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Archive for the ‘particle physics’ category: Page 10

Sep 24, 2019

Theorists discover the ‘Rosetta Stone’ for neutrino physics

Posted by in categories: engineering, mathematics, particle physics, robotics/AI

Linear algebra is a field of mathematics that has been thoroughly investigated for many centuries, providing invaluable tools used not only in mathematics, but also across physics and engineering as well as many other fields. For years physicists have used important theorems in linear algebra to quickly calculate solutions to the most complicated problems.

This August, three theoretical physicists—Peter Denton, a scientist at Brookhaven National Laboratory and a scholar at Fermilab’s Neutrino Physics Center; Stephen Parke, at Fermilab; and Xining Zhang, a University of Chicago graduate student working under Parke—turned the tables and, in the context of particle physics, discovered a fundamental in .

The identity relates eigenvectors and eigenvalues in a direct way that hadn’t been previously recognized. Eigenvectors and eigenvalues are two important ways of reducing the properties of a matrix to their most basic components and have applications in many math, physics and real-world contexts, such as in analyzing vibrating systems and facial recognition programs. The eigenvectors identify the directions in which a transformation occurs, and the eigenvalues specify the amount of stretching or compressing that occurs.

Sep 24, 2019

NA62 spots two potential instances of rare particle decay

Posted by in categories: cosmology, particle physics

Are there new, unknown particles that can explain dark matter and other mysteries of the universe? To try to answer this question, particle physicists typically sift through the myriad of particles that are produced in particle collisions. But they also have an indirect but powerful way of looking for new particles, which is to measure processes that are both rare and precisely predicted by the Standard Model of particle physics. A slight discrepancy between the Standard Model prediction and a high-precision measurement would be a sign of new particles or phenomena never before observed.

One such process is the transformation, or “decay”, of a positively charged variant of a particle known as kaon into a positively charged pion and a neutrino–antineutrino pair. In a seminar that took place today at CERN, the NA62 collaboration reported two potential instances of this ultra-rare kaon decay. The result, first presented at the International Conference on Kaon Physics, shows the experiment’s potential to make a precise test of the Standard Model.

The Standard Model predicts that the odds of a positively charged kaon decaying into a positively charged pion and a neutrino–antineutrino pair (K+ → π+ ν ν) are only about one in ten billion, with an uncertainty of less than ten percent. Finding a deviation, even if small, from this prediction would indicate new physics beyond the Standard Model.

Sep 24, 2019

2000 atoms in two places at once: A new record in quantum superposition

Posted by in categories: information science, particle physics, quantum physics

The quantum superposition principle has been tested on a scale as never before in a new study by scientists at the University of Vienna in collaboration with the University of Basel. Hot, complex molecules composed of nearly two thousand atoms were brought into a quantum superposition and made to interfere. By confirming this phenomenon—” the heart of quantum mechanics,” in Richard Feynman’s words—on a new mass scale, improved constraints on alternative theories to quantum mechanics have been placed. The work will be published in Nature Physics.

Quantum to classical?

The superposition principle is a hallmark of quantum theory which emerges from one of the most fundamental equations of quantum mechanics, the Schrödinger equation. It describes particles in the framework of wave functions, which, much like on the surface of a pond, can exhibit . But in contrast to water waves, which are a collective behavior of many interacting , quantum waves can also be associated with isolated single particles.

Sep 24, 2019

Even Huge Molecules Follow the Quantum World’s Bizarre Rules

Posted by in categories: particle physics, quantum physics

A record-breaking experiment shows an enormous molecule is also both a particle and a wave—and that quantum effects don’t only apply at tiny scales.

Sep 23, 2019

Theory proposes that LIGO/Virgo black holes originate from a first order phase transition

Posted by in categories: cosmology, particle physics

A few years ago, the LIGO/Virgo collaboration detected gravitational waves arising from a binary black hole merger using the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO). This eventually led to the observation of black holes with masses that are roughly 30 times the mass of the sun. Since then, researchers worldwide have been investigating these black holes, specifically examining whether they could be of primordial origin, meaning that they were produced in the early universe before stars and galaxies were formed.

Hooman Davoudiasl, a at the Brookhaven National Laboratory in New York, has recently introduced a new theory suggesting that the black holes observed by the LIGO/Virgo collaboration originate from a first order quark confinement phase transition. In his paper, published in Physical Review Letters, Davoudiasl implemented this idea using a light scalar that could turn out to be a good dark matter candidate.

Recent detections by the LIGO/Virgo collaboration suggest that there are several black holes that have similar masses (approximately 30 solar masses). This suggests that there might be a population of black holes that are characterized by a typical mass value.

Sep 23, 2019

Atoms spin backward while flying along a surface

Posted by in category: particle physics

Atoms experience a kind of rolling friction when they fly along a surface.

Sep 21, 2019

Viewpoint: Cold Atoms Bear a Quantum Scar

Posted by in categories: computing, particle physics, quantum physics

Theorists attribute the unexpectedly slow thermalization of cold atoms seen in recent experiments to an effect called quantum many-body scarring.

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Researchers still have some way to go before they can assemble enough quantum bits (qubits) to make a practical, large-scale quantum computer. But already the best prototypes, made up of several tens of qubits, are opening our eyes to new behavior in the quantum realm. Last year, a team from Harvard University and the Massachusetts Institute of Technology (MIT) unveiled a quantum “simulator” made up of a row of 51 interacting atoms [1]. Exciting the individual atoms in various patterns (Fig. 1), they discovered something unexpected: atoms in certain patterns took at least 10 times longer to relax towards thermal equilibrium than atoms in other patterns. Four groups of theorists have tried to make sense of this observation [2–6], in all cases attributing the slow thermalization to a never-before-seen effect called quantum many-body scarring.

Sep 19, 2019

Bridge between quantum mechanics and general relativity still possible

Posted by in categories: particle physics, quantum physics, space

Quantum mechanics and the general theory of relativity form the bedrock of the current understanding of physics—yet the two theories don’t seem to work together. Physical phenomena rely on relationship of motion between the observed and the observer. Certain rules hold true across types of observed objects and those observing, but those rules tend to break down at the quantum level, where subatomic particles behave in strange ways.

An international team of researchers developed a unified framework that would account for this apparent break down between classical and , and they put it to the test using a quantum satellite called Micius. They published their results ruling out one version of their theory on Sept 19th in Science.

Micius is part of a Chinese research project called Quantum Experiments at Space Scale (QUESS), in which researchers can examine the relationship with quantum and classical physics using light experiments. In this study, the researchers used the satellite to produce and measure two entangled particles.

Sep 19, 2019

Physicists discover topological behavior of electrons in 3D magnetic material

Posted by in categories: materials, particle physics

An international team of researchers led by scientists at Princeton University has found that a magnetic material at room temperature enables electrons to behave counterintuitively, acting collectively rather than as individuals. Their collective behavior mimics massless particles and anti-particles that coexist in an unexpected way and together form an exotic loop-like structure.

The key to this behavior is topology—a branch of mathematics that is already known to play a powerful role in dictating the behavior of electrons in crystals. Topological materials can contain in the form of light, or photons. In a topological crystal, the electrons often behave like slowed-down light yet, unlike light, carry electrical charge.

Topology has seldom been observed in , and the finding of a magnetic topological material at room temperature is a step forward that could unlock new approaches to harnessing topological materials for future technological applications.

Sep 19, 2019

What came before the Big Bang? A trip through cosmology, multiverses, fifth dimensions and a big bounce

Posted by in categories: cosmology, particle physics

Where were you before you were conceived?

The question itself has no meaning: there was no “you” to be anywhere at all.

Asking questions like “what happened before the Big Bang?” is similarly meaningless.

Continue reading “What came before the Big Bang? A trip through cosmology, multiverses, fifth dimensions and a big bounce” »

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