Because of their robustness trapped ions exhibit some of the lowest error rates of any qubit technology., , , Enter the superconducting qubit, Ions are natural quantum objects: Two of the discrete energy levels of their remaining electrons can represent a 0 or 1., Ions-atoms that have lost one or more of their electrons-emerged as a promising qubit platform at the dawn of experimental quantum computing in the mid-1990s., , , Quantum entanglement (in which multiple qubits share a common quantum state), Quantum superposition (the ability to be in a mixed state-a weighted combination of 1 and 0), Researchers produced the first qubit implemented in a superconducting circuit in which an electric current oscillates back and forth around a microscopic circuit etched onto a chip., Superconducting circuits struggle against decoherence as well., Symmetry Magazine, Taking advantage of techniques used to make computer chips a manufacturer can fabricate superconducting circuits on large wafers., The biggest quantum computer unveiled in November 2021 by IBM contains 127 qubits., The goal of building a quantum computer is to harness the quirks of quantum physics to solve certain problems far faster than a traditional computer can., The list of possible qubits goes on. Photons; semiconductors; molecules—these and other platforms have potential., The quantum bit-or qubit—the quantum equivalent of the 1s and 0s that underlie our digital lives., Two promising approaches currently in focus to implement qubits: superconducting circuits and trapped ions   

    From Symmetry: “More than one way to make a qubit” 

    Symmetry Mag

    From Symmetry

    01/19/22
    Christopher Crockett

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    Scientists are exploring a variety of ways to make quantum bits. We may not need to settle on a single one.

    The goal of building a quantum computer is to harness the quirks of quantum physics to solve certain problems far faster than a traditional computer can. And at the heart of a quantum computer is the quantum bit, or qubit—the quantum equivalent of the 1s and 0s that underlie our digital lives.

    “A qubit is the fundamental building block of quantum information science technology,” says Joseph Heremans, an electrical engineer at DOE’s Argonne National Laboratory(US).

    Traditional bits can be any sort of switch, anything that can flip from 0 to 1. But building a qubit takes something more.

    “A qubit is essentially a quantum state of matter,” Heremans says. “And it has weird properties that allow you to store more information and process more information” than a traditional bit.

    Those weird properties include superposition (the ability to be in a mixed state, a weighted combination of 1 and 0) and entanglement (in which multiple qubits share a common quantum state). Both might seem like they would be hard to come by. Fortunately, nature has provided lots of options, and engineers have cooked up a couple more.

    Researchers are exploring more than half a dozen ways to implement qubits, with two promising approaches currently in focus: superconducting circuits and trapped ions.

    Out in front

    Ions—atoms that have lost one or more of their electrons—emerged as a promising qubit platform at the dawn of experimental quantum computing in the mid-1990s. In fact, the first qubit ever built was fashioned out of a single beryllium ion.

    Ions are natural quantum objects: Two of the discrete energy levels of their remaining electrons can represent a 0 or 1; those energy levels are readily manipulated by lasers; and because ions are electrically charged they are easily held in place by electromagnetic fields. Not much new needed to be invented to produce trapped-ion qubits. Existing technology could handle it.

    Another upside of trapped ions is that they are stalwart defenders against a qubit’s greatest nemesis: loss of information. Quantum states are fragile, and superpositions stick around only if the qubits don’t interact with anything. A stray atom or an unexpected photon can collapse the quantum state. In physics speak, the qubit “decoheres.” And decoherence is the death knell to any quantum information technology.

    “We want a system where we can manipulate it, because we want to do calculations, but the environment doesn’t talk to it too much,” says Kenneth Brown, an electrical engineer at Duke University.

    Trapped ions check both boxes. Held safely in a darkened vacuum, they have a low interaction with the environment, he says.

    Because of their robustness trapped ions exhibit some of the lowest error rates of any qubit technology. But they struggle to grow beyond small-scale demos. Adding more ions to the mix makes it harder for the lasers that control them to single out which one of them to talk to. And scaling up to more qubits means getting lots of auxiliary tech, such as vacuum systems, lasers and electromagnetic traps, to play along.

    The largest trapped-ion quantum computer on the market is a 32-qubit machine built by IonQ, headquartered in College Park, Maryland.

    2
    IonQ Releases A New 32-Qubit Trapped-Ion Quantum Computer With Massive Quantum Volume Claims. Credit: Forbes Magazine.

    But quantum engineers want machines with hundreds, if not thousands, of qubits.

    Enter the superconducting qubit

    Just a few years after the first trapped-ion qubit, researchers produced the first qubit implemented in a superconducting circuit, in which an electric current oscillates back and forth around a microscopic circuit etched onto a chip.

    When cooled to temperatures just a few hundredths of a degree above absolute zero, the oscillator circuit can behave as a quantum object: A flash of radio waves tuned to just the right frequency can put the circuit into one of two distinct energy levels, corresponding to a quantum 1 or 0. Follow-up zaps can steer it into a superposition of those two states.

    “They’re a really promising route to make quantum computers” because they can be made on microchips, says Paul Welander, a physicist at DOE’s SLAC National Accelerator Laboratory (US). “And microfabrication is something that we’ve been doing in the semiconductor industry for a long time.”

    Taking advantage of techniques used to make computer chips a manufacturer can fabricate superconducting circuits on large wafers.

    Another advantage of the superconducting circuit is “the ability to make a device that’s hundreds of micrometers across and yet, it behaves like an atom,” Welander says.

    Engineers get all the quantumness of an atom but with the ability to design and customize its properties by tuning circuit parameters.

    These circuits are also extremely fast, cranking through each step in a computation in mere nanoseconds. And because they are circuits, they can be designed to suit the needs of engineers.

    Superconducting qubits have found a home in the largest general-purpose quantum computers in operation. The biggest, unveiled in November 2021 by IBM, contains 127 qubits.

    3
    IBM Unveils Breakthrough 127-Qubit Quantum Processor. Credit: IBM Corp.

    That chip is a step toward the company’s goal of creating a 433-qubit processor in 2022, followed by a 1,121-qubit machine by 2023.

    But superconducting circuits struggle against decoherence as well.

    “They are made of many, many atoms,” Welander says.

    That provides ample opportunity for something to go wrong—materials and fabrication processes present a particularly thorny challenge when attempting to mass-produce millions of qubits at a time.

    Material interfaces are especially problematic. Metal electrodes, for example, readily oxidize. “Now we have an uncontrolled state at the surface,” Welander says, which can lead to decoherence of the quantum state and loss of information.

    Another drawback is that superconducting circuits must stay frigid, hovering at temperatures just above absolute zero. That requires extreme refrigeration, which presents challenges for scaling superconducting quantum computers to thousands or millions of qubits.

    A menu of options

    While these two qubit technologies are perhaps the best known, they are not the only game in town.

    Another approach employs flaws in diamonds. These gemstones are made up of carbon atoms arranged in a rigid, repeating latticework. But sometimes, another type of atom gets in. For example, a nitrogen atom or a vacancy—the absence of an atom—can take the place of a carbon atom. Such nitrogen and vacancy impurities are “a bit a like a trapped molecule in the diamond crystal,” Heremans says.

    Here, electrons trapped in the crystaline flaw store information in a quantum property called spin, a type of intrinsic rotational momentum. When measured, the spin takes on only one of two options—perfect for encoding a 1 or 0. Those options can be toggled with laser light, radio waves or even mechanical strain.

    Researchers are also exploring making qubits out of electrically neutral atoms, trapped using lasers instead of electromagnetic fields. “Neutral atoms are the most natural qubit candidate,” says Mikhail Lukin, a physicist at Harvard University (US).

    Like ions, neutral atoms can be isolated from the environment and stay coherent for long stretches of time. But modern laser technology gives scientists more flexibility with neutral atoms than electromagnetic traps do with trapped ions. Neutral atoms can be organized into many different 2D patterns, providing more ways to connect the atoms and entangle them, leading to more efficient algorithms.

    Using neutral atoms, Lukin and colleagues recently unveiled a 256-qubit special-purpose quantum computer known as a quantum simulator, the largest of its kind, with plans to build a 1,000-qubit simulator in the next two years.

    The list of possible qubits goes on. Photons; semiconductors; molecules—these and other platforms have potential.

    But despite all these options, there’s no clear winner. It’s not yet obvious what can be scaled up to 1,000 qubits or beyond. It’s not even certain that there is just one best approach.

    “We’re still in hunting-and-finding mode,” Welander says. For quantum computing, “it may actually end up being something hybrid,” using multiple quantum materials and systems.

    Perhaps a single processor will employ superconducting qubits working alongside diamond-defect qubits, which might talk to other quantum processors using photon-based qubits.

    In the end, what makes the “best” qubit depends on how the qubit is being used: A good qubit for quantum computing might be different from a good qubit for quantum sensing or a good qubit for quantum communication, Heremans says.

    Beyond physics

    What is clear is that qubit progress isn’t just a physics problem. “It really requires expertise in a wide range of fields,” from materials science to chemical and electrical engineering, Welander says.

    And it’s not just the qubits themselves that need attention. Qubits require a lot of support technology—vacuum systems, cryogenics, lasers, microwave components, nests of cables—all working in sync to get the most out of any quantum processor.

    In many ways, quantum computers are where digital computers were in the 1950s and ’60s. Then too, researchers were searching for the right technology to represent 1s and 0s and perform the logic operations necessary for any calculation. Bulky vacuum tubes gave way to more compact transistors; germanium transistors yielded to better-performing ones made of silicon; integrated circuits let engineers cram many transistors and support electronics onto single wafers of silicon.

    For quantum computing to reach its full potential, qubits still need the right technology. “There’s a lot of areas where people who are interested and people who are intrigued can plug in and make an impact,” Welander says.

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 11:15 am on January 18, 2022 Permalink | Reply
    Tags: "What is quantum information?", A classical bit is definitely a 0 or a 1 but a quantum bit- called a qubit- can be a bit of both., , , Classical information follows a set of rules. Quantum information breaks those rules., Classical information is discrete: A bit is always either a 0 or a 1 and nothing in between., In a classical computer information travels in the form of a string of bits-a pattern of 1s and 0s., , Quantum information allows a qubit to carry a different kind of information: continuous information about the relative balance of 0 and 1 within the qubit., Quantum information breaks the rules of classical information in a way that could allow us to answer questions that a classical computer cannot., Quantum information has to be carefully protected from its environment lest it become entangled with that environment and effectively lost., Quantum information is not discrete. A classical bit is definitely a 0 or a 1, , Symmetry Magazine, The way we process and interact with quantum information is fundamentally different.   

    From Symmetry: “What is quantum information?” 

    Symmetry Mag

    From Symmetry

    01/18/22
    Nathan Collins

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    Quantum information breaks the rules of classical information in a way that could allow us to answer questions that a classical computer cannot.

    Imagine mailing a letter. You, as the person sending the letter, know what the letter says. But the situation is different for the person you’re mailing the letter to. Until they read it, they generally won’t know what it says.

    This is the way scientists think about information, at least in the classical sense.

    A computer stores information, sends and receives information, and processes information. In a classical computer, the information travels in the form of a string of bits—a pattern of 1s and 0s. As each bit arrives, the recipient doesn’t know what value it will have; from their point of view, it is just as likely to be a 0 as it is to be a 1. To be sure, it will definitely be one or the other, but which it is will be revealed only once it arrives.

    In this sense, upon its arrival each bit resolves a certain amount of uncertainty.

    Now, it could be that knowing the start of a message gives clues about the rest of it. If a message starts, “O Romeo, Romeo,” it’s a good bet the message will conclude, “wherefore art thou Romeo?”

    Still, knowing the first part of the message does not determine—perhaps more to the point, it does not affect—the next part of the message. It could be that the rest of the message is “could you get me a sandwich?”

    All of this makes sense because classical information follows a set of rules.

    Quantum information breaks those rules, making it at once a powerful basis for computing and an exquisitely fragile beast.

    The quantum difference

    The rules of classical information are so intuitive that they are easy to take for granted.

    First, classical information is discrete: A bit is always either a 0 or a 1 and nothing in between. Second, bits are deterministic. That is, to the extent there is uncertainty in a bit, that uncertainty exists in the mind of someone who has not yet received a message (or in the possibility that an error might change the value of the bit). Finally, classical information is local—as in the Shakespeare example, a bit may suggest what’s coming, but observing that bit doesn’t actually affect any other bits.

    Quantum information, on the other hand, is not discrete. A classical bit is definitely a 0 or a 1, but a quantum bit, called a qubit, can be a bit of both.

    This feature allows a qubit to carry a different kind of information: continuous information about the relative balance of 0 and 1 within the qubit. Quantum algorithms can sometimes use this fact to run more efficiently than their classical counterparts.

    Quantum information is also not deterministic. When someone takes a look at a classical bit, it simply is a 0 or a 1, as it was beforehand and as it will be afterward, apart from the possibility of error. Not so with qubits, which are affected by the measurement.

    Although the qubit can be in any mix of 0 and 1, measuring it—as one would need to do to read the output of a calculation—forces it to be either 0 or 1. In general, there is some chance the answer will come out 0 and some complementary chance it will come out 1. This is not an error, and it is not the same as a message recipient simply not yet knowing the bit’s value—it is a fundamental feature of quantum physics.

    Importantly, this feature also means that reading the output of a quantum computer—a kind of measurement—destroys most of the information it stores. Where once there was a superposition, measurement makes it so that all that’s left is a 0 or a 1.

    Finally, quantum information is not local. While each classical bit is independent of every other bit, a qubit is typically not independent of other qubits.

    For instance, engineers can prepare a pair of qubits in a state such that if we measured one qubit as a 0, the other would have to be a 1, and vice versa. In theory, engineers can build up systems with as many qubits as they want, where each qubit’s state depends on many other qubits’ states, and all are part of a complex entangled system.

    This observation has a curious consequence: Where classical bits store information locally and independently of each other, quantum information is typically stored in the relationships between individual qubits.

    The upside of quantum information

    Quantum superposition, measurement and entanglement introduce certain difficulties. For instance, there are more ways for errors to creep into the system. And quantum information has to be carefully protected from its environment, lest it become entangled with that environment and effectively lost. Quantum error correction is in turn more challenging, since a problem that affects one qubit can end up corrupting the entire system.

    But quantum information brings with it some remarkable advantages as well, and these advantages are big enough to make it worth solving the challenges that arise.

    One early argument for quantum computing goes something like this: Classical computers are deterministic things—that is, when they perform a calculation, they produce only one answer. Nature, on the other hand, is not perfectly predictable. Since some aspects of it are fundamentally quantum mechanical, nature can produce more than one answer. That means a classical computer is going to have a hard time simulating quantum behavior.

    Imagine using a classical computer to simulate a single qubit. At a bare minimum, a classical computer would need many bits to describe what state the qubit was in, since the qubit could be in any combination of the 0 and 1 states. A classical computer would need still more bits to encode how qubits are entangled with each other, and even more to simulate what happens when someone performs a quantum algorithm and measures the output.

    In other words, it takes a lot more than 10 classical bits to simulate 10 quantum bits, suggesting that one might be able to do a lot more with 10 quantum bits than one could with 10 classical bits.

    But even that thought experiment doesn’t fully capture the distinction. There isn’t simply more information in a quantum bit—quantum superposition, measurement and entanglement also mean that the way we process and interact with quantum information is fundamentally different.

    One consequence is that quantum computers could be better than classical computers even when it comes to solving some deterministic problems. A now-classic example is factoring, or finding the prime numbers that multiply together to make another number. While there is only one way to factor any number, factoring large numbers is a very hard problem on classical computers. On a quantum computer, it’s relatively easy.

    These distinctions don’t mean that quantum computers are better than classical computers at everything. The main point is that they are different and therefore suited to solving different kinds of problems, and indeed researchers are working hard to understand which computational problems quantum computers would be best suited to. What’s clear is that quantum information opens up new possibilities, and the future is still unwritten.

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 2:55 pm on January 15, 2022 Permalink | Reply
    Tags: "Playing by the quantum rules", , , , , , Spooky action: on the quantum scale the universe doesn’t work the way you might expect., Symmetry Magazine   

    From Symmetry : “Playing by the quantum rules” 

    Symmetry Mag
    From Symmetry

    01/11/22
    Nathan Collins

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    Uncertainty, entanglement, spooky action: On the quantum scale the universe doesn’t work the way you might expect.

    While driving down the highway, physicist Werner Heisenberg is stopped by a police officer, the physics joke begins.

    “Do you know how fast you were going?” the officer demands.

    When Heisenberg shakes his head, the officer tells him: “You were doing 90.”

    “Great,” Heisenberg complains. “Now I don’t know where I am.”

    To get the joke, you need to be familiar with the Heisenberg uncertainty principle, Heisenberg’s observation that it’s impossible to simultaneously measure both the velocity and position of certain objects.

    It’s a joke because, of course, the uncertainty principle does not apply to something the size of a person or a car.

    The uncertainty principle comes from quantum physics, which deals with much smaller objects—things like atoms and quarks. The quantum world differs from the classical world we’re used to in a variety of ways.

    Being in two places at once

    In the classical world, a satellite is either traveling at 6,753 miles per hour, or it isn’t. Similarly, a rock is either sitting at 37°25’12.7”N, 122°12’16.5”W, or it isn’t. In both cases, in the classical world, there’s no ambiguity.

    A quantum mechanical satellite or rock would be different: It could be in many places, traveling at many speeds, all at the same time.

    Physicists refer to this as an object being in a superposition of states. At any given moment, a quantum system can be in a superposition of states with different positions, speeds, energies or whatever other property one can imagine.

    Only observing the object, taking a measure of it at a specific point in time, would collapse this superposition of possibilities. If an observer measured the position or speed of our quantum rock, they would get a definite answer.

    There’s a caveat, however: Because of the quantum uncertainty principle, the observer cannot perfectly determine both the position and the speed of the quantum rock at the same time. The more precisely the observer measures position, the less precisely they can measure speed, and vice versa.

    The truly weird part: However precisely one measures the quantum rock’s position or speed, quantum physics does not determine what that position or speed will be, only the probability that the rock will be in one place or another or have one speed or another.

    Entanglement and spooky action at a distance

    Unfortunately, there is no simple way to map the fact of quantum superposition and its consequences onto our intuitions. It is something one must simply accept about quantum physics.

    If you think that sounds difficult, you’re not alone. A number of highly regarded physicists tried to find a way around this befuddling feature.

    To illustrate their frustrations, Albert Einstein, Boris Podolsky and Nathan Rosen came up with a thought experiment they hoped would show something was missing from quantum theory. They were ultimately proved wrong, but the example helps explain another key idea, called quantum entanglement.

    First, here’s the thought experiment: Start with a particle that decays into a particle-antiparticle pair. In their example, the physicists chose a neutral pion decaying into an electron and a positron.

    Each of these particles has a fundamental property called spin, so named because it obeys some of the same rules as spinning objects in classical physics. Spin is conserved, so the total spin of the particle-antiparticle pair needs to add up to the spin of their parent particle.

    The neutral pion from the example has 0 spin, while electrons and positrons can have one of two possibilities: either spin +1/2 or -1/2. Since their spins must add up to 0, the electron-positron pair either could be in a state where the electron has spin +1/2 and the positron has spin -1/2, or the other way around. Physics does not determine which state the system is in, and in fact it will be in a superposition of the two states until a measurement is made.

    To physicists, the electron and positron are entangled. We don’t know the electron’s spin state, but we know that whatever it is, it’s the opposite of the positron’s spin state.

    Einstein, Podolsky and Rosen—EPR for short—noticed that this state of things, entanglement, implied what came to be known popularly as “spooky action at a distance.”

    In their thought experiment, the next step would be to separate the electron and positron by a great distance and then measure the electron’s spin. At that instant, the electron would no longer be in a superposition of states—its spin would be either +1/2 or -1/2.

    Say they measure the electron’s spin to be +1/2. Because the electron and positron are entangled, the positron’s spin instantly, in that moment, must become -1/2. Crucially, this happens before the positron could receive any signal from the electron—even if the signal traveled at the speed of light, the fastest possible speed in the universe.

    The thought experiment—which eventually was confirmed experimentally using larger and larger distances between the two entangled particles—seems to imply that, for entanglement to work, the electron must send a faster-than-light signal to the positron about what state it should be in. This is impossible, since the transmission of this signal would violate the rules of causality that govern all of physics.

    EPR regarded their thought experiment as proof that quantum mechanics was missing something, and they and others argued that there must be some so-called hidden variables that predetermined what states the electron and positron were actually in. The rules of quantum theory were correct, the argument went, but those rules were incomplete until these hidden variables could be discovered.

    But in 1964, physicist John Bell showed that quantum mechanics did not allow for any such hidden variables. Hidden variables would, in fact, violate the rules of quantum mechanics.

    Subsequent experiments have proven Bell correct. As counterintuitive as they are, entanglement and spooky action at a distance are real.

    Pixel by pixel

    There’s one more feature to mention: the one that gives the field its “quantum” name.

    In the classical world, most everything is continuous. You can stand anywhere between point A and point B. You can travel at any speed, up to the speed of light. And, with some constraints, orbits around a planet can have any radius.

    That’s sometimes true in the quantum world, but not often. In general, the quantum world is discrete, or quantized.

    One of the first signs that the quantum world might be discrete arrived in the late 19th century when physicists noticed that atoms emitted only certain specific wavelengths, or colors, of light. Hydrogen, for instance, emits only four visible wavelengths: 410, 434, 486 and 656 nanometers. These discrete wavelengths, physicists worked out, were the result of electrons orbiting the hydrogen nucleus hopping between different, discrete energy levels.

    Quantum physics is filled with examples of discrete systems, including one you already know about: spin. If one measures the spin of an electron or a positron, the answer is always either +1/2 or -1/2, never anything in between. Something similar holds for atoms and other particles.

    All of this is just the beginning. Superposition, the uncertainty principle, entanglement and quantized properties such as spin are some of the most important features of quantum physics. But scientists already knew about all of them by the 1930s. In the decades that followed, physicists developed quantum electrodynamics, a quantum theory of electromagnetic fields, as well as a completely quantum view of nearly all elementary particles and their interactions, today known as the Standard Model.

    And even now questions remain. There is still no adequate quantum theory of gravity, something that physicists will need to develop to understand black holes and the origins of our universe, when all matter was compressed in an extraordinarily tiny volume. The solution to those puzzles may lie in the idea that space itself is quantized or pixelated in some way, or in links between spacetime geometry, the standard way of describing gravity, and quantum physics. Right now, no one can say for sure.

    For physicists and others alike, it’s not easy to get a grasp on quantum physics. But understanding that the quantum world works differently from the world that we know is the beginning of understanding our universe at its most fundamental level.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 12:07 pm on January 15, 2022 Permalink | Reply
    Tags: , , , Symmetry Magazine, , , , , , "From bits to qubits"   

    From Symmetry: “From bits to qubits” 

    Symmetry Mag

    From Symmetry

    01/13/22
    Sarah Charley

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    Quantum computers go beyond the binary.

    The first desktop computer was invented in the 1960s. But computing technology has been around for centuries, says Irfan Siddiqi, director of the Quantum Nanoelectronics Laboratory at The University of California- Berkeley (US).

    “An abacus is an ancient computer,” he says. “The materials science revolution made bits smaller, but the fundamental architecture hasn’t changed.”

    Both modern computers and abaci use basic units of information that have two possible states. In a classical computer, a binary digit (called a bit) is a 1 or a 0, represented by on-off switches in the hardware. On an abacus, a sliding bead can also be thought of as being “on” or “off,” based on its position (left or right on an abacus with horizontal rods, or up or down on an abacus with vertical ones). Bits and beads can form patterns that represent other numbers and, in the case of computers, letters and symbols.

    But what if there were even more possibilities? What if the beads of an abacus could sit in between two positions? What if the switches in a computer could consult each other before outputting a calculation?

    This is the fundamental idea behind quantum computers, which embrace the oddities of quantum mechanics to encode and process information.

    “Information in quantum mechanics is stored in very different ways than in classical mechanics, and that’s where the power comes from,” says Heather Gray, an assistant professor and particle physicist at UC Berkeley.

    Classical computer; classical mechanics

    Computing devices break down numbers into discrete components. A simple abacus could be made up of three rows: one with beads representing 100s, one with beads representing 10s, and one with beads representing 1s. In this case, the number 514 could be indicated by sliding to the right 5 beads in the 100s row, 1 bead in the 10s row, and 4 beads in the 1s row.

    The computer you may be using to read this article does something similar, counting by powers of two instead of 10s. In binary, the number 514 becomes 1000000010.

    The more complex the task, the more bits or time a computer needs to perform the calculation. To speed things up, scientists have over the years found ways to fit more and more bits into a computer. “You can now have one trillion transistors on a small silicon chip, which is a far cry from the ancient Chinese abacus,” Siddiqi says.

    But as engineers make transistors smaller and smaller, they’ve started to notice some funny effects.

    The quantum twist on computing

    Bits that behave classically are determinate: A 1 is a 1. But at very small scales, an entirely new set of physical rules comes into play.

    “We are hitting the quantum limits,” says Alberto Di Meglio, the head of CERN’s Quantum Technology Initiative. “As the scale of classic computing technology becomes smaller and smaller, quantum mechanics’ effects are not negligible anymore, and we do not want this in classic computers.”

    But quantum computers use quantum mechanics to their benefit. Rather than offering decisive answers, quantum bits, called qubits, behave like a distribution of probable values.

    Di Meglio likens qubits to undecided voters in an election. “You might know how a particular person is likely to vote, but until you actually ask them to vote, you won’t have a definite answer,” Di Meglio says.

    Qubits can be made from subatomic particles, such as electrons. Like other, similar particles, electrons have a property called spin that can exist in one of two possible states (spin-up or spin-down).

    If we think of these electrons as undecided voters, the question they are voting on is their direction of spin. Quantum computers process information while the qubits are still undecided—somewhere in between spin-up and spin-down.

    The situation becomes even more complicated when the “voters” can influence one another. This happens when two qubits are entangled. “For example, if one person votes yes, then an entangled ‘undecided’ voter will automatically vote no,” Di Meglio says. “The relationships become important, and the more voters you put together, the more chaotic it becomes.”

    When the qubits start talking to each other, each qubit can find itself in many different configurations, Siddiqi says. “An entangled array of qubits—with ‘n’ number of qubits—can exist in 2^n configurations. A quantum computer with 300 good qubits would have 2^300 possible configurations, which is more than the number of particles in the known universe.”

    With great power comes great… noise

    Entanglement allows a quantum computer to perform a complex task in a fraction of the time it would take a classical computer. But entanglement is also the quantum computer’s greatest weakness.

    “A qubit can get entangled with something else that you don’t have access to,” Siddiqi says. “Information can leave the system.”

    An electron from the computer’s power supply or a stray photon can entangle with a qubit and make it go rogue.

    “Quantum computing is not just about the number of qubits,” Di Meglio says. “You might have a quantum computer with thousands of qubits, but only a fraction are reliable.”

    Because of the problem of rogue qubits, today’s quantum computers are classified as noisy intermediate-scale quantum, or NISQ, devices. “Most quantum computers look like a physics experiment,” Gray says. “We’re very far from having one you could use at home.”

    But scientists are trying. In the future, scientists hope that they can use quantum computers to quickly search through large databases and calculate complex mathematical matrices.

    Today, physicists are already experimenting with quantum computers to simulate quantum processes, such as how particles interact with each other inside the detectors at the Large Hadron Collider. “You can do all sorts of cool things with entangled qubits,” Gray says.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 9:44 pm on August 10, 2021 Permalink | Reply
    Tags: "A collective strategy for physics in Africa", Africa is far from a monolith. The continent includes 56 sovereign states 54 of which are members of the African Union and the United Nations., By the end of 2022 the group aims to submit its final recommendations to the African Physical Society Executive Committee., For the first time African physicists and other researchers are creating a grassroots strategy for the future of physics research and education., , Symmetry Magazine   

    From Symmetry: “A collective strategy for physics in Africa” 

    Symmetry Mag

    From Symmetry

    08/10/21
    Rachel Crowell

    For the first time African physicists and other researchers are creating a grassroots strategy for the future of physics research and education.

    1
    Illustration by Sandbox Studio, Chicago

    Faïrouz Malek says that after she earned her doctorate in nuclear and particle physics at the University of Grenoble Alpes [Université Grenoble Alpes] (FR) in 1990, she “had only one idea: to go back home” to Algeria.

    But then, a little over a year later, a coup in her country kicked off a civil war that did not end until February 2002.

    Malek is now a senior scientist and research director at National Centre for Scientific Research [Centre national de la recherche scientifique, [CNRS] (FR). She says the war kept her away from Algeria for so long that it eventually felt too late to return. “I have my life. I have my family. I have my work,” she says.

    African researchers around the world have their own stories about the paths they have taken through academia and research. Like Malek, many of them want to ensure that the next generations of researchers find themselves with more options to stay in or return to Africa.

    For that reason and others, a large group of physicists and other researchers in Africa and the African diaspora have come together to develop a grassroots plan for the future of African physics.

    Physicists in regions such as Europe and Latin America and in countries such as the United States, Japan, India and China have conducted or are conducting similar planning processes to prepare for the future of physics research.

    “The [African Strategy for Fundamental and Applied Physics] has a vision that Africa is an ideal location for global research infrastructure,” reads the preamble of the strategy’s founding document. “This is a vision and a dream, and even if it’s not immediately realisable, it is very important for Africa as a continent to seriously consider its commitment to this option. It is equally important that the rest of the world also seriously consider this option.”

    By the end of 2022 the group aims to submit its final recommendations—endorsed by an international advisory committee—to the African Physical Society Executive Committee, African Academy of Sciences and other stakeholders.

    Speaking up

    Africa is far from a monolith. The continent includes 56 sovereign states 54 of which are members of the African Union and the United Nations. The approximately 1.3 billion residents speak as many as 2000 languages. The population of the continent is expanding more rapidly than any other region of the world.

    Africa is home to several large research facilities in physics and astronomy. To name a few, the South African Astronomical Observatory, Boyden Observatory, Hartesbeesthoek Radio Astronomy Observatory, UNISA Observatory, and the MeerKAT and Square Kilometer Array radio telescope projects are all located in South Africa. The H.E.S.S. observatory is in Namibia. Oukaïmeden Observatory is in Morocco.

    Boyden Observatory (SA), Hartesbeesthoek Radio Astronomy Observatory (SA), UNISA Observatory (SA), and the SKA MeerKAT (SA) and SARAO – SKA South Africa radio telescope (SA) projects are all located in South Africa.

    SKA SARAO Meerkat telescope , 90 km outside the small Northern Cape town of Carnarvon, SA.(SA)

    H.E.S.S. Čerenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg searches for cosmic rays, altitude, 1,800 m (5,900 ft).

    Physicists across Africa are involved in international particle physics research. Scientists and students from institutions in Algeria, Egypt, Ghana, Madagascar, Morocco, Mozambique, Rwanda, South Africa and Tunisia, for example, all participate in research at European physics laboratory CERN.

    LHC

    European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN]

    The African Union and African Academy of Sciences have developed top-down strategies for the continent. But until recently, physicists from throughout Africa and the diaspora have not come together to create a grassroots regional plan like this one.

    This was highlighted when Malek attended a meeting in Granada as part of the process to update the European Strategy for Particle Physics.

    Also at the meeting was Kétévi Adiklè Assamagan, an experimental particle physicist at the DOE’s Brookhaven National Laboratory (US) and a Fellow of the African Academy of Sciences. Assamagan, who was born in Gabon and raised in Togo, is also involved in the future planning process for US particle physics, called Snowmass.

    As part of the meeting, scientists contributed papers and were called to talk about the strategies for the future of physics in different regions and countries. “Because resources are scarce, it is important for the world community of particle physics and funding agencies to come together and define a concerted strategy,” Malek and Assamagan later wrote about the symposium in a letter to the African Physics Newsletter.

    The two wrote the letter because they noticed something about the international input that was being requested: “No one was invited from Africa to say ‘What is your strategy? How can we fit or how can you fit in our strategy?’” Malek says.

    Malek and Assamagan discussed the situation.

    “Particle physics draws on worldwide efforts with a small yet steadily increasing presence of developing countries from Asia, South America and Africa,” they wrote. “While we can be proud of African countries such as Morocco, Egypt and South Africa gaining footholds in international projects at the Large Hadron Collider, the cooperation between African countries and the rest of the world is not well developed… Indeed, from the institutional representations at the symposium, it was evident, yet again, that in many areas of fundamental and applied research, Africa was missing.”

    Imagining a bright future

    Malek and Assamagan joined with professors Simon Henry Connell at the University of Johannesburg (SA), Farida Fassi at MOHAMMED V UNIVERSITY IN RABAT (MA) جامعة محمد الخامس, and Shaaban Khalil at the Center for Fundamental Physics in Egypt to create a steering committee for the African Strategy for Fundamental and Applied Physics.

    In late 2020, they launched the effort with a founding document, the formation of an international advisory committee, and the formation of working groups on physics topics (such as accelerators and particle physics) and areas of engagement (such as community engagement and women in physics).

    Researchers are working to identify key ideas and resources needed to build a bright future for physics in Africa—a future where researchers have the resources they need in their home countries or other areas of the continent, if they so choose.

    Chilufya Mwewa, a Zambian-born experimental particle physicist and a research associate at Brookhaven National Laboratory who is currently conducting research at CERN, joined the process as a convener for the African Strategy’s ethics committee. The committee is charged with maintaining, updating and disseminating a code of conduct and other guidelines for the proposal’s numerous working groups.

    Mwewa says she hasn’t given much thought to the physical infrastructure she would need to be able to conduct her research in Zambia. “To be honest, because I never imagined that we would get to that point soon,” she says.

    But the planning process has given her some ideas. For one, she could find funding to participate from Zambia in research at a laboratory like CERN. Alternatively, she could set up something on a much smaller scale in Zambia.

    “If I were to do something on a smaller scale, I wouldn’t even need a big accelerator,” she says. “I would need very basic equipment just to start having something to play around with students.”

    Mohamed Chabab, a professor of physics and director of the High Energy and Astrophysics Laboratory at Cadi-Ayyad University in Morocco, joined the African Strategy as a convener of the particle physics working group. The strategy is an exciting challenge, he wrote in an email.

    “Indeed, beyond the personal satisfaction, it is also one of my responsibilities as an African physicist to contribute to such initiatives aiming for improvement of the scientific research system in Africa and the reform of higher education, which are among the essential keys to unlock the minds and boost the economic growth and sustainability.”

    Scientists in many African countries face challenges such as limited research infrastructure, scant or nonexistent sources of local funding for scientists, inadequate educational opportunities for youth, and cultural and political forces that pressure girls and women to leave school and science.

    African Strategy participants want to make sure the solutions to these problems come from African scientists. And participating in strategic discussions is an important part of that.

    “We feel that the African participation in these discourses has major benefits,” Malek and Assamagan wrote in their letter. “It would allow international partners interested in capacity development and retention in Africa to integrate inputs from Africans themselves, rather than to default to their own views of how they may want to ‘help’ Africans. In addition, the help—in whichever form it is delivered—will have more impact.”

    Looking ahead

    From now until October, scientists are invited to submit letters of intent that will be used to form white-paper study groups for the strategy. They plan to hold a community planning meeting December 12-18 during the African Conference on Fundamental and Applied Physics, which will take place at Cadi Ayyad University in Morocco.

    “The world is a global village today because of technology, and you cannot separate technology from physics,” wrote Iroka Chidinma Joy, an African Strategy group convener and chief engineer in the engineering and space systems division at the National Space Research and Development Agency in Nigeria, in an email.

    “So the ASFAP is trying to encourage Africans to remember that everything starts with physics and will end with it, and the key goal is to get everyone—policymakers, educators, researchers, communities, institutions, etc.—involved in bringing every aspect of physics together for social-economic development in Africa,” she wrote. “There’s no time that’s more perfect than now.”

    In July, African Strategy organizers held their first virtual Community Town Hall.

    This time, speakers came to present on physics strategies from Japan, China, India, Europe, the United States and Latin America—and how they might inform the development of the African Strategy.

    See the full article here .


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    Please help promote STEM in your local schools.


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:31 am on June 15, 2021 Permalink | Reply
    Tags: , , Compact Accelerator System for Performing Astrophysical Research (CASPAR) at SURF., FNAL DUNE LBNF (US) from FNAL to SURF, LBNL LZ Dark Matter Experiment (US) Dark Matter project at SURF, , , Sanford Underground Research Facility (US), Symmetry Magazine, U Washington Lux Dark Matter 2 at SURF, U Washington MAJORANA Neutrinoless Double-beta Decay Experiment (US) at SURF   

    From Symmetry: “The other particle detector” 

    Symmetry Mag

    From Symmetry

    06/15/21
    Ali Sundermier

    When studying mysterious subatomic particles, researchers use a different kind of particle detector to prevent run-of-the-mill dust particles from getting in the way.

    If you’ve got physics on your brain, there’s a good chance the word “particle” immediately summons the subatomic realm. Maybe it calls to mind the protons, neutrons, quarks and electrons that make up our bodies and the world around us, or super-high-energy particles like neutrinos that zoom through space at nearly the speed of light.

    But there’s a whole other class of particles. The kind that are kicked up when the wind blows, that collect on your countertops and windowsills, that visibly cloud the air when there’s nearby smoke and pollution. A major obstacle to many particle physics experiments is that these types of particles—gas, dust, soot, smoke—can cause pesky background noise and obscure experimental results. This is why many of the highly sensitive detectors used for these experiments are kept in cleanrooms.

    “A lot of times when you talk about particle detectors in high-energy and nuclear physics, it’s the kind that detects particles like neutrinos,” says Peggy Norris, Education and Outreach Deputy Director at Sanford Underground Research Facility (US), or SURF, in South Dakota, the deepest underground lab in the US.


    Homestake Mining, Lead, South Dakota, USA.

    “But instruments called particle counters, which measure the amount of dust and other particulates in the air, are crucial to maintaining the cleanliness of the air in the cleanrooms where many of these experiments are built or performed.”

    Escaping the dust

    Deep underground, where many experiments are performed at SURF, the surrounding rocks are laced with radioactive elements such as thorium and uranium, which decay and produce radon gas. These radon gas particles can stick to plastic and contaminate materials.

    “The whole reason you go a mile underground is to get away from the cosmic rays and cell phone signals,” says Mark Hanhardt, an experiment support scientist at SURF. “But something else that causes background is dust, and a large amount of dust down there contains some radioactive elements. If you can’t get rid of this dust, then what’s the point of going underground?”

    SURF employs a collection of particle counters to keep track of the levels of these and other particles (such as microscopic flakes of human skin) that might compromise experiments. Although there are a few different types of particle counters, they all pull in surrounding air and use tricks of light, such as scattering or blocking, to count and measure the size of the particles in any given space. When the counts are high enough to endanger the data they’re collecting, the researchers know to take extra cleaning precautions to bring them back down.

    Hanhardt often tests the instruments in his office to make sure they’re running correctly. On a typical day, his office—which he keeps quite tidy—has a particle count of about a million 0.5-micron-sized particles per cubic foot.

    “Step down into the Common Corridor at the Davis Campus, a part of the lab that is kept as clean as possible, and that particle count drops to only a few hundred particles per cubic foot,” Hanhardt says. “Once you enter a cleanroom, that particle count will drop below 10, rarely going above 100.”

    At first, to monitor the particle count Hanhardt and his colleagues would have to physically travel to each counter every three or four months to download its data onto a USB drive. But in July of 2017, Hanhardt worked with an undergraduate summer intern at SURF to hook the instruments up to tiny microcomputers called Raspberry Pis, which enabled them to track the particle count in real time.

    “In the past, we wouldn’t know about spikes in the particle count until after they occurred,” he says. “With the new system, we have alarms built in that alert us when the counts start going up. This makes it easier to pinpoint what’s causing the increase.”

    Counting the invisible

    In addition to tracking the cleanliness of the air, these devices also provide a learning opportunity for young students, giving them the chance to take and analyze real data.

    “Some years ago we hosted a group of seventh-grade girls at Sanford Lab,” Norris says. “I set up a particle counter in an empty room and sent them into the room one at a time so we could see how the particle count changed with each new person.”

    The exercise illustrated why scientists cover themselves head-to-toe when entering a cleanroom. Each person sheds millions of skin particles per day and may also leave behind hair, clothing fibers, cosmetics particles, microbes and dust.

    “[The students] were shocked to learn just how much invisible stuff is in the air,” Norris says. “Eventually we used the data to plot a graph of dust versus number of students.”

    Stephen Gabriel, a physics teacher at a local high school, is involved in a project investigating ventilation at the lab. His students participate by analyzing the data, and he hopes that this will get them interested in STEM fields.

    “Getting involved in real research with real data is what got me hooked on science,” Gabriel says. “But it’s hard to show students what science is really like when you’re tied into a typical high school schedule. My hope is that if I give students first-hand experience doing real research, they’ll be inspired to pursue careers in science.”

    See the full article here .


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    Please help promote STEM in your local schools.


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 9:42 pm on May 20, 2021 Permalink | Reply
    Tags: "Argonaut project launches design effort for super-cold robotics", , , , , Symmetry Magazine   

    From Symmetry: “Argonaut project launches design effort for super-cold robotics” 

    Symmetry Mag

    From Symmetry

    05/20/21
    Brianna Barbu

    Fermilab scientists are developing one of the most cold-tolerant robots ever made so they can monitor the interiors of particle detectors.

    1
    Illustration by Sandbox Studio, Chicago.

    The Argonauts of Greek mythology braved sharp rocks, rough seas, magic and monsters to find the fabled Golden Fleece. A new robotics project at the Department of Energy’s Fermi National Accelerator Laboratory will share that same name and spirit of adventure.

    Argonaut’s mission will be to monitor conditions within ultracold particle detectors by voyaging into a sea of liquid argon kept at minus 193 degrees Celsius—as cold as some of the moons of Saturn and Jupiter. The project, funded in March, aims to create one of the most cold-tolerant robots ever made, with potential applications not only in particle physics but also deep space exploration.

    Argon, an element commonly found in the air around us, has become a key ingredient in scientists’ quests to better understand our universe. In its liquid form, argon is used to study particles called neutrinos in several Fermilab experiments, including MicroBooNE, ICARUS, SBND, and the next-generation international Deep Underground Neutrino Experiment. Liquid argon is also used in dark matter detectors like DEAP 3600, ARDM, MiniCLEAN, and DarkSide-50.

    2
    DarkSide-50 at Gran Sasso (IT)

    Liquid argon has many perks. It’s dense, which increases the chance that notoriously aloof neutrinos will interact. It’s inert, so electrons knocked free by a neutrino interaction can be recorded to create a 3D picture of the particle’s trajectory. It’s transparent, so researchers can also collect light to “time stamp” the interaction. It’s also relatively cheap—a huge plus, since DUNE will use 70,000 tons of the stuff.

    But liquid-argon detectors are not without their challenges. To produce quality data, the liquid argon must be kept extremely cold and extremely pure. That means the detectors must be isolated from the outside world to keep the argon from evaporating or becoming contaminated. With access restricted, diagnosing or addressing issues inside a detector can be difficult. Some liquid-argon detectors, such as the ProtoDUNE detectors at CERN, have cameras mounted inside to look for issues like bubbles or sparks.

    “Seeing stuff with our own eyes sometimes is much easier than interpreting data from a sensor,” says Jen Raaf, a Fermilab physicist who works on liquid-argon detectors for several projects including MicroBooNE, LArIAT and DUNE.

    The idea for Argonaut came when Fermilab engineer Bill Pellico wondered if it would be possible to make the interior cameras movable. A robotic camera may sound simple—but engineering it for a liquid-argon environment presents unique challenges.

    All of the electronics have to be able to operate in an extremely cold, high-voltage environment. All of the materials have to withstand the cooling from room to cryogenic temperatures without contracting too much or becoming brittle and falling apart. Any moving pieces must move smoothly without grease, which would contaminate the detector.

    “You can’t have something that goes down and breaks and falls off and shorts out something or contaminates the liquid argon, or puts noise into the system,” Pellico says.

    Pellico received funding for Argonaut through the Laboratory Directed Research and Development program, an initiative established to foster innovative scientific and engineering research at Department of Energy national laboratories. At this early stage of the project, the team—Pellico, mechanical engineers Noah Curfman and Mayling Wong-Squires, and neutrino scientist Flavio Cavanna—is focused on evaluating components and basic design aspects. The first goal is to demonstrate that it’s possible to power, move and communicate with a robot in a cryogenic environment.

    “We want to prove that we can have, at a bare minimum, a camera that can move around and pan and tilt in liquid argon, without contaminating the liquid argon or causing any bubbles, with a reliability that shows that it can last for the life of the detector,” Curfman says.

    The plan is to power Argonaut through a fiber-optic cable so as not to interfere with the detector electronics. The fist-sized robot will only get about 5-10 watts of power to move and communicate with the outside world.

    The motor that will move Argonaut along a track on the side of the detector will be situated outside of the cold environment. It will move very slowly, but that’s not a bad thing—going too fast would create unwanted disturbances in the argon.

    “As we get more advanced, we’ll start adding more degrees of freedom and more rails,” Curfman says.

    Other future upgrades to Argonaut could include a temperature probe or voltage monitor, movable mirrors and lasers for calibrating the light detectors, or even extendable arms with tools for minor electronics repair.

    Much of the technology Argonaut is advancing will be broadly applicable for other cryogenic environments—including space exploration. The project has already garnered some interest from universities and NASA engineers.

    Deep space robots “are going to go to remote locations where they have very little power, and the lifetime has to be 20-plus years just like in our detectors, and they have to operate at cryogenic temperatures,” Pellico says. The Argonaut team can build on existing robotics know-how along with Fermilab’s expertise in cryogenic systems to push the boundaries of cold robotics.

    Even the exteriors of active interstellar space probes such as Voyager 1 and 2 don’t reach temperatures as low as liquid argon—they use thermoelectric heaters to keep their thrusters and science instruments warm enough to operate.

    “There’s never been a robotic system that operated at these temperatures,” Pellico says. “NASA’s never done it; we’ve never done it; nobody’s ever done it, as far as I can tell.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 7:14 pm on May 18, 2021 Permalink | Reply
    Tags: "Exhibit explores layers of SNOLAB", A part of Creighton Mine has since been developed into an underground laboratory-SNOLAB-where scientists continue to study neutrinos along with other underground science pursuits., About 1.8 million years ago a meteorite tore through part of what is now Ontario leaving a scar greater than 20 miles in diameter that bled precious metals like copper and nickel into the exposed eart, , , In 1990 scientists used the mine as a natural shield to protect SNO-an experiment studying the behavior of strange particles called neutrinos., , Recently four artists-in-residence accepted an invitation to come learn about dark matter., Symmetry Magazine, The artists traveled to SNOLAB in Sudbury Ontario Canada and to the Arthur B. McDonald Canadian Astroparticle Physics Research Institute-a seven-hour drive away in Kingston.   

    From Symmetry: “Exhibit explores layers of SNOLAB” 

    Symmetry Mag

    From Symmetry

    05/18/21
    Stephanie Melchor

    In Drift: Art and Dark Matter, pieces by four artists-in-residence dig deep into the underground laboratory.

    1
    Installation view from Drift: Art and Dark Matter.

    About 1.8 million years ago a meteorite tore through part of what is now Ontario leaving a scar greater than 20 miles in diameter that bled precious metals like copper and nickel into the exposed earth. In 1901, European colonists began to carve away the layers of rock, eventually digging one of the deepest mines on the planet, Creighton Mine.

    In 1990 scientists used the mine as a natural shield to protect SNO-an experiment studying the behavior of strange particles called neutrinos. In 2015, the results of the SNO experiment would earn Canadian scientist Art McDonald a portion of the Nobel Prize in Physics.

    A part of Creighton Mine has since been developed into an underground laboratory-SNOLAB-where scientists continue to study neutrinos along with other underground science pursuits. It’s also where, recently four artists-in-residence accepted an invitation to come learn about dark matter.

    The artists traveled to SNOLAB in Sudbury Ontario Canada and to the Arthur B. McDonald Canadian Astroparticle Physics Research Institute-a seven-hour drive away in Kingston. They visited the laboratory and spent time with the physicists who build experiments there. They descended through layers of rock—and dug back through layers of history—to produce an exhibit that is about more than just physics.

    Looking through layers

    In 2019 artists Anne Riley; Nadia Lichtig; Joséfa Ntjam; and Jol Thoms began the residency that would result in the exhibition: Drift: Art and Dark Matter. As they plummeted into the heart of the Creighton Mine via an industrial mining elevator, many of them had the same question: Why do we have to go so deep underground to try to interact with particles coming from space?

    It seems poetic. But the answer isn’t poetry—it’s science. The more than a mile of dense norite rock the lab is buried beneath filters out a constant shower of cosmic radiation from above.

    In a detector on the surface, that radiation would drown out rare signals from neutrinos and possibly dark matter. Particles such as these, which are loath to interact with other matter, are much more likely than their compatriots to pass through the layers of rock and earth and make it to detectors located underground.

    Physicists know that neutrinos interact with other matter. As for dark matter—it has never been detected directly, though indirect signs point to it outweighing known types of matter 5-to-1. It may be all around; we just can’t see it.

    Thoms has spent time with physicists searching for hard-to-find particles in other extreme locations, including Laboratori Nazionali del Gran Sasso under Gran Sasso mountain in Italy and the Baikal Deep Underwater Neutrino Telescope in Siberia.

    He says he enjoys these “landscape laboratories,” which he describes as “meaningful infrastructures” embedded in lakes, ice shelves, mountains and mines.

    Ntjam admits she struggled with the physics concepts that scientists introduced during the residency at SNOLAB and the McDonald Institute. “Every night I read about dark matter when I was in Canada,” she says. “I read every note I took during the day and tried to be a good student.”

    But still, she says, it took nearly the full two weeks of the residency for things to start clicking.

    One concept that finally resonated was Heisenberg’s Uncertainty Principle: the idea that you can calculate the velocity of a particle, or its position, but never both.

    Ntjam says this made her think about the many layers, visible and hidden, that make up a person. “A person can be in multiple categories at the same time,” she says. “But you can’t calculate all the categories at the same time.”

    Thoms spent the residency thinking about layers as well.

    For part of the exhibit, he created a video. Called n-Land: the holographic (principle), it features 3D scans of SNOLAB that have been flattened and then layered back on themselves, an artistic nod to the “many-worlds” hypothesis in quantum mechanics that posits that every possible reality simultaneously exists.

    One layer takes the viewer back to 1850, when the Robinson-Huron Treaty granted the British Crown access to land and resources, including those in the area that is now Sudbury, belonging to the people of the Anishinabek Nations. The treaty promised the Anishinaabe peoples an annual share of revenues generated as compensation, with an augmentation clause to account for economic growth over time. Twenty-one First Nations tribes are currently involved in a lawsuit against the federal and provincial governments regarding these payments, which, despite the terms of the treaty, have not increased since 1874—before Creighton Mine even opened.

    To Thoms, the history of the site matters as much to the experiment as the showers of cosmic rays. It’s not just math that makes the experiments possible, he says; “also there’s minerals and there’s treaties and there’s meteorite impacts.”

    Dealings with dust

    Lichtig says the artists were allowed to think beyond the physics thanks to the flexibility of the Drift residency. “I thought it was very open-minded and really experimental—and gave enough freedom to the artists to imagine something new.”

    Lichtig was inspired to create her piece Dust after hearing Nobel Laureate McDonald share a fact made popular by astronomer Carl Sagan—that we are all made of stardust. The idea of stardust stuck in Lichtig’s mind long after she returned to her home studio in southern France.

    She also spent time thinking about the everyday kind of dust, which, just like cosmic radiation, can interfere with the detectors underground and has to be eliminated. Scientists take several measures to keep both dirt from the mine and other particulates from making their way into the experimental areas of the laboratory. The name Drift comes from the name of the long, rocky underground tunnel that leads researchers from the dusty entrance of the mine to SNOLAB’s immaculate underground cleanroom. Lichtig says it was a memorable experience “to go through stone and to be in the middle of stone—and then suddenly to switch into this ultra-technological world where everything is completely dust-free.”

    To make Dust, Lichtig applied dust to photo-sensitive paper and then added different cleaning agents, capturing snapshots of their interactions.

    But Lichtig’s second piece in the exhibit, Untitled, was the one that most stood out to SNOLAB physicist Erica Caden. Caden participated in a pair of sessions led by Elvira Hufschmid, a doctoral fellow at Agnes Etherington Art Centre, to introduce physicists to the works in Drift.

    “To me, [Untitled] looks like a blackboard that was being erased and rewritten,” Caden says. “And that led to the thought of how science is a constantly evolving process, and how we think we know things and we’re traveling down this one road with our theories and our experiments—and then our results tell us, ‘Nope, what we got was not what we expected.’ So we have to start over.”

    Untitled, a collection of black panels with mysterious, chalky markings, does not necessarily represent the ephemeral nature of physicists’ calculations. To others, it might look like images of the night sky. Caden says she was surprised by how differently her fellow scientists interpreted the same piece of artwork. Caden says the exhibition is a good chance for SNOLAB scientists to step back and see how other people understand the work they are doing as well.

    Drift was developed by SNOLAB, the McDonald Institute, and the Agnes Etherington Art Centre at Queen’s University (CA). The exhibit will be at the Agnes until May 30, after which it will go on tour through Canada for three years. The art is also available in an interactive version of the exhibit online.

    During her time in Sudbury, Ntjam visited the planetarium at the Science North interactive science center. She remembers watching a video presentation there about how the Indigenous people in the area mapped the night sky. Indigenous constellations are different from the classical Greek ones Ntjam learned as a child.

    Like descending into the depths of the Earth to study particles from the sky, or recruiting artists to examine concepts in physics, studying a new set of constellations can help us better understand the ones we already know.

    “In fact, they’re the same stars in the sky,” Ntjam says. “We are just connecting the dots differently.”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 11:21 am on May 4, 2021 Permalink | Reply
    Tags: , Clifford Johnson, Outreach, , Symmetry Magazine   

    From Symmetry: “On the marvels of physics” Clifford Johnson 

    Symmetry Mag

    From Symmetry

    05/04/21
    Brianna Barbu

    1
    Illustration by Sandbox Studio, Chicago with Corinne Mucha.

    Theoretical physicist Clifford Johnson answers Symmetry writer Brianna Barbu’s questions about his work in science and outreach, including advising on movies like Avengers: Endgame.

    Clifford Johnson, a theoretical physicist at the University of Southern California (US), is an accomplished scientist working on ways to describe the origin and fabric of the universe.

    He is also a multitalented science communicator and one of the rare scientists that can boast his own IMDb page.

    Johnson’s efforts to engage the public with science have spanned blogging, giving public lectures, appearing on television and web shows, writing and illustrating a graphic novel, and acting as a science advisor for television shows and blockbuster films including Star Trek: Discovery and Avengers: Endgame.

    In the spirit of his 2017 popular science book The Dialogues, I hopped on a Zoom call with Johnson for a dialogue of my own. What follows is an edited version of our conversation about how and why he came to study quantum physics, why he decided to create a graphic novel about science, the ups and downs of Hollywood consulting, and why public engagement with science matters.

    S.How did you decide to study physics?

    CJ:From a very early age, I was asking questions about how the world works and trying to figure out how things worked by tinkering with old radios and things. Then at some point, I learned that there’s a career where you can make a living from that sort of curiosity—being a scientist.

    And then some family friend asked me what kind of scientist I wanted to be. I didn’t realize there were different kinds. So I found a dictionary and I went through page by page and read the definitions of “chemist,” “biologist,” all of the “-ists” and “-ologists.” And when I hit “physicist,” I thought, “this is the one,” because the entry said that physics underlies all the other sciences—which appealed to me because I wanted to keep my options open.

    You were awarded a National Science Foundation (US) CAREER Award in 1997 and received the 2005 Maxwell Medal and Prize for your early-career contributions to string theory and quantum gravity research. What drew you to theoretical physics and quantum gravity?

    CJ: I got interested in particle physics reading authors such as Paul Davies and Abraham Pais as a teenager. And then in my undergraduate studies at Imperial College, I began to learn about the issues of trying to quantize gravity, which led me to study string theory for my PhD at the University of Southampton. The universe really does seem to be fundamentally quantum mechanical. So, it’s a real problem if we don’t know quantum mechanically how to understand gravity, spacetime and where the universe comes from.

    You also do a lot of public engagement on top of your research. The American Association for Physics Teachers awarded you the 2018 Klopsteg Award for your outreach. How did you get started in science communication and outreach?

    CJ: I’ve been doing outreach in a way since I was 8 or 10 years old. I was that annoying kid who was always explaining things. In school, people would call me “the professor.” Everyone thought they were giving me a hard time, but secretly I thought it was an awesome nickname.

    Outreach, for me, is a natural part of being a scientist. Research is all about the story of how things work and where they came from. And what’s the point of knowing the story, if you can’t also get other people excited about it? If someone wants to know, I’m going to tell them. I got reasonably good at explaining things in a coherent way. Word got around, and I started presenting on radio and TV.

    Sometimes, people would get in touch from the media because of something they read on my blog. I co-founded a blog called Cosmic Variance with four other physicists in 2005, and also started a solo blog called Asymptotia in 2006. I’d write about interesting ideas and what was going on in research, as well as my other interests and day-to-day life. Blogging created communities where people would engage in conversation and we’d have great discussions, and then that would encourage us to write more.
    Why is engaging the public in science so important to you?

    It is very frustrating to me that science is often portrayed as a special thing done by a special group of people. It is a special thing, but anyone can be involved, and everyone should be involved. I often say that science should be put back into the culture where it belongs.

    Public outreach is important because a lot of people think they wouldn’t understand scientific issues, and so they leave it to a small group of people to make decisions. And that’s not democratic. We aren’t a democracy if people aren’t more familiar and comfortable with science and the people who do science.

    Your book The Dialogues is a graphic novel structured as a series of conversations about science, which you wrote and also illustrated yourself. How did that come together?

    CJ: I agonized over writing a book for the general public for a long time because I didn’t think there was any urgency to write one of the standard kinds of books that get written by people in my field. Not that there’s anything wrong with those books. But I thought that if we could break out of the narrow mold of how popular science books are supposed to be, we could reach so many more people.

    Though I was a comic book fan from a young age, I essentially snuck up on the on the graphic-novel concept backwards. The ratio between prose and illustration changed as I began to conceptualize what I really wanted to be able to do with the book. The illustration aspect began to eat the prose aspect and became a narrative in its own right. And then I realized it was going to be a graphic novel. Writers often say that you try and create the book that you want to see in the world—so I did, and I even took the time out to teach myself to draw at the level needed to do it.

    In all graphic novels, spacetime is created by the reader. When you’re looking at a series of comic panels, your mind constructs how space and time come alive on the page. So what better medium to talk about physics, the subject that is about spacetime, than graphic novels? I could take advantage of the medium to illustrate ideas, like arranging panels to swirl into the interior of a black hole and mess up the order to convey how space and time get messed up there.

    Do you plan to write another book?

    CJ: Yes. The plan is to do a new set of dialogues. Unfortunately, I’m still working on the time machine in the basement so I can manufacture more hours in the day. Sooner or later, I’ll get it to work.

    Okay, you know I had to ask this—what’s it like working with the Science and Entertainment Exchange and being a science advisor for movies and TV?

    CJ: Most of the work is not the glamorous, sitting-around-chatting-with-Spielberg kind of thing that people envision. There’s no industry standard for science consulting. The work can be anything from a writer getting in touch with me and asking if I’ll take a look at a script, or if I’ll talk with them about an idea they have. Or the directors call consultants in at the end and ask us to fix something before they start shooting, although by then it’s usually too late for a good conversation.

    If the science is going to be part of the DNA of the story, then it’s best if conversations happen early. The best stuff happens when there’s an environment where science can be an inspiration at the writing stage. For the Avengers: Endgame and Infinity War movies, one of the smart things the filmmakers did is they got in touch early on and then we brainstormed ideas. They did this with other scientists, too, gathering a lot of good material to draw from.

    How much of your advice gets used?

    CJ: Anywhere from zero to a hundred percent. I have no control over how much. When I give public talks, I talk about the trade-off between how much control you have and the size of the audience you can reach. I have complete control over the content of a public lecture to a few hundred people. I had zero control of what ended up in the final cut of Avengers, with an audience of many millions.

    In a few projects I advised on, there are even scenes where I wrote most of the words. I either went over the script and revised the science talk, or the writers left a hole for me to tell them how to say something, and then they used my suggestions verbatim. That’s not common, but it happens sometimes.

    Overall, the science is more likely to survive all the way to the screen if it’s for television, which is more of a writer’s medium. In television, the director works for the writers. In film, the writers work for the directors, who may or may not care about the science content.

    Can you give me some examples of projects where you had a significant impact?

    CJ: Season two of the show Agent Carter is a great model of how things between TV writers and science consultants are supposed to work. Entire characters and storylines on the show were invented based on things we brainstormed together in the writers’ room. A few times, I sketched an idea about what a machine might look like and they just went away and built the machine for the set!

    Another project where I was involved very early on was the first season of National Geographic’s series Genius, about the life and work of Einstein. Not only did I teach the writers a lot about relativity, but I helped pick pieces of science that they could unpack thematically for episodes and helped them write scenes so that the science could really be on show.

    Maybe most importantly, they took seriously my encouragement to show that Einstein discussed his ideas with others around him, to help break that “lone genius” mythology that often drives people away from thinking they can be scientists.

    What are the most important things for films and TV shows to get right when it comes to science?

    CJ: Some people get hung up on getting all the facts right, but I’d rather focus on things like representing the scientific process correctly, as opposed to making it seem like magic—representing the thought processes and the people doing those thought processes.

    I care about whether the scientists are portrayed like real people with narratives that help you relate to them and understand them. When I’m working with artists and media people creating images of scientists, I encourage them to make those people more real, make them more accessible, show that they’re human beings.

    You do so much! How do you balance your work, your outreach and the rest of your life?

    CJ: I think the most important skill to learn is dealing with interruption and knowing how to put something on hold and then come back to it. I’ve gotten better at doing a lot of stuff in my head in preparation for that short time I’m going to have where I will be able to sit at my desk and do my physics.

    I hope that I am helping to dispel the myth that if you’re good at outreach, it means that you’re not good—or not interested—in research at the highest level. That’s often used to discourage people from spending time on outreach and engagement, or as an excuse to dismiss people of color or women in the field. The fact that I have been very successful at research and teaching and also science outreach shows that it is possible to be a significant player in both realms.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.


    Stem Education Coalition

    Symmetry is a joint Fermilab/SLAC publication.


     
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