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Quantum field theory (QFT) was a crucial step in our understanding of the fundamental nature of the Universe. In its current form, however, it is poorly suited for describing composite particles, made up of multiple interacting elementary particles. Today, QFT for hadrons has been largely replaced with quantum chromodynamics, but this new framework still leaves many gaps in our understanding, particularly surrounding the nature of strong nuclear force and the origins of dark matter and dark energy. Through a new algebraic formulation of QFT, Dr Abdulaziz Alhaidari at the Saudi Center for Theoretical Physics hopes that these issues could finally be addressed.

The emergence of quantum field theory (QFT) was one of the most important developments in modern physics. By combining the theories of special relativity, quantum mechanics, and the interaction of matter via classical field equations, it provides robust explanations for many fundamental phenomena, including interactions between charged particles via the exchange of photons.

Still, QFT in its current form is far from flawless. Among its limitations is its inability to produce a precise description of composite particles such as hadrons, which are made up of multiple interacting elementary particles that are confined (cannot be observed in isolation). Since these particles possess an internal structure, the nature of these interactions becomes far more difficult to define mathematically, stretching the descriptive abilities of QFT beyond its limits.

Here, the authors demonstrate a combined atom array-nanophotonic chip platform for quantum networking and distributed quantum computing, enabled by a high-fidelity background-free imaging technique, a semi-open photonic chip geometry, and free-space coupling to the nanophotonic cavities.

Quantum information systems offer faster, more powerful computing methods than standard computers to help solve many of the world’s toughest problems. Yet fulfilling this ultimate promise will require bigger and more interconnected quantum computers than scientists have yet built. Scaling quantum systems up to larger sizes, and connecting multiple systems, has proved challenging.

Twisting the graphene sheets in a bilayer stack, so that the 2D orientations of the sheets are offset from one another, can drastically affect how the stack reacts to light. Researchers have observed the effect experimentally, but they lack an accurate theory of the behavior. Now Lorenzo Cavicchi at the Scuola Normale Superiore in Italy and collaborators have developed a theory that predicts that light-impinged twisted graphene bilayers could host two kinds of electron oscillations known as plasmons [1]. One of these plasmons, the acoustic plasmon, is tightly confined between the two graphene layers, giving it properties that could allow for its use in studying light–matter interactions.

The electrons in a twisted graphene bilayer are distributed unevenly across the system. This inhomogeneous distribution results from the system’s misaligned carbon atoms. Cavicchi and his colleagues accounted for the electron inhomogeneity in their theory. They also modeled the bilayer as two distinct sheets rather than as a single unit, as was done previously.

The team’s theory predicts the bilayer can host two kinds of plasmon oscillations: the previously known optical plasmon, where all electrons move in the same direction at the same time, and an acoustic plasmon, where the electrons in each sheet move in opposite directions. For a graphene bilayer with a 5° twist angle between the sheets, the researchers predict that the acoustic plasmon should have a velocity of about 840,000 meters per second. That velocity is slow enough that the oscillations are confined within the 0.3-nm gap between the graphene sheets. The researchers say that this tight confinement leads to interactions between the plasmon and incoming light that enhance the intensity of that incoming light. This behavior could be useful for applications in quantum cavities.

In high-energy physics, researchers have unveiled how high-energy partons lose energy in nucleus-nucleus collisions, an essential process in studying quark-gluon plasma (QGP). This finding could enhance our knowledge of the early universe moments after the Big Bang.

New research explores the Cherenkov effect where superluminal speeds generate radiation and discusses new research using this principle to create terahertz radiation for advanced imaging and radar applications.

When charged particles travel through a medium at a speed greater than the phase speed of light in that medium (a phenomenon known as superluminal speed), they emit radiation. The resulting radiation forms a conical pattern. This phenomenon, known as the Cherenkov effect, has numerous fundamental and practical applications. The explanation of this effect earned the Nobel Prize in Physics in 1958.

The oblique incidence of light on the interface between two media is a similar phenomenon; in this case, a wave of secondary radiation sources is formed along the interface, which propagates at a speed exceeding the phase speed of light. The refraction and reflection of light from an interface is the result of the addition of the amplitudes of waves from all sources formed during light incidence.

Fusion vessels have a Goldilocks problem: The plasma within needs to be hot enough to generate net power, but if it’s too hot, it can damage the vessel’s interior. Researchers at the Princeton Plasma Physics Laboratory (PPPL) are exploring ways to draw away excess heat, including several methods that use liquid metal.

One possibility, say researchers at the U.S. Department of Energy Lab, involves flowing liquid lithium up and down a series of slats in tiles lining the bottom of the vessel. The liquid metal could also help to protect the components that face the plasma against a bombardment of particles known as neutrons.

“The prevailing option for an economical commercial fusion reactor is a compact design,” said PPPL’s Egemen Kolemen, co-author of a 2022 paper on the research and an associate professor of mechanical and aerospace engineering and the Andlinger Center for Energy and the Environment. However, compactness makes handling the heat flux and neutron bombardment a bigger challenge.

What is the nature of quantum physics? Neil deGrasse Tyson and comedian Chuck Nice get quantum, exploring Schrodinger’s Cat, electrons, Hilbert Space, and the biggest ideas in the universe (in the smallest particles) with theoretical physicist Sean Carroll.

When did the idea of fields originate? Are fields even real or are they just mathematically convenient? We explore electrons, whether they are a field, and whether they exist at all. We also discuss the wave function, Hilbert Space, and what quantum mechanics really is. Do superpositions always exist?

Continue reading “Neil deGrasse Tyson and Sean Carroll Discuss Controversies in Quantum Mechanics” »

Dark matter could bring black holes together.

Dark matter that interacts with itself could extract significant momentum from a binary supermassive black hole system, causing the black holes to merge.

A gravitational-wave “hum” pervades the Universe.

Continue reading “Astrophysicists uncover supermassive black hole/dark matter connection in solving the ‘final parsec problem’” »