Fabricating some structures using niobium instead of aluminum could lead to more resilient superconducting quantum computers.
Category: quantum physics – Page 9
Ultra-thin metasurface can generate and direct quantum entanglement
Quantum technologies, devices and systems that process, store, detect, or transfer information leveraging quantum mechanical effects, have the potential to outperform classical technologies in a variety of tasks. An ongoing quest within quantum engineering is the realization of a so-called quantum internet: a network conceptually analogous to today’s internet, in which distant nodes are linked through shared quantum resources, most notably quantum entanglement.
Researchers at Nanjing University and University of Science and Technology of China have developed a new ultra-thin metasurface that could contribute to this goal, as it can control the behavior of light, while also generating and directing entanglement across many channels.
This metasurface, presented in a paper published in Physical Review Letters, has so far proved to be promising for the development of scalable and integrated quantum technologies.
A new class of strange one-dimensional particles
Physicists have long categorized every elementary particle in our three-dimensional universe as being either a boson or a fermion—the former category mostly capturing force carriers like photons, the latter including the building blocks of everyday matter like electrons, protons, or neutrons. But in lower dimensions of space, the neat categorization starts to break down.
Since the ’70s, a third class capturing anything in between a fermion and a boson, dubbed anyon, has been predicted to exist—and in 2020, these odd particles were observed experimentally at the interface of supercooled, strongly magnetized, one-atom thick (that is, two-dimensional) semiconductors. And now, in two joint papers published in Physical Review A, researchers from the Okinawa Institute of Science and Technology (OIST) and the University of Oklahoma have identified a one-dimensional system where such particles can exist and explored their theoretical properties.
Thanks to the recent developments in experimental control over single particles in ultracold atomic systems, these works also set the stage for investigating the fundamental physics of tunable anyons in realistic experimental settings. “Every particle in our universe seems to fit strictly into two categories: bosonic or fermionic. Why are there no others?” asks Professor Thomas Busch of the Quantum Systems Unit at OIST.
Superconductivity exposes altermagnetism by breaking symmetries, study suggests
How are superconductivity and magnetism connected? A puzzling relation between magnetism and superconductivity in a quantum material has lingered for decades—now, a study from TU Wien offers a surprising new explanation.
Some materials conduct electricity without any resistance when cooled to very low temperatures. This phenomenon, known as superconductivity, is closely linked to other important material properties. However, as new work by physicist Aline Ramires from the Institute of Solid State Physics at TU Wien now shows: in certain materials, superconductivity does not generate exotic magnetic properties, as was widely assumed. Instead, it merely makes an unusual form of magnetism experimentally observable—so-called altermagnetism.
Cryogenic cooling material composed solely of abundant elements reaches 4K
In collaboration with the National Institute of Technology (KOSEN), Oshima College, the National Institute for Materials Science (NIMS) succeeded in developing a new regenerator material composed solely of abundant elements, such as copper, iron, and aluminum, that can achieve cryogenic temperatures (approx. 4K = −269°C or below) without using any rare-earth metals or liquid helium.
By utilizing a special property called “frustration” found in some magnetic materials, where the spins cannot simultaneously satisfy each other’s orientations in a triangular lattice, the team demonstrated a novel method that replaces the conventional rare-earth-dependent cryogenic cooling technology.
The developed material holds promise for responding to the lack of liquid helium as well as for stable cooling in medical magnetic resonance imaging (MRI) and quantum computers, which are expected to see further growth in demand. The results are published in Scientific Reports.
Niobium’s superconducting switch cuts near-field radiative heat transfer 20-fold
When cooled to its superconducting state, niobium blocks the radiative flow of heat 20 times better than when in its metallic state, according to a study led by a University of Michigan Engineering team. The experiment marks the first use of superconductivity—a quantum property characterized by zero electrical resistance—to control thermal radiation at the nanoscale.
Leveraging this effect, the researchers also experimentally demonstrated a cryogenic thermal diode that rectifies the flow of heat (i.e., the heat flow exhibits a directional preference) by as much as 70%.
“This work is exciting because it experimentally shows, for the very first time, how nanoscale heat transfer can be tuned by superconductors with potential applications for quantum computing,” said Pramod Sangi Reddy, a professor of mechanical engineering and materials science and engineering at U-M and co-corresponding author of the study published in Nature Nanotechnology.
Using duality to construct and classify new quantum phases
A team of theoretical researchers has found duality can unveil non-invertible symmetry protected topological phases, which can lead to researchers understanding more about the properties of these phases, and uncover new quantum phases. Their study is published in Physical Review Letters.
Symmetry is one of the most fundamental concepts for understanding phases of matter in modern physics—in particular, symmetry-protected topological (SPT) phases, whose quantum mechanical properties are protected by symmetries, with possible applications in quantum computing and other fields.
Over the past few years, non-invertible symmetries, which extend the framework of conventional symmetries, have attracted significant attention in high energy physics and condensed matter physics. However, their complex mathematical structures have made it difficult to understand their corresponding phases of matter, or SPT phases.
A remarkable book on quantum mechanics reveals a really big idea
Where is physics headed? No one knows for sure, but Beyond the Quantum by Antony Valentini is a striking new book that reminds us what a big idea really looks like, finds Jon Cartwright
A Manufacturing Approach That Brings Diamond Quantum Photonics Closer To Industrial Production (MIT, KAUST et al.)
“Foundry-Enabled Patterning of Diamond Quantum Microchiplets for Scalable Quantum Photonics” was published by researchers at MIT, KAUST, PhotonFoundries and MITRE.
Abstract
Quantum technologies promise secure communication networks and powerful new forms of information processing, but building these systems at scale remains a major challenge. Diamond is an especially attractive material for quantum devices because it can host atomic-scale defects that emit single photons and store quantum information with exceptional stability. However, fabricating the optical structures needed to control light in diamond typically relies on slow, bespoke processes that are difficult to scale. In this work, we introduce a manufacturing approach that brings diamond quantum photonics closer to industrial production. Instead of sequentially defining each device by lithography written directly on diamond, we fabricate high-precision silicon masks using commercial semiconductor foundries and transfer them onto diamond via microtransfer printing.