Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: quantum physics – Page 7

New quantum chip architecture could use built-in vibrations to link distant qubits

A new concept from Warwick researchers could help solve one of the biggest challenges to building large-scale quantum computers: enabling communication between vast numbers of quantum bits (qubits) over long distances across a single chip.

Published in APL Quantum, researchers from the University of Warwick and NRC Canada introduce the concept of Quantum Phononic Links (QPLs), a new approach to communication between qubits. It uses sound-like vibrations traveling through a specially engineered material to carry quantum information between qubits that are physically far apart.

Today’s leading quantum chips typically allow only neighboring qubits to communicate directly with each other. To build useful quantum computers, engineers expect to need to coordinate millions of qubits spread across an entire semiconductor chip, not just clusters of adjacent qubits. The team’s proposed approach uses sound vibrations, known as phonons, as an inherent communication system, allowing qubits to exchange quantum information over much greater distances than currently possible.

Simple semiconductor films break light’s front-back symmetry

Light typically interacts with a material the same way whether it enters through the front or the back—like polarized sunglasses that work the same from either side. Cornell researchers have demonstrated a simple route to breaking that symmetry, opening new possibilities for photonics and quantum information processing.

Optical reciprocity, the principle that a system responds identically regardless of which side faces the light, underlies most lenses, mirrors and other optical devices. A new study published in Nature Materials demonstrates that some materials can be engineered to exhibit nonreciprocal absorption and emission of linearly polarized light.

“Imagine window blinds with sunlight coming through their horizontal slats, but from the opposite side, the same blinds let light through as if the slats were vertical, completely inverted,” said corresponding author Richard Robinson, professor of materials science and engineering in the Cornell Duffield College of Engineering. “To get this type of behavior, you typically need complex metamaterials or external magnetic fields, but we show that it can be achieved in simple, solution-processed semiconductor nanoclusters.”

A quantum heat engine that simultaneously provides work and refrigeration

The laws of thermodynamics state that heat naturally flows from hotter systems or regions to colder systems or regions until a state of thermal equilibrium is reached. This simple principle underpins the operation of numerous technologies, ranging from refrigerators to power plants.

Yet quantum systems, which are governed by quantum mechanics, can exhibit unusual behaviors that cannot be explained by classical physics. These behaviors could be used to create innovative thermal devices.

Researchers at Qufu Normal University, the University of Hong Kong and the University of Palermo recently observed an anomalous thermal effect that allows a quantum system to absorb heat from colder thermal reservoirs. This unusual effect, outlined in a paper in Physical Review Letters, was leveraged to develop a new quantum heat engine that simultaneously produces work (i.e., mechanical energy created by converting heat into motion or power) and refrigeration.

Near a black hole, gravity changes a quantum circuit’s readings, not its rules

Imagine holding one of our most precise quantum devices at a fixed position outside a black hole. A Josephson junction—two superconductors separated by an ultrathin barrier—can turn a voltage into a quantum oscillation with extraordinary precision. Would intense gravity change that quantum rule, or only change how a faraway observer reads the device?

In our study published in the Journal of High Energy Physics, we found a clean answer. The local Josephson physics remains intact. Gravity instead changes the translation between measurements made beside the circuit and measurements assigned by an observer far from the black hole.

Physicists say quantum mechanics may not need imaginary numbers after all

Physicists from Heinrich Heine University Düsseldorf (HHU) have examined a fundamental property of quantum mechanics in collaboration with the German Aerospace Center (DLR). In the scientific journal Physical Review Letters, they show that this theory does not necessarily need to be formulated with imaginary numbers – real numbers can in fact also be used.

Quantum mechanics is the branch of physics that explains how matter and energy behave at the atomic and subatomic scale. Developed in the early 1900s by pioneers including Max Planck, Niels Bohr, Werner Heisenberg, and Erwin Schrödinger, it has become one of the most successful scientific theories ever created.

The theory accurately describes a wide range of microscopic phenomena. These include the famous double slit experiment, in which particles also display wave like behavior, and quantum tunneling, where particles have a probability of passing through a barrier even when they do not have enough energy to overcome it in the classical sense. Other key quantum effects, such as entanglement and coherence, now form the foundation of emerging technologies including quantum computing and quantum communication.

World’s first ‘zinc oxide spin qubit’ could advance scalable quantum devices

A research team led by SKKU professor Hosung Seo of the Department of Quantum Information Engineering and the SKKU Advanced Institute of Nanotechnology, working with the University of Wisconsin–Madison and the University of Washington, has identified—for the first time—an atomic defect structure in the zinc oxide (ZnO) semiconductor with outstanding properties for use as a “spin qubit,” a core building block of future quantum computers, quantum communications and quantum sensors.

The results are published in PRX Quantum.

Electron spins trapped at point defects in solid-state crystals can operate at room temperature and retain quantum information for long periods, making them a leading platform not only for quantum computing but also for quantum communications and ultrasensitive quantum sensing. The nitrogen-vacancy (NV) center in diamond has been the most prominent candidate, but diamond is difficult to grow into large-area, high-quality crystals and is poorly suited to standard semiconductor fabrication, posing major obstacles to the integration and mass production of quantum devices.

Long-lived ytterbium states could sharpen quantum computing and atomic clocks

Researchers from the University of Amsterdam and the University of New South Wales have answered a question that has been around for decades: whether ions of the metal ytterbium can enter certain long-lived, nearly stable states and, if so, for how long. The measured long-lived states may find applications in quantum computers and atomic clocks.

Many modern atomic clocks and quantum computers have so-called trapped ions at their core. Ions, electrically charged atoms, can be in many different states, all with different amounts of energy. Because of their charge, these ions can be suspended in empty space and kept in place using electromagnetic fields. The operation of the clock or computer then relies on precisely controlling which energy state an ion occupies.

Researchers from the University of Amsterdam and the University of New South Wales have now discovered that the ytterbium ion (Yb⁺), a leading candidate for both technologies, can remain in previously unexplored states for surprisingly long periods.

Quantum dots reveal hidden light waves on metal surfaces

Photographs can reveal things that are otherwise impossible for the naked eye to see, be they distant galaxies or microscopic cells. Researchers at Osaka Metropolitan University have developed a practical and versatile imaging technique that makes another usually invisible phenomenon visible: surface plasmon polaritons (SPPs), light waves that travel along metal surfaces.

The new method, published in the journal Nano Letters, could boost the development of next-generation optical and plasmonic technologies.

SPPs are electromagnetic waves that travel along the boundary between a metal and a dielectric material, such as air or glass. Unlike ordinary light, which spreads freely through three-dimensional space, SPPs remain tightly confined to this interface, allowing them to be guided and manipulated at the nanoscale. This unique property makes them fundamental to emerging technologies including ultrasensitive sensors, optical circuits and quantum devices.

/* */