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Category: quantum physics – Page 6

New three‑dimensional magnetic structure discovered with laser light

Flashes of femtosecond laser light, lasting just a few trillionths of a second, have made it possible to observe new magnetic structures for the first time. By using light as a remote control, researchers were able to switch magnetism into previously unseen three-dimensional states at the nanoscale.

Magnetism is often imagined as something simple, pointing in one direction or another. At very small scales, however, magnetism can behave in far more complex ways. Magnetism originates from a quantum property of electrons known as spin, which can be thought of as a tiny internal compass carried by each electron. When many spins interact inside a solid material, they can organize into stable patterns.

Supercharging solar cells: Quantum dot-molecule hybrid states enable near-maximum efficiency

Solar panels have become more efficient over the years, but even the best designs still lose a large fraction of the energy they absorb. Scientists around the world have been searching for ways to capture more energy from every ray of sunlight and unlock the true potential of solar technology.

In a study published in Nature Photonics, researchers from the University of Osaka and collaborating institutions identified a new mechanism that could help us do exactly that. The study shows how specially designed combinations of molecules and quantum dots can be used to dramatically increase solar cell efficiency beyond currently known limits.

Singlet exciton fission is a photophysical phenomenon in which one particle of light creates two excited energy states instead of one. In theory, this allows solar cells to generate more electricity from the same amount of sunlight. However, the most effective photophysical processes require extra energy and are usually inefficient and difficult to control.

Randomization can improve quantum computer performance in presence of noise

New research led by a graduating Ph.D. student in The University of New Mexico Department of Electrical and Computer Engineering has shown that randomization can improve quantum computer performance in the presence of noise.

Ph.D. student Leeseok Kim led the research under the advice of Assistant Professor Milad Marvian, with support from Changhao Yi, a former member of Marvian’s group. Their findings, titled “Faster Randomized Dynamical Decoupling,” are published in the journal Physical Review Letters and were presented at QSim 2025, an international conference in quantum simulation.

Quantum computers have the potential to solve certain problems faster than classical computers, with promising applications in areas such as simulation and discovery of new materials, optimization, and cryptography. However, building quantum computers that can solve practically relevant problems at scale remains difficult because they are susceptible to noise. Reducing noise more effectively is therefore a key challenge.

Tuning into quantum sounds: Acoustic devices simplify quantum sensors

When a singer belts out a tune while a guitar player strums along, sound waves travel through the air, driving collective oscillations of the molecules within. Meanwhile, at the quantum level, something similar is going on. Atoms inside materials, everything from our bodies to metals and more, naturally jiggle around, creating tiny vibrational waves that ripple across the material. These vibrations are known as phonons: the quantum version of sound waves.

Now, physicists at Caltech and Stanford University have developed devices called nanoelectromechanical systems (NEMS) that allow phonons to exhibit their quantum behavior purely through the intrinsic properties of the material that makes up the device. Previously, it was not possible to observe such behavior without the help of an external quantum device, such as a superconducting qubit.

This means that, through this newly discovered mechanism, a solitary NEMS device can, for example, serve as a greatly simplified and very compact quantum sensor or qubit.

Scientists trained an AI model using an IBM quantum computer — and it answered questions correctly that the base model couldn’t

When running an AI model through a quantum computer, scientists have increased accuracy by only adding a relatively small number of parameters.

Scientists discover strange “narwhal” waves that trap light beyond known limits

Physicists at Peking University have uncovered a new way to confine light far beyond conventional limits — without relying on metals and their inherent energy dissipation. By formulating the singular dispersion equation, the team discovered narwhal-shaped wavefunctions that trap light at deep-subwavelength volumes in purely dielectric materials. The advance, dubbed singulonics, could pave the way for ultra-efficient photonic chips, new quantum technologies, and imaging tools with unprecedented resolution.

Different Flows of Time All Exist at the Same Moment”: Scientists Claim Trapped-Ion Atomic Clocks Can Observe “Quantum Superposition of Time

Scientists claim they can improve the sensitivity of atomic clocks to measure the quantum superposition of time and possibly explain gravity.

Quantum metasurface boosts terahertz detection sensitivity by exploiting in-plane photoelectric effect

Being able to see light and detect radiation is of utmost importance at any frequency. While this challenge has been solved in the visible range, radiation detectors in the far-infrared and terahertz regimes are either not sensitive, slow, or require bulky and expensive, often cryogenically cooled devices, which hinders practical applications.

A recent study reported in Advanced Photonics combines quantum physics with a carefully designed metasurface to develop a compact detector that improves how THz radiation is captured and converted into an electrical signal.

Canceling Quantum Noise

A new technique uses an ‘anti-noise’ signal to cancel out the unavoidable quantum noise associated with precision measurements like those needed for gravitational-wave detection.

When light is used to detect motion with high-precision—for example, in accelerometers or gravitational-wave detectors—its ultimate sensitivity is limited by quantum noise, which is unavoidable. A research team has now demonstrated a tabletop device that can reduce the disruption of quantum noise by modifying a light beam before using it to make a measurement [1]. This beam preparation cancels out the noise in a manner reminiscent of noise-canceling headphones [1]. Working across a wide frequency range and potentially offering up to 77% noise reduction, the system might ultimately find additional uses in quantum information processing.

Observing gravitational waves involves detecting changes in the interference pattern created by a pair of interacting laser beams, each of which has bounced off a remote mirror whose distance changes slightly when a wave passes. Such detections require very high sensitivity, which is compromised by inherent quantum fluctuations in the light field. To reduce quantum noise, researchers currently use a technique called squeezing, in which the quantum fluctuations can be shifted from one parameter, such as the phase, to another, such as the intensity [2, 3].

Superconducting vortices moonlight as controllable qubits, turning a disruption into a resource

Vortices in superconductors have so far been considered a disruption, as they can impair the superconducting properties. Researchers at the Karlsruhe Institute of Technology (KIT) have proved in experiments that magnetic vortices can be used as controllable quantum systems in certain materials. This means that a previously unwanted phenomenon is becoming a potential resource in quantum technologies, opening up new avenues for the development of quantum computers, highly sensitive sensor systems, and innovative approaches in materials research. These results are published in Nature.

Superconductors are materials that, under certain conditions, conduct electricity with zero resistance, entirely expelling magnetic fields. However, once the magnetic flux exceeds a critical threshold, magnetic fields start to penetrate into the material as tiny, quantized vortices. Such vortices have so far been considered unwanted disruptive factors, as they have an energy-draining effect, limiting the efficiency of superconducting systems.

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