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A team of DESY scientists has built a miniature double particle accelerator that can recycle some of the laser energy fed into the system to boost the energy of the accelerated electrons a second time. The device uses narrowband terahertz radiation which lies between infrared and radio frequencies in the electromagnetic spectrum, and a single accelerating tube is just 1.5 centimetres long and 0.79 millimetres in diameter. Dongfang Zhang and his colleagues from the Center for Free-Electron laser Science (CFEL) at DESY present their experimental accelerator in the journal Physical Review X.

The miniature size of the device is possible due to the short wavelength of terahertz radiation. “Terahertz-based accelerators have emerged as promising candidates for next-generation compact electron sources,” explains Franz Kärtner, Lead Scientist at DESY and head of the CFEL group that built the device. Scientists have successfully experimented with terahertz accelerators before, which could enable applications where large particle accelerators are just not feasible or necessary. “However, the technique is still in an early stage, and the performance of experimental terahertz accelerators has been limited by the relatively short section of interaction between the terahertz pulse and the electrons,” says Kärtner.

For the new device, the team used a longer pulse comprising many cycles of terahertz waves. This multicycle pulse significantly extends the interaction section with the particles. “We feed the multicycle terahertz pulse into a waveguide that is lined with a dielectric material”, says Zhang. Within the waveguide, the pulse’s speed is reduced. A bunch of electrons is shot into the central part of the waveguide just in time to travel along with the pulse. “This scheme increases the interaction region between the terahertz pulse and the electron bunch to the centimetre range—compared to a few millimetres in earlier experiments,” reports Zhang.

In the heart of a galaxy cluster 200 million light-years away, astronomers have failed to detect hypothetical particles called axions.

This places new constraints on how we believe these particles work — but it also has pretty major implications for string theory, and the development of a Theory of Everything that describes how the physical Universe works.

“Until recently I had no idea just how much X-ray astronomers bring to the table when it comes to string theory, but we could play a major role,” said astrophysicist Christopher Reynolds of the University of Cambridge in the UK.

Abstract: The Higgs mechanism predicts, apart from the existence of a new scalar boson, the presence of a constant Higgs field that permeates all of space. The vacuum expectation value (VEV) of this field is affected by quantum corrections which are mainly generated by the self-interactions and couplings of the Higgs field to gauge bosons and heavy quarks. In this work we show that gravity can affect, in a non-trivial way, these quantum corrections through the finite parts of the one-loop contributions to the effective potential. In particular, we consider the corrections generated by the Standard Model Higgs self-interactions in slowly-varying weak gravitational backgrounds. The obtained results amount to the existence of non-negligible inhomogeneities in the Higgs VEV. Such inhomogeneities translate into spatial variations of the particle masses, and in particular of the proton-to-electron mass ratio. We find that these Higgs perturbations in our Solar System are controlled by the Eddington parameter, and are absent in pure General Relativity. Yet, they may be present in modified gravity theories. This predicted effect may be constrained by atomic clocks or high-resolution spectroscopic measurements, which could allow to improve current limits on modifications of Einstein’s gravity.

Two teams of physicists have created the “Higgs mode” – a link between particle physics and the physics of matter. The work could help researchers understand the strange behavior of deeply quantum systems.

A quantum sensor could give Soldiers a way to detect communication signals over the entire radio frequency spectrum, from 0 to 100 GHz, said researchers from the Army.

Such wide spectral coverage by a single antenna is impossible with a traditional receiver system, and would require multiple systems of individual antennas, amplifiers and other components.

In 2018, Army scientists were the first in the world to create a quantum receiver that uses highly excited, super-sensitive atoms—known as Rydberg atoms—to detect communications signals, said David Meyer, a scientist at the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. The researchers calculated the receiver’s channel capacity, or rate of data transmission, based on fundamental principles, and then achieved that performance experimentally in their lab—improving on other groups’ results by orders of magnitude, Meyer said.

In a multiyear effort involving three national laboratories from across the United States, researchers have successfully built and tested a powerful new magnet based on an advanced superconducting material. The eight-ton device—about as long as a semi-truck trailer—set a record for the highest field strength ever recorded for an accelerator focusing magnet and raises the standard for magnets operating in high-energy particle colliders.

The Department of Energy’s Fermilab, Brookhaven National Laboratory and Lawrence Berkeley National Laboratory designed, built and tested the new magnet, one of 16 they will provide for operation in the High-Luminosity Large Hadron Collider at CERN laboratory in Europe. The 16 magnets, along with another eight produced by CERN, serve as “optics” for charged particles: They will focus beams of protons into a tiny, infinitesimal spot as they approach collision inside two different particle detectors.

Continue reading “Three national laboratories achieve record magnetic field for accelerator focusing magnet” »

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The new experiment demonstrated a bizarre quantum effect from the double-slit experiment at an unprecedented scale.

To understand the behavior of quantum particles, imagine a pinball game—but rather than one metal ball, there are billions or more, all ricocheting off each other and their surroundings.

Physicists have long tried to study this interactive system of strongly correlated particles, which could help illuminate elusive physics phenomena like high-temperature superconductivity and magnetism.

One classic method is to create a simplified model that can capture the essence of these particle interactions. In 1963, physicists Martin Gutzwiller, Junjiro Kanamori and John Hubbard—working separately—proposed what came to be called the Hubbard model, which describes the essential physics of many interacting quantum particles. The solution to the model, however, only exists in one dimension. For decades, physicists have tried to realize the Hubbard model in two or three dimensions by creating quantum simulators that can mimic it.

An advanced communications system comprising an emitter and an improved receiver (detector) utilizing modulated beams of neutrino and antineutrino waves as information carriers between the emitter and the receiver. of modulated neutrino and antineutrino beams in the emitter is achieved by a laser-like medium, while detection and demodulation of the neutrino and antineutrino beams is accomplished by a second laser-like medium which registers the flux (or of modulated neutrinos and antineutrinos passing there-through by means of resonant stimulated deexcitation of lasable excited states. In addition to the information transmission utilization, the neutrino emitter and receiver (detector) system may also be employed to gather information by the probing of internal earth structures. Such structures cause measurable refractions and retardations of the propagated pulses of monochromatic neutrino waves traveling through the earth between the emitter and receiver (detector), at certain predetermined neutrino