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Category: quantum physics – Page 16

Nanoscale ‘Bragg gratings’ on photonic chips suppress noise in laser light

Researchers at the University of Sydney have cracked a long-standing problem in microchip-scale lasers by carving tiny “speed bumps” into the devices’ optical cavity in their quest to produce exceptionally “clean” light. This exquisitely narrow spectrum light could be used in future quantum computers, advanced navigation systems, ultra-fast communications networks and precision sensors.

In a new study published in APL Photonics, the team shows how to eliminate a critical source of noise in Brillouin lasers, a special class of light source known for its extraordinary purity, producing an ultranarrow spectrum that is almost a perfect single wavelength (or color) of light.

Light produced from sources like lightbulbs have a broad wavelength spectrum and are fine for everyday use but are too “noisy” for precision scientific purposes, where lasers are needed.

Superconductivity for addressing global challenges

High‑energy physics has always been one of the main drivers of progress in superconducting science and technology. None of the flagship accelerators that have shaped modern particle physics could have succeeded without large‑scale superconducting systems. CERN continues to lead the efforts in this field. Its next accelerator, the High‑Luminosity LHC, relies on high-grade superconductors that were not available in industry before they were developed for high-energy physics. Tomorrow’s colliders will require a new generation of high‑temperature superconductors (HTS) to be able to realise their research potential with improved energy efficiency and long‑term sustainability.

Beyond the physics field, next‑generation superconductors have the potential to reshape key technological sectors. Their ability to transmit electricity without resistance, generate intense magnetic fields and operate efficiently at high temperatures makes them suitable for applications in fields as diverse as healthcare, mobility, computing, novel fusion reactors, zero‑emission transport and quantum technologies. This wide range of applications shows that advances driven by fundamental physics can generate broad societal impact far beyond the laboratory.

The Catalysing Impact – Superconductivity for Global Challenges event seeks to accelerate the transition from science to societal applications. By bringing together top-level researchers, industry leaders, policymakers and investors, the event provides a structured meeting point for technical expertise and strategic financing. Its purpose is not simply to present progress but to build bridges across sectors, disciplines and funding landscapes in order to move superconducting technologies from early demonstrations to impactful applications.

Single-crystalline monolayer semiconductors with coherent quantum transport by vicinal van der Waals epitaxy

By controlling the coalescence of multiple unidirectional grains on vicinal sapphire substrates, wafer-scale channels of single-crystalline molybdenum disulfide can be grown, which exhibit coherent quantum transport across large length scales.

X-Ray Imaging Uncovers Hidden Structures in Liquid-Metal-Grown Crystals

The delicate internal structure of platinum crystals growing in liquid metal has been revealed, according to new research employing a powerful X-ray technique that reveals new implications for quantum computing.

UNSW Professor Kourosh Kalantar-Zadeh, with the University of New South Wales (UNSW), led the study, which was reported in a recent paper in Nature Communications. The team behind the project has a history of specializing in exploiting liquid metals to produce new materials and green catalysts that improve industrial chemical reactions.

Physicist delineates limits on the precision of quantum thermal machines

Quantum thermal machines are devices that leverage quantum mechanical effects to convert energy into useful work or cooling, similarly to traditional heat engines or refrigerators. Thermodynamics theory suggests that increasing the reliability with which all thermal machines produce the same thermodynamic processes in time comes at a cost, such as the wasted heat or the need for extra energy.

Drawing from theories and concepts rooted in thermodynamics, physicist Yoshihiko Hasegawa at the University of Tokyo recently set out to pinpoint the limits that would constrain the precision of finite-dimensional quantum thermal machines. In a recent paper, published in Physical Review Letters, he delineates these limits and shows that quantum coherence could reduce fluctuations, improving the accuracy of quantum thermal machines.

“Thermodynamic uncertainty relations have clarified an important ‘no free lunch’ principle: if you want an operation to be more precise, you must pay more thermodynamic cost, i.e., entropy production,” Hasegawa told Phys.org. “However, those thermodynamic uncertainty relations do not forbid, in principle, pushing entropy production arbitrarily high.

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