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Category: particle physics – Page 313

Spectra from quasars suggest that intergalactic gas may have been heated by a form of dark matter called dark photons.

Dense gas clouds across the Universe absorb light from distant quasars, producing absorption lines in the quasar spectra. A new study shows that the larger-than-predicted widths of these lines from nearby gas clouds could result from a form of dark matter called dark photons [1]. These particles could heat the clouds, leading to a widening of the absorption lines. Other explanations of the broadening—based on more conventional heating sources—have been proposed, but if the dark-photon mechanism is at work, it might also cause heating in low-density clouds from earlier epochs of the Universe. Researchers are already planning to test this prediction.

When viewing the spectrum of a distant quasar, astronomers often observe absorption lines coming from the intervening clouds of gas. The most prominent absorption line is the Lyman-alpha line of hydrogen. Indeed, some quasar spectra have a “forest” of Lyman-alpha lines, with each coming from a cloud at a different distance from our Galaxy (or different epochs). By examining the widths, depths, and other details of the line shapes, researchers can extract information about the density, the temperature, and other features of the clouds. This information can be compared with the results of cosmological simulations that try to reproduce the clumping of matter into galaxies and other large-scale structures.

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Two-dimensional materials, which consist of just a single layer of atoms, can be packed together more densely than conventional materials, so they could be used to make transistors, solar cells, LEDs, and other devices that run faster and perform better.

One issue holding back these next-generation electronics is the heat they generate when in use. Conventional electronics typically reach about 80 degrees Celsius, but the in 2D devices are packed so densely in such a small area that the devices can become twice as hot. This can damage the device.

This problem is compounded by the fact that scientists don’t have a good understanding of how 2D materials expand when temperatures rise. Because the materials are so thin and optically transparent, their thermal expansion coefficient (TEC)—the tendency for the material to expand when temperatures increase—is nearly impossible to measure using standard approaches.

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O.o!!!

How to Spot a Neutrino

Neutrinos are very shy fundamental particles that don’t often interact with anything else. When they were first detected in the 1950s, physicists soon realized they would in some ways be ideal for astronomy.

Because neutrinos so rarely have anything to do with other particles, they can travel unimpeded across the universe. However, their shyness also makes them difficult to detect. To catch enough to be useful, you need a very big detector.

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Ancient bacteria might be sleeping beneath the surface of Mars, where it has been shielded from the harsh radiation of space for millions of years, according to new research.

While no evidence of life has been found on the red planet, researchers simulated conditions on Mars in a lab to see how bacteria and fungi could survive. The scientists were surprised to discover that bacteria could likely survive for 280 million years if it was buried and protected from the ionizing radiation and solar particles that bombard the Martian surface.

The findings suggested that if life ever existed on Mars, the dormant evidence of it might still be located in the planet’s subsurface — a place that future missions could explore as they drill into Martian soil.

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In a recently published paper in Nature Electronics, an international research group from Italy, Germany, the UK, and China examined significant development directions in the field of electronic materials with curved geometries at the nanoscale. From microelectronic devices with enhanced functionality to large-scale nanomembranes consisting of networks of electronic sensors that can provide improved performance.

The scientists argue that exciting developments induced by curvature at the nanoscale allow them to define a completely new field—curved nanoelectronics. The paper examines in detail the origin of curvature effects at the and illustrates their potential applications in innovative electronic, spintronic and superconducting devices.

Curved solid-state structures also offer many application opportunities. On a , shape deformations in electronic nanochannels give rise to complex three-dimensional spin textures with an unbound potential for new concepts in spin-orbitronics, which will help develop energy-efficient electronic devices.

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Quantum researchers require access to different types of quantum hardware from digital, also known as gate-based, quantum processing units (QPUs) to analog devices that are capable of addressing specific problems that are hard to solve using classical computers. Today, Amazon Braket, the quantum computing service from AWS, continues to deliver on its commitment to provide that choice by launching Aquila, pictured in Figure 1 below, a new neutral-atom QPU from QuEra Computing with up to 256 qubits. As a special purpose device designed for solving optimization problems and simulating quantum phenomena in nature, it enables researchers to explore a new analog paradigm of quantum computing.

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Quantum superposition is not just a property of subatomic particles but also of the most massive objects in the universe. That is the conclusion of four theoretical physicists in Australia and Canada who calculated the hypothetical response of a particle detector placed some distance from a black hole. The researchers say the detector would see novel signs of superimposed space–times, implying that the black hole may have two different masses simultaneously.

Black holes are formed when extremely massive objects like stars collapse to a singularity – a point of infinite density. The gravitational field of a black hole is so great that nothing can escape its clutches, not even light. This creates a spherical region of space around the singularity entirely cut off from the rest of the universe and bounded by what is known as an event horizon.

An active area of research into the physics of black holes seeks to develop a consistent theory of quantum gravity. This is an important goal of theoretical physics that would reconcile quantum mechanics and Einstein’s general theory of relativity. In particular, by considering black holes in quantum superposition, physicists hope to gain insights into the quantum nature of space–time.

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The discovery of magnetism in two-dimensional (2D) ultrathin crystals opens up opportunities to explore new physics and to develop next-generation spintronic devices. However, 2D magnetic semiconductors with Curie temperatures higher than room temperature have rarely been reported. Researchers now show that high-quality, nonlayered cobalt ferrite nanosheets as thin as a single unit cell can be synthesized via van der Waals epitaxy.

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Life isn’t really like a box of chocolates, but it seems that something out there is. Neutron stars – some of the densest objects in the Universe – can have structures very similar to chocolates, with either gooey or hard centers.

What kinds of particle configurations those centers consist of is still unknown, but new theoretical work revealing this surprising result could put us a step closer to understanding the strange guts of these dead stars, and the wild extremes possible in our Universe.

Neutron stars are pretty incredible. If we consider black holes to be objects of immense (if not infinite) concentrations of matter, neutron stars win second place in the Universe’s Most Dense Award. Once a star with a mass of around 8 to 30 times that of the Sun’s runs out of matter to fuse in its core, it’s no longer supported by heat’s outward pressure, allowing the core to collapse under gravity as its shell of surrounding gases drift off into space.

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