Moiré systems incorporating lead iodide can host exotic quantum states and enable near-lossless electrical transport.
Category: quantum physics
Superconductor Theory Under Cold-Atom Scrutiny
Snapshot measurements of cold-atom gases reveal hidden spin correlations that could force an update of some superconductivity theories.
Our understanding of nature is inherently bound to the experimental tools we build to observe the world. Superconductivity, for example, has been traditionally studied using current and voltage meters under a variety of temperatures and other environmental conditions. From these observations, theorists have developed models—notably the Bardeen-Cooper-Schrieffer (BCS) theory, which assumes that the zero-resistance flow in a superconductor arises from electrons forming so-called Cooper pairs. This theory has been successful in explaining a large class of superconductors, but Tarik Yefsah from the Ecole Normale Supérieure in Paris and colleagues have now observed behavior that contradicts BCS predictions [1]. Using a recently developed technique called atom-resolved continuum quantum gas microscopy, the researchers directly observed spatial correlations in cold atoms that mimic superconducting electrons.
Quantum-inspired algorithm solves 268 million-site quasicrystal simulation in a heartbeat
Quantum technologies like quantum computers are built from quantum materials. These types of materials exhibit quantum properties when exposed to the right conditions. Curiously, engineers can also trigger quantum behavior by manipulating a material’s structure; for example, by stacking layers of graphene on top of each other and twisting them to create a moiré pattern, which suddenly turns them into a superconductor.
The layers can be arranged in increasingly complex ways all the way to quasicrystals and super-moiré materials. The fundamental problem is that scientists must first calculate the properties of potential new materials to predict if they could be useful. Quasicrystals, for example, are so complex they can require processing more than a quadrillion numbers—far beyond the capacity of the world’s most powerful supercomputers.
Now researchers at Aalto University’s Department of Applied Physics have shown how a quantum-inspired algorithm makes solving these colossal, non-periodic quantum materials possible in a heartbeat. The research is published in the journal Physical Review Letters as an Editor’s suggestion.
Spatiotemporal light pulses could secure optical communication by masking data
Researchers at Ben-Gurion University of the Negev have developed a new approach to secure optical communication that hides information in the physical structure of light, making it difficult for unauthorized parties to intercept or decode. The study addresses a growing challenge: advances in quantum computing are expected to weaken many of today’s encryption methods. While most security solutions rely on complex mathematical algorithms, this research adds protection earlier in the process—during the transmission of the signal itself.
The research was led by Dr. Judith Kupferman and Prof. Shlomi Arnon from the School of Electrical and Computer Engineering at Ben-Gurion University of the Negev. The findings were published in Optical and Quantum Electronics.
The researchers propose a communication method based on specially shaped light pulses, known as spatiotemporal optical vortices. These light beams are designed so that their key features are not visible in standard measurements.
Quantum simulations reveal spin transport in 1D materials
Researchers from the Department of Energy’s Quantum Science Center (QSC) headquartered at Oak Ridge National Laboratory (ORNL) have achieved a significant milestone by demonstrating the first digital quantum simulations of how spin currents change over time in a 1-D model of a quantum spin material. The results, now published in Physical Review Letters, establish a new, programmable way to use quantum computers to study the transport of spin—a fundamental quantum variable—in materials.
Spin transport measurements are a cornerstone of condensed matter physics, providing important insight into how quantum materials carry energy and information. In this work, QSC researchers, led by Purdue University’s Arnab Banerjee, demonstrated how a quantum computer can simulate spin transport behavior across ballistic, diffusive, and superdiffusive—meaning a faster and farther spread than typical diffusion—motion.
These different cases of spin transport represent fundamental changes in how the material responds to experimental probes. The simulation results make a direct comparison with experimental materials and open new avenues for understanding complex quantum phenomena such as coherence and energy flow in quantum materials.
Any color you like: Scientists create ‘any wavelength’ lasers in tiny circuits for light
Computer chips that cram billions of electronic devices into a few square inches have powered the digital economy and transformed the world. Scientists may be on the cusp of launching a similar technological revolution—this time using light.
In a significant advance toward that goal, National Institute of Standards and Technology (NIST) scientists and collaborators have pioneered a way to make integrated circuits for light by depositing complex patterns of specialized materials onto silicon wafers. These so-called photonics chips use optical devices such as lasers, waveguides, filters and switches to shuttle light around and process information.
The new advance could provide a big boost for emerging technologies such as artificial intelligence, quantum computers and optical atomic clocks.
Why this single-chip LED advance could shrink AR glasses and boost quantum links
Researchers at The University of Osaka, in collaboration with ULVAC, Inc. and Ritsumeikan University, have developed a new LED structure that generates circularly polarized light from a single chip. By combining a semipolar InGaN light-emitting structure with a stripe-shaped silicon nitride metasurface, the team created a compact light source that reduces energy-conversion loss and operates at room temperature.
This advancement could help bring ultra-compact, durable light sources closer to practical use in AR/VR, 3D displays, quantum communication, and optical security. The work is published in the journal Optical Materials Express.
Circularly polarized light is useful for a wide range of next-generation technologies. However, previous circularly polarized LEDs have struggled to combine high polarization, high efficiency, durability, and scalable manufacturing. In many previous designs, only one circular polarization component can be extracted from unpolarized light, placing a theoretical limit of 50% on conversion efficiency.
Scientists capture superconductivity’s ‘dancing pairs’ for first time, revealing missing pieces in a decades-old theory
For the first time, scientists have directly imaged the quantum process underlying superconductivity, a phenomenon in which paired electrons cause electric current to flow without resistance at sufficiently low temperatures. The results weren’t quite what they expected.
In the study, published April 15 in Physical Review Letters, the scientists directly imaged individual atoms pairing up in a special gas cooled nearly to absolute zero—the unreachable limit to how cold things can get. The type of gas, called a Fermi gas, allows scientists to substitute electrons with atoms and probe the physics of superconductors in a controlled way.
Surprisingly, the scientists found that after pairing up, the atoms moved in a synchronized dance, with their positions dependent on those of other pairs—a phenomenon not predicted by the 70-year-old, Nobel-prize-winning theory of superconductivity.
Multitasking quantum sensors can measure several properties at once
A special class of sensors leverages quantum properties to measure tiny signals at levels that would be impossible using classical sensors alone. Such quantum sensors are currently being used to study the inner workings of cells and the outer depths of our universe.
Particularly promising are solid-state quantum sensors, which can operate at room temperature. Unfortunately, most solid-state quantum sensors today only measure one physical quantity at a time—such as the magnetic field, temperature, or strain in a material. Trying to measure both the magnetic field and temperature of a material at the same time causes their signals to get mixed up and measurements to become unreliable.
Now, MIT researchers have created a way to simultaneously measure multiple physical quantities with a solid-state quantum sensor. They achieved this by exploiting entanglement, where particles become correlated into a single quantum state. In a new paper, the team demonstrated its approach in a commonly used quantum sensor at room temperature, measuring the amplitude, frequency, and phase of a microwave field in a single measurement. They also showed the approach works better than sequentially measuring each property or using traditional sensors.
“You Have To Iterate, You Have To Fail, You Have To Quickly Pick Yourself Up”: Genome Loaded Onto Quantum Computer For First Time
The achievement marks a milestone in the quest to use quantum computing to unlock the full complexity of human genetic diversity, with implications for cancer, drug design, and personalised medicine.