A comparison of neutrinos measured 1 km and 810 km from their source finds no evidence of a putative fourth neutrino flavor.
Category: particle physics
A new formula that connects a material’s magnetic permeability to spin dynamics has been derived and tested 84 years after the debut of its electric counterpart.
If antiferromagnets, altermagnets, and other emerging quantum materials are to be harnessed for spintronic devices, physicists will need to better understand the spin dynamics in these materials. One possible path forward is to exploit the duality between electric and magnetic dynamics expressed by Maxwell’s equations. From this duality, one could naively expect mirror-like similarities in the behavior of electric and magnetic dipoles. However, a profound difference between the quantized lattice electric excitations—such as phonons—and spin excitations—such as paramagnetic and antiferromagnetic spin resonances and magnons—has now been unveiled in terms of their corresponding contributions to the static electric susceptibility and magnetic permeability. Viktor Rindert of Lund University in Sweden and his collaborators have derived and verified a formula that relates a material’s magnetic permeability to the frequencies of magnetic spin resonances [1].
A research team led by Professor Takayuki Hoshino of Nagoya University’s Graduate School of Engineering in Japan has demonstrated the world’s smallest shooting game by manipulating nanoparticles in real time, resulting in a game that is played with particles approximately 1 billionth of a meter in size.
This research is a significant step toward developing a computer interface system that seamlessly integrates virtual objects with real nanomaterials. They published their study in the Japanese Journal of Applied Physics.
The game demonstrates what the researchers call “nano-mixed reality (MR),” which integrates digital technology with the physical nanoworld in real time using high-speed electron beams. These beams generate dynamic patterns of electric fields and optical images on a display surface, allowing researchers to control the force field acting on the nanoparticles in real time to move and manipulate them.
Laying the groundwork for quantum communication systems of the future, engineers at Caltech have demonstrated the successful operation of a quantum network of two nodes, each containing multiple quantum bits, or qubits—the fundamental information-storing building blocks of quantum computers.
To achieve this, the researchers developed a new protocol for distributing quantum information in a parallel manner, effectively creating multiple channels for sending data, or multiplexing. The work was accomplished by embedding ytterbium atoms inside crystals and coupling them to optical cavities—nanoscale structures that capture and guide light. This platform has unique properties that make it ideal for using multiple qubits to transmit quantum information-carrying photons in parallel.
“This is the first-ever demonstration of entanglement multiplexing in a quantum network of individual spin qubits,” says Andrei Faraon (BS ‘04), the William L. Valentine Professor of Applied Physics and Electrical Engineering at Caltech. “This method significantly boosts quantum communication rates between nodes, representing a major leap in the field.”
Researchers at the National Graphene Institute at the University of Manchester have achieved a significant milestone in the field of quantum electronics with their latest study on spin injection in graphene. The paper, published recently in Communications Materials, outlines advancements in spintronics and quantum transport.
Spin transport electronics, or spintronics, represents a revolutionary alternative to traditional electronics by utilizing the spin of electrons rather than their charge to transfer and store information. This method promises energy-efficient and high-speed solutions that exceed the limitations of classical computation, for next generation classical and quantum computation.
The Manchester team, led by Dr. Ivan Vera-Marun, has fully encapsulated monolayer graphene in hexagonal boron nitride, an insulating and atomically flat 2D material, to protect its high quality. By engineering the 2D material stack to expose only the edges of graphene, and laying magnetic nanowire electrodes over the stack, they successfully form one-dimensional (1D) contacts.
A new study from the University of Eastern Finland (UEF) explores the behavior of photons, the elementary particles of light, as they encounter boundaries where material properties change rapidly over time. This research uncovers remarkable quantum optical phenomena that may enhance quantum technology and paves the road for an exciting nascent field: four-dimensional quantum optics.
Four-dimensional optics is a research area investigating light scattering from structures which change in time and space. It holds immense promise for advancing microwave and optical technologies by enabling functionalities such as frequency conversion, amplification, polarization engineering and asymmetric scattering. That is why it has captured the interest of many researchers across the globe.
Previous years have seen significant strides in this area. For instance, a 2024 study published in Nature Photonics and also involving UEF highlights how incorporating optical features like resonances can drastically influence the interaction of electromagnetic fields with time-varying two-dimensional structures, opening exotic possibilities to control light.
To develop a practical fusion power system, scientists need to fully understand how the plasma fuel interacts with its surroundings. The plasma is superheated, which means some of the atoms involved can strike the wall of the fusion vessel and become embedded. To keep the system working efficiently, it’s important to know how much fuel might be trapped.
“The less fuel is trapped in the wall, the less radioactive material builds up,” said Shota Abe, a staff research physicist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL).
Abe is the lead researcher on a study published in Nuclear Materials and Energy. The study looks specifically at how much deuterium —thought to be one of the best fuels for fusion —might get stuck in the boron-coated, graphite walls of a doughnut-shaped fusion vessel known as a tokamak. Boron is used in some experimental fusion systems to reduce plasma impurities. However, researchers do not fully understand how a boron coating might impact the amount of fusion fuel that leaves the plasma and becomes embedded in the vessel walls.
A team of scientists from Princeton University has measured the energies of electrons in a new class of quantum materials and has found them to follow a fractal pattern. Fractals are self-repeating patterns that occur on different length scales and can be seen in nature in a variety of settings, including snowflakes, ferns, and coastlines.
A quantum version of a fractal pattern, known as “Hofstadter’s butterfly,” has long been predicted, but the new study marks the first time it has been directly observed experimentally in a real material. This research paves the way toward understanding how interactions among electrons, which were left out of the theory originally proposed in 1976, give rise to new features in these quantum fractals.
The study was made possible by a recent breakthrough in materials engineering, which involved stacking and twisting two sheets of carbon atoms to create a pattern of electrons that resembles a common French textile known as a moiré design.
Scientists are hunting for axions, tiny particles that could solve major physics mysteries, including why neutrons don’t have an electric dipole moment and what dark matter is made of. Using the powerful European XFEL in Hamburg, researchers fired X-rays through special crystals, hoping to witness axions converting into light—a sign of their existence. This pioneering experiment, already competitive with major particle accelerator studies, demonstrates that XFEL technology could be a game-changer in particle physics.
Dark matter is an elusive type of matter that does not emit, absorb or reflect light and is thus impossible to detect using conventional techniques employed in particle physics. In recent years, groups of physicists worldwide have been trying to observe this matter indirectly using advanced detectors and equipment, by detecting signals other than electromagnetic radiation that could be linked to its activity or interactions with other matter.
Researchers at Tokyo Metropolitan University, PhotoCross Co. Ltd, Kyoto Sangyo University and other collaborating institutions recently released the findings of the first search for dark matter that relied on data collected by WINERED, a near-infrared and high-dispersion spectrograph mounted on a large telescope in Chile.
Their paper, published in Physical Review Letters, sets the most stringent constraints to date on the lifetime of dark matter particles with masses between 1.8 and 2.7 eV.