Archive for the ‘particle physics’ category: Page 12

Nov 24, 2023

Telescope Array detects second-highest-energy cosmic ray ever

Posted by in categories: particle physics, space

In 1991, the University of Utah Fly’s Eye experiment detected the highest-energy cosmic ray ever observed. Later dubbed the Oh-My-God particle, the cosmic ray’s energy shocked astrophysicists. Nothing in our galaxy had the power to produce it, and the particle had more energy than was theoretically possible for cosmic rays traveling to Earth from other galaxies. Simply put, the particle should not exist.

The Telescope Array has since observed more than 30 ultra-high-energy , though none approaching the Oh-My-God-level energy. No observations have yet revealed their origin or how they are able to travel to Earth.

Continue reading “Telescope Array detects second-highest-energy cosmic ray ever” »

Nov 23, 2023

A universal framework describing the scrambling of quantum information in open systems

Posted by in categories: particle physics, quantum physics

In recent years, physicists have been trying to better understand how quantum information spreads in systems of interacting particles—a phenomenon often referred to as “scrambling.” Scrambling in closed systems, physical systems that can only exchange energy with degrees of freedom within the system, is a characteristic feature of chaotic many-body quantum dynamics.

In open systems, which can exchange both energy and matter with their surroundings, scrambling is influenced by various additional factors, including noise and errors. While the effects of these additional influences are well-documented, leading for example to decoherence, how they affect scrambling remains poorly understood.

Two researchers from the University of California Berkeley (UC Berkeley) and Harvard University recently introduced a new framework, published in Physical Review Letters, that provides a universal picture for how information scrambling occurs in open quantum systems. Their framework offers a particularly simple viewpoint on how to understand and model the propagation of errors in an open quantum system and might already help to explain some previously puzzling observations gathered in magnetic resonance experiments.

Nov 23, 2023

DARPA and Materials

Posted by in categories: computing, engineering, particle physics

In 1960, DARPA funded three university-based Inderdisciplinary Laboratories (IDLs) that opened the way toward an enormous field of research and development known today as materials science and engineering. In this video, DARPA program managers, DARPA-funded researchers, and a Naval Research Laboratory scientist tell this field-building story as it unfolded over the past six decades, all the while delivering breakthroughs in the way materials are designed, processed, and deployed to push technologies forward. Intelligent processing of materials (IPM), accelerated insertion of materials (AIM), and integrated computational materials engineering (ICME) are among the specific programs detailed in the video. DARPA is currently developing technologies that enable the crafting of new materials with unprecedented properties by designing and controlling matter from atoms on up to human-scale systems.

Nov 23, 2023

Electrons Lead Their Lattice by the Nose

Posted by in categories: materials, particle physics

Experiments with an unconventional superconductor show that a change in the properties of the material’s electrons can, unexpectedly, cause the material to become dramatically less stiff.

Electrons flowing through a crystal lattice don’t usually get to call the shots: their behavior is generally set by the lattice structure. But certain materials exhibit an electron–lattice coupling that allows the conduction electrons to influence the lattice behavior. This electron version of “wagging the dog” is predicted to be quite weak, making it a surprise that experiments with an unconventional superconductor now uncover a large electron-driven softening of the material’s lattice [1]. The finding could provide new insights into the mechanisms underlying unconventional superconductivity.

The lattice in a crystalline material is a periodic framework of atoms held together by electrostatic bonds. That framework dictates the properties of electrons moving through the material. For example, if the lattice is altered by applying mechanical strain or by adding dopant atoms, the electron momenta will correspondingly change, which can affect the material’s electronic band structure.

Nov 23, 2023

Midcircuit Operations in Atomic Arrays

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

Three research groups have exploited the nuclear spins of ytterbium-171 to manipulate qubits before they are read out—an approach that could lead to efficient error-correction schemes for trapped-atom computing platforms.

Quantum computing on neutral-atom platforms has reached remarkable milestones in the past two decades. However, researchers have yet to overcome a key barrier to the realization of a neutral-atom-based quantum computer: the efficient correction of errors. In principle that barrier can be lowered with so-called midcircuit operations. These operations involve probing the quantum state of “ancilla” qubits without disturbing nearby “data” qubits used for computation. The ancilla qubit measurements can indicate whether the data qubits have undergone faulty operations, allowing for the data qubits to be corrected midcircuit—that is, during the execution of the computation rather than after its completion. Now three independent research groups have achieved midcircuit operation, or made progress toward this goal, with a novel choice of atom: ytterbium-171 (171 Yb) [13].

A neutral-atom qubit platform consists of a two-dimensional (2D) array of atoms trapped by optical tweezers—tightly focused laser beams whose wavelengths are tuned far away from the atomic transitions. The size of the traps, limited by diffraction, is typically about 1 µm. Thanks to the large electric-dipole force from the focused laser and to a high vacuum, the atoms can stay trapped for as long as tens of seconds.

Nov 23, 2023

Nuclear Ground State Has Molecule-Like Structure

Posted by in category: particle physics

The protons and neutrons in a nucleus can form clusters analogous to atoms in a molecule, even in the nuclear ground state.

Nov 23, 2023

Uncertainty beyond the Uncertainty Principle

Posted by in categories: particle physics, quantum physics

Heisenberg’s uncertainty principle limits the precision with which two observables that do not commute with each other can be simultaneously measured. The Wigner-Araki-Yanase (WAY) theorem goes further. If observables A and B do not commute, and if observable A is conserved, observable B cannot be measured with arbitrary precision even if A is not measured at all. In its original 1960 formulation, the WAY theorem applied only to observables, such as spin, whose possible values are discrete and bounded. Now Yui Kuramochi of Kyushu University and Hiroyasu Tajima of the University of Electro-Communications—both in Japan—have proven that the WAY theorem also encompasses observables, such as position, that are continuous and unbounded [1]. Besides resolving the decades-long problem of how to deal with such observables, the extension will likely find practical applications in quantum optics.

The difficulty of extending the WAY theorem arose from how an unbounded observable L is represented: as an infinite-dimensional matrix with unbounded eigenvalues. To tame the problem, Kuramochi and Tajima avoided considering L directly. Instead, they looked at an exponential function of L, which forms a one-parameter unitary group. Although the exponential function is also unbounded, its spectrum of eigenvalues is contained within the complex plane’s unit circle. Thanks to that boundedness, Kuramochi and Tajima could go on to use off-the-shelf techniques from quantum information to complete their proof.

Because momentum is conserved, the extended WAY theorem implies that a particle’s position cannot be measured with arbitrary precision even if its momentum is not measured simultaneously. Similar pairs of observables crop up in quantum optics. Kuramochi and Tajima anticipate that their theorem could be useful in setting limits on the extent to which quantum versions of transmission protocols can outperform the classical ones.

Nov 23, 2023

Quantum Riddle Solved: Purple Bronze Discovery Unveils “Perfect Switch” for Future Tech

Posted by in categories: particle physics, quantum physics

Quantum scientists have discovered a phenomenon in purple bronze, a one-dimensional metal, that allows it to switch between insulating and superconducting states. This switch, triggered by minimal stimuli like heat or light, is due to ’emergent symmetry’. This groundbreaking finding, initiated by research into the metal’s magnetoresistance, could lead to the development of perfect switches in quantum devices, a potential milestone in quantum technology.

Quantum scientists have discovered a phenomenon in purple bronze that could be key to the development of a ‘perfect switch’ in quantum devices which flips between being an insulator and superconductor.

The research, led by the University of Bristol and published in Science, found these two opposing electronic states exist within purple bronze, a unique one-dimensional metal composed of individual conducting chains of atoms.

Nov 23, 2023

Unraveling the Mysteries of ϕ Mesons: A New Breakthrough in Heavy-Ion Collision Physics

Posted by in categories: innovation, particle physics

A team of researchers headed by Prof. Wang Qun at the University of Science and Technology of China, under the Chinese Academy of Sciences, has achieved a breakthrough in the theoretical understanding of vector meson spin physics, focusing on the unique properties of ϕ mesons produced during collisions between gold nuclei.

Their findings published in the journal Physical Review Letters

Physical Review Letters (PRL) is a peer-reviewed scientific journal published by the American Physical Society. It is one of the most prestigious and influential journals in physics, with a high impact factor and a reputation for publishing groundbreaking research in all areas of physics, from particle physics to condensed matter physics and beyond. PRL is known for its rigorous standards and short article format, with a maximum length of four pages, making it an important venue for rapid communication of new findings and ideas in the physics community.

Nov 22, 2023

First experimental evidence of hopfions in crystals: Research opens up new dimension for future technology

Posted by in categories: mathematics, particle physics

Hopfions, magnetic spin structures predicted decades ago, have become a hot and challenging research topic in recent years. In a study published in Nature, the first experimental evidence is presented by a Swedish-German-Chinese research collaboration.

“Our results are important from both a fundamental and applied point of view, as a new bridge has emerged between and abstract , potentially leading to hopfions finding an application in spintronics,” says Philipp Rybakov, researcher at the Department of Physics and Astronomy at Uppsala University, Sweden.

A deeper understanding of how different components of materials function is important for the development of innovative materials and future technology. The research field of spintronics, for example, which studies the spin of electrons, has opened up promising possibilities to combine the electrons’ electricity and magnetism for applications such as new electronics.

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