Category Archives: Quantum Physics
All objects and some questions | American Journal of Physics – American Institute of Physics
In Fig. 2, we plot all the composite objects in the Universe: protons, atoms, life forms, asteroids, moons, planets, stars, galaxies, galaxy clusters, giant voids, and the Universe itself. Humans are represented by a mass of 70kg and a radius of 50cm (we assume sphericity), while whales are represented by a mass of 105kg and a radius of 7 m. Objects with uniform density are described by m r 3. Thus, in a log(m)log(r) plot such as Fig. 2, all objects of the same density fall along the same isodensity line of slope 3. For example, atoms and objects made of atoms, such as life on Earth (viruses, bacteria, fleas, humans, and whales) asteroids, moons, planets, and main sequence stars, lie close to the atomic density line atomic water = 1 gm / cm 3. At the top of the plot, this line is labeled atomic 10 3 s, because objects along this isodensity line have the density of water, and because the entire Universe had this density at the end of Big Bang Nucleosynthesis, 10 3 s after the big bang. Protons, neutrons, and neutron stars are found along the slope = 3, nuclear density line which is 14 orders of magnitude more dense than anything made of atoms: nuclear / atomic 10 14. It is labeled nuclear 10 6 s because the entire Universe was at this nuclear density a millionth of a second after the big bang.
The largest objects in the upper right are super-clusters of galaxies with densities approximately 20% larger than the current matter density of the Universe. For completeness, we have also plotted the largest known voids. The current matter density is the longest diagonal isodensity line on the right labeled at the top now 10 17 s). This density is the value in Fig. 1 of the black ( r + m) line at t=now.
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All objects and some questions | American Journal of Physics - American Institute of Physics
World-leading quantum computer will give USask ‘Quantum Boost’ – USask News
This is a really exciting moment in quantum science and quantum innovation, said Dr. Steven Rayan (PhD), professor in USasks College of Arts and Sciences Department of Mathematics and Statistics. The machine being unveiled [today] is one of the fastest and most powerful quantum computers in the world Its an incredible engineering feat ... and its here on Canadian soil.
Rayan, who is also the director of USasks Centre for Quantum Topology and its Applications (quanTA), and lead of USasks Quantum Innovation Signature Area of Research, joined government representatives, industry leaders and researchers from across U15 universities in Bromont, Que., for the inauguration event on Sept. 22, 2023. Having worked closely with IBM Canada and PINQ to envision and expand the use applications for Quantum System One in institutional and industrial settings across Canada, Rayan is now championing a quantum boost to existing and future RSAW at USask.
While affordable and widely accessible, traditional computing relies on a binary bit system that limits its capacity to effectively manage highly complex data sets and models. By contrast, quantum computing systems use qubits elements that embrace the principles of quantum physics and entanglement to exist in multiple states at the same time. As a result, these highly specialized systems can compute extremely complicated data sets and produce predictive models in ways more profound than the computer you are currently reading this on.
Though Quantum System One itself is stationed in Quebec, Rayan noted that emerging partnerships and USasks strong relationships with both IBM Canada and PINQ will allow use of the new quantum computer by faculty, staff and students across the university. Researchers can design quantum programs, get data in a quantum-ready state, open a remote session with Quantum System One, then use and interpret the data in-house. This ground-breaking direct access model reflects an exciting leap forward for the wider deployment of quantum technologies.
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World-leading quantum computer will give USask 'Quantum Boost' - USask News
Michigan Tech Research Award Winner Pursues Discovery of … – Michigan Technological University
An internationally recognized expert in high-energy gamma-ray astronomy and galactic cosmic rays, Petra Huentemeyer serves as a vice-spokesperson for a globally collaborative observatory and mentors her students to seek their own bright futures. The experimental astrophysicist and distinguished professor of physics is the 2023 recipient of the Michigan Technological University Research Award.
Huentemeyer views the career path she has followed as a natural if not always easy progression. Fueled by a persistent curiosity to probe the unknown origins of the universe, her work has led her to study and conduct research at the worlds leading institutions in her field.
The researcher, who enjoys watching movies in her leisure time, said summer 2023s blockbuster biopic Oppenheimer sparked reflections on how she chose her discipline. In the context of Oppenheimer, I thought about how I actually started in the field of physics coming out of high school, she said. I grew up in the Cold War era. In 1991 I was watching a German miniseries, called the End of Innocence, about the competition with the Manhattan Project and the work of Otto Hahn.
Hahn won the Nobel Prize for chemistry in 1944 and is credited as the father of nuclear fission.For more than 30 years he worked with Lise Meitner a figure only briefly touched on in the TV program who nonetheless made an impression on a teenage Huentemeyer. She was one of the first women in physics to earn a Ph.D. There were a lot of people who thought she should have also gotten the award, said Huentemeyer. I was like, Wow, this is interesting. This was really impactful on society. That was a tipping point. I knew that I wanted to try physics, even though it was a little daunting.
As the director of Michigan Techs Earth, Planetary, and Space Sciences Institute, Huentemeyer helped to found and is the former U.S. spokesperson for the High Altitude Water Cherenkov (HAWC) gamma-ray observatory near Puebla, Mexico. She is vice-spokesperson for the multinational Southern Wide-field Gamma-ray Observatory (SWGO). Currently under development, it will be the first instrument of its kind in the southern hemisphere, and like HAWC, it will use water Cherenkov detectors for ground-level particle detection. One of Huentemeyers most important missions is advocating for the updated instrumentation and expanded capacity at higher altitudes that is essential to probe some of the most extreme environments in the known universe while seeking further discoveries.
Among the top three cited authors at Michigan Tech, Huentemeyer participated in a paper on multimessenger observations of a binary neutron star merger that has been cited more than 3,200 times.
Grasping concepts that seem impossible to understand requires both curiosity and persistence, Huentemeyer said. Spoiler alert: Theres a scene in Oppenheimer thats reminiscent of how she met the challenge.
In the movie, they show how quantum mechanics was a new thing that had just come out of Europe. There were skeptics everywhere. Oppenheimer came back from his time in Europe to teach quantum mechanics at Caltech in 1946. The first day theres one student in class. Hes all excited that this one student shows up. And then, as it is in movies, they cut to scenes where more and more students show up each time. That reminded me of me as a student, she said. I couldnt understand it. It was so contrary to anything I had learned previously about physics. Everything was deterministic. Not saying quantum mechanics is not at all deterministic, but it has a probabilistic aspect to it.
The annual Michigan Tech Research Award sets a high bar for outstanding achievement in sustained research or a single noteworthy breakthrough. Nominations open each spring. The winner receives a plaque and $2,500 cash award.
The more unknowns she discovered, the more certain Huentemeyer became regarding a career path. I really wanted to dig deeper and do particle physics, she said. There were semesters during my undergrad when I was very close to quitting, because it was rough. But I stuck with it.
Her graduate and postdoctoral research took her to places where pioneers like Oppenheimer also worked and studied, including Los Alamos National Laboratory, which was covertly erected in 1943 for development and testing of the worlds first atom bomb, known as The Gadget. Projects she was involved in include the Milagro Observatory collaboration in New Mexico; the High Resolution Flys Eye (HiRes) Experiment in Utah; Fluorescence in Air From Showers (FLASH) Experiment at the national particle accelerator laboratory located at Stanford Linear Accelerator Center (SLAC); and the Omni-Purpose Apparatus at LEP (OPAL) Experiment at CERN in Geneva, Switzerland.
"Maybe solid-state physics would have been more lucrative and provided a clearer path to a career outside academia, Huentemeyer said. But I ended up just doing what I wanted to do, which was particle physics and experimental fundamental research.
Huentemeyers students have also become important members of the research community. The postdoctoral researchers and doctoral students she has mentored have taken positions at top-ranked institutions, including NASAs Marshall and Goddard space flight centers, Los Alamos National Laboratory and the Tsung-Dao Lee Institute at Shanghai Jiao Tong University. Kelci Mohrman, who received a U.S. Department of Energy Award among other honors during her time as an undergraduate student at Tech, went on to pursue a graduate degree at Notre Dame, winning the 2023 Department of Physics and Astronomy Research and Dissertation Award.
In her own words, the 2023 Research Award Winner reflects on her research, teaching and service and how her career trajectory led her to Michigan Tech.
Q: Say youre in a caf or some other place where people strike up conversations. How do you describe your work?
PH: Its not easy to explain, but let me try. First, Im a physicist. Then if you were to ask me what I do as a physicist, I may say Im an astrophysicist and then people get somewhat nervous (laughs). But what I often notice is people tend to think of astrophysicists as maybe more theoretical people who develop models, and cosmologists and Im not. Im clearly, squarely an experimentalist. I would also tell them that my background is in particle physics. I got my Ph.D. at the University of Hamburg working with a CERN experiment in Switzerland. I moved as a postdoc into a subset of astrophysics called astroparticle physics. I focus on particle acceleration in space. If I had to sum it up in a sentence, I would say that I do experimental fundamental research to learn more about the nature and transport of matter and energy in the universe.
Q: Why does your research matter?PH: CERN is where the World Wide Web was born. Its not like the scientists coming there from all parts of the world said, Oh, lets invent the World Wide Web. It was that people needed to communicate across the globe and there was one person who had this idea about having all these servers and pretending they are somewhere else and they talk to each other. He developed the HTTP (hypertext transfer) protocol in order to accomplish that: the basis of the World Wide Web. Before, there was the internet as we know it developed by DARPA (Defense Advanced Research Projects Agency). But the innovation became more used by physicists and scientists across the globe, and then by everyone else. Physics research thrives when we talk to one another. Thats how we come up with new ideas. Theres no way to accomplish our goals without communication. Thats how that happened. So they didnt set out to do something that ultimately changed how we all interact. It was a byproduct.
Similarly, we might wonder whether Otto Hahn, when he was doing experiments in his basement in Berlin with Meitner and others, was thinking about building a nuclear power plant. Maybe they were. But I bet what they really wanted to understand was what the force is that keeps the nucleus together. Their focus was really understanding. The path to understanding is the path to discovery.
Semiconductors are another example leading to applications that some people might find very useful and others find annoying (laughs and points to her laptop and smartphone).
Q: Tell us more about the international observatories youre involved in founding and maintaining. Why are HAWC and SWGO so important?
PH: Gamma and cosmic rays are everywhere in the universe and we can eventually measure them here on Earth after they interact with its atmosphere, which causes extensive air showers of secondary particles. To increase instrument sensitivity, we want to measure air showers at high altitudes, before too many of the secondary particles are absorbed. The collected particles from cascades are detected in faint flashes of light in water tanks. Catching more of these particles means we have more and better information. Once weve collected data from the showers, what were really interested in is the energy of the original particles and the direction of the particles they give us information about extreme energy processes in space.
Q: Why did you come to Michigan Tech?
PH: When this position came up it was shared with different collaborations, including the Milagro, which I was involved in while at Los Alamos. Tech had not been on my radar but I thought it was interesting and looked like a good fit. I knew that professors Brian Fick and David Nitz were in the physics department they are two of the pioneers in the field of experimental particle astrophysics. There are papers from the 1990s where both of their names are on them along with Jim Cronin, whos a Nobel Prize winner. We also have Bob Nemiroff, one of the founders of APOD (NASAs Astronomy Picture of the Day).
Everyone seemed extremely nice and welcoming. I knew there were people I could talk to about my research and they would have good insights. I remember flying in. It was November. It wasnt great weather, but I could imagine what it would look like in the summer and fall, with all those trees, and I was like Wow, this is beautiful.
Q: What have you learned from your students? Whats your favorite aspect of teaching?
PH: Teaching helps me to become more precise in what Im saying. If youre using all these technical terms you havent introduced, students are just looking at you like, What are you talking about? Or if you use terms they may know from another context, but that have a very specific meaning in physics.
For me, the rewarding part is when I get feedback from students directly. I really, really like advising students, undergrad as well as graduate, on their research topics. Its also great when you can tell a colleague about a student whos really good and they are like, Oh, I need a postdoc.
Q: Whats next in your research?
PH: I need to go get a lot of money (laughs). Theres a lot of work ahead for our collaboration to secure funding for SWGO, which will be sited in South America between 10 and 30 degrees south at an altitude of 4.4 kilometers or higher. The collaboration hasnt yet decided on an exact location. Besides potential sites, there are several other ongoing research and development tasks that go into establishing the observatory. We have 14 countries from five continents who are working on this project, which will be larger than HAWC, with better sensitivity.
I also have an interest in making astroparticle physics and what we are doing with HAWC and SWGO more known to astronomers. Astronomers think on different scales, like the James Webb telescope, way more expensive but way out there, detecting light which we do, too, but we are detecting the most energetic form of light. I understand why its not often on their radar. We have detected between 200 to 300 sources of gamma rays. And they have billions of stars to work with. On the other hand, we are testing a phase space that they are not. I hope more astronomers will pay attention to that. Its always a concerted effort. Its not an isolated scientist sitting in a lab and doing things. We all need to build bigger and more sensitive instruments.
My field can contribute to understanding things we dont quite have a handle on yet. Dark matter, for example. The more sensitive our instruments become at HAWC or SWGO, for instance, we can look for these signatures that would be a sign of dark matter in space. We know its there. We just dont know what it is.
Q: On a lighter note, besides movies, what else do you like to do in your free time?PH: I like to hike, but havent had much chance lately. I bought a new ebike recently and enjoy cycling to work. I also enjoy winter camping with friends at least once a year.
Michigan Technological University is a public research university founded in 1885 in Houghton, Michigan, and is home to more than 7,000 students from 55 countries around the world. Consistently ranked among the best universities in the country for return on investment, Michigans flagship technological university offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, computing, forestry, business and economics, health professions, humanities, mathematics, social sciences, and the arts. The rural campus is situated just miles from Lake Superior in Michigan's Upper Peninsula, offering year-round opportunities for outdoor adventure.
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Michigan Tech Research Award Winner Pursues Discovery of ... - Michigan Technological University
Exploring the relationship between thermalization dynamics and quantum criticality in lattice gauge theories – Phys.org
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Researchers from the University of Science and Technology of China(USTC) of the Chinese Academy of Sciences (CAS) have developed an ultra-cold atom quantum simulator to study the relationship between the non-equilibrium thermalization process and quantum criticality in lattice gauge field theories. The research was led by Pan Jianwei and Yuan Zhensheng, in collaboration with Zhai Hui from Tsinghua University and Yao Zhiyuan from Lanzhou University.
Their findings reveal that multi-body systems possessing gauge symmetry tend to thermalize to an equilibrium state more easily when situated in a quantum phase transition critical region. The results were published in Physical Review Letters.
Gauge theory and statistical mechanics are two foundational theories of physics. From the Maxwell's equations of classical electromagnetism to quantum electrodynamics and the Standard Model, which describe the interactions of fundamental particles, all adhere to specific gauge symmetries. On the other hand, statistical mechanics connects the microscopic states of large ensembles of particles (such as atoms and molecules) to their macroscopic statistical behaviors, based on the principle of maximum entropy proposed by Boltzmann and others. It elucidates, for instance, how the energy distribution of microscopic particles affects macroscopic quantities like pressure, volume, or temperature.
So, does a quantum many-body system described by gauge theory thermalize to a thermodynamic equilibrium when it's far from equilibrium? Answering this question would advance our understanding of gauge theory, statistical mechanics, and their interrelation. While theoretical physicists have proposed various models to analyze this issue, it remains experimentally challenging to construct a physical system that is both described by gauge theory and that can be artificially manipulated and observed during its thermalization process.
The emergence of ultracold atomic quantum simulators has provided an ideal experimental platform for studying gauge theories and statistical physics concurrently. In 2020, a research team from USTC developed an ultracold atomic optical lattice quantum simulator with 71 lattice points. This marked the first experimental simulation of the quantum phase transition process in the U(1) lattice gauge theory, specifically the Schwinger Model.
In 2022, the team simulated the thermalization dynamics of transitioning from a non-equilibrium to an equilibrium state in lattice gauge field theories. For the first time experimentally, they verified the "loss" of initial state information due to quantum many-body thermalization under gauge symmetry constraints.
Collaborators on this project, Zhai Hui and Yao Zhiyuan, have pointed out through theoretical research that there exists a correlation between quantum thermalization and quantum phase transitions in such lattice gauge models. Starting from the antiferromagnetic Neel state, they predicted that the system can achieve full thermalization only in the vicinity of the quantum phase transition point.
Observing the relationship between quantum thermalization and quantum phase transitions in lattice gauge theories poses new challenges to previous experimental capabilities: the challenge lies in how to control and detect many-body quantum states in situ with single lattice point precision and distinguishable atomic numbers.
On the foundation of their ultracold atomic quantum simulator, the team has combined techniques including quantum gas microscopy, spin-dependent superlattices, and programmable optical potentials. This amalgamation has paved the way for the development of atomic operations and detection techniques with single-site precision and distinguishable particle numbers.
Leveraging these advancements, the researchers were able to prepare and probe multi-atomic quantum states with any atomic configuration. Moreover, they tracked the dynamical evolution of many-body quantum states under the constraints of gauge symmetry.
In their study, the team experimentally prepared initial states with specific atomic configurations. They utilized the method of adiabatic evolution to investigate the quantum phase transition process under gauge symmetry constraints. For the first time in experimental conditions, they accurately pinpointed the phase transition point through finite-size scaling theory.
In addition, they explored the annealing dynamics of the same initial configuration when far from equilibrium. Their work unveiled a pattern wherein many-body systems with gauge symmetry, when near the quantum phase transition critical point, tend to thermally stabilize into an equilibrium state.
The journal Physics highlighted their achievements in an article titled "Watching a Quantum System Thermalize."
More information: Han-Yi Wang et al, Interrelated Thermalization and Quantum Criticality in a Lattice Gauge Simulator, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.050401
Charles Day, Watching a Quantum System Thermalize, Physics (2023). DOI: 10.1103/Physics.16.s115
Journal information: Physical Review Letters
Provided by University of Science and Technology of China
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ATLAS Collaboration Sheds Light on the Strongest Force in Nature – AZoQuantum
The force responsible for binding quarks together to form protons, neutrons, and atomic nuclei is known as the strong force, and it's aptly named due to its incredible strength.
The ATLAS experiment at CERN (Image Credit: CERN)
This force, carried by particles called gluons, is thestrongestamong all the fundamental forces of nature, which include electromagnetism, the weak force, and gravity.
Interestingly, it is also the least precisely measured of these four forces. However, in a recently submitted paper to Nature Physics, the ATLAS collaboration has detailed how they harnessed the power of the Z boson, an electrically neutral carrier of the weak force, to determine the strength of the strong force with an unprecedented level of precision, achieving an uncertainty below 1%.
This measurement is important because it is described by a fundamental parameter in the Standard Model of particle physics known as the strong coupling constant. Although knowledge of this constant has improved over the years, its uncertainty is still much larger than the constants for the other fundamental forces.
A more precise measurement is needed for accurate calculations in particle physics and to answer big questions like whether all fundamental forces were once the same or if there are new, unknown forces at play.
Studying the strong force is not only vital for understanding the fundamental aspects of nature but also for addressing significant unanswered questions. For instance, could all the fundamental forces have equal strength at extremely high energies, hinting at a potential common origin? Additionally, could there be new and unknown interactions modifying the behavior of the strong force in specific processes or at certain energy levels?
In their latest examination of the strong coupling constant, the ATLAS collaboration focused on Z bosons generated during proton-proton collisions at CERN's Large Hadron Collider (LHC), operating at a collision energy of 8 TeV.
The production of Z bosons typically occurs when two quarks within the colliding protons annihilate. In this process driven by weak interactions, the strong force becomes involved through the emission of gluons from the annihilating quarks.
This gluon radiation imparts a "kick" to the Z boson, perpendicular to the collision axis, known as transverse momentum. The strength of this kick is directly linked to the strong coupling constant. By precisely measuring the distribution of Z-boson transverse momenta and comparing it with equally precise theoretical calculations, the researchers were able to determine the strong coupling constant.
In the new analysis, the ATLAS team focused on cleanly selected Z-boson decays to two leptons (electrons or muons) and measured the Z-boson transverse momentum via its decay products.
A comparison of these measurements with theoretical predictions enabled the researchers to precisely determine the strong coupling constant at the Z-boson mass scale to be 0.1183 0.0009. With a relative uncertainty of only 0.8%, the result is the most precise determination of the strength of the strong force made by a single experiment to date.
It agrees with the current world average of experimental determinations and state-of-the-art calculations known as lattice quantum chromodynamics.
This record precision was accomplished thanks to both experimental and theoretical advances. On the experimental side, the ATLAS physicists achieved a detailed understanding of the detection efficiency and momentum calibration of the two electrons or muons originating from the Z-boson decay, which resulted in momentum precisions ranging from 0.1% to 1%.
On the theoretical side, the ATLAS researchers used, among other ingredients, cutting-edge calculations of the Z-boson production process that consider up to four loops in quantum chromodynamics. These loops represent the complexity of the calculation in terms of contributing processes. Adding more loops increases the precision.
The strength of the strong nuclear force is a key parameter of the Standard Model, yet it is only known with percent-level precision. For comparison, the electromagnetic force, which is 15 times weaker than the strong force at the energy probed by the LHC, is known with a precision better than one part in a billion.
Stefano Camarda, Physicist, CERN
Stefano Camarda concludes, That we have now measured the strong force coupling strength at the 0.8% precision level is a spectacular achievement. It showcases the power of the LHC and the ATLAS experiment to push the precision frontier and enhance our understanding of nature.
Source: https://home.cern/
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ATLAS Collaboration Sheds Light on the Strongest Force in Nature - AZoQuantum
Theoretical study shows that Kerr black holes could amplify new physics – Phys.org
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Black holes are regions in space characterized by extremely strong gravity, which prevents all matter and electromagnetic waves from escaping it. These fascinating cosmic bodies have been the focus of countless research studies, yet their intricate physical nuances are yet to be fully uncovered.
Researchers at University of CaliforniaSanta Barbara, University of Warsaw and University of Cambridge recently carried out a theoretical study focusing on a class of black holes known as extremal Kerr black holes, which are uncharged stationary black holes with a coinciding inner and outer horizon. Their paper, published in Physical Review Letters, shows that these black holes' unique characteristics could make them ideal "amplifiers" of new, unknown physics.
"This research has its origin in a previous project started during my visit to UC Santa Barbara," Maciej Kolanowski, one of the researchers who carried out the study, told Phys.org. "I started discussing very cold (so called, extremal) black holes with Gary Horowitz (UCSB) and Jorge Santos (at Cambridge). Soon we realized that in fact, generic extremal black holes look very different than it was previously believed."
In their previous paper, Kolanowski, Horowitz and Santos showed that in the presence of a cosmological constant extremal black holes are affected by infinite tidal forces. This means that if living beings were to fall into the black hole, they would be crushed by gravity before they moved even remotely close to the black hole's center. Yet the team showed that if the cosmological constant is zero, as it is assumed to be in many astrophysical scenarios, this effect vanishes.
"The spark for the current paper arose at UC Santa Barbara's weekly Gravity Lunch," Grant Remmen explained. "Chatting with Horowitz after a talk on his work on black hole horizon singularities, I asked whether other effects could give rise to such phenomena. My previous work on effective field theories (EFTs), particularly development of physics models with quantum corrections, gave me an idea. Talking with Horowitz, I wondered whether the higher-derivative terms in a gravitational EFT (i.e., quantum corrections to the Einstein equations) could themselves lead to singularities on the horizons of extreme black holes."
After Remmen shared his idea with Horowitz, they started collaboration with Kolanowski and Santos, aimed at testing this idea via a series of calculations. In their calculations, the researchers considered Einstein gravity coupled to its leading quantum corrections.
"The Einstein equations are linear in the Riemann tensor, a mathematical object describing the curvature of spacetime," Remmen explained. "In three space dimensions, the leading corrections to Einstein are terms that are cubic (third power) and quartic (fourth power) in the curvature. Because curvature is a measure of derivatives of the spacetime geometry, such terms are called 'higher-derivative terms.' We calculated the effect of these higher-derivative terms on rapidly spinning black holes."
Extremal black holes rotate at a maximum possible rate corresponding to the horizon moving at the speed of light. The researchers' calculations showed that the higher-derivative EFT corrections of extremal black holes make their horizons singular, with infinite tidal forces. This is in stark contrast with typical black holes, which have finite tidal forces that only become infinite at the center of the black hole.
"Surprisingly, EFT corrections make the singularity jump all the way from the center of the black hole out to the horizon, where you wouldn't expect it to be," Remmen said. "The value of the coefficient in front of a given EFT termthe 'dial settings' in the laws of physicsare dictated by the couplings and types of particle that are present at high energies and short distances. In this sense, EFT coefficients are sensitive to new physics."
Kolanowski, Horowitz, Remmen and Santos also found that the strength of the divergence in tides at the horizon of extremal black holes, and the possible occurrence of tidal singularity, heavily depends on the EFT coefficients. The results of their calculations thus suggest that the spacetime geometry near the horizon of these black holes is sensitive to new physics at higher energies.
"Interestingly, this unexpected singularity is present for the values of these EFT coefficients generated by the Standard Model of particle physics," Remmen said.
"Our results are surprising, since they imply that the low-energy description of physics can break down in a situation where you wouldn't expect that to happen. In physics, there's usually a sense of 'decoupling' between different distance scales. For example, you don't need to know the details of water molecules to describe waves using hydrodynamics. Yet for rapidly spinning black holes, that's precisely what happens: the low-energy EFT breaks down at the horizon."
Overall, the calculations carried out by this team of researchers hint at the promise of extremal Kerr black holes for probing new physical phenomena. While the horizon of these black holes can be very large, it was not expected to have an infinitely large curvature (i.e., infinite tidal forces) in the EFT. Their results show that it does.
"In future work, we are interested in exploring whether the singularities can be resolved by ultraviolet physics," Remmen added. "A pressing question is whether the sensitivity of the horizon to new physics persists all the way to the Planck scale, or whether the horizon 'smooths out' at the short-distance scale associated with the EFT. We are also looking for other situations in which short distance effects might show up unexpected at large distances."
More information: Gary T. Horowitz et al, Extremal Kerr Black Holes as Amplifiers of New Physics, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.091402
Journal information: Physical Review Letters
2023 Science X Network
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Theoretical study shows that Kerr black holes could amplify new physics - Phys.org
Automotive Battery Market is Likely to Garner Revenue of US$ 82.80 … – GlobeNewswire
Wilmington, Delaware, United States, Sept. 26, 2023 (GLOBE NEWSWIRE) -- The Automotive Battery market was estimated to have acquired US$ 45 billion in 2020. It is anticipated to register a 5.70% CAGR from 2021 to 2031 and by 2031; the market is likely to gain US$ 82.80 billion.
The automotive battery market is experiencing a dynamic transformation driven by several key factors. The foremost driver is the increasing demand for electric vehicles (EVs), fueled by environmental concerns and stringent emission regulations worldwide. Lithium-ion batteries have emerged as the dominant technology, offering higher energy density and longer ranges.
Innovations are shaping the market, with a notable focus on solid-state batteries, promising improved safety and energy efficiency. As EVs become more accessible and affordable, consumer awareness is growing, amplifying market opportunities.
Sustainability and circular economy initiatives are gaining traction, with a growing emphasis on battery recycling and second-life applications. The industry is witnessing significant investments in research and development to enhance battery performance and cost-effectiveness.
Collaborations between automakers and battery manufacturers are becoming more prevalent, accelerating technological advancements. The automotive battery market is on an exciting trajectory, with sustainability, innovation, and electrification as its guiding trends.
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Market for Automotive Batteries: Regional Outlook
The global market for automotive batteries is not only characterized by its rapid growth but also by distinct regional variations that shape its trajectory. Here's a snapshot of the regional outlook in this dynamic market:
Global Automotive Battery Market: Key Players The competitive landscape in the automotive battery market is fierce, with major players like Panasonic, LG Chem, and CATL dominating, while newcomers and startups focus on niche innovations and regional markets. The following companies are well-known participants in the global Automotive Battery market:
Key developments in the global Automotive Battery market are:
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Researchers Studying the Quantum Realm Observe Alice in … – The Debrief
A team of researchers studying the quantum realm say they have observed an otherworldly mirror universe through the eye of a decaying monopole that is eerily reminiscent of the mirror universe written about by author Lewis Carroll in his Alices Adventures in Wonderland.
Dubbed an Alice ring in honor of Carrolls mirror universe, these fleeting, quantum world events may help to unravel the mysteries of the quantum realm.
In quantum physics, monopoles are the proposed counterpart to dipoles, which have a positive and negative charge at opposing ends, just like a conventional magnet. In contrast, the monopole is only negatively or positively charged.
For decades, scientists have theorized how an actual magnetic monopole might decay, with the most common theory being that it would create a brief, fleeting ring-like structure that might open the door to an alternate mirror universe. As noted, the mirror universe revealed by these decaying rings reminded theorists of the mirror universe in Lewis Carrols Alices Adventures in Wonderland, where everything is the opposite of the real world.
Such theoretical Alice rings have remained particularly elusive for decades. But now, a team of researchers who have been studying the phenomenon for years say they have spotted these structures in nature for the first time ever. And as they suspected, Alice rings may indeed be a portal to what they describe as an otherworldly mirror universe.
The hunt for a real-world Alice ring involved a years-long collaboration between Professor Mikko Mttnen of Aalto University and Professor David Hall from Amherst College. In fact, their first discovery on the road to Carrolls mirror universe took place in 2014, when the duo successfully proved the existence of an analog of a quantum monopole.In 2015, they actually isolated a quantum monopole, and then in 2017 actually observed one decaying into the other. Still, it wasnt until their latest research that they witnessed the appearance of the doorway to the mirror universe known as the elusive Alice ring.
This was the first time our collaboration was able to create Alice rings in nature, which was a monumental achievement, Mttnen said.
According to the press release announcing this once-in-a-career feat, the research team, which was aided by Ph.D. candidate Alina Blinova, manipulated a gas of rubidium atoms prepared in a nonmagnetic state near absolute zero temperature. Then, operating under these extreme conditions, the researchers were able to create a monopole by steering a zero point of a three-dimensional magnetic field into the quantum gas. As previously theorized, the result was a perfectly formed Alice ring.
Notably, the researchers point out that Alice rings only last for a few milliseconds, as they are extremely fragile. This means that when a magnetic monopole is exposed to the slightest external force, it immediately decays into an Alice ring.
Think of the monopole as an egg teetering at the top of a hill, Mttnen said. The slightest perturbations can send it crashing down. In the same way, monopoles are subject to noise that triggers their decay into Alice rings.
Perhaps even more astonishing, and as the longtime collaborators had hoped, their Alice ring seemed to offer a glimpse into a mirror universe just like Carrolls.
From a distance, the Alice ring just looks like a monopole, but the world takes a different shape when peering through the centre of the ring, Hall said.
It is from this perspective that everything seems to be mirrored, as if the ring were a gateway into a world of antimatter instead of matter, Mttnen added.
Published in the journal Nature Communications, the researchers say that the verified observation of an Alice ring in the real world could one day lead to a better understanding of quantum physics. However, there is still no indication whether or not it will lead to attending a tea party with a mad hatter.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.
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Researchers Studying the Quantum Realm Observe Alice in ... - The Debrief
Teleportation fidelity the big winner in the quantum lottery – ANU College of Science
Running your quantum system as a lottery turns out to be a way to improve the transmission of data via quantum teleportation.
Researchers at the Research School of Physics used a probabilistic twist to develop a new transmission protocol that set a new record in data transmission: 92 percent fidelity, which more than halves the loss in previous experiments.
The new protocol will enable encrypted data, for example in finance or military settings, to be sent with higher accuracy.
Our protocol improves the capability of the quantum teleporter to protect fragile quantum states during long-distance transmission, making the system resilient to noise and loss, said lead researcher Dr Sophie Jie Zhao, from the Department of Quantum Sciences and the CQC2T ARC Centre of Excellence, who is the lead author in the teams publication inNature Communications.
Quantum teleportation is already being used in encrypted networks. It allows information to be shared instantly between linked, or entangled, quantum objects.
However, the entanglement between the objects can easily be destroyed by interactions with external entities. This at once makes quantum teleportation extremely secure as any tampering instantly destroys the data transfer but also very prone to degradation through noise due to environmental interactions.
With entanglement degradation limiting their existing teleportations fidelity and distance, the team set their mind to improving the teleportation efficacy by leveraging the paradoxes of the Heisenberg Uncertainty Principle.
In these experiments, the ends of the teleportation link are two photons from the same source, which creates entanglement in their properties. These photons are sent to two separate locations, untouched, which leaves their properties unknown, and able to appear in any possible state.
The signaller then gets the information to be teleported to interact with one of the photons, and measures the photons properties in this case amplitude and phase making the photon choose a state. This causes the other photon (the receiver) to instantly choose its state as well. Because the two photons are linked, information about the signallers experiment can be deduced by the receiver.
This deduction relies on the sender separately conveying to the receiver the result of the experiment. This does not reveal the teleported information, as it is the result of the mashup between that information and the original photon. However, this result acts as a key that allows the receiver to work backwards from the result at their end and disentangle the teleported information.
It is crucial that the sender cant know what the teleported information is that would constitute a measurement and collapse the quantum information, said University of Queensland researcher and CQC2T member Professor Tim Ralph.
The information needs to be hidden in uncertainty so the sender doesnt know exactly what they are sending. The more they know about the signal, the more they destroy it, he said.
Quantum uncertainty resulting from the mixing of possible states can be cancelled out with the key, however uncertainty resulting from noise from entanglement degradation is harder to cancel out.
To filter this noise the team leveraged the fact that the mixed states have a Gaussian distribution. They realised that a lottery, a protocol in which a subset of the measurements was selected randomly in a way that actually narrowed the Gaussian distribution, while other measurements were randomly discarded, could help filter out noise.
Adding an element of chance to our protocol has the effect of distilling the quantum information, Dr Zhao said.
The post-selection effectively biases the Gaussian distribution in favour of high-amplitude outcomes than outcomes close to the origin of phase space, hence acting as an amplifier. Since this amplification is noiseless and takes over from part of the amplification applied by the receiver in standard teleportation protocols, the teleported states suffer less from the noise added due to imperfect entanglement.
An interesting quirk of the system is that the balance between the probabilistic factor and the noise reduction can be tuned. By simply reducing the probability of measurements being selected in the protocol the teleportation fidelity can be increased.
To achieve their record 92 percent fidelity the team used a success rate of less than one in a hundred thousand, sampling the system for around two hours.
In the new protocol, the success of the teleportation relies on the stability of the laser system, instead of being limited by environmental noise, Dr Zhao said.
You can always get better fidelity if you are willing to sacrifice your success rate. But then you need a longer sampling time.
If the system were stable enough to allow us to sample for say, 20 hours, then I believe we could go above 95 percent, she said.
This article was first published by ANU Research School of Physics.
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Teleportation fidelity the big winner in the quantum lottery - ANU College of Science
Zentropy A New Theory That Could Transform Material Science – SciTechDaily
A snapshot of the ab initio molecule dynamics simulations at 753 degrees Kelvin, showing the polarized titanium oxide bonding with local tetragonal structures in various orientations, which depict the local 90 and 180 degree domain walls. Credit: Courtesy Zi-Kui Liu
The universe naturally gravitates towards disorder, and only through the input of energy can we combat this inevitable chaos. This idea is encapsulated in the concept of entropy, evident in everyday phenomena like ice melting, fires burning, and water boiling. However, zentropy theory introduces an additional layer to this understanding.
This theory was developed by a team led by Zi-Kui Liu, the distinguished Dorothy Pate Enright Professor of Materials Science and Engineering at Penn State. The Z in zentropy is derived from the German term Zustandssumm, which translates to the sum over states of entropy.
Alternatively, Liu said, zentropy may be considered as a play on the term zen from Buddhism and entropy to gain insight on the nature of a system. The idea, Liu said, is to consider how entropy can occur over multiple scales within a system to help predict potential outcomes of the system when influenced by its surroundings.
Liu and his research team have published their latest paper on the concept, providing evidence that the approach may offer a way to predict the outcome of experiments and enable more efficient discovery and design of new ferroelectric materials. The work, which incorporates some intuition and a lot of physics to provide a parameter-free pathway to predicting how advanced materials behave, was published inScripta Materialia.
Ferroelectrics have unique properties, making them valuable for a variety of applications both now and in developing materials, researchers said. One such property is spontaneous electric polarization that can be reversed by applying an electric field, which facilitates technologies ranging from ultrasounds to ink-jet printers to energy-efficient RAM for computers to the ferroelectric-driven gyroscope in smartphones that enable smooth videos and sharp photos.
To develop these technologies, researchers need to experiment to understand the behavior of such polarization and its reversal. For efficiencys sake, the researchers usually design their experiments based on predicted outcomes. Typically, such predictions require adjustments called fitting parameters to closely match real-world variables, which take time and energy to determine. But zentropy can integrate top-down statistical and bottom-up quantum mechanics to predict experimental measures of the system without such adjustments.
Of course, at the end of the day, the experiments are the ultimate test, but we found that zentropy can provide a quantitative prediction that can narrow down the possibilities significantly, Liu said. You can design better experiments to explore ferroelectric material and the research work can move much faster, and this means you save time, energy, and money and are more efficient.
While Liu and his team have successfully applied zentropy theory to predict the magnetic properties of a range of materials for various phenomena, discovering how to apply it to ferroelectric materials has been tricky. In the current study, the researchers reported finding a method to apply zentropy theory to ferroelectrics, focusing on lead titanate. Like all ferroelectrics, lead titanate possesses electric polarization that can be reversed when external electric fields, temperature changes, or mechanical stress is applied.
As an electric field reverses electric polarization reverses, the system transitions from ordered in one direction to disordered and then to ordered again as the system settles into the new direction. However, this ferroelectricity occurs only below a critical temperature unique to each ferroelectric material. Above this temperature, ferroelectricity the ability to reverse polarization disappears and paraelectricity the ability to become polarized emerges. The change is called the phase transition. The measurement of those temperatures can indicate critical information about the outcome of various experiments, Liu said. However, predicting the phase transition prior to an experiment is nearly impossible.
No theory and method can accurately predict the free energy of the ferroelectric materials and the phase transitions prior to the experiments, Liu said. The best prediction of transition temperature is more than 100 degrees away from the experiments actual temperature.
This discrepancy arises due to the unknown uncertainties in models, as well as fitting parameters that could not consider all salient information affecting the actual measurements. For example, an often-used theory characterizes macroscopic features of ferroelectricity and paraelectricity but does not consider microscopic features such as dynamic domain walls boundaries between regions with distinct polarization characteristics within the material. These configurations are building blocks of the system and fluctuate significantly with respect to temperature and electric field.
In ferroelectrics, the configuration of electric dipoles in the material can change the direction of polarization. The researchers applied zentropy to predict the phase transitions in lead titanate, including identifying three types of possible configurations in the material.
The predictions made by the researchers were effective and in agreement with observations made during experiments reported in the scientific literature, according to Liu. They used publicly available data on domain wall energies to predict a transition temperature of 776 degrees Kelvin, showing a remarkable agreement withthe observed experimental transition temperature of 763 degrees Kelvin. Liu said the team is working on further reducing the difference between predicted and observed temperatures with better predictions of domain wall energies as a function of temperature.
This ability to predict transition temperature so closely to the actual measurements can provide valuable insights into the physics of ferroelectric material and help scientists to better their experimental designs, Liu said.
This basically means you can have some intuitions and a predictive approach on how a material behaves both microscopically and macroscopically before you conduct the experiments, Liu said. We can start predicting the outcome accurately before the experiment.
Along with Liu, other researchers in the study from Penn State include Shun-Li Shang, research professor of materials science and engineering; Yi Wang, research professor of materials science and engineering; and Jinglian Du, research fellow in materials science and engineering at the time of the study.
Reference: Parameter-free prediction of phase transition in PbTiO3 through combination of quantum mechanics and statistical mechanics by Zi-Kui Liu, Shun-Li Shang, Jinglian Du and Yi Wang, 20 April 2023, Scripta Materialia.DOI: 10.1016/j.scriptamat.2023.115480
The Department of Energys Basic Energy Sciences program supported this research.
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Zentropy A New Theory That Could Transform Material Science - SciTechDaily