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Category: particle physics – Page 61

A Versatile Design for a Metasurface Cavity

Periodic structures known as metamaterials can interact with electromagnetic waves in unusual ways. In one counterintuitive example, standing waves remain trapped in a volume even though they’re surrounded by radiating waves that should carry their energy away. These standing waves, called bound states in the continuum (BICs), can provide a boost to resonant systems—such as lasers, filters, or sensors—by mitigating radiative losses. Researchers have recently demonstrated a promising design that produces high-quality BICs; however, it works only at microwave frequencies. Simulations by Pietro Brugnolo and his colleagues at the Technical University of Denmark now suggest that a straightforward change could allow the design to be adapted to optical wavelengths [1].

The previous design involves thin metamaterials, or metasurfaces, made of metallic bars arranged around cylindrical cavities. In such a configuration, BICs emerge when characteristic metasurface resonances match the cavity resonance. The metallic elements, however, result in resistive losses when used at wavelengths shorter than those of microwaves. Brugnolo’s team thus set out to investigate an all-dielectric version of the scheme.

The researchers simulated devices in which the metallic elements were replaced with silicon particles distributed on a cylindric surface. Their results showed that the structure displayed both an electrical and an effective magnetic response, which could be tailored to create the standing-wave patterns characteristic of BICs. For a wave at telecommunication wavelengths (1550 nm), their simulations predicted a cavity quality factor of 1.7 × 104, on par with the microwave version of the same scheme.

An unexpected connection between the equations for crystalline lattice defects and electromagnetism

A fundamental goal of physics is to explain the broadest range of phenomena with the fewest underlying principles. Remarkably, seemingly disparate problems often exhibit identical mathematical descriptions.

For instance, the rate of heat flow can be modeled using an equation very similar to that governing the speed of particle diffusion. Another example involves wave equations, which apply to the behavior of both water and sound. Scientists continuously seek such connections, which are rooted in the principle of the “universality” of underlying physical mechanisms.

In a study published in the journal Royal Society Open Science, researchers from Osaka University uncovered an unexpected connection between the equations for defects in a and a well-known formula from electromagnetism.

Cold atoms on a chip: Opening the doors to accessible quantum research

UC Santa Barbara researchers are working to move cold atom quantum experiments and applications from the laboratory tabletop to chip-based systems, opening new possibilities for sensing, precision timekeeping, quantum computing and fundamental science measurements.

“We’re at the tipping point,” said electrical and computer engineering professor Daniel Blumenthal.

In an invited article that was also selected for the cover of Optica Quantum, Blumenthal, along with graduate student researcher Andrei Isichenko and postdoctoral researcher Nitesh Chauhan, lays out the latest developments and future directions for trapping and cooling the atoms that are fundamental to these experiments—and that will bring them to devices that fit in the palm of your hand.

Quantum Breakthrough: New Study Uncovers Hidden Behavior in Superconductors

Researchers discovered how Floquet Majorana fermions can improve quantum computing by controlling superconducting currents, potentially reducing errors and increasing stability. A new study has revealed significant insights into the behavior of electric current flow in superconductors, which could contribute to advancements in controlled quantum information processing.

Collaborative analysis improves theoretical understanding of hyperfine splitting in hydrogen

Two experiment collaborations, the g2p and EG4 collaborations, combined their complementary data on the proton’s inner structure to improve calculations of a phenomenon in atomic physics known as the hyperfine splitting of hydrogen. An atom of hydrogen is made up of an electron orbiting a proton.

The overall energy level of depends on the spin orientation of the proton and electron. If one is up and one is down, the atom will be in its lowest energy state. But if the spins of these particles are the same, the energy level of the atom will increase by a small, or hyperfine, amount. These spin-born differences in the energy level of an atom are known as hyperfine splitting.

While it’s commonplace for many scientists to collaborate on nuclear physics experiments at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility, it’s rarer for the lab’s individual experiments to collaborate with each other. But that’s exactly what g2p in Jefferson Lab’s Experimental Hall A and EG4 in Experimental Hall B did.

ALPHA experiment successfully installs helium dilution fridge to aid search for dark matter

The Axion Longitudinal Plasma Haloscope (ALPHA) experiment reached a milestone on February 24 with the successful installation of a Bluefors helium dilution fridge at the site of the experiment in Wright Lab.

ALPHA will extend the search for a hypothetical dark matter candidate—a very low-mass particle called the axion—to a higher mass range than has been searched for previously.

Michael Jewell, associate research scientist in physics and a member of Yale’s Wright Lab is the ALPHA project technical coordinator. Jewell explained, “In order for ALPHA to achieve its physics goal, we need to limit any potential source. For us, the biggest source of noise is thermal noise from the experiment. So we operate the whole experiment in the coldest commercially available systems, which are helium dilution fridges that are able to cool down to ~10 millikelvin (mK).”

Scientists unravel spiraling secrets of magnetic materials for next-generation electronics

Deep within certain magnetic molecules, atoms arrange their spins in a spiral pattern, forming structures called chiral helimagnets. These helical spin patterns have intrigued researchers for years due to their potential for powering next-generation electronics. But decoding their properties has remained a mystery—until now.

Researchers at the University of California San Diego have developed a to accurately model and predict these complex spin structures using quantum mechanics calculations. Their work was published on Feb. 19 in Advanced Functional Materials.

“The helical spin structures in two-dimensional layered materials have been experimentally observed for over 40 years. It has been a longstanding challenge to predict them with precision,” said Kesong Yang, professor in the Aiiso Yufeng Li Family Department of Chemical and Nano Engineering at the UC San Diego Jacobs School of Engineering and senior author of the study. “The helical period in the layered compound extends up to 48 nanometers, making it extremely difficult to accurately calculate all the electron and spin interactions at this scale.”

Infodynamics and the Natural Foundations of Spiritual Phenomena

In the annals of scientific inquiry, few endeavors have been as audacious as the attempt to bridge the chasm between the tangible and the intangible, the empirical and the experiential. The declassification of the 1983 U.S. Army Intelligence report, “Analysis and Assessment of The Gateway Process,” offers a compelling case study in this regard. Authored by Lieutenant Colonel Wayne M. McDonnell, the report delves into altered states of consciousness, suggesting that human consciousness may transcend the physical plane, potentially supporting concepts akin to reincarnation. This proposition invites us to explore the intersection of infodynamics — the study of information dynamics within physical systems — and phenomena traditionally deemed spiritual, under the premise that all such phenomena are rooted in the natural order.

At the heart of this exploration lies the principle that information, much like energy, is conserved within the universe. This concept is reminiscent of the first law of thermodynamics, which asserts that energy cannot be created or destroyed, only transformed. In the realm of information theory, this translates to the idea that information persists, undergoing transformations but never facing annihilation. This perspective aligns with the notion that consciousness, as a form of information, may continue beyond the cessation of its current physical embodiment.

Quantum mechanics further enriches this discourse. The phenomenon of quantum entanglement, wherein particles become interconnected in such a way that the state of one instantaneously influences the state of another, regardless of the spatial separation, challenges our classical understanding of locality and separability. This non-locality suggests a deeply interconnected fabric of reality, where information is not confined to a singular point in space or time. Such a framework provides a plausible basis for understanding how consciousness, as an informational construct, could transcend individual physical forms, offering a naturalistic foundation for phenomena like reincarnation.

EPFL scientists explore molecular collisions with gold

When molecules collide with surfaces, they exchange energy with the surface atoms. This complex process is influenced by quantum interference, where different pathways overlap, creating patterns where some paths enhance each other while others cancel out. This affects how molecules exchange energy and react with surfaces.

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Observing quantum interference in collisions with heavier molecules like methane (CH4) was challenging due to the many possible pathways. Scientists wondered if quantum effects would disappear, making classical physics enough to describe these processes.

Quantum Milestones, 1959: Ghostly Influence of Magnetic Field

In classical electromagnetism, electric and magnetic fields are the fundamental entities responsible for all physical effects. There is a compact formulation of electromagnetism that expresses the fields in terms of another quantity known as the electromagnetic potential, which can have a value everywhere in space. The fields are easily derived theoretically from the potential, but the potential itself was taken to be purely a mathematical device, with no physical meaning.

In quantum mechanics, shifts in the electromagnetic potential alter the description of a charged particle only by shifting its phase—that is, by advancing or retarding the crests and troughs in its quantum wave function. In general, however, such a phase change does not lead to any difference in the measurable properties of a particle.

But in 1959 Yakir Aharonov and David Bohm of the University of Bristol, UK, devised a thought experiment that linked the potential to a measurable result. In their scenario, a beam of electrons is split, with the two halves made to travel around opposite sides of a cylindrical electromagnet, or solenoid. The magnetic field is concentrated inside the solenoid and can be made arbitrarily weak outside by making the cylinder extremely narrow. So Aharonov and Bohm argued that the two electron paths can travel through an essentially field-free region that surrounds the concentrated field within the electromagnet.