Lifeboat Foundation

The potential of quantum computers to solve problems that are intractable for classical computers has driven advances in hardware fabrication. In practice, the main challenge in realizing quantum computers is that general, many-particle quantum states are highly sensitive to noise, which inevitably causes errors in quantum algorithms. Some noise sources are inherent to the current materials platforms. de Leon et al. review some of the materials challenges for five platforms for quantum computers and propose directions for their solution.

Science, this issue p. eabb2823.

In a way, entangled particles behave as if they are aware of how the other particle is behaving. Quantum particles, at any point, are in a quantum state of probabilities, where properties like position, momentum, and spin of the particle are not precisely determined until there is some measurement. For entangled particles, the quantum state of each depends on the quantum state of the other; if one particle is measured and changes state, for example, the other particle’s state will change accordingly.

The study aimed to teleport the state of quantum qubits, or “quantum bits,” which are the basic units of quantum computing. According to the study, the researchers set up what is basically a compact network with three nodes: Alice, Charlie, and Bob. In this experiment, Alice sends a qubit to Charlie. Bob has an entangled pair of qubits, and also sends one qubit to Charlie, where it interferes with Alice’s qubit. Charlie projects Alice’s qubit onto an entangled quantum Bell State that transfers the state of Alice’s original qubit to Bob’s remaining qubit.

The breakthrough is notable for a few reasons. Many previous demonstrations of quantum teleportation have proven to be unstable over long distances. For example, in 2016, researchers at the University of Calgary were able to perform quantum teleportation at a distance of six kilometers. This was the world record at the time and was seen as a major achievement.

Matter and anti-matter are always thought of as opposites. If they interact, they turn into pure energy. But there are cases, thanks to the peculiar laws of quantum mechanics, where particles and antiparticles are somewhat coexisting. Now, a new particle can be added to those cases.

The nature of dark matter continues to perplex astronomers. As the search for dark matter particles continues to turn up nothing, it’s tempting to throw out the dark matter model altogether, but indirect evidence for the stuff continues to be strong. So what is it? One team has an idea, and they’ve published the results of their first search.

The conditions of dark matter mean that it can’t be regular matter. Regular matter (atoms, molecules, and the like) easily absorbs and emits light. Even if dark matter were clouds of molecules so cold they emitted almost no light, they would still be visible by the light they absorb. They would appear like dark nebula commonly seen near the galactic plane. But there aren’t nearly enough of them to account for the effects of dark matter we observe. We’ve also ruled out neutrinos. They don’t interact strongly with light, but neutrinos are a form of “hot” dark matter since neutrinos move at nearly the speed of light. We know that most dark matter must be sluggish, and therefore “cold.” So if dark matter is out there, it must be something else.

In this latest work, the authors argue that dark matter could be made of particles known as scalar bosons. All known matter can be placed in two large categories known as fermions and bosons. Which category a particle is in depends on a quantum property known as spin. Fermions such as electrons and quarks have fractional spin such as 1/2 or 3/2. Bosons such as photons have an integer spin such as 1 or 0. Any particle with a spin of 0 is a scalar boson.

PROVIDENCE, R.I. [Brown University] — Whether for use in cybersecurity, gaming or scientific simulation, the world needs true random numbers, but generating them is harder than one might think. But a group of Brown University physicists has developed a technique that can potentially generate millions of random digits per second by harnessing the behavior of — tiny magnetic anomalies that arise in certain two-dimensional materials.

Their research, published in Nature Communications, reveals previously unexplored dynamics of single, the researchers say. Discovered around a half-decade ago, have sparked interest in physics as a path toward next-generation computing devices that take advantage of the magnetic properties of particles — a field known as spintronics.

“There has been a lot of research into the global dynamics of, using their movements as a basis for performing computations,” said Gang Xiao, chair of the Department of Physics at Brown and senior author of the research. “But in this work, we show that purely random fluctuations in the size of can be useful as well. In this case, we show that we can use those fluctuations to generate random numbers, potentially as many as 10 million digits per second.”

A few years ago, a novel measurement technique showed that protons are probably smaller than had been assumed since the 1990s. The discrepancy surprised the scientific community; some researchers even believed that the Standard Model of particle physics would have to be changed. Physicists at the University of Bonn and the Technical University of Darmstadt have now developed a method that allows them to analyze the results of older and more recent experiments much more comprehensively than before. This also results in a smaller proton radius from the older data. So there is probably no difference between the values — no matter which measurement method they are based on. The study appeared in Physical Review Letters.

Shaken optical lattice undergoes discontinuous phase transition.

A hundred years of physics tells us that collective atomic vibrations, called phonons, can behave like particles or waves. When they hit an interface between two materials, they can bounce off like a tennis ball. If the materials are thin and repeating, as in a superlattice, the phonons can jump between successive materials.

Now there is definitive, experimental proof that at the nanoscale, the notion of multiple thin materials with distinct vibrations no longer holds. If the materials are thin, their atoms arrange identically, so that their vibrations are similar and present everywhere. Such structural and vibrational coherency opens new avenues in materials design, which will lead to more energy efficient, low-power devices, novel material solutions to recycle and convert waste heat to electricity, and new ways to manipulate light with heat for advanced computing to power 6G wireless communication.

The discovery emerged from a long-term collaboration of scientists and engineers at seven universities and two U.S. Department of Energy national laboratories. Their paper, “Emergent Interface Vibrational Structure of Oxide Superlattices,” was published January 26 in Nature.