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Category: quantum physics – Page 42

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.

Does Fine-Tuning Point to God? — Brian Greene

The full episode with Brian Greene is out now for Substack subscribers: https://open.substack.com/pub/alexoconnor/p/brian-greene-on-…ine?r=2cuw…

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Brian Greene is a professor of physics and mathematics at Columbia University, director of its centre for theoretical physics, and the chairman of the World Science Festival. He is best known for his work on string theory, especially in his book “The Elegant Universe”, which turns 25 this year.

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