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  • richardmitnick 12:02 pm on February 15, 2018 Permalink | Reply
    Tags: , , , , , Quantum Mechanics, U Vienna   

    From U Vienna: “Fingerprints of quantum entanglement” 

    University of Vienna

    15. February 2018

    Dr. Borivoje Dakic
    Fakultät für Physik
    Universität Wien & IQOQI Wien, ÖAW
    1090 – Wien, Boltzmanngasse 5
    + 43-4277-725 80
    borivoje.dakic@univie.ac.at

    Rückfragehinweis
    Mag. Alexandra Frey
    Pressebüro der Universität Wien
    Forschung und Lehre
    Universität Wien
    1010 – Wien, Universitätsring 1
    +43-1-4277-175 33
    +43-664-60277-175 33
    alexandra.frey@univie.ac.at

    Dipl.-Soz. Sven Hartwig
    Leitung Öffentlichkeit & Kommunikation
    Österreichische Akademie der Wissenschaften
    1010 – Wien, Dr. Ignaz Seipel-Platz 2
    +43 1 51581-13 31
    sven.hartwig@oeaw.ac.at

    1
    Entangled qubits are sent to measurement devices which output a sequence of zeroes and ones. This pattern heavily depends on the type of measurements performed on individual qubits. If we pick the set of measurements in a peculiar way, entanglement will leave unique fingerprints in the measurement patterns (Copyright: Juan Palomino).

    Quantum entanglement is a key feature of a quantum computer. Yet, how can we verify that a quantum computer indeed incorporates a large-scale entanglement? Using conventional methods is hard since they require a large number of repeated measurements. Aleksandra Dimić from the University of Belgrade and Borivoje Dakić from the Austrian Academy of Sciences and the University of Vienna have developed a novel method where in many cases even a single experimental run suffices to prove the presence of entanglement. Their surprising results will be published in the online open access journal npj Quantum Information of the Nature Publishing group.

    The ultimate goal of quantum information science is to develop a quantum computer, a fully-fledged controllable device which makes use of the quantum states of subatomic particles to store information. As with all quantum technologies, quantum computing is based on a peculiar feature of quantum mechanics, quantum entanglement. The basic units of quantum information, the qubits, need to correlate in this particular way in order for the quantum computer to achieve its full potential.

    One of the main challenges is to make sure that a fully functional quantum computer is working as anticipated. In particular, scientists need to show that the large number of qubits are reliably entangled. Conventional methods require a large number of repeated measurements on the qubits for reliable verification. The more often a measurement run is repeated the more certain one can be about the presence of entanglement. Therefore, if one wants to benchmark entanglement in large quantum systems it will require a lot of resources and time, which is practically difficult or simply impossible. The main question arises: can we prove entanglement with only a low number of measurement trials?

    Now researchers from the University of Belgrade, the University of Vienna and the Austrian Academy of Sciences have developed a novel verification method which requires significantly fewer resources and, in many cases, even only a single measurement run to prove large-scale entanglement with a high confidence. For Aleksandra Dimić from the University of Belgrade, the best way to understand this phenomenon is to use the following analogy: “Let us consider a machine which simultaneously tosses, say, ten coins. We manufactured the machine such that it should produce correlated coins. We now want to validate whether the machine produces the anticipated result. Imagine a single trial revealing all coins landing on tails. This is a clear signature of correlations, as ten independent coins have 0.01% chance to land on the same side simultaneously. From such an event, we certify the presence of correlations with more than 99.9% confidence. This situation is very similar to quantum correlations captured by entanglement.” Borivoje Dakić says: “In contrast to classical coins, qubits can be measured in many, many different ways. The measurement result is still a sequence of zeros and ones, but its structure heavily depends on how we choose to measure individual qubits”, he continues. “We realized that, if we pick these measurements in a peculiar way, entanglement will leave unique fingerprints in the measured pattern”, he concludes.

    The developed method promises a dramatic reduction in time and resources needed for reliable benchmark of future quantum devices.

    Publication in npj Quantum Information:
    A.Dimić and B.Dakić, “Single-copy enntaglement detection”, npj Quantum Information, 2018.
    DOI: 10.1038/s41534-017-0055-x
    http://www.nature.com/articles/s41534-017-0055-x

    See the full article here .

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    The University of Vienna (German: Universität Wien) is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is one of the oldest universities in the German-speaking world. With its long and rich history, the University of Vienna has developed into one of the largest universities in Europe, and also one of the most renowned, especially in the Humanities. It is associated with 15 Nobel prize winners and has been the academic home to a large number of scholars of historical as well as of academic importance.

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  • richardmitnick 8:19 am on February 8, 2018 Permalink | Reply
    Tags: , , , , Quantum Mechanics,   

    From STFC: “UK laser experiment mimics black hole environment” 


    STFC

    7 February 2018

    1
    The Gemini laser at CLF. (Credit: STFC)

    UK physicists have for the first time used an extremely powerful laser beam to slow down electrons travelling at near-light speeds – a quantum mechanical phenomenon thought to occur only around objects like black holes. By producing this effect in a lab, scientists hope to provide valuable insight into subatomic processes in the universe’s most extreme environments.

    Fast electrons, especially when they travel at near light speeds, are very difficult to stop. Often you require highly dense materials – such as lead – to stop them or slow them down. But now, scientists have shown that they can slow these superfast electrons using a very thin sheet of light; they squeeze trillions of light particles – photons – into a sheet that is a fraction of human hair in thickness.

    When light hits an object some of the light bounces back from the surface, often changing its colour (to even X-rays and gamma rays if the object is moving fast) – however, if the object is moving extremely fast and if the light is incredibly intense, strange things can happen.

    Electrons, for example, can be shaken so violently that they actually slow down because they radiate so much energy. Quantum physics is required to fully explain this phenomenon. Physicists call this process ‘radiation reaction’, which is thought to occur around objects such as black holes and quasars.

    Now, a team of researchers have demonstrated radiation reaction for the first time using the Gemini laser at the Science and Technology Facilities Council’s Central Laser Facility in Oxfordshire.

    Gemini scientist Dr Dan Symes said: “Experiments like these are extremely complicated to set up and very difficult to perform. Essentially, you need to focus a laser beam as big as an A4 size paper sheet down to a few microns and hit it with a micron-sized electron bullet that’s travelling very close to the speed of light.”

    Gemini Group Leader, Dr Rajeev Pattathil added: “You need two extremely well-synchronised high power laser beams for this: one to produce the high energy electron beam and another to shoot it. Gemini’s dual-beam capability makes it an ideal facility for these types of experiments. Gemini is one of the very few places in the world where such cutting-edge experiments can be performed.”

    The research team, led by Imperial College academic Dr Stuart Mangles, were able to observe this radiation reaction by colliding a laser beam that is one quadrillion times brighter than light at the surface of the Sun with a high-energy beam of electrons. All this energy had to be delivered in a very short duration – just 40 femtoseconds long, or 40 quadrillionths of a second.

    Senior author of the study [Physical Review X] Dr Mangles said: “We knew we had been successful in colliding the two beams when we detected very bright high energy gamma-ray radiation.

    “The real result then came when we compared this detection with the energy in the electron beam after the collision. We found that these successful collisions had a lower than expected electron energy, which is clear evidence of radiation reaction.”

    Study co-author Professor Alec Thomas, from Lancaster University and the University of Michigan, added: “One thing I always find so fascinating about this is that the electrons are stopped as effectively by this sheet of light, a fraction of a hair’s breadth thick, as by something like a millimetre of lead. That is extraordinary.”

    However more experiments at even higher intensity or with even higher energy electron beams will be needed to confirm if this is true. The team will be carrying out these experiments in the coming year.

    See the full article here .

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    STFC Hartree Centre

    Helping build a globally competitive, knowledge-based UK economy

    We are a world-leading multi-disciplinary science organisation, and our goal is to deliver economic, societal, scientific and international benefits to the UK and its people – and more broadly to the world. Our strength comes from our distinct but interrelated functions:

    Universities: we support university-based research, innovation and skills development in astronomy, particle physics, nuclear physics, and space science
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    We support an academic community of around 1,700 in particle physics, nuclear physics, and astronomy including space science, who work at more than 50 universities and research institutes in the UK, Europe, Japan and the United States, including a rolling cohort of more than 900 PhD students.

    STFC-funded universities produce physics postgraduates with outstanding high-end scientific, analytic and technical skills who on graduation enjoy almost full employment. Roughly half of our PhD students continue in research, sustaining national capability and creating the bedrock of the UK’s scientific excellence. The remainder – much valued for their numerical, problem solving and project management skills – choose equally important industrial, commercial or government careers.

    Our large-scale scientific facilities in the UK and Europe are used by more than 3,500 users each year, carrying out more than 2,000 experiments and generating around 900 publications. The facilities provide a range of research techniques using neutrons, muons, lasers and x-rays, and high performance computing and complex analysis of large data sets.

    They are used by scientists across a huge variety of science disciplines ranging from the physical and heritage sciences to medicine, biosciences, the environment, energy, and more. These facilities provide a massive productivity boost for UK science, as well as unique capabilities for UK industry.

    Our two Campuses are based around our Rutherford Appleton Laboratory at Harwell in Oxfordshire, and our Daresbury Laboratory in Cheshire – each of which offers a different cluster of technological expertise that underpins and ties together diverse research fields.

    The combination of access to world-class research facilities and scientists, office and laboratory space, business support, and an environment which encourages innovation has proven a compelling combination, attracting start-ups, SMEs and large blue chips such as IBM and Unilever.

    We think our science is awesome – and we know students, teachers and parents think so too. That’s why we run an extensive Public Engagement and science communication programme, ranging from loans to schools of Moon Rocks, funding support for academics to inspire more young people, embedding public engagement in our funded grant programme, and running a series of lectures, travelling exhibitions and visits to our sites across the year.

    Ninety per cent of physics undergraduates say that they were attracted to the course by our sciences, and applications for physics courses are up – despite an overall decline in university enrolment.

     
  • richardmitnick 8:16 am on February 2, 2018 Permalink | Reply
    Tags: , , Entangled time, Quantum Mechanics   

    From Aeon: “You thought quantum mechanics was weird: check out entangled time” 

    1

    aeon

    2.2.18
    Sally Davies

    1
    No image caption or credit.

    In the summer of 1935, the physicists Albert Einstein and Erwin Schrödinger engaged in a rich, multifaceted and sometimes fretful correspondence about the implications of the new theory of quantum mechanics. The focus of their worry was what Schrödinger later dubbed entanglement: the inability to describe two quantum systems or particles independently, after they have interacted.

    Until his death, Einstein remained convinced that entanglement showed how quantum mechanics was incomplete. Schrödinger thought that entanglement was the defining feature of the new physics, but this didn’t mean that he accepted it lightly. ‘I know of course how the hocus pocus works mathematically,’ he wrote to Einstein on 13 July 1935. ‘But I do not like such a theory.’ Schrödinger’s famous cat, suspended between life and death, first appeared in these letters, a byproduct of the struggle to articulate what bothered the pair.

    The problem is that entanglement violates how the world ought to work. Information can’t travel faster than the speed of light, for one. But in a 1935 paper [Physical Review Journals Archive], Einstein and his co-authors showed how entanglement leads to what’s now called quantum nonlocality, the eerie link that appears to exist between entangled particles. If two quantum systems meet and then separate, even across a distance of thousands of lightyears, it becomes impossible to measure the features of one system (such as its position, momentum and polarity) without instantly steering the other into a corresponding state.

    Up to today, most experiments have tested entanglement over spatial gaps. The assumption is that the ‘nonlocal’ part of quantum nonlocality refers to the entanglement of properties across space. But what if entanglement also occurs across time? Is there such a thing as temporal nonlocality?

    The answer, as it turns out, is yes. Just when you thought quantum mechanics couldn’t get any weirder, a team of physicists at the Hebrew University of Jerusalem reported in 2013 [Physical Review Letters] that they had successfully entangled photons that never coexisted. Previous experiments involving a technique called ‘entanglement swapping’ had already showed quantum correlations across time, by delaying the measurement of one of the coexisting entangled particles; but Eli Megidish and his collaborators were the first to show entanglement between photons whose lifespans did not overlap at all.

    Here’s how they did it. First, they created an entangled pair of photons, ‘1-2’ (step I in the diagram below). Soon after, they measured the polarisation of photon 1 (a property describing the direction of light’s oscillation) – thus ‘killing’ it (step II). Photon 2 was sent on a wild goose chase while a new entangled pair, ‘3-4’, was created (step III). Photon 3 was then measured along with the itinerant photon 2 in such a way that the entanglement relation was ‘swapped’ from the old pairs (‘1-2’ and ‘3-4’) onto the new ‘2-3’ combo (step IV). Some time later (step V), the polarisation of the lone survivor, photon 4, is measured, and the results are compared with those of the long-dead photon 1 (back at step II).

    2
    Figure 1. Time line diagram: (I) Birth of photons 1 and 2, (II) detection of photon 1, (III) birth of photons 3 and 4, (IV) Bell projection of photons 2 and 3, (V) detection of photon 4.

    The upshot? The data revealed the existence of quantum correlations between ‘temporally nonlocal’ photons 1 and 4. That is, entanglement can occur across two quantum systems that never coexisted.

    What on Earth can this mean? Prima facie, it seems as troubling as saying that the polarity of starlight in the far-distant past – say, greater than twice Earth’s lifetime – nevertheless influenced the polarity of starlight falling through your amateur telescope this winter. Even more bizarrely: maybe it implies that the measurements carried out by your eye upon starlight falling through your telescope this winter somehow dictated the polarity of photons more than 9 billion years old.

    Lest this scenario strike you as too outlandish, Megidish and his colleagues can’t resist speculating on possible and rather spooky interpretations of their results. Perhaps the measurement of photon 1’s polarisation at step II somehow steers the future polarisation of 4, or the measurement of photon 4’s polarisation at step V somehow rewrites the past polarisation state of photon 1. In both forward and backward directions, quantum correlations span the causal void between the death of one photon and the birth of the other.

    Just a spoonful of relativity helps the spookiness go down, though. In developing his theory of special relativity, Einstein deposed the concept of simultaneity from its Newtonian pedestal. As a consequence, simultaneity went from being an absolute property to being a relative one. There is no single timekeeper for the Universe; precisely when something is occurring depends on your precise location relative to what you are observing, known as your frame of reference. So the key to avoiding strange causal behaviour (steering the future or rewriting the past) in instances of temporal separation is to accept that calling events ‘simultaneous’ carries little metaphysical weight. It is only a frame-specific property, a choice among many alternative but equally viable ones – a matter of convention, or record-keeping.

    The lesson carries over directly to both spatial and temporal quantum nonlocality. Mysteries regarding entangled pairs of particles amount to disagreements about labelling, brought about by relativity. Einstein showed that no sequence of events can be metaphysically privileged – can be considered more real – than any other. Only by accepting this insight can one make headway on such quantum puzzles.

    The various frames of reference in the Hebrew University experiment (the lab’s frame, photon 1’s frame, photon 4’s frame, and so on) have their own ‘historians’, so to speak. While these historians will disagree about how things went down, not one of them can claim a corner on truth. A different sequence of events unfolds within each one, according to that spatiotemporal point of view. Clearly, then, any attempt at assigning frame-specific properties generally, or tying general properties to one particular frame, will cause disputes among the historians. But here’s the thing: while there might be legitimate disagreement about which properties should be assigned to which particles and when, there shouldn’t be disagreement about the very existence of these properties, particles, and events.

    These findings drive yet another wedge between our beloved classical intuitions and the empirical realities of quantum mechanics. As was true for Schrödinger and his contemporaries, scientific progress is going to involve investigating the limitations of certain metaphysical views. Schrödinger’s cat, half-alive and half-dead, was created to illustrate how the entanglement of systems leads to macroscopic phenomena that defy our usual understanding of the relations between objects and their properties: an organism such as a cat is either dead or alive. No middle ground there.

    Most contemporary philosophical accounts of the relationship between objects and their properties embrace entanglement solely from the perspective of spatial nonlocality. But there’s still significant work to be done on incorporating temporal nonlocality – not only in object-property discussions, but also in debates over material composition (such as the relation between a lump of clay and the statue it forms), and part-whole relations (such as how a hand relates to a limb, or a limb to a person). For example, the ‘puzzle’ of how parts fit with an overall whole presumes clear-cut spatial boundaries among underlying components, yet spatial nonlocality cautions against this view. Temporal nonlocality further complicates this picture: how does one describe an entity whose constituent parts are not even coexistent?

    Discerning the nature of entanglement might at times be an uncomfortable project. It’s not clear what substantive metaphysics might emerge from scrutiny of fascinating new research by the likes of Megidish and other physicists. In a letter to Einstein, Schrödinger notes wryly (and deploying an odd metaphor): ‘One has the feeling that it is precisely the most important statements of the new theory that can really be squeezed into these Spanish boots – but only with difficulty.’ We cannot afford to ignore spatial or temporal nonlocality in future metaphysics: whether or not the boots fit, we’ll have to wear ’em.
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    Since 2012, Aeon has established itself as a unique digital magazine, publishing some of the most profound and provocative thinking on the web. We ask the big questions and find the freshest, most original answers, provided by leading thinkers on science, philosophy, society and the arts.

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    Aeon was founded in London by Paul and Brigid Hains. It now has offices in London, Melbourne and New York. We are a not-for-profit, registered charity operated by Aeon Media Group Ltd. Aeon is endorsed as a Deductible Gift Recipient (DGR) organisation in Australia and, through its affiliate Aeon America, registered as a 501(c)(3) charity in the US.

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  • richardmitnick 11:18 am on December 25, 2017 Permalink | Reply
    Tags: , Counterfactual communication, , , Quantum Mechanics, ,   

    From U Cambridge via phys.org: “Researchers chart the ‘secret’ movement of quantum particles” 

    U Cambridge bloc

    University of Cambridge

    phys.org

    December 22, 2017

    1
    Credit: Robert Couse-Baker

    Researchers from the University of Cambridge have taken a peek into the secretive domain of quantum mechanics. In a theoretical paper published in the journal Physical Review A, they have shown that the way that particles interact with their environment can be used to track quantum particles when they’re not being observed, which had been thought to be impossible.

    One of the fundamental ideas of quantum theory is that quantum objects can exist both as a wave and as a particle, and that they don’t exist as one or the other until they are measured. This is the premise that Erwin Schrödinger was illustrating with his famous thought experiment involving a dead-or-maybe-not-dead cat in a box.

    “This premise, commonly referred to as the wave function, has been used more as a mathematical tool than a representation of actual quantum particles,” said David Arvidsson-Shukur, a Ph.D. student at Cambridge’s Cavendish Laboratory, and the paper’s first author. “That’s why we took on the challenge of creating a way to track the secret movements of quantum particles.”

    Any particle will always interact with its environment, ‘tagging’ it along the way. Arvidsson-Shukur, working with his co-authors Professor Crispin Barnes from the Cavendish Laboratory and Axel Gottfries, a Ph.D. student from the Faculty of Economics, outlined a way for scientists to map these ‘tagging’ interactions without looking at them. The technique would be useful to scientists who make measurements at the end of an experiment but want to follow the movements of particles during the full experiment.

    Some quantum scientists have suggested that information can be transmitted between two people – usually referred to as Alice and Bob – without any particles travelling between them. In a sense, Alice gets the message telepathically. This has been termed counterfactual communication because it goes against the accepted ‘fact’ that for information to be carried between sources, particles must move between them.

    “To measure this phenomenon of counterfactual communication, we need a way to pin down where the particles between Alice and Bob are when we’re not looking,” said Arvidsson-Shukur. “Our ‘tagging’ method can do just that. Additionally, we can verify old predictions of quantum mechanics, for example that particles can exist in different locations at the same time.”

    The founders of modern physics devised formulas to calculate the probabilities of different results from quantum experiments. However, they did not provide any explanations of what a quantum particle is doing when it’s not being observed. Earlier experiments have suggested that the particles might do non-classical things when not observed, like existing in two places at the same time. In their paper, the Cambridge researchers considered the fact that any particle travelling through space will interact with its surroundings. These interactions are what they call the ‘tagging’ of the particle. The interactions encode information in the particles that can then be decoded at the end of an experiment, when the particles are measured.

    The researchers found that this information encoded in the particles is directly related to the wave function that Schrödinger postulated a century ago. Previously the wave function was thought of as an abstract computational tool to predict the outcomes of quantum experiments. “Our result suggests that the wave function is closely related to the actual state of particles,” said Arvidsson-Shukur. “So, we have been able to explore the ‘forbidden domain’ of quantum mechanics: pinning down the path of quantum particles when no one is observing them.”

    See the full article here .

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    U Cambridge Campus

    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 4:10 pm on December 7, 2017 Permalink | Reply
    Tags: , , , Quantum Mechanics, Quantum Simulation Could Shed Light on the Origins of Life   

    From MIT Tech Review: “Quantum Simulation Could Shed Light on the Origins of Life” 

    MIT Technology Review
    M.I.T Technology Review

    December 7, 2017
    No writer credit

    For decades computer scientists have created artificial life to test ideas about evolution. Doing so on a quantum computer could help capture the role quantum mechanics may have played.

    What role does quantum mechanics play in the machinery of life? Nobody is quite sure, but in recent years, physicists have begun to investigate all kinds of possibilities. In the process, they have gathered evidence suggesting that quantum mechanics plays an important role in photosynthesis, in bird navigation, and perhaps in our sense of smell.

    There is even a speculative line of thought that quantum processes must have governed the origin of life itself and the formulation of the genetic code. The work to study these questions is ongoing and involves careful observation of the molecules of life.

    But there is another way to approach this question from the bottom up. Computer scientists have long toyed with artificial life forms built from computer code. This code lives in a silicon-based landscape where its fitness is measured against some selection criteria.

    1
    The process of quantum evolution and the creation of artificial quantum life. No image credit.

    It reproduces by combining with other code or by the mutation of its own code. And the fittest code has more offspring while the least fit dies away. In other words, the code evolves. Computer scientists have used this approach to study various aspects of life, evolution, and the emergence of complexity.

    This is an entirely classical process following ordinary Newtonian steps, one after the other. The real world, on the other hand, includes quantum mechanics and the strange phenomena that it allows. That’s how the question arises of whether quantum mechanics can play a role in evolution and even in the origin of life itself.

    So an important first step is to reproduce this process of evolution in the quantum world, creating artificial quantum life forms. But is this possible?

    Today we get an answer thanks to the work of Unai Alvarez-Rodriguez and a few pals at the University of the Basque Country in Spain. These guys have created a quantum version of artificial life for the first time. And they say their results are the first examples of quantum evolution that allows physicists to explore the way complexity emerges in the quantum world.

    The experiment is simple in principle. The team think of quantum life as consisting of two parts—a genotype and a phenotype. Just as with carbon-based life, the quantum genotype contains the quantum information that describes the individual—its genetic code. The genotype is the part of the quantum life unit that is transmitted from one generation to the next.

    The phenotype, on the other hand, is the manifestation of the genotype that interacts with the real world—the “body” of the individual. “This state, together with the information it encodes, is degraded during the lifetime of the individual,” say Alvarez-Rodriguez and co.

    So each unit of quantum life consists of two qubits—one representing the genotype and the other the phenotype. “The goal is to reproduce the characteristic processes of Darwinian evolution, adapted to the language of quantum algorithms and quantum computing,” say the team.

    The first step in the evolutionary process is reproduction. Alvarez-Rodriguez and co do this using the process of entanglement, which allows the transmission of quantum states from one object to another. In this case, they entangle the genotype qubit with a blank state, and then transfer its quantum information.

    The next stage is survival, which depends on the phenotype. Alvarez-Rodriguez and co do this by transfering an aspect of the genotype state to another blank state, which becomes the phenotype. The phenotype then interacts with the environment and eventually dissipates.

    This process is equivalent to aging and dying, and the time it takes depends on the genotype. Those that live longer are implicitly better suited to their environment and are preferentially reproduced in the next generation.

    There is another important aspect of evolution—how individuals differ from each other. In ordinary evolution, variation occurs in two ways. The first is through sexual recombination, where the genotype from two individuals combines. The second is by mutation, where random changes occur in the genotype during the reproductive process.

    Alvarez-Rodriguez and co employ this second type of variation in their quantum world. When the quantum information is transferred from one generation to the next, the team introduce a random change—in this case a rotation of the quantum state. And this, in turn, determines the phenotype and how it interacts with its environment.

    So that’s the theory. The experiment itself is tricky because quantum computers are still in their infancy. Nevertheless, Alvarez-Rodriguez and co have made use of the IBM QX, a superconducting quantum computer at IBM’s T.J. Watson Laboratories that the company has made publicly accessible via the cloud. The company claims that some 40,000 individuals have signed up to use the service and have together run some 275,000 quantum algorithms through the device.

    Alvarez-Rodriguez and co used the five-qubit version of the machine, which runs quantum algorithms that allow two-qubit interactions. However, the system imposes some limitations on the process of evolution that the team want to run. For example, it does not allow the variations introduced during the reproductive process to be random.

    Instead, the team run the experiment several times, introducing a different known rotation in each run, and then look at the results together. In total, they run the experiment thousands of times to get a good sense of the outcomes.

    In general, the results match the theoretical predictions with high fidelity. “The experiments reproduce the characteristic properties of the sought quantum natural selection scenario,” say Alvarez-Rodriguez and co.

    And the team say that the mutations have an important impact on the outcomes: “[They] significantly improved the fidelity of the quantum algorithm outcome.” That’s not so different from the classical world, where mutations help species adapt to changing environments.

    Of course, there are important caveats. The limitations of IBM’s quantum computer raise important questions about whether the team has really simulated evolution. But these issues should be ironed out in the near future.

    All this work is the result of the team’s long focus on quantum life. Back in 2015, we reported on the team’s work in simulating quantum life on a classical computer. Now they have taken the first step in testing these ideas on a real quantum computer.

    And the future looks bright. Quantum computer technology is advancing rapidly, which this should allow Alvarez-Rodriguez and co to create quantum life in more complex environments. IBM, for example, has a 20-qubit processor online and is testing a 50-qubit version.

    That will make possible a variety of new experiments on quantum life. The most obvious will include the ability for quantum life forms to interact with each other and perhaps reproduce by sexual recombination—in other words, by combining elements of their genotypes. Another possibility will be to allow the quantum life forms to move and see how this influences their interactions and fitness for survival.

    Just what will emerge isn’t clear. But Alvarez-Rodriguez and co hope their quantum life forms will become important models for exploring the emergence of complexity in the quantum world.

    Eventually, that should feed into our understanding of the role of quantum processes in carbon-based life forms and the origin of life itself. The ensuing debate will be fascinating to watch.

    Ref: Quantum Artificial Life in an IBM Quantum Computer

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    • stewarthoughblog 10:48 pm on December 7, 2017 Permalink | Reply

      It is always nice for computer simulations to be developed for virtually all scientific phenomenon. However, the true realism is the critical measure of their relevance and veracity. Since there are no known methods for origin of life development sequences, only possible scenarios for the complexity progression essential for a first organism are possible following some logical progression of events.

      Consequently, the computer code can simulate some logical process and provide a learning method for what logically must have happened, but its relevance to reality is unknown without experimental verification.

      Like

  • richardmitnick 2:39 pm on December 7, 2017 Permalink | Reply
    Tags: A space mission to test how objects fall in a vacuum has released its first results providing an improved foundation for Einstein's famous theory, , , , , , , , , Quantum Mechanics, The theory is fundamentally incompatible with another well-tested theory: quantum mechanics which describes the physics of the extremely small, The theory of general relativity and the conclusions it draws about gravity have been shown to be true wherever tested, This first result is going to shake the world of physics and will certainly lead to a revision of alternative theories to general relativity   

    From ICL: “European satellite confirms general relativity with unprecedented precision” 

    Imperial College London
    Imperial College London

    07 December 2017
    Hayley Dunning

    A space mission to test how objects fall in a vacuum has released its first results, providing an improved foundation for Einstein’s famous theory.

    The first results of the ‘Microscope’ satellite mission were announced this week by a group of researchers led by the French space agency CNES and including Imperial scientists. The findings are published in the journal Physical Review Letters.

    CNES Microscope satellite

    Launched in April 2016, the mission set out to test the ‘equivalence principle’, the founding assumption of Einstein’s theory of general relativity. The theory poses that gravity is not a ‘pulling’ force, but is the result of large bodies, like the Earth, bending spacetime.

    As a result, when two objects are dropped in a vacuum under the same force of gravity, they fall at the same rate, no matter what their difference in weight or composition. This principle was demonstrated by Apollo 15 astronaut David Scott, who dropped a hammer and a feather on the Moon and showed them both reaching the ground at the same time.

    However, dropping household objects on the lunar surface does not allow very precise measurements – it could be that they reach the ground fractions of a second apart. This is important for scientists to know, because if the equivalence principle does not hold absolutely, then it could provide clues to a unifying theory of physics.

    Finding a single theory

    The theory of general relativity, and the conclusions it draws about gravity, have been shown to be true wherever tested. However, the theory is fundamentally incompatible with another well-tested theory: quantum mechanics, which describes the physics of the extremely small.

    The major goal for 21st Century physics is a single theory that ties them all together neatly. Certain candidate theories predict that the equivalence principle may be violated at very weak levels.

    The new results have measured the equivalence principle with ten times the precision of any previous experiment, and show that objects in a vacuum fall with the same acceleration.

    Professor Timothy Sumner, from the Department of Physics at Imperial was involved in the early discussions for the project thirty years ago, which led to the current mission. He more recently joined the Science Working Team. Commenting on the latest results, he said: “The equivalence principle has proven unshakeable yet again.

    “This result is the first new measurement for several years and demonstrates the possibility of taking such difficult ‘laboratory’ experiments into the quiet and interference-free space environment. There will more results from this impressive experiment.”

    1,900 orbits of the Earth

    To test the principle, the Microscope satellite contains a series of ‘test masses’: blocks of metals of different weights with very precisely measured properties. These masses are isolated from any other influence and are monitored as they freefall in space while orbiting the Earth.

    This means their acceleration due to the freefall can be measured and compared to test the equivalence principle. If two test masses of equal size but different composition are accelerated differently during the freefall, then the equivalence principle is violated.

    The science phase of the mission began in December 2016 and has already collected data from 1,900 orbits of the Earth. This means that altogether the objects have been freefalling in space for the equivalent of 85 million kilometres, or half the Earth-Sun distance.

    The mission’s principle investigator, Pierre Touboul from France’s national aerospace research centre, ONERA, said: “The satellite’s performance is far exceeding expectations. Data from more than 1,900 additional orbits are already available and more are to come.

    “This first result is going to shake the world of physics and will certainly lead to a revision of alternative theories to general relativity.”

    The Microscope experiment is continuing to collect data, and the team hope that the final analysis will have a precision within a tenth of a trillionth of a percent.

    See the full article here .

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    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 3:21 pm on November 26, 2017 Permalink | Reply
    Tags: Einstein, ER - for Einstein-Rosen bridges, ER = EPR - (the EPR paradox named for its authors - Einstein Boris Podolsky and Nathan Rosen), Eventually Susskind — in a discovery that shocked even him — realized (with Gerard ’t Hooft) that all the information that fell down the hole was actually trapped on the black hole’s two-dimen, , , , Quantum Mechanics, , The particles still inside the hole would be directly connected to particles that left long ago,   

    From Quanta: “Wormholes Untangle a Black Hole Paradox” 2015 but Worth It. 

    Quanta Magazine
    Quanta Magazine

    April 24, 2015
    K.C. Cole

    1
    Hannes Hummel for Quanta Magazine

    One hundred years after Albert Einstein developed his general theory of relativity, physicists are still stuck with perhaps the biggest incompatibility problem in the universe. The smoothly warped space-time landscape that Einstein described is like a painting by Salvador Dalí — seamless, unbroken, geometric. But the quantum particles that occupy this space are more like something from Georges Seurat: pointillist, discrete, described by probabilities. At their core, the two descriptions contradict each other. Yet a bold new strain of thinking suggests that quantum correlations between specks of impressionist paint actually create not just Dalí’s landscape, but the canvases that both sit on, as well as the three-dimensional space around them. And Einstein, as he so often does, sits right in the center of it all, still turning things upside-down from beyond the grave.

    Like initials carved in a tree, ER = EPR, as the new idea is known, is a shorthand that joins two ideas proposed by Einstein in 1935. One involved the paradox implied by what he called “spooky action at a distance” between quantum particles (the EPR paradox, named for its authors, Einstein, Boris Podolsky and Nathan Rosen). The other showed how two black holes could be connected through far reaches of space through “wormholes” (ER, for Einstein-Rosen bridges). At the time that Einstein put forth these ideas — and for most of the eight decades since — they were thought to be entirely unrelated.

    1
    When Einstein, Podolsky and Rosen published their seminal paper pointing out puzzling features of what we now call entanglement, The New York Times treated it as front-page news. The New York Times

    But if ER = EPR is correct, the ideas aren’t disconnected — they’re two manifestations of the same thing. And this underlying connectedness would form the foundation of all space-time. Quantum entanglement — the action at a distance that so troubled Einstein — could be creating the “spatial connectivity” that “sews space together,” according to Leonard Susskind, a physicist at Stanford University and one of the idea’s main architects. Without these connections, all of space would “atomize,” according to Juan Maldacena, a physicist at the Institute for Advanced Study in Princeton, N.J., who developed the idea together with Susskind. “In other words, the solid and reliable structure of space-time is due to the ghostly features of entanglement,” he said. What’s more, ER = EPR has the potential to address how gravity fits together with quantum mechanics.

    Not everyone’s buying it, of course (nor should they; the idea is in “its infancy,” said Susskind). Joe Polchinski, a researcher at the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, whose own stunning paradox about firewalls in the throats of black holes triggered the latest advances, is cautious, but intrigued. “I don’t know where it’s going,” he said, “but it’s a fun time right now.”

    The Black Hole Wars

    3
    Juan Maldacena at the Institute for Advanced Study in Princeton, N.J. Andrea Kane/Institute for Advanced Study

    The road that led to ER = EPR is a Möbius strip of tangled twists and turns that folds back on itself, like a drawing by M.C. Escher.

    A fair place to start might be quantum entanglement. If two quantum particles are entangled, they become, in effect, two parts of a single unit. What happens to one entangled particle happens to the other, no matter how far apart they are.

    Maldacena sometimes uses a pair of gloves as an analogy: If you come upon the right-handed glove, you instantaneously know the other is left-handed. There’s nothing spooky about that. But in the quantum version, both gloves are actually left- and right-handed (and everything in between) up until the moment you observe them. Spookier still, the left-handed glove doesn’t become left until you observe the right-handed one — at which moment both instantly gain a definite handedness.

    Entanglement played a key role in Stephen Hawking’s 1974 discovery that black holes could evaporate. This, too, involved entangled pairs of particles. Throughout space, short-lived “virtual” particles of matter and anti-matter continually pop into and out of existence. Hawking realized that if one particle fell into a black hole and the other escaped, the hole would emit radiation, glowing like a dying ember. Given enough time, the hole would evaporate into nothing, raising the question of what happened to the information content of the stuff that fell into it.

    But the rules of quantum mechanics forbid the complete destruction of information. (Hopelessly scrambling information is another story, which is why documents can be burned and hard drives smashed. There’s nothing in the laws of physics that prevents the information lost in a book’s smoke and ashes from being reconstructed, at least in principle.) So the question became: Would the information that originally went into the black hole just get scrambled? Or would it be truly lost? The arguments set off what Susskind called the “black hole wars,” which have generated enough stories to fill many books. (Susskind’s was subtitled My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics.)

    4
    Leonard Susskind at home in Palo Alto, Calif. Jeff Singer

    5
    Stephen Hawking. No image credit

    Eventually Susskind — in a discovery that shocked even him — realized (with Gerard ’t Hooft) that all the information that fell down the hole was actually trapped on the black hole’s two-dimensional event horizon, the surface that marks the point of no return. The horizon encoded everything inside, like a hologram. It was as if the bits needed to re-create your house and everything in it could fit on the walls. The information wasn’t lost — it was scrambled and stored out of reach.

    Susskind continued to work on the idea with Maldacena, whom Susskind calls “the master,” and others. Holography began to be used not just to understand black holes, but any region of space that can be described by its boundary. Over the past decade or so, the seemingly crazy idea that space is a kind of hologram has become rather humdrum, a tool of modern physics used in everything from cosmology to condensed matter. “One of the things that happen to scientific ideas is they often go from wild conjecture to reasonable conjecture to working tools,” Susskind said. “It’s gotten routine.”

    Holography was concerned with what happens on boundaries, including black hole horizons. That left open the question of what goes on in the interiors, said Susskind, and answers to that “were all over the map.” After all, since no information could ever escape from inside a black hole’s horizon, the laws of physics prevented scientists from ever directly testing what was going on inside.

    Then in 2012 Polchinski, along with Ahmed Almheiri, Donald Marolf and James Sully, all of them at the time at Santa Barbara, came up with an insight so startling it basically said to physicists: Hold everything. We know nothing.

    The so-called AMPS paper (after its authors’ initials) presented a doozy of an entanglement paradox — one so stark it implied that black holes might not, in effect, even have insides, for a “firewall” just inside the horizon would fry anyone or anything attempting to find out its secrets.

    Scaling the Firewall

    Here’s the heart of their argument: If a black hole’s event horizon is a smooth, seemingly ordinary place, as relativity predicts (the authors call this the “no drama” condition), the particles coming out of the black hole must be entangled with particles falling into the black hole. Yet for information not to be lost, the particles coming out of the black hole must also be entangled with particles that left long ago and are now scattered about in a fog of Hawking radiation. That’s one too many kinds of entanglements, the AMPS authors realized. One of them would have to go.

    The reason is that maximum entanglements have to be monogamous, existing between just two particles. Two maximum entanglements at once — quantum polygamy — simply cannot happen, which suggests that the smooth, continuous space-time inside the throats of black holes can’t exist. A break in the entanglement at the horizon would imply a discontinuity in space, a pileup of energy: the “firewall.”


    Video: David Kaplan explores one of the biggest mysteries in physics: the apparent contradiction between general relativity and quantum mechanics. Filming by Petr Stepanek. Editing and motion graphics by MK12. Music by Steven Gutheinz.

    The AMPS paper became a “real trigger,” said Stephen Shenker, a physicist at Stanford, and “cast in sharp relief” just how much was not understood. Of course, physicists love such paradoxes, because they’re fertile ground for discovery.

    Both Susskind and Maldacena got on it immediately. They’d been thinking about entanglement and wormholes, and both were inspired by the work of Mark Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, who had conducted a pivotal thought experiment suggesting that entanglement and space-time are intimately related.

    “Then one day,” said Susskind, “Juan sent me a very cryptic message that contained the equation ER = EPR. I instantly saw what he was getting at, and from there we went back and forth expanding the idea.”

    Their investigations, which they presented in a 2013 paper, “Cool Horizons for Entangled Black Holes,” argued for a kind of entanglement they said the AMPS authors had overlooked — the one that “hooks space together,” according to Susskind. AMPS assumed that the parts of space inside and outside of the event horizon were independent. But Susskind and Maldacena suggest that, in fact, particles on either side of the border could be connected by a wormhole. The ER = EPR entanglement could “kind of get around the apparent paradox,” said Van Raamsdonk. The paper contained a graphic that some refer to half-jokingly as the “octopus picture” — with multiple wormholes leading from the inside of a black hole to Hawking radiation on the outside.

    4
    The ER = EPR idea posits that entangled particles inside and outside of a black hole’s event horizon are connected via wormholes. Olena Shmahalo/Quanta Magazine.

    In other words, there was no need for an entanglement that would create a kink in the smooth surface of the black hole’s throat. The particles still inside the hole would be directly connected to particles that left long ago. No need to pass through the horizon, no need to pass Go. The particles on the inside and the far-out ones could be considered one and the same, Maldacena explained — like me, myself and I. The complex “octopus” wormhole would link the interior of the black hole directly to particles in the long-departed cloud of Hawking radiation.

    Holes in the Wormhole

    No one is sure yet whether ER = EPR will solve the firewall problem. John Preskill, a physicist at the California Institute of Technology in Pasadena, reminded readers of Quantum Frontiers, the blog for Caltech’s Institute for Quantum Information and Matter, that sometimes physicists rely on their “sense of smell” to sniff out which theories have promise. “At first whiff,” he wrote, “ER = EPR may smell fresh and sweet, but it will have to ripen on the shelf for a while.”

    Whatever happens, the correspondence between entangled quantum particles and the geometry of smoothly warped space-time is a “big new insight,” said Shenker. It’s allowed him and his collaborator Douglas Stanford, a researcher at the Institute for Advanced Study, to tackle complex problems in quantum chaos through what Shenker calls “simple geometry that even I can understand.”

    To be sure, ER = EPR does not yet apply to just any kind of space, or any kind of entanglement. It takes a special type of entanglement and a special type of wormhole. “Lenny and Juan are completely aware of this,” said Marolf, who recently co-authored a paper describing wormholes with more than two ends. ER = EPR works in very specific situations, he said, but AMPS argues that the firewall presents a much broader challenge.

    Like Polchinski and others, Marolf worries that ER = EPR modifies standard quantum mechanics. “A lot of people are really interested in the ER = EPR conjecture,” said Marolf. “But there’s a sense that no one but Lenny and Juan really understand what it is.” Still, “it’s an interesting time to be in the field.”

    See the full article here .

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    Formerly known as Simons Science News, Quanta Magazine is an editorially independent online publication launched by the Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.

     
  • richardmitnick 9:28 pm on November 24, 2017 Permalink | Reply
    Tags: , , Free-fall experiment could test if gravity is a quantum force, , , , Quantum Mechanics,   

    From New Scientist: “Free-fall experiment could test if gravity is a quantum force” 

    NewScientist

    New Scientist

    22 November 2017
    Anil Ananthaswamy

    1
    Free-falling. Manuela Schewe-Behnisch/EyeEm/Getty

    Despite decades of effort, a theory of quantum gravity is still out of grasp. Now a group of physicists have proposed an experimental test of whether gravity is quantum or not, to settle questions about the force’s true nature.

    The search for quantum gravity is an effort to reconcile Einstein’s general relativity with quantum mechanics, which is a theory of all the fundamental particles and the forces that act on them – except gravity. Both are needed to explain what happens inside black holes and what happened at the big bang. But the two theories are incompatible, leading to apparent paradoxes and things like singularities, where the theories break down.

    If gravity is a quantum mechanical force, adjacent free-falling masses, each of which is in a superposition of being in two places at once, could get entangled by gravity such that measuring the properties of one mass could instantly influence the other. To test this, Sougato Bose of University College London and his colleagues have proposed an experiment.

    Branching paths

    It starts with a neutrally charged mass weighing about 10^-14 kilograms. Embedded within the mass is some material with a property called spin, which can be up or down. This mass falls through a continuously varying magnetic field, which changes the path of the mass depending on its spin. It is like the mass encounters a fork in the road and takes one path if its spin is up, and another if its spin is down.

    As it falls, the mass is in a superposition of being on both paths. Next, a series of microwave pulses manipulate the spin at various stages of descent and thus the paths the mass takes. At the bottom, the paths then come together again and the mass is brought to its original state.

    To use this set-up to test the quantum nature of gravity, two such masses would be dropped through the magnetic field. Each mass has two possible paths. This results in four possible states for the two masses combined. One of these states represents paths in which the masses come closest together.

    This distance should be no less than 200 micrometres to avoid other interactions that can dominate gravity. Once the masses are back to their original state, a test to see if their spin components are entangled should tell us if gravity is indeed a quantum force. The assumption, of course, is that the experiment ensures there are no other ways in which the masses can get entangled – such as via electromagnetic interactions or the Casimir force.

    Bose points out, however, that a null result – in which no entanglement is observed – wouldn’t constitute proof that gravity is classical, unless the experiment can definitively rule out all other interactions with the environment that can destroy entanglement, such as collisions with stray photons or molecules.

    Quantum roots?

    Antoine Tilloy at the Max Planck Institute of Quantum Optics in Germany is impressed. But he points out that a positive result will falsify only some classes of theories of classical gravity. “That said, the class is sufficiently large that I think the result would still be amazing,” he says.

    Even a verifiable null result would be exciting because it would mean gravity doesn’t have quantum roots, says Maaneli Derakhshani of Utrecht University in the Netherlands. “This would then raise tough but interesting questions about how and when exactly gravity ‘turns on’ in the quantum-classical transition for ordinary matter,” says Derakhshani. “A null result would be the most surprising and interesting outcome.”

    The biggest hurdle to carrying out the experiment for real would be putting such relatively large masses in a superposition. The most massive objects that have been observed to be in two places at once are still orders of magnitude smaller than what is required here. But efforts to go higher are ongoing.

    This work is soon to be published in Physical Review Letters.

    Reference: arxiv.org/abs/1707.06050

    See the full article here .

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  • richardmitnick 4:58 pm on November 14, 2017 Permalink | Reply
    Tags: , , , , , Quantum Circuits Company, , Quantum Mechanics, , Robert Schoelkopf is at the forefront of a worldwide effort to build the world’s first quantum computer,   

    From NYT: “Yale Professors Race Google and IBM to the First Quantum Computer” 

    New York Times

    The New York Times

    NOV. 13, 2017
    CADE METZ

    1
    Prof. Robert Schoelkopf inside a lab at Yale University. Quantum Circuits, the start-up he has created with two of his fellow professors, is located just down the road. Credit Roger Kisby for The New York Times

    Robert Schoelkopf is at the forefront of a worldwide effort to build the world’s first quantum computer. Such a machine, if it can be built, would use the seemingly magical principles of quantum mechanics to solve problems today’s computers never could.

    Three giants of the tech world — Google, IBM, and Intel — are using a method pioneered by Mr. Schoelkopf, a Yale University professor, and a handful of other physicists as they race to build a machine that could significantly accelerate everything from drug discovery to artificial intelligence. So does a Silicon Valley start-up called Rigetti Computing. And though it has remained under the radar until now, those four quantum projects have another notable competitor: Robert Schoelkopf.

    After their research helped fuel the work of so many others, Mr. Schoelkopf and two other Yale professors have started their own quantum computing company, Quantum Circuits.

    Based just down the road from Yale in New Haven, Conn., and backed by $18 million in funding from the venture capital firm Sequoia Capital and others, the start-up is another sign that quantum computing — for decades a distant dream of the world’s computer scientists — is edging closer to reality.

    “In the last few years, it has become apparent to us and others around the world that we know enough about this that we can build a working system,” Mr. Schoelkopf said. “This is a technology that we can begin to commercialize.”

    Quantum computing systems are difficult to understand because they do not behave like the everyday world we live in. But this counterintuitive behavior is what allows them to perform calculations at rate that would not be possible on a typical computer.

    Today’s computers store information as “bits,” with each transistor holding either a 1 or a 0. But thanks to something called the superposition principle — behavior exhibited by subatomic particles like electrons and photons, the fundamental particles of light — a quantum bit, or “qubit,” can store a 1 and a 0 at the same time. This means two qubits can hold four values at once. As you expand the number of qubits, the machine becomes exponentially more powerful.

    Todd Holmdahl, who oversees the quantum project at Microsoft, said he envisioned a quantum computer as something that could instantly find its way through a maze. “A typical computer will try one path and get blocked and then try another and another and another,” he said. “A quantum computer can try all paths at the same time.”

    The trouble is that storing information in a quantum system for more than a short amount of time is very difficult, and this short “coherence time” leads to errors in calculations. But over the past two decades, Mr. Schoelkopf and other physicists have worked to solve this problem using what are called superconducting circuits. They have built qubits from materials that exhibit quantum properties when cooled to extremely low temperatures.

    With this technique, they have shown that, every three years or so, they can improve coherence times by a factor of 10. This is known as Schoelkopf’s Law, a playful ode to Moore’s Law, the rule that says the number of transistors on computer chips will double every two years.

    2
    Professor Schoelkopf, left, and Prof. Michel Devoret working on a device that can reach extremely low temperatures to allow a quantum computing device to function. Credit Roger Kisby for The New York Times

    “Schoelkopf’s Law started as a joke, but now we use it in many of our research papers,” said Isaac Chuang, a professor at the Massachusetts Institute of Technology. “No one expected this would be possible, but the improvement has been exponential.”

    These superconducting circuits have become the primary area of quantum computing research across the industry. One of Mr. Schoelkopf’s former students now leads the quantum computing program at IBM. The founder of Rigetti Computing studied with Michel Devoret, one of the other Yale professors behind Quantum Circuits.

    In recent months, after grabbing a team of top researchers from the University of California, Santa Barbara, Google indicated it is on the verge of using this method to build a machine that can achieve “quantum supremacy” — when a quantum machine performs a task that would be impossible on your laptop or any other machine that obeys the laws of classical physics.

    There are other areas of research that show promise. Microsoft, for example, is betting on particles known as anyons. But superconducting circuits appear likely to be the first systems that will bear real fruit.

    The belief is that quantum machines will eventually analyze the interactions between physical molecules with a precision that is not possible today, something that could radically accelerate the development of new medications. Google and others also believe that these systems can significantly accelerate machine learning, the field of teaching computers to learn tasks on their own by analyzing data or experiments with certain behavior.

    A quantum computer could also be able to break the encryption algorithms that guard the world’s most sensitive corporate and government data. With so much at stake, it is no surprise that so many companies are betting on this technology, including start-ups like Quantum Circuits.

    The deck is stacked against the smaller players, because the big-name companies have so much more money to throw at the problem. But start-ups have their own advantages, even in such a complex and expensive area of research.

    “Small teams of exceptional people can do exceptional things,” said Bill Coughran, who helped oversee the creation of Google’s vast internet infrastructure and is now investing in Mr. Schoelkopf’s company as a partner at Sequoia. “I have yet to see large teams inside big companies doing anything tremendously innovative.”

    Though Quantum Circuits is using the same quantum method as its bigger competitors, Mr. Schoelkopf argued that his company has an edge because it is tackling the problem differently. Rather than building one large quantum machine, it is constructing a series of tiny machines that can be networked together. He said this will make it easier to correct errors in quantum calculations — one of the main difficulties in building one of these complex machines.

    But each of the big companies insist that they hold an advantage — and each is loudly trumpeting its progress, even if a working machine is still years away.

    Mr. Coughran said that he and Sequoia envision Quantum Circuits evolving into a company that can deliver quantum computing to any business or researcher that needs it. Another investor, Canaan’s Brendan Dickinson, said that if a company like this develops a viable quantum machine, it will become a prime acquisition target.

    “The promise of a large quantum computer is incredibly powerful,” Mr. Dickinson said. “It will solve problems we can’t even imagine right now.”

    See the full article here .

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  • richardmitnick 10:05 am on November 8, 2017 Permalink | Reply
    Tags: A computer for completely new problems, , Basel researchers lead the field, , Collaboration with industrial partner IBM, , Quantum Mechanics,   

    From U Basel: “The second revolution in quantum physics” 

    u-basel-bloc

    U Basel

    11.8.17
    Dominik Zumbühl

    1
    Dominik Zumbühl, U Basel

    Quantum physics promises to deliver revolutionary new technologies such as the quantum computer – with far-reaching consequences for the economy and society. For many years, the University of Basel has been playing a pioneering role in quantum research.

    2
    Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons

    07-09-2017
    We have demonstrated a quantum memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency, and with an acceptance bandwidth of δf=0.66 GHz. This memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. These results were published in Physical Review Letters 119, 060502.

    In the first third of the 20th century, physicists such as Max Planck, Albert Einstein, Erwin Schrödinger, and Werner Heisenberg fundamentally changed the way we understand nature. With the development of quantum mechanics, a theory was emerging that would challenge human understanding and intuition. Its pioneers were simultaneously astonished and bewildered, and used thought experiments to try to illustrate the paradoxical consequences of the new theory. In the most famous example, Schrödinger describes a cat that, according to the laws of quantum physics, is alive and dead at the same time. However absurd ideas like this may seem, quantum theory is now seen as one of the greatest achievements in science and has revolutionized the way we see the world.

    Over the last 20 years or so, quantum physics has given rise to a second revolution. With a steady stream of new experiments, scientists have shown that we can use the crazy world of quantum physics to do useful things that would be impossible in classical physics.

    Today, highly sensitive quantum sensors allow us to measure magnetic fields faster and more accurately than ever before. In the near future, quantum physics could pave the way for secure communication channels. In the past, medical diagnostic devices such as magnetic resonance imaging (MRI) scanners have been developed based on the laws of quantum physics.

    A computer for completely new problems

    Quantum physics offers breathtaking potential for innovation. Against this backdrop, physicists at the University of Basel are pursuing the vision of a computer that takes advantage of the laws of quantum mechanics.

    A quantum computer can perform a large number of computing operations in parallel. It is therefore incredibly fast and solves problems in a matter of hours that would take today’s supercomputers billions of years. Whereas the latest supercomputers contain a billion transistors, a quantum computer would contain a billion quantum bits (qubits). While classical bits can adopt only states of 0 or 1, qubits allow you to define more than just two states. In the future, their sheer computing power could allow us to answer questions we have not even dared to ask yet. It is conceivable, for example, that we will be able to create molecules and therefore materials with previously unknown properties: new types of pharmaceutical active substances, for example. Or superconductors for transporting electricity without loss at room temperature. Or chlorophyll-like substances that convert sunlight into useful energy. Until now, innovative substances tended to be discovered by chance. However, in the future, quantum computers could allow scientists to design materials with desirable properties in a targeted manner.

    The quantum computer is a highly promising innovation. Its realization is now the subject of work by leading researchers from Harvard to Tokyo. One promising implementation is based on an idea, formulated 20 years ago by the physicist Daniel Loss, that the angular momentum (spin) of individual electrons can be used as the smallest information carrier in a quantum computer. In laboratories around the world, qubits of this kind are considered the most promising candidates for building a quantum computer. The idea’s originator, Daniel Loss, works in Basel and devotes his time to developing a Basel qubit. Manufactured from a semiconducting material, this qubit is extremely small and fast. As silicon is a thoroughly tried-and-tested material for computer chips, silicon qubits offer key advantages over other qubit concepts. Developing a qubit is the overarching objective of Basel’s physics department, where 12 professors are channeling the expertise of their research teams into achieving this common goal.

    Basel researchers lead the field

    Let me state clearly the magnitude of the challenge: the Department of Physics at the University of Basel is not an industrial laboratory seeking to build a quantum computer in the next few months or years. Rather, we are carrying out research on the foundations of the quantum computer. Research of this kind is very time-consuming but has the potential to bring about genuine innovations. It is worth remembering that, after the transistor was discovered in 1947, it took half a century for personal computers and mobile phones to make their way into our everyday lives and to turn the world of work upside down. With regard to the quantum computer, the marathon has only just begun. Today, companies like Microsoft, Google, and Intel are pinning their hopes on the quantum computer as they realize that the increasing miniaturization of classical CMOS chips is reaching its limits. Basel’s ambition is to be among the front-runners.

    So far, we’ve been making great progress. In recent years, Basel’s physicists have secured eight of the prestigious grants from the European Research Council (ERC), with the last two going to our professors Jelena Klinovaja and Ilaria Zardo. This success demonstrates the excellence of our research portfolio. Many young researchers are attracted to the brilliance of the quantum research carried out in Basel. Operating since autumn 2016, the PhD school for “Quantum Computing and Quantum Technologies” currently brings together 20 doctoral researchers. In addition, generous support from the Georg H. Endress Foundation will allow us to set up a cross-border postdoc cluster in cooperation with the University of Freiburg from January 2018. As a result, there will be ten additional scientists working in the field of quantum computing. This initiative is modeled on foundations in the US that provide funding for postdocs at top centers of research.

    Collaboration with industrial partner IBM

    There are some critical decisions that we currently have to make in the field of quantum physics in order to further strengthen this strategic focus at the University of Basel. These include participation in the EU’s billion-euro flagship project on quantum technologies, which is planned to begin next year. At present, we are preparing an application for a National Centre of Competence in Research (NCCR) from the Swiss National Science Foundation with Basel as the leading house on the topic of scalable quantum computing.

    For this NCCR, we have chosen the IBM Zurich Research Laboratory as our main, coleading partner, together with other universities as partners. Our goal is to build silicon spin qubits. In 12 years, the ambitious target is to have a fully scalable logical qubit consisting of ca. 15 physical qubits. Although this is not yet a complete quantum computer, it does provide a copy-paste blueprint for a quantum chip.

    When the first concepts for a quantum computer emerged, they did so in Europe. With this as our starting point, we now have the opportunity to build the foundation of a new Silicon Valley. Research on the quantum computer is an investment in a future technology and therefore in Switzerland’s industrial base. Our laboratories are also currently home to a rising generation of experts who can understand, shape and disseminate this emergent technology. Only with their help can we succeed in turning the second revolution of quantum physics to the advantage of society as a whole.

    See the full article here .

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    Purposes

    The University of Basel fosters the development of critically thinking and tolerant individuals who are capable of taking initiative and taking on responsibility. It is the aim of the University to enable these individuals to deepen their knowledge and field-specific academic training and further education.

    Through research and teaching, the University imparts the insights past down over the ages in addition to producing new knowledge. It is guided by the principle of meaningfulness and purpose rather than feasibility.

    The University is aware of the duties arising from knowledge, fulfilling these duties through critical reflection and the services it provides. It takes its own position concerning problems facing society.

    The University realizes its aims by taking responsibility with respect to future generations, the society that supports them, the international academic community and the culture that is passed down from generation to generation.

     
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