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  • richardmitnick 3:13 pm on January 1, 2021 Permalink | Reply
    Tags: "Active matter", "By controlling sequences of low rattling states we were able to make the system reach configurations that do useful work.", "Spontaneous Robot Dances Highlight a New Kind of Order in Active Matter", Active matter systems can spontaneously order without need for higher level instructions or even programmed interaction among the agents., , Georgia Institute of Technology, Low rattling is either very slight or highly organized-or both., More challenging to predict are the collective behaviors that can be achieved when the particles become more complicated such that they can move under their own power., Predicting when and how collections of particles robots or animals become orderly remains a challenge across science and engineering., Rattling can be greater either when the motion is more violent or more random., Rattling is when matter takes energy flowing into it and turns it into random motion., Rattling theory, , Smarticles   

    From Georgia Institute of Technology: “Spontaneous Robot Dances Highlight a New Kind of Order in Active Matter” 

    From Georgia Institute of Technology

    December 31, 2020

    John Toon
    Research News
    (404) 894-6986
    john.toon@comm.gatech.edu

    1
    The flower-like set of points represents all possible shapes that the smarticle swarm can take on. In line with rattling theory, the most common shapes are also the most orderly with the lowest rattling (shown in blue). Credit: Thomas A. Berrueta.

    Predicting when and how collections of particles, robots, or animals become orderly remains a challenge across science and engineering.

    In the 19th century, scientists and engineers developed the discipline of statistical mechanics, which predicts how groups of simple particles transition between order and disorder, as when a collection of randomly colliding atoms freezes to form a uniform crystal lattice.

    More challenging to predict are the collective behaviors that can be achieved when the particles become more complicated, such that they can move under their own power. This type of system — observed in bird flocks, bacterial colonies, and robot swarms — goes by the name “active matter.”

    As reported in the January 1, 2021 issue of the journal Science, a team of physicists and engineers have proposed a new principle by which active matter systems can spontaneously order, without need for higher level instructions or even programmed interaction among the agents. And they have demonstrated this principle in a variety of systems, including groups of periodically shape-changing robots called “smarticles” — smart, active particles.

    The theory, developed by Postdoctoral Researcher Pavel Chvykov at the Massachusetts Institute of Technology while a student of Prof. Jeremy England, who is now a researcher in the School of Physics at Georgia Institute of Technology, posits that certain types of active matter with sufficiently messy dynamics will spontaneously find what the researchers refer to as “low rattling” states.

    “Rattling is when matter takes energy flowing into it and turns it into random motion,” England said. “Rattling can be greater either when the motion is more violent, or more random. Conversely, low rattling is either very slight or highly organized — or both. So, the idea is that if your matter and energy source allow for the possibility of a low rattling state, the system will randomly rearrange until it finds that state and then gets stuck there. If you supply energy through forces with a particular pattern, this means the selected state will discover a way for the matter to move that finely matches that pattern.”

    To develop their theory, England and Chvykov took inspiration from a phenomenon — dubbed thermophoresis — discovered by the Swiss physicist Charles Soret in the late 19th century. In Soret’s experiments, he discovered that subjecting an initially uniform salt solution in a tube to a difference in temperature would spontaneously lead to an increase in salt concentration in the colder region — which corresponds to an increase in order of the solution.

    Chvykov and England developed numerous mathematical models to demonstrate the low rattling principle, but it wasn’t until they connected with Daniel Goldman, Dunn Family Professor of Physics at the Georgia Institute of Technology, that they were able to test their predictions.

    Said Goldman, “A few years back, I saw England give a seminar and thought that some of our smarticle robots might prove valuable to test this theory.” Working with Chvykov, who visited Goldman’s lab, Ph.D. students William Savoie and Akash Vardhan used three flapping smarticles enclosed in a ring to compare experiments to theory. The students observed that instead of displaying complicated dynamics and exploring the container completely, the robots would spontaneously self-organize into a few dances — for example, one dance consists of three robots slapping each other’s arms in sequence. These dances could persist for hundreds of flaps, but suddenly lose stability and be replaced by a dance of a different pattern.

    After first demonstrating that these simple dances were indeed low rattling states, Chvykov worked with engineers at Northwestern University, Prof. Todd Murphey and Ph.D. student Thomas Berrueta, who developed more refined and better controlled smarticles. The improved smarticles allowed the researchers to test the limits of the theory, including how the types and number of dances varied for different arm flapping patterns, as well as how these dances could be controlled. “By controlling sequences of low rattling states, we were able to make the system reach configurations that do useful work,” Berrueta said. The Northwestern University researchers say that these findings may have broad practical implications for micro-robotic swarms, active matter, and metamaterials.

    As England noted: “For robot swarms, it’s about getting many adaptive and smart group behaviors that you can design to be realized in a single swarm, even though the individual robots are relatively cheap and computationally simple. For living cells and novel materials, it might be about understanding what the ‘swarm’ of atoms or proteins can get you, as far as new material or computational properties.”

    The study’s Georgia Tech-based team includes Jeremy L. England, a Physics of Living Systems scientist who researches with the School of Physics; Dunn Family Professor Daniel Goldman; professor Kurt Wiesenfeld, and graduate students Akash Vardhan (Quantitative Biosciences) and William Savoie (School of Physics). They join Pavel Chvykov (Massachusetts Institute of Technology), along with professor Todd D. Murphey and graduate students Thomas A. Berrueta and Alexander Samland of Northwestern University.

    This material is based on work supported by the Army Research Office under awards from ARO W911NF-18-1-0101, ARO MURI Award W911NF-19-1-0233, ARO W911NF-13-1-0347, by the National Science Foundation under grants PoLS-0957659, PHY-1205878, PHY-1205878, PHY-1205878, and DMR-1551095, NSF CBET-1637764, by the James S. McDonnell Foundation Scholar Grant 220020476, and the Georgia Institute of Technology Dunn Family Professorship. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsoring agencies.

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 11:45 am on November 8, 2020 Permalink | Reply
    Tags: "Simulation Gives a Peek Into The Cosmic 'Dark Age' of Star Formation", , , , , Georgia Institute of Technology, MACS 1149-JD, , ,   

    From Georgia Institute of Technology via Science Alert (AU): “Simulation Gives a Peek Into The Cosmic ‘Dark Age’ of Star Formation” 

    From Georgia Institute of Technology

    via

    ScienceAlert

    Science Alert (AU)

    8 NOVEMBER 2020
    MATT WILLIAMS

    1
    Credit: NASA/ESA/UCSC/Leiden University/HUDF09 Team.

    For astronomers, astrophysicists, and cosmologists, the ability to spot the first stars that formed in our Universe has always been just beyond reach. On the one hand, there are the limits of our current telescopes and observatories, which can only see so far.

    The farthest object ever observed was MACS 1149-JD, a galaxy located 13.2 billion light-years from Earth that was spotted in the Hubble eXtreme Deep Field (XDF) image.

    Hubble Ultra Deep Field NASA/ESA Hubble.

    1
    Early Galaxy Found from the Cosmic ‘Dark Ages’
    In the big image at left, the many galaxies of a massive cluster called MACS J1149+2223 dominate the scene. Gravitational lensing by the giant cluster brightened the light from the newfound galaxy, known as MACS 1149-JD, some 15 times. At upper right, a partial zoom-in shows MACS 1149-JD in more detail, and a deeper zoom appears to the lower right. Image credit: NASA/ESA/STScI/JHU via Universe Today.

    3
    The Distant Galaxy MACS 1149-JD – NASA Spitzer Space Telescope
    Creator: Space Telescope Science Institute Office of Public Outreach. Credit: NASA/ESA/STScI/W. Zheng (JHU), and the CLASH team.

    On the other, up until about 1 billion years after the Big Bang, the Universe was experiencing what cosmologists refer to as the “Dark Ages” when the Universe was filled with gas clouds that obscured visible and infrared light.

    ALMA Schematic diagram of the history of the Universe. The Universe is in a neutral state at 400 thousand years after the Big Bang, until light from the first generation of stars starts to ionise the hydrogen. After several hundred million years, the gas in the Universe is completely ionised. Credit. NAOJ.

    Luckily, a team of researchers from Georgia Tech’s Center for Relativistic Astrophysics recently conducted simulations that show what the formation of the first stars looked like.

    The study that describes their findings, published in the MNRAS, was led by Gen Chiaki and John Wise – a post-doctoral researcher and associate professor from the CfRA (respectively).

    They were joined by researchers from the Sapienza Università di Roma (IT), the Astronomical Observatory of Rome (IT), the Istituto Nazionale di Astrofisica (INAF) (IT), and the Istituto Nazionale di Fisica Nucleare (INFN) (IT).

    Based on the life and death cycles of stars, astrophysicists theorize that the first stars in the Universe were very metal-poor. Having formed about 100 million years after the Big Bang, these stars formed from a primordial soup of hydrogen gas, helium, and trace amounts of light metals.

    These gases would collapse to form stars that were up to 1,000 times more massive than our Sun.

    Because of their size, these stars were short-lived and probably only existed for a few million years. In that time, the new and heavier elements in their nuclear furnaces, which were then dispersed once the stars collapsed and exploded in supernovae.

    As a result, the next generation of stars with heavier elements would contain carbon, leading to the designation of Carbon-Enhanced Metal-Poor (CEMP) stars.

    The composition of these stars, which may be visible to astronomers today, is the result of the nucleosynthesis (fusion) of heavier elements from the first generation of stars.

    By studying the mechanism behind the formation of these metal-poor stars, scientists can infer what was happening during the cosmic ‘Dark Ages’ when the first stars formed. As Wise said in a Texas Advanced Computer Center (TACC) press release:

    “We can’t see the very first generations of stars. Therefore, it’s important to actually look at these living fossils from the early universe, because they have the fingerprints of the first stars all over them through the chemicals that were produced in the supernova from the first stars.

    That’s where our simulations come into play to see this happening. After you run the simulation, you can watch a short movie of it to see where the metals come from and how the first stars and their supernovae actually affect these fossils that live until the present day.”

    6
    Density, temperature, and carbon abundance (top) and the formation cycle of Pop III stars (bottom). Credit: Chiaki, et al.

    For the sake of their simulations, the team relied predominantly on the Georgia Tech PACE cluster.

    Georgia Tech Hive Pace HPC supercomputer cluster.

    Additional time was allocated by the National Science Foundation’s (NSF) Extreme Science and Engineering Discovery Environment (XSEDE), the Stampede2 supercomputer at TACC and NSF-funded Frontera system (the fastest academic supercomputer in the world), and the Comet cluster at the San Diego Supercomputer Center (SDSC).

    TACC DELL EMC Stampede2 supercomputer.

    TACC Frontera Dell EMC supercomputer fastest at any university.

    SDSC Dell Comet supercomputer at San Diego Supercomputer Center (SDSC).

    With the massive amounts of processing power and data storage these clusters provided, the team was able to model the faint supernova of the first stars in the Universe.

    What this revealed was that the metal-poor stars that formed after the first stars in the Universe became carbon-enhanced through the mixing and fallback of bits ejected from the first supernovae.

    Their simulations also showed the gas clouds produced by the first supernovae were seeding with carbonaceous grains, leading to the formation of low-mass ‘giga-metal-poor’ stars that likely still exist today (and could be studied by future surveys). Said Chiaki of these stars:

    “We find that these stars have very low iron content compared to the observed carbon-enhanced stars with billionths of the solar abundance of iron. However, we can see the fragmentation of the clouds of gas. This indicates that the low mass stars form in a low iron abundance regime. Such stars have never been observed yet. Our study gives us theoretical insight of the formation of first stars.”

    7
    A new study looked at 52 submillimeter galaxies to help us understand the early ages of our Universe. Credit:U Nottingham/Omar Almaini.

    With the massive amounts of processing power and data storage these clusters provided, the team was able to model the faint supernova of the first stars in the Universe.

    These investigations are part of a growing field known as “galactic archaeology.”

    Much like how archaeologists rely on fossilized remains and artifacts to learn more about societies that disappeared centuries or millennia ago, astronomers look for ancient stars to study in order to learn more about those that have long since died.

    According to Chiaki, the next step is to branch out beyond the carbon features of ancient stars and incorporate other heavier elements into larger simulations. In so doing, galactic archaeologists hope to learn more about the origins and distribution of life in our Universe. Said Chiaki:

    “The aim of this study is to know the origin of elements, such as carbon, oxygen, and calcium. These elements are concentrated through the repetitive matter cycles between the interstellar medium and stars. Our bodies and our planet are made of carbon and oxygen, nitrogen, and calcium. Our study is very important to help understand the origin of these elements that we human beings are made of.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 11:18 am on June 20, 2020 Permalink | Reply
    Tags: "This Supernova in a Lab Mimics the Cosmic Blast's Splendid Aftermath", , , , , Georgia Institute of Technology   

    From Georgia Institute of Technology: “This Supernova in a Lab Mimics the Cosmic Blast’s Splendid Aftermath” 

    From Georgia Institute of Technology

    1

    June 17, 2020
    Ben Brumfield

    Nestled in the constellation Taurus, a spectacle of swirling cosmic gases measuring half a dozen light-years across glows in shades of emerald and auburn. The Crab Nebula was born of a supernova, the explosion of a giant star, and now, a lab machine the size of a double door replicates how the immense blast paints these astronomical swirls into existence.

    Supernova remnant Crab nebula

    “It’s 6 feet tall and looks like a big slice of pizza that’s about 4 feet wide at the top,” said Ben Musci of the supernova machine he built for a study at the Georgia Institute of Technology.

    The machine is also about as thin as a door and stands vertically with the point of the “slice of pizza” at the bottom. A concise detonation in that tip thrusts a blast wave toward the top, and in the middle of the machine, the wave passes through two layers of gas, making them mix turbulently into swirls like those left by supernovas.

    Laser light illuminates the swirls, and through a window, a high-speed camera with a close-up lens captures the beauty, along with data on a centimeter scale that can be extrapolated to astronomical scales using well-established physics math. Getting the machine to produce results useful for studying nature took 2 1/2 years of engineering adjustments.

    3
    Supernova Machine

    Matching up swirls

    “We suddenly go from a perfectly still chamber to a little supernova. There was a lot of engineering done to contain the blast and at the same time make it realistic where it hits the gas interface in the visualization window,” said Devesh Ranjan, the study’s principal investigator and a professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering.

    “The hard part was troubleshooting the artifacts that were not part of supernova physics. I spent a year getting rid of things like an extra shock wave bouncing around in the chamber or air leaking in from the room,” said Musci, the study’s first author and a graduate research assistant in Ranjan’s lab. “I also had to make sure that gravity, background radiation, and temperature did not throw off the physics.”

    The researchers published their results in The Astrophysical Journal on June 17,2020. The research was funded by the U.S. Department of Energy’s Fusion Energy Science program. Musci plans to collaborate with Lawrence Livermore National Laboratory to compare the machine’s gas patterns with actual data on supernova remnants.

    4
    A series of frames showing the visual effects produced by the supernova machine

    Supernova’s special blast

    Not all nebulas are remnants of supernovas, but many are. They and other supernova remnants start out with a massive star. Stars are balls of gases, which are arranged in layers, and when a star explodes in a supernova, those layers enable the formation of the beautiful swirls.

    “On the outside, the gases have low density and on the inside high density, and very deep in the star, the density begins to force the gases together to make iron in the star’s core,” Ranjan said.

    “After this point the star runs out of nuclear fuel, so the outward force caused by nuclear fusion stops balancing the inward gravitational force. The extreme gravitation collapses the star,” Musci said.

    In the center of the star, there is a point explosion, which is the supernova. It sends a blast wave traveling at about a tenth of the speed of light ripping through the gases, jamming their layers together.

    Heavier gas in inner layers stabs turbulent outcrops into lighter gas in the outer layers. Then behind the blast wave, pressure drops, stretching the gases back out for a different kind of turbulent mixing.

    “It’s a hard push followed by a prolonged pull or stretch,” Musci said.

    6

    Explosive mimics supernova

    The researchers used small amounts of a commercially available detonator (containing RDX, or Research Department eXplosive, and PETN, or pentaerythritol tetranitrate) to make the concise miniature blast, which sent a clean wave through the interface between the heavier and lighter gases in the machine.

    In nature, the blast wave goes out spherically in all directions, and Musci achieved a partial representation of its curvature in the machine’s blast wave. In nature and in the machine, interfaces between the gases are full of small, uneven twists and turns called perturbations, and the blast wave whacks them at skewed angles.

    “That is important to growing the initial perturbation that leads to turbulence because that unevenness puts a torque on the interface between the gas layers,” Musci said.

    Convolutions and curlicues ensue to make supernova remnants, which expand for thousands of years to become softer and smoother forms that stir our hearts with their splendor. To physicists, those initial twists are highly recognizable structures interesting for study: turbulent spikes of heavy gas protruding into light gas, “bubbles” of light gas isolated in areas of heavy gas, and curls typical of early turbulent flow.

    “One of the most interesting things we saw related to a mystery about supernovas — they shoot high density gas called ejecta way out, which may help create new stars. We saw some of this gas propulsion in the device where heavy gas was propagated way out into the light gas,” Musci said.

    Supernova remnants perpetually expand at speeds of hundreds of miles per second, and the new machine could help refine calculations of those speeds and help characterize remnants’ changing forms. The Crab Nebula’s supernova was recorded in the year 1054 by Chinese astronomers, but for many other remnants, the machine could also help calculate their moment of birth.

    Inertial confinement fusion

    The machine’s insights would apply in reverse to help with the development of nuclear fusion energy. The process called inertial confinement fusion applies extreme force and heat from the outside inward evenly onto a tiny area where two isotopes of hydrogen gas are layered upon each other, one denser than the other.

    The layers are forced together until the atoms’ nuclei fuse, unleashing energy. Fusion researchers are striving to eliminate turbulent mixing. What is beautiful in the supernova makes nuclear fusion less efficient.

    These researchers also collaborated on this study: Samuel Petter, Gokul Pathikonda, and Bradley Ochs from Georgia Tech; the Department of Energy’s Fusion Energy Sciences program funded the research (grant DE-SC0016181, Early Career Award). Any findings, conclusions, or recommendations are those of the authors and not necessarily of the Department of Energy.

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 11:01 am on May 12, 2020 Permalink | Reply
    Tags: "What’s Creating Galaxy-Spanning Cold Gas Filaments in Galaxy Clusters? Research Points to Burps from Supermassive Black Holes", , , , , Georgia Institute of Technology   

    From Georgia Institute of Technology: “What’s Creating Galaxy-Spanning Cold Gas Filaments in Galaxy Clusters? Research Points to Burps from Supermassive Black Holes” 

    From Georgia Institute of Technology

    May 4, 2020

    Renay San Miguel
    Communications Officer
    College of Sciences
    404-894-5209

    In Nature Astronomy, Yu Qiu and Tamara Bogdanović shine new light on the formation of dusty, cold gas filaments immersed in hot, X-ray emitting plasma and extending 100,000 light-years from the centers of galaxy clusters.

    A galaxy’s size can be enough to stagger the imagination. Now try to imagine galaxy clusters, the largest gravitationally bound structures in the universe, dotted with hundreds to thousands of galaxies and permeated by large amounts of hot, X-ray emitting plasma.

    1
    Comparison of the Hubble Space Telescope observation of the filaments in the Perseus cluster (left) with the Yu Qiu research team’s thermal energy illustration of the simulated cluster (right).

    One of the mysteries inside those clusters is how super-hot and super-cold materials co-exist inside them — and a possible solution explaining the dynamic is the subject of a new research article in Nature Astronomy, co-written by two Georgia Tech researchers, Yu Qiu and Tamara Bogdanović, in collaboration with Yuan Li (UC Berkeley), Michael McDonald (MIT) and Brian McNamara (University of Waterloo).

    Galaxy clusters are filled with super-hot plasma, known as intracluster medium, that sends out a lot of X-rays. But astronomical observations show that a significant number of clusters also have large amounts of cold gas within their cores. These “cool-core clusters” feature wispy filaments of gas that can extend tens of thousands of light years from their center. Some could be “stellar nurseries” — birthplaces of stars. The article theorizes the causes of those filaments, which have captured the attention and imagination of astrophysicists, are supermassive black holes hidden within those clusters.

    The primary author of the paper “The Formation of Dusty Cold Gas Filaments from Galaxy Cluster Simulations” is Qiu, now a postdoctoral fellow at the Kavli Institute for Astronomy and Astrophysics in Beijing. Qiu started the research while a Georgia Tech graduate student working with Bogdanovic, an associate professor in the School of Physics and the Center for Relativistic Astrophysics. Qiu received his Ph.D. in physics from Georgia Tech in 2019.

    Bogdanović says the article addresses the “cooling flow problem” in galaxy clusters and is also related to the co-evolution of supermassive black holes within them. “For almost 30 years now, it has been argued on the basis of data from imaging X-ray telescopes that the intracluster medium (ICM) in the core regions of some clusters is radiatively cooling on time scales shorter than the age of these clusters,” Bogdanović says. But there’s been no evidence of complete cooling of that gas within those clusters. “The resolution of this contradiction has been sought in different heating mechanisms that could prevent the catastrophic cooling of the ICM.”

    Qiu’s research focused on the Perseus cluster, one of the largest galaxy clusters, located nearly 250 million light years from Earth. Are the gas filaments extending from the cluster capable of birthing stars, much like the Pillars of Creation dust and gas clouds, famously captured by the Hubble Space Telescope?

    “They are very similar in the sense that both consist primarily of cold gas, less than several thousand Kelvin, and when cold gas gathers in clumps, it can lead to the formation of new stars,” Qiu says. “However, the cold gas filaments observed in galaxy clusters, such as the Perseus cluster modeled in this work, expand more than 100,000 light years beyond the nucleus, and are larger than the host galaxy.”

    “Unlike the Pillars of Creation, which is likely created by an expanding bubble irradiated by a massive star, the vast scale and the prevailing radial structure of these filaments indicate that they are driven by a much more energetic source, which we think is the central supermassive black hole.” The research examines the process for how black holes could help create those filaments.

    That involves a closer look at what Qiu discovered to be an important part of the process: active galactic nucleus (AGN) feedback. AGNs are active regions in the centers of galaxies, and they throw off a lot of light and gas.

    “It has been widely acknowledged that AGNs are associated with growing supermassive black holes,” Qiu says. As a black hole attracts matter from the surrounding material due to its gravity, that matter forms an accretion disk near the black hole. It can convert part of that energy into radiation and gas outflow.

    Qiu’s research uses 3D radiation-hydrodynamic simulations and reveals a possible new mechanism, a combination of the cooling that happens to gas filaments as they flow outward from the cluster center, and what’s called ram pressure – the “headwind” that impacts those filaments as they race through the ICM plasma.

    This new mechanism, “naturally promotes outflows whose cooling time is shorter than their rising time, giving birth to spatially extended cold gas filaments. Our results strongly suggest that the formation of cold gas and AGN feedback in galaxy clusters are inextricably linked and shed light on how AGN feedback couples to the intracluster medium,” Qiu writes in the article.

    “By accounting for these physical phenomena in the context of a galaxy cluster, Yu reproduced many of the observed properties of the cold gas filaments and the surrounding X-ray emitting ICM,” Bogdanović says. “This gives us confidence that this model is on the right track and provides a more realistic description than some earlier models, where AGNs played a passive role or were unimportant altogether.”
    Could this research tell us more about process of birthing stars, or even galaxies?

    “While there is evidence for star formation in some of the filaments, others seem to have suppressed star formation within the cold gas. So it is still under debate whether these filaments are fueling star formation directly,” says Qiu.

    “What this study focuses on is how outflows powered by the central supermassive black hole facilitate the formation of these filaments,” he adds. “Because the creation and evolution path of the filaments have a great impact on the properties of the cold gas within, the ideas advanced in this work can in principle help us better predict how and when stars may form in them.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 10:48 am on May 12, 2020 Permalink | Reply
    Tags: "Surfaces That Grip Like Gecko Feet Could Be Easily Mass-Produced", , Georgia Institute of Technology,   

    From Georgia Institute of Technology: “Surfaces That Grip Like Gecko Feet Could Be Easily Mass-Produced” 

    From Georgia Institute of Technology

    May 7, 2020
    Ben Brumfield
    (404-272-2780)
    ben.brumfield@comm.gatech.edu


    The slightest bit of shear tension makes gecko adhesion surfaces grip, and the release of that same tension makes them let go. The same gripping surfaces can pick up objects of all shapes, sizes, and materials with the exception of Teflon and other non-stick surfaces. Credit: Georgia Tech / Varenberg lab

    1
    The inset on the upper right illustrates how the gecko adhesion surface is made by pushing lab razor blades into a setting polymer. The razor blades are pulled out, leaving indentations and stretching some of the polymer up, resulting in flexible walls that produce the gecko adhesion effect. Credit: Georgia Tech / Varenberg lab

    Why did the gecko climb the skyscraper? Because it could; its toes stick to about anything. Engineers can already emulate the secrets of gecko stickiness to make strips of rubbery materials that can pick up and release objects, but simple mass production for everyday use has been out of reach until now.

    Researchers at the Georgia Institute of Technology have developed, in a new study [below], a method of making gecko-inspired adhesive materials that is much more cost-effective than current methods. It could enable mass production and the spread of the versatile gripping strips to manufacturing and homes.

    Polymers with “gecko adhesion” surfaces could be used to make extremely versatile grippers to pick up very different objects even on the same assembly line. They could make picture hanging easy by adhering to both the picture and the wall at the same time. Vacuum cleaner robots with gecko adhesion could someday scoot up tall buildings to clean facades.

    “With the exception of things like Teflon, it will adhere to anything. This is a clear advantage in manufacturing because we don’t have to prepare the gripper for specific surfaces we want to lift. Gecko-inspired adhesives can lift flat objects like boxes then turn around and lift curved objects like eggs and vegetables,” said Michael Varenberg, the study’s principal investigator and an assistant professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering.

    Current grippers on assembly lines, such as clamps, magnets, and suction cups, can each lift limited ranges of objects. Grippers based on gecko-inspired surfaces, which are dry and contain no glue or goo, could replace many grippers or just fill in capability gaps left by other gripping mechanisms.

    Drawing out razors

    The adhesion comes from protrusions a few hundred microns in size that often look like sections of short, floppy walls running parallel to each other across the material’s surface. How they work by mimicking geckos’ feet is explained below.

    Up to now, molding has produced these mesoscale walls by pouring ingredients onto a template, letting the mixture react and set to a flexible polymer then removing it from the mold. But the method is inconvenient.

    “Molding techniques are expensive and time-consuming processes. And there are issues with getting the gecko-like material to release from the template, which can disturb the quality of the attachment surface,” Varenberg said.

    The researchers’ new method formed those walls by pouring ingredients onto a smooth surface instead of a mold, letting the polymer partially set then dipping rows of laboratory razor blades into it. The material set a little more around the blades, which were then drawn out, leaving behind micron-scale indentations surrounded by the desired walls.

    Varenberg and first author Jae-Kang Kim published details of their new method in the journal ACS Applied Materials & Interfaces on April 6, 2020.

    Forget about perfection

    Though the new method is easier than molding, developing it took a year of dipping, drawing, and readjusting while surveying finicky details under an electron microscope.

    “There are many parameters to control: Viscosity and temperature of the liquid; timing, speed, and distance of withdrawing the blades. We needed enough plasticity of the setting polymer to the blades to stretch the walls up, and not so much rigidity that would lead the walls to rip up,” Varenberg said.

    Gecko-inspired surfaces have a fine topography on a micron-scale and sometimes even on a nanoscale, and surfaces made via molding are usually the most precise. But such perfection is unnecessary; the materials made with the new method did the job well and were also markedly robust.

    “Many researchers demonstrating gecko adhesion have to do it in a cleanroom in clean gear. Our system just plain works in normal settings. It is robust and simple, and I think it has good potential for use in industry and homes,” said Varenberg, who studies surfaces in nature to mimic their advantageous qualities in human-made materials.

    Gecko foot fluff

    Behold the gecko’s foot. It has ridges on its toes, and this has led some in the past to think their feet stick by suction or some kind of clutching by the skin.

    But electron microscopes reveal a deeper structure – spatula-shaped bristly fibrils protrude a few dozen microns long off those ridges. The fibrils make such thorough contact with surfaces down to the nanoscale that weak attractions between atoms on both sides appear to add up enormously to create overall strong adhesion.

    In place of fluff, engineers have developed rows of shapes covering materials that produce the effect. A common shape makes a material’s surface look like a field of mushrooms that are a few hundred microns in size; another is rows of short walls like those in this study.

    “The mushroom patterns touch a surface, and they are attached straightaway, but detaching requires applying forces that can be disadvantageous. The wall-shaped projections require minor shear force like a tug or a gentle grab to generate adherence, but that is easy, and letting go of the object is uncomplicated, too,” Varenberg said.

    Varenberg’s research team used the drawing method to make walls with U-shaped spaces in between them and walls with V-shaped spaces in between. They worked with polyvinylsiloxane (PVS) and polyurethane (PU). The V-shape made in PVS worked best, but polyurethane is the better material for industry, so Vanenberg’s group will now work toward achieving the V-shape gecko gripping pattern in PU for the best possible combination.

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 11:02 am on January 30, 2020 Permalink | Reply
    Tags: , , Georgia Institute of Technology, IBM Q Hub, , This is to help advance the fundamental research and use of quantum computing in building software infrastructure and developing specialized error mitigation techniques.   

    From Georgia Institute of Technology: “Georgia Tech Collaborates with IBM to Develop Software Stacks for Quantum Computers” 

    From Georgia Institute of Technology

    January 8, 2020 [Just now in social media.]

    John Toon
    Research News
    (404) 894-6986
    jtoon@gatech.edu

    1
    Georgia Tech has announced an agreement to join the IBM Q Hub at the Oak Ridge National Laboratory to advance the fundamental research and use of quantum computing. (IBM photo)

    The Georgia Institute of Technology has announced its agreement to join the IBM Q Hub at the Oak Ridge National Laboratory (ORNL) to help advance the fundamental research and use of quantum computing in building software infrastructure and developing specialized error mitigation techniques. Georgia Tech will have cloud access, via the Oak Ridge Hub, to the world’s largest fleet of universal quantum computing systems for commercial use case exploration and fundamental research.

    “Access to IBM machines will allow Georgia Tech to build software infrastructure to make it easier to operate quantum machines, create specialized error mitigation techniques in software – thereby mitigating some of the hardware errors – and develop algorithms and applications for the emerging noisy intermediate-scale quantum (NISQ) computing paradigm,” said Moinuddin Qureshi, a professor in Georgia Tech’s School of Electrical and Computer Engineering. “Access will also allow Georgia Tech researchers to better understand the error patterns in existing quantum computers, which can help with developing the architecture for future machines.”

    As part of the ORNL hub, Georgia Tech will join a community of Fortune 500 companies, startups, academic institutions and research labs working to advance quantum computing and explore practical applications. Georgia Tech will leverage IBM’s quantum expertise and resources, Qiskit software and developer tools, and will have cloud-based access to IBM’s Quantum Computation Center. IBM makes available through the cloud 15 of the most-advanced universal quantum computing systems available, including a 53-qubit system – the most qubits of a universal quantum computer commercially available in the industry.

    Since the IBM Q Network’s launch in 2017 it has grown to more than 100 organizations, collaborating with IBM and one another to advance fundamental quantum computing research, and the development of practical applications for business and science.

    Research is being conducted worldwide to develop a new type of computational device known as a quantum computer, based on the principles of quantum physics. Quantum computers could tackle specialized computational problems such as integer factorization, understanding materials properties or optimization challenges much faster than conventional digital computers. Quantum computers will use one of a number of possible approaches to create quantum bits – units known as qubits – to compute and store data, giving them unique advantages over computers based on silicon transistors.

    While the machines have great promise, there are difficult challenges in operating such machines and in writing software that will take advantage of their power, Qureshi said.

    The agreement will give Georgia Tech access to IBM’s premium systems, including the 53-qubit quantum computer. “In the regime between 50 and 60 qubits is where quantum machines can potentially do computations that are beyond the capabilities of existing conventional computers,” Qureshi said.

    About IBM Q

    IBM Q is an industry-first initiative to build commercial universal quantum systems for business and science applications. For more information about IBM’s quantum computing efforts, please visit http://www.ibm.com/ibmq. IBM Q Network™ and IBM Q™ are trademarks of International Business Machines Corporation.

    • Written in collaboration with IBM.

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 10:38 am on December 18, 2019 Permalink | Reply
    Tags: "Tiny Magnetic Particles Enable New Material to Bend, and Grab", Georgia Institute of Technology, Magnetic shape memory polymer, , Twist   

    From Georgia Institute of Technology and Ohio State University: “Tiny Magnetic Particles Enable New Material to Bend, Twist, and Grab” 

    From Georgia Institute of Technology

    and

    OSU

    Ohio State University

    December 10, 2019
    Josh Brown
    Research News
    (404) 385-0500
    Email: josh.brown@comm.gatech.edu

    A team of researchers from the Georgia Institute of Technology and The Ohio State University has developed a soft polymer material, called magnetic shape memory polymer, that uses magnetic fields to transform into a variety of shapes. The material could enable a range of new applications from antennas that change frequencies on the fly to gripper arms for delicate or heavy objects.

    1

    The material is a mixture of three different ingredients, all with unique characteristics: two types of magnetic particles, one for inductive heat and one with strong magnetic attraction, and shape-memory polymers to help lock various shape changes into place.

    “This is the first material that combines the strengths of all of these individual components into a single system capable of rapid and reprogrammable shape changes that are lockable and reversible,” said Jerry Qi, a professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech.

    The research, which was reported Dec. 9 in the journal Advanced Materials, was sponsored by the National Foundation of Science, the Air Force Office of Scientific Research, and the Department of Energy.

    To make the material, the researchers began by distributing particles of neodymium iron boron (NdFeB) and iron oxide into a mixture of shape memory polymers. Once the particles were fully incorporated, the researchers then molded that mixture into various objects designed to evaluate how the material performed in a series of applications.

    For example, the team made a gripper claw from a t-shaped mold of the magnetic shape memory polymer mixture. Applying a high-frequency, oscillating magnetic field to the object caused the iron oxide particles to heat up through induction and warm the entire gripper. That temperature rise, in turn, caused the shape memory polymer matrix to soften and become pliable. A second magnetic field was then applied to the gripper, causing its claws to open and close. Once the shape memory polymers cool back down, they remain locked in that position.

    The shape-changing process takes only a few seconds from start to finish, and the strength of the material at its locked state allowed the gripper to lift objects up to 1,000 times its own weight.

    “We envision this material being useful for situations where a robotic arm would need to lift a very delicate object without damaging it, such as in the food industry or for chemical or biomedical applications,” Qi said.

    The new material builds on earlier research that outlined actuation mechanisms for soft robotics and active materials and evaluated the limitations in current technologies.

    “The degree of freedom is limited in conventional robotics” said Ruike (Renee) Zhao, an assistant professor in the Department of Mechanical and Aerospace Engineering at Ohio State. “With soft materials, that degree of freedom is unlimited.”

    The researchers also tested other applications, where coil-shaped objects made from the new material expanded and retracted – simulating how an antenna could potentially change frequencies when actuated by the magnetic fields.

    “This process requires us to use of magnetic fields only during the actuation phase,” Zhao said. “So, once an object has reached its new shape, it can be locked there without constantly consuming energy.”

    This research was supported by The Ohio State University Materials Research Seed Grant Program, funded by the National Science Foundation’s Center for Emergent Materials under grant No. DMR-1420451. The project was also supported by the Center for Exploration of Novel Complex Materials, the Institute for Materials Research, the Air Force Office of Scientific Research under grant No. FA9550-19-1-0151, the U.S. Department of Energy under grant No. DE-SC0001304, and by grants from the Haythornthwaite Foundation. The content is the responsibility of the authors and does not necessarily represent the official views of the sponsoring agencies.

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
  • richardmitnick 11:14 am on October 16, 2019 Permalink | Reply
    Tags: "Diversity May Be Key to Reducing Errors in Quantum Computing", A new technique known as Ensemble of Diverse Mappings depends on using different qubits to create diversity in errors to mitigate the errors., Error rates in conventional silicon-based computers are practically negligible., Georgia Institute of Technology, Repeating operations on different qubit sets that have different error signatures won’t produce the same correlated errors., Using quantum we can solve problems that are virtually impossible to solve with even the fastest supercomputers., When you combine the results from diverse sets the right answer appears even though each of them individually did not get the right answer.   

    From Georgia Institute of Technology: “Diversity May Be Key to Reducing Errors in Quantum Computing” 

    From Georgia Institute of Technology

    October 14, 2019
    John Toon
    404-894-6986
    jtoon@gatech.edu.

    1
    In quantum computing, as in team building, a little diversity can help get the job done better, computer scientists have discovered. A new technique, known as Ensemble of Diverse Mappings, depends on using different qubits to create diversity in errors to mitigate the errors.

    Unlike conventional computers, the processing in quantum-based machines is noisy, which produces error rates dramatically higher than those of silicon-based computers. So quantum operations are repeated thousands of times to make the correct answer stands out statistically from all the wrong ones.

    But running the same operation over and over again on the same qubit set may just generate the same incorrect answers that can appear statistically to be the correct answer. The solution, according to researchers at the Georgia institute of Technology, is to repeat the operation on different qubit sets that have different error signatures – and therefore won’t produce the same correlated errors.

    “The idea here is to generate a diversity of errors so you are not seeing the same error again and again,” said Moinuddin Qureshi, a professor in Georgia Tech’s School of Electrical and Computer Engineering, who worked out the technique with his senior Ph.D. student, Swamit Tannu. “Different qubits tend to have different error signatures. When you combine the results from diverse sets, the right answer appears even though each of them individually did not get the right answer,” said Tannu.

    Tannu compares the technique, known as Ensemble of Diverse Mappings (EDM), to the game show Who Wants to be a Millionaire. Contestants who aren’t sure of the answer to a multiple choice question can ask the studio audience for help.

    “It’s not necessary that the majority of the people in the audience know the right answer,” Qureshi said. “If even 20% know it, you can identify it. If the answers go equally in the four buckets from the people who don’t know, the right answer will get 40% and you can select it even if only a relatively small number of people get it right.”

    Experiments with an existing Noisy Intermediate Scale Quantum (NISQ) computer showed that EDM improves the inference quality by 2.3 times compared to state-of-the-art mapping algorithms. By combining the output probability distributions of the diverse ensemble, EDM amplifies the correct answer by suppressing the incorrect ones.

    The EDM technique, Tannu admits, is counterintuitive. Qubits can be ranked according to their error rate on specific types of problems, and the most logical course of action might be to use the set that’s most accurate. But even the best qubits produce errors, and those errors are likely to be the same when the operation is done thousands of times.

    Choosing qubits with different error rates – and therefore different types of error – guards against that by ensuring that the one correct answer will rise above the diversity of errors.

    “The goal of the research is to create several different versions of the program, each of which can make a mistake, but they will not make identical mistakes,” Tannu explained. “As long as they make diverse mistakes, when you average things out, the mistakes get canceled out and the right answer emerges.”

    Qureshi compares the EDM technique to team-building techniques promoted by human resource consultants.

    “If you form a team of experts with identical backgrounds, all of them may have the same blind spot,” he said, adding a human dimension. “If you want to make a team resilient to blind spots, collect a group of people who have different blind spots. As a whole, the team will be guarded against specific blind spots.”

    Error rates in conventional silicon-based computers are practically negligible, about one in a thousand-trillion operations, but today’s NISQ quantum computers produce an error in a mere 100 operations.

    “These are really early-stage machines in which the devices have a lot of error,” Qureshi said. “That will likely improve over time, but because we are dependent on matter that has extremely low energy and lacks stability, we will never get the reliability we have come to expect with silicon. Quantum states are inherently about a single particle, but with silicon you are packing a lot of molecules together and averaging their activity.

    “If the hardware is inherently unreliable, we have to write software to make the most of it,” he said. “We have to take the hardware characteristics into account to make these unique machines useful.”

    The notion of running a quantum operation thousands of times to get what’s likely to be the right answer at first seems counterproductive. But quantum computing is so much faster than conventional computing that nobody would object to doing a few thousand duplicate runs.

    “The objective with quantum computers is not to take a current program and run it faster,” Qureshi said. “Using quantum, we can solve problems that are virtually impossible to solve with even the fastest supercomputers. With several hundred qubits, which is beyond the current state of the art, we could solve problems that would take a thousand years with the fastest supercomputer.”

    Added Qureshi: “You don’t mind doing the computation a few thousand times to get an answer like that.”

    The quantum error mitigation scheme is scheduled to be presented on Oct. 14 at the 52nd Annual IEEE/ACM International Symposium on Microarchitecture. The work was supported by a gift from Microsoft.

    CITATION: Swamit S. Tannu and Moinuddin Qureshi, “Ensemble of Diverse Mappings: Improving Reliability of Quantum Computers by Orchestrating Dissimilar Mistakes.” (MICRO-52). ACM DL

    See the full article here .

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

    Please help promote STEM in your local schools.

    The Georgia Institute of Technology, commonly referred to as Georgia Tech, is a public research university and institute of technology located in the Midtown neighborhood of Atlanta, Georgia. It is a part of the University System of Georgia and has satellite campuses in Savannah, Georgia; Metz, France; Athlone, Ireland; Shenzhen, China; and Singapore.

    The school was founded in 1885 as the Georgia School of Technology as part of Reconstruction plans to build an industrial economy in the post-Civil War Southern United States. Initially, it offered only a degree in mechanical engineering. By 1901, its curriculum had expanded to include electrical, civil, and chemical engineering. In 1948, the school changed its name to reflect its evolution from a trade school to a larger and more capable technical institute and research university.

    Today, Georgia Tech is organized into six colleges and contains about 31 departments/units, with emphasis on science and technology. It is well recognized for its degree programs in engineering, computing, industrial administration, the sciences and design. Georgia Tech is ranked 8th among all public national universities in the United States, 35th among all colleges and universities in the United States by U.S. News & World Report rankings, and 34th among global universities in the world by Times Higher Education rankings. Georgia Tech has been ranked as the “smartest” public college in America (based on average standardized test scores).

    Student athletics, both organized and intramural, are a part of student and alumni life. The school’s intercollegiate competitive sports teams, the four-time football national champion Yellow Jackets, and the nationally recognized fight song “Ramblin’ Wreck from Georgia Tech”, have helped keep Georgia Tech in the national spotlight. Georgia Tech fields eight men’s and seven women’s teams that compete in the NCAA Division I athletics and the Football Bowl Subdivision. Georgia Tech is a member of the Coastal Division in the Atlantic Coast Conference.

     
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