Electrons oscillate around the nucleus of an atom on extremely short timescales, typically completing a cycle in just a few hundred attoseconds. Because of their ultrafast motions, directly observing electron behavior in molecules has been challenging. Now researchers from UC San Diego’s Department of Chemistry and Biochemistry have suggested a new method to make visualizing electron motion a reality.
This new method describes an experimental concept called ultrafast vortex electron diffraction, which allows for direct visualization of electron movement in molecules on attosecond timescales. The paper is published in the journal Physical Review Letters.
The key idea behind this approach is the use of a specialized electron beam that spirals as it travels, enabling precise tracking of electron motion in both space and time. This method is especially sensitive to electronic coherence, where electrons move in a synchronized, harmonious manner.
As the carriers of the weak force, the W and Z bosons are central to the Standard Model of particle physics. Though discovered four decades ago, the W and Z bosons continue to provide physicists with new avenues for exploration.
In a new study available on the arXiv preprint server, the ATLAS collaboration analyzed its full data set from the second run of the Large Hadron Collider (recorded from 2015 to 2018) in search of a rare process in which a Z boson is produced alongside two other weak-force carriers, or vector (V) bosons, as the W and Z are known.
“The production of three vector bosons is a very rare process at the LHC,” says Fabio Cerutti, ATLAS Physics Coordinator. “Its measurement provides information on the interactions among multiple bosons, which are linked to underlying symmetries of the Standard Model. This is a powerful tool for uncovering new physics phenomena, such as new, undiscovered particles that are too heavy to be directly produced at the LHC.”
Ever since physicist Ernest Rutherford discovered the atomic nucleus in 1911, studying its structure and behavior has remained a challenging task. More than a century later, even with today’s high-tech tools for researching nuclear physics, mysteries of the universe abound.
Relying on leading-edge germanium detectors developed by researchers at the Department of Energy’s Oak Ridge National Laboratory, the scientific community pursues elusive nuclear processes to unlock persistent mysteries. Answers to questions they hope to resolve hold the potential to redefine the universe itself. Why does the universe contain more matter than antimatter? Can a particle be both a matter and antimatter version of itself? Is there a mismatch between what the Big Bang produced and what the Standard Model of particle physics suggests?
Long at the vanguard of international efforts to answer questions like these, ORNL’s contributions remain strong today. David Radford, head of the lab’s Fundamental Nuclear and Particle Physics section, is an internationally renowned expert in the field who has had an indelible impact on the development of germanium detectors. Vital experimentation tools at the forefront of fundamental physics research, germanium detectors are large, single crystals of germanium—a metallic element—used to detect radiation and enable incredibly precise energy measurements.
Majorana’s theory proposed that a particle could be its own antiparticle. That means it’s theoretically possible to bring two of these particles together, and they will either annihilate each other in a massive release of energy (as is normal) or can coexist stably when pairing up together — priming them to store quantum information.
These subatomic particles do not exist in nature, so to nudge them into being, Microsoft scientists had to make a series of breakthroughs in materials science, fabrication methods and measurement techniques. They outlined these discoveries — the culmination of a 17-year-long project — in a new study published Feb. 19 in the journal Nature.
Chief among these discoveries was the creation of this specific topoconductor, which is used as the basis of the qubit. The scientists built their topoconductor from a material stack that combined a semiconductor made of indium arsenide (typically used in devices like night vision goggles) with an aluminum superconductor.
In this episode I am looking forward to exploring more about alternate interpretations of Quantum Mechanics. In previous episodes exploring consciousness, I’ve encountered several people who believe that Quantum Mechanics is at the root of consciousness. My current thinking is that it replaces one mystery with another one without really providing an explanation for consciousness. We are still stuck with the options of consciousness being a pre-existing property of the universe or some aspect of it, vs. it being an emergent feature of a processing network. Either way, quantum mechanics is an often misunderstood brilliant theory at the root of physics. It tells us that basic particles don’t exist at a specific position and momentum—they are, however, represented very accurately as a smooth wavefunction that can be used to calculate the distribution of a set of measurements on identical particles. The process of observation seems to cause the wavefunction to randomly collapse to a localized spot. Nobody knows for certain what causes this collapse. This is known as the measurement problem. The many worlds theorem says the wavefunction doesn’t collapse. It claims that the wavefunction describes all the possible universes that exist and the process of measurement just tells us which universe we are living in.
My guest is a leading proponent of transactional quantum mechanics.
Dr. Ruth E. Kastner earned her M.S. in Physics and Ph.D. in History and Philosophy of Science from the University of Maryland. Since that time, she has taught widely and conducted research in Foundations of Physics, particularly in interpretations of quantum theory. She was one of three winners of the 2021 Alumni Research Award at the University of Maryland, College Park (https://tinyurl.com/2t56yrp2). She is the author of 3 books: The Transactional Interpretation of Quantum Theory: The Reality of Possibility (Cambridge University Press, 2012; 2nd edition just published, 2022), Understanding Our Unseen Reality: Solving Quantum Riddles (Imperial College Press, 2015); and Adventures In Quantumland: Exploring Our Unseen Reality (World Scientific, 2019). She has presented talks and interviews throughout the world and in video recordings on the interpretational challenges of quantum theory, and has a blog at transactionalinterpretation.org. She is also a dedicated yoga practitioner and received her 200-Hour Yoga Alliance Instructor Certification in February, 2020.
Researchers have found that a two-dimensional carbon material is tougher than graphene and resists cracking—even the strongest crack under pressure, a problem materials scientists have long been grappling with. For instance, carbon-derived materials like graphene are among the strongest on Earth, but once established, cracks propagate rapidly through them, making them prone to sudden fracture.
A new carbon material known as monolayer amorphous carbon (MAC) however, is both strong and tough. In fact, MAC—which was recently synthesized by the group of Barbaros Özyilmaz at the National University of Singapore (NUS)—is eight times tougher than graphene, according to a new study from Rice University scientists and collaborators, published in the journal Matter.
Like graphene, MAC is also a 2D or single atom-thick material. But unlike graphene where atoms are arranged in an ordered (crystalline) hexagonal lattice, MAC is a composite material that incorporates both crystalline and amorphous regions. It is this composite structure that gives MAC its characteristic toughness, suggesting that a composite design approach could be a productive way to make 2D materials less brittle.
When atoms collide, their exact structure—for example, the number of electrons they have or even the quantum spin of their nuclei—has a lot to say about how they bounce off each other. This is especially true for atoms cooled to near-zero Kelvin, where quantum mechanical effects give rise to unexpected phenomena. Collisions of these cold atoms can sometimes be caused by incoming laser light, resulting in the colliding atom-pair forming a short-lived molecular state before disassociating and releasing an enormous amount of energy.
These so-called light-assisted collisions, which can happen very quickly, impact a broad range of quantum science applications, yet many details of the underlying mechanisms are not well understood.
In a new study published in Physical Review Letters, JILA Fellow and University of Colorado Boulder physics professor Cindy Regal, along with former JILA Associate Fellow Jose D’Incao (currently an assistant professor of physics at the University of Massachusetts, Boston) and their teams developed new experimental and theoretical techniques for studying the rates at which light-assisted collisions occur in the presence of small atomic energy splittings.
Scientists are racing to develop new materials for quantum technologies in computing and sensing for ultraprecise measurements. For these future technologies to transition from the laboratory to real-world applications, a much deeper understanding is needed of the behavior near surfaces, especially those at interfaces between materials.
Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have unveiled a new technique that could help advance the development of quantum technology. Their innovation, surface-sensitive spintronic terahertz spectroscopy (SSTS), provides an unprecedented look at how quantum materials behave at interfaces.
The work is published in the journal Science Advances.
Atomic nuclei exhibit multiple energy scales simultaneously—ranging from hundreds down to fractions of a megaelectronvolt. A new study demonstrates that these drastically different scales can be explained through calculations based on the strong nuclear force. The research also predicts that the atomic nucleus neon-30 exhibits several coexisting shapes.
“This discovery is incredibly important for understanding the stability limits of visible matter and how they can be anchored in our theory of the strong force,” says Christian Forssén, professor at the Department of Physics at Chalmers University of Technology.
Together with Andreas Ekström, professor at the same department, they have been part of the research group that has now published their findings in Physical Review X. In addition to Chalmers, the researchers behind the study are active at Oak Ridge National Laboratory and the University of Tennessee in the United States.
Researchers have announced results from a new search at the European X-ray Free Electron Laser (European XFEL) Facility at Hamburg for a hypothetical particle that may make up the dark matter of the universe. The experiment is described in a study published in Physical Review Letters.
This experiment looks for axions, a particle which was proposed to solve a major problem in particle physics: why neutrons, although composed of smaller charged particles called quarks, do not possess an electric dipole moment. To explain this, it was suggested that axions, tiny and incredibly light particles, can “cancel out” this imbalance. If observed, this process would provide direct evidence for new physics beyond the Standard Model.
Additionally, axions turn out to be a natural candidate for dark matter, the mysterious substance that constitutes most of the structure of the universe.
