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A new method developed by Amsterdam researchers uses non-Gaussian states to efficiently describe and configure quantum spin-boson systems, promising advancements in quantum computing and sensing.

Many modern quantum devices operate using groups of qubits, or spins, which have just two energy states: ‘0’ and ‘1’. However, in actual devices, these spins also interact with photons and phonons, collectively known as bosons, making the calculations much more complex. In a recent study published in Physical Review Letters, researchers from Amsterdam have developed a method to effectively describe these spin-boson systems. This breakthrough could help in efficiently setting up quantum devices to achieve specific desired states.

Quantum devices use the quirky behavior of quantum particles to perform tasks that go beyond what ‘classical’ machines can do, including quantum computing, simulation, sensing, communication, and metrology. These devices can take many forms, such as a collection of superconducting circuits, or a lattice of atoms or ions held in place by lasers or electric fields.

Time loops have long been the stuff of science fiction. Now, using the rules of quantum mechanics, we have a way to effectively transport a particle back in time – here’s how.

By Miriam Frankel

Year 2023 face_with_colon_three

A team led by researchers at Osaka University and University of California, San Diego has conducted simulations of creating matter solely from collisions of light particles. Their method circumvents what would otherwise be the intensity limitations of modern lasers and can be readily implemented by using presently available technology. This work might help experimentally test long-standing theories such as the Standard Model of particle physics, and possibly the need to revise them.

One of the most striking predictions of quantum physics is that matter can be generated solely from light (i.e., photons), and in fact, the astronomical bodies known as pulsars achieve this feat. Directly generating matter in this manner has not been achieved in a laboratory, but it would enable further testing of the theories of basic quantum physics and the fundamental composition of the universe.

Continue reading “Let there be matter: Simulating the creation of matter from photon–photon collisions” »

In the last year, two independent groups have observed electrons behaving like quasiparticles with fractional amounts of charge, like –²⁄₃ and –³⁄₅, without the influence of a magnetic field.

In the 127 years since the electron was discovered, it has undergone more scrutiny than perhaps any other particle. As a result, its properties are not just well known, but rote, textbook material: Electrons have a smidgen of mass and negative electric charge. In a conductor, they swim relatively unimpeded as a current; in an insulator, they barely move.

Over time, caveats have cropped up. Under an intense magnetic field, for example, electrons can lose their individual identities and form “quasiparticles”: collective entities, like the shape formed by a school of fish. But even these collective states have been well cataloged.

Continue reading “Physicists Puzzle Over Emergence of Strange Electron Aggregates” »

The team spent years perfecting an intricate process for manufacturing two-dimensional arrays of atom-sized qubit microchiplets and transferring thousands of them onto a carefully prepared complementary metal-oxide semiconductor (CMOS) chip. This transfer can be performed in a single step.

“We will need a large number of qubits, and great control over them, to really leverage the power of a quantum system and make it useful. We are proposing a brand new architecture and a fabrication technology that can support the scalability requirements of a hardware system for a quantum computer,” says Linsen Li, an electrical engineering and computer science (EECS) graduate student and lead author of a paper on this architecture.

Microscopic chinks in material just several atoms thick have the potential to advance a multitude of quantum technologies, new research shows – getting us closer to the widespread use of quantum networks and sensors.

Right now, storing quantum data in the spin properties of electrons, known as spin coherence, requires a very particular and delicate laboratory setup. It’s not something you can do without a carefully controlled environment.

Here, an international team of researchers managed to demonstrate observable spin coherence at room temperature, using the tiny defects in a layered 2D material called Hexagonal Boron Nitride (hBN).

Group theory and first-principles calculations combine to predict which antiferromagnets have potentially useful net surface magnetization.

Antiferromagnetism was discovered in the 1930s by Louis Néel but had long been considered of scientific, not practical, interest. Antiferromagnets (AFM) are internally magnetic, but the magnetic moments of their atoms and molecules are antiparallel to each other, canceling out and resulting in no net magnetization. This cancellation renders bulk antiferromagnets effectively invisible to external magnetic fields, so that their magnetic properties are difficult to harness in applications. Recently, however, a new paradigm has appeared—antiferromagnetism-based spintronics—which seeks to apply antiferromagnets’ unique properties (such as fast spin dynamics, the absence of strong stray fields, and the stability of these materials) to the processing and storage of information [1].

In a surprise discovery, Flinders University nanotechnology researchers have produced a range of different types of gold nanoparticles by adjusting water flow in the novel vortex fluidic device—without the need for toxic chemicals. The article, “Nanogold Foundry Involving High-Shear-Mediated Photocontact Electrification in Water,” has been published in Small Science.

Ask anyone working in quantum computing and they may tell you they have been dealing with the frustratingly contrarian and intricately delicate state of entanglement since the beginning of time. However, a new study suggests this might be impossible. In fact, entanglement may have been absent in the earliest moments of the universe, researchers are reporting — a hypothesis that would — if validated — challenge our understanding of quantum mechanics and the nature of time itself.

The research, detailed in a paper by Jim Al-Khalili, of the University of Surrey and Eddy Keming Chen, University of California, San Diego and published on the pre-print server ArXiv, explores the so-called entanglement past hypothesis. In the study, the researchers explore why time only flows in one direction, a fundamental concept in both quantum physics and thermodynamics.

According to the researchers the concept of quantum entanglement, where two particles become so deeply linked that their properties seem to remain interconnected regardless of the distance between them, is central to modern quantum mechanics. It’s also a key ingredient for the potential of quantum computers to tackle massively complex calculations. It’s also why quantum computing is so vexing, because entanglement can be disrupted by external influences, leading to a process known as decoherence.