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Category: particle physics – Page 426

A multitasking nanomachine that can act as a heat engine and a refrigerator at the same time has been created by RIKEN engineers. The device is one of the first to test how quantum effects, which govern the behavior of particles on the smallest scale, might one day be exploited to enhance the performance of nanotechnologies.

Conventional heat engines and refrigerators work by connecting two pools of fluid. Compressing one pool causes its fluid to heat up, while rapidly expanding the other pool cools its fluid. If these operations are done in a periodic cycle, the pools will exchange and the system can be used as either a heat engine or a fridge.

It would be impossible to set up a macroscale machine that does both tasks simultaneously—nor would engineers want to, says Keiji Ono of the RIKEN Advanced Device Laboratory. “Combining a traditional heat engine with a refrigerator would make it a completely useless machine,” he says. “It wouldn’t know what to do.”

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A viable quantum internet—a network in which information stored in qubits is shared over long distances through entanglement—would transform the fields of data storage, precision sensing and computing, ushering in a new era of communication.

This month, scientists at Fermi National Accelerator Laboratory—a U.S. Department of Energy national laboratory affiliated with the University of Chicago—along with partners at five institutions took a significant step in the direction of realizing a .

In a paper published in PRX Quantum, the team presents for the first time a demonstration of a sustained, long-distance teleportation of qubits made of photons (particles of light) with fidelity greater than 90%.

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Researchers at Osaka University synthesized twisted molecular wires just one molecule thick that can conduct electricity with less resistance compared with previous devices. This work may lead to carbon-based electronic devices that require fewer toxic materials or harsh processing methods.

Organic conductors, which are carbon-based materials that can conduct electricity, are an exciting new technology. Compared with conventional silicon electronics, can be synthesized more easily, and can even be made into molecular wires. However, these structures suffer from reduced , which prevents them from being used in consumer devices. Now, a team of researchers from The Institute of Scientific and Industrial Research and the Graduate School of Engineering Science at Osaka University has developed a new kind of made from oligothiophene with periodic twists that can carry electric current with less resistance.

Molecular wires are composed by several-nanometer-scale long molecules that have alternating single and double chemical bonds. Orbitals, which are states that electrons can occupy around an atom or molecule, can be localized or extended in space. In this case, the pi orbitals from overlap to form large “islands” that electrons can hop between. Because electrons can hop most efficiently between levels that are close in energy, fluctuations in the can create energy barriers. “The mobility of charges, and thus the overall conductivity of the molecular , can be improved if the charge mobility can be improved by suppressing such fluctuations,” first author Yutaka Ie says.

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Over the past few decades, many experimental physicists have been probing the existence of particles called axions, which would result from a specific mechanism that they think could explain the contradiction between theories and experiments describing a fundamental symmetry. This symmetry is associated with a matter-antimatter imbalance in the Universe, reflected in interactions between different particles.

If this mechanism took place in the early Universe, such a particle might have a very small mass and be ‘invisible. Subsequently, researchers proposed that the might also be a promising candidate for dark matter, an elusive, hypothetical type of matter that does not emit, reflect or absorb light.

While dark matter has not yet been experimentally observed, it is believed to make up 85% of universe’s mass. Detecting axions could have important implications for ongoing dark matter experiments, as it could enhance the present understanding of these elusive particles.

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Circa 2012

(PhysOrg.com) — During the past few years, CERN physicist Dragan Hajdukovic has been investigating what he thinks may be a widely overlooked part of the cosmos: the quantum vacuum. He suggests that the quantum vacuum has a gravitational charge stemming from the gravitational repulsion of virtual particles and antiparticles. Previously, he has theoretically shown that this repulsive gravity can explain several observations, including effects usually attributed to dark matter. Additionally, this additional gravity suggests that we live in a cyclic Universe (with no Big Bang) and may provide insight into the nature of black holes and an estimate of the neutrino mass. In his most recent paper, published in Astrophysics and Space Science, he shows that the quantum vacuum could explain one more observation: the Universe’s accelerating expansion, without the need for dark energy.

“The was predicted theoretically more than 60 years ago,” Hajdukovic told PhysOrg.com. “Today, there is significant experimental evidence that the quantum vacuum exists. I have decided to combine one reality (the quantum vacuum) with one hypothesis (the negative gravitational charge of antiparticles) and to study the consequences. The hypothesis of the gravitational repulsion between matter and antimatter is older than half a century, but before me no one has used it in the combination with the quantum vacuum. … The results are surprising; there is potential to explain [the Universe’s accelerating expansion] in the framework of the quantum vacuum enriched with the gravitational repulsion between matter and antimatter.”

According to Hajdukovic, in the quantum vacuum arises from the gravitational between the positive gravitational charge of matter and the (hypothetical) negative gravitational charge of antimatter. While matter and antimatter are gravitationally self-attractive, they are mutually repulsive. (This part is similar to Massimo Villata’s theory from part 1, in which negatively charged antimatter exists in voids rather than in the quantum vacuum.) Although the quantum vacuum does not contain real matter and antimatter, short-lived and virtual antiparticles could momentarily appear and form pairs, becoming gravitational dipoles.

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Hydrogen is a clean energy source that can be produced by splitting water molecules with light. However, it is currently impossible to achieve this on a large scale. In a recent breakthrough, scientists at Tokyo University of Science, Japan, developed a novel method that uses plasma discharge in solution to improve the performance of the photocatalyst in the water-splitting reaction. This opens doors to exploring a number of photocatalysts that can help scale-up this reaction.

The ever-worsening global environmental crisis, coupled with the depletion of fossil fuels, has motivated scientists to look for clean energy sources. Hydrogen (H2) can serve as an eco-friendly fuel, and hydrogen generation has become a hot research topic. While no one has yet found an energy-efficient and affordable way to produce hydrogen on a large scale, progress in this field is steady and various techniques have been proposed.

One such technique involves using light and catalysts (materials that speed up reactions) to split water (H2O) into hydrogen and oxygen. The catalysts have crystalline structures and the ability to separate charges at the interfaces between some of their sides. When light hits the crystal at certain angles, the energy from the light is absorbed into the crystal, causing certain electrons to become free from their original orbits around atoms in the material. As an electron leaves its original place in the crystal, a positively charged vacancy, known as a hole, is created in the structure. Generally, these “excited” states do not last long, and free electrons and holes eventually recombine.

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“FUJIFILM Corporation (President: Kenji Sukeno) is pleased to announce that it has achieved the world’s record 317 Gbpsi recording density with magnetic tapes using a new magnetic particle called Strontium Ferrite (SrFe)*4. The record was achieved in tape running test, conducted jointly with IBM Research. This represents the development of epoch-making technology that can produce data cartridges with the capacity of 580TB (terabytes), approximately 50 times greater than the capacity of current cartridges*5. The capacity of 580TB is enough to store data equivalent to 120000 DVDs.”

TOKYO, December 162020 — FUJIFILM Corporation (President: Kenji Sukeno) is pleased to announce that it has achieved the world’s record 317 Gbpsi recording density with magnetic tapes using a new magnetic particle called Strontium Ferrite (SrFe) *4. The record was achieved in tape running test, conducted jointly with IBM Research. This represents the development of epoch-making technology that can produce data cartridges with the capacity of 580TB (terabytes), approximately 50 times greater than the capacity of current cartridges *5. The capacity of 580TB is enough to store data equivalent to 120000 DVDs.

SrFe is a magnetic material that has very high magnetic properties and is stable to maintain high performance even when processed into fine particles. It is widely used as a raw material for producing magnets for motors. Fujifilm has applied its proprietary technology to successfully develop ultra-fine SrFe magnetic particles, which can be used as a magnetic material for producing particulate magnetic tape media for data storage. The company has been conducting R&D for commercial use of SrFe magnetic particles as potential replacement of Barium Ferrite (BaFe) magnetic particles, currently used in magnetic tape data storage media. Magnetic tapes used in this test have been produced at the company’s existing coating facility, confirming the ability to support mass production and commercialization.

The amount of data in the society is exponentially increasing due to the introduction of high-definition 4K / 8K video, advancement in IoT / ICT, and the proliferation of Big Data analysis. “Cold Data,” or data that was generated a long time ago and rarely accessed, is said to account for over 80% of all data available today. There is a fast-growing trend of utilizing such Cold Data and other accumulated data, creating the need to secure safe, affordable and long-term data storage. Magnetic tapes have been used by major data centers and research organizations for many years as they not only offer benefits including large storage capacity, low cost and long-term storage performance, but also create air gap data protection, physically isolated from the network, thereby minimizing the risk of data damage or loss caused by cyberattacks.

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The LHCb experiment at CERN has developed a penchant for finding exotic combinations of quarks, the elementary particles that come together to give us composite particles such as the more familiar proton and neutron. In particular, LHCb has observed several tetraquarks, which, as the name suggests, are made of four quarks (or rather two quarks and two antiquarks). Observing these unusual particles helps scientists advance our knowledge of the strong force, one of the four known fundamental forces in the universe. At a CERN seminar held virtually on 11 August, LHCb announced the first signs of an entirely new kind of tetraquark with a mass of 2.9 GeV/c²: the first such particle with only one charm quark.

First predicted to exist in 1964, scientists have observed six kinds of quarks (and their antiquark counterparts) in the laboratory: up, down, charm, strange, top and bottom. Since quarks cannot exist freely, they group to form composite particles: three quarks or three antiquarks form “baryons” like the proton, while a quark and an antiquark form “mesons”.

The LHCb detector at the Large Hadron Collider (LHC) is devoted to the study of B mesons, which contain either a bottom or an antibottom. Shortly after being produced in proton–proton collisions at the LHC, these heavy mesons transform – or “decay” – into a variety of lighter particles, which may undergo further transformations themselves. LHCb scientists observed signs of the new tetraquark in one such decay, in which the positively charged B meson transforms into a positive D meson, a negative D meson and a positive kaon: B+→D+D−K+. In total, they studied around 1300 candidates for this particular transformation in all the data the LHCb detector has recorded so far.

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O,.o Circa 2018

Light might have no mass, but it can still push things around. This is known as radiation pressure. Light particles (photons) carry a momentum with them, but how this momentum is transferred is not exactly clear. However, new research has come up with a way to actually study these interactions between light and matter.

An international team constructed a very special experiment to study the momentum of light. Photons carry a tiny momentum and their effect can only be studied cumulatively. Still, there were no devices sensitive enough to measure the effect. This is why it has been so difficult to study how radiation pressure is converted into force or movement.

As reported in Nature Communications, the team built a mirror fitted with acoustic sensors. They shot laser pulses at the mirror and studied the effects.

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Famous medieval poet and author Geoffrey Chaucer once wrote that “‘time and tide wait for no man,” and that certainly rings true whether you’ve still got a ’90s Swatch watch strapped to your wrist, your name is Doc Brown, or you’re a brilliant scientist working on the latest atomic clock design — which employs lasers to trap and measure oscillations of quantum entangled atoms to maintain precise timekeeping.

The official time for the United States is set at the atomic clock located at the National Institute of Standards and Technology in Boulder, Colorado, where this Cesium Fountain Atomic Clock remains accurate to within one second every 300 million years. Its cesium-133 atom vibrates exactly 9, 192, 631, 770 times per second, a permanent statistic that has officially measured one second since the machine’s inception and operational rollout back in 1968.

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