Phys.org Physics

• Focusing and defocusing light without a lens: First demonstration of the structured Montgomery effect in free space

  Applied physicists in the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have demonstrated a new way to structure light in custom, repeatable, three-dimensional patterns, all without the use of traditional optical elements like lenses and mirrors. Their breakthrough provides experimental evidence of a peculiar natural phenomenon that had been confined mostly to theory.

• Imaging the Wigner crystal state in a new type of quantum material

  In some solid materials under specific conditions, mutual Coulomb interactions shape electrons into many-body correlated states, such as Wigner crystals, which are essentially solids made of electrons. So far, the Wigner crystal state remains sensitive to various experimental perturbations. Uncovering their internal structure and arrangement at the atomic scale has proven more challenging.

• Optical atomic clocks poised to redefine how the world measures seconds

  Time is almost up on the way we track each second of the day, with optical atomic clocks set to redefine the way the world measures one second in the near future. Researchers from Adelaide University worked with the National Institute of Standards and Technology (NIST) in the United States and the National Physical Laboratory (NPL) in the United Kingdom to review the future of the next generation of timekeeping.

• Using complex networks to tame combustion instability

  Engineers have long battled a problem that can cause loud, damaging oscillations inside gas turbines and aircraft engines: combustion instability. These unwanted pressure fluctuations create vibrations so intense that they can cause fatal structural damage to combustor walls, posing a serious threat in many applications. Combustion instability occurs when acoustic waves, heat release, and flow patterns interact in a strong feedback loop, amplifying each other until the entire system becomes unstable.

• Record-breaking photons at telecom wavelengths—on demand

  A team of researchers from the University of Stuttgart and the Julius-Maximilians-Universität Würzburg led by Prof. Stefanie Barz (University of Stuttgart) has demonstrated a source of single photons that combines on-demand operation with record-high photon quality in the telecommunications C-band—a key step toward scalable photonic quantum computation and quantum communication. "The lack of a high-quality on-demand C-band photon source has been a major problem in quantum optics laboratories for over a decade—our new technology now removes this obstacle," says Prof. Stefanie Barz.

• Lab study suggests longer waves fracture floating ice sheets at lower stress

  When waves are moving across ice-covered seas, they can cause sheets of ice to bend and ultimately break. Understanding the processes underlying these wave-induced ice fractures and predicting when they will occur could help to better forecast how climate change will impact the environment and marine ecosystems on Earth.

• Quantum mechanical effects help overcome a fundamental limitation of optical microscopy

  Researchers from Regensburg and Birmingham have overcome a fundamental limitation of optical microscopy. With the help of quantum mechanical effects, they succeeded for the first time in performing optical measurements with atomic resolution. Their work is published in the journal Nano Letters.

• Beamline measurements of unstable ruthenium nuclei confirm advanced nuclear models

  A novel apparatus at the U.S. Department of Energy's (DOE) Argonne National Laboratory has made extremely precise measurements of unstable ruthenium nuclei. The measurements are a significant milestone in nuclear physics because they closely match predictions made by sophisticated nuclear models.

• Random driving on a 78-qubit processor reveals controllable prethermal plateau

  Time-dependent driving has become a powerful tool for creating novel nonequilibrium phases such as discrete time crystals and Floquet topological phases, which do not exist in static systems. Breaking continuous time-translation symmetry typically leads to the outcome that driven quantum systems absorb energy and eventually heat up toward a featureless infinite-temperature state, where coherent structure is lost.

• Direct imaging captures the crystalline vibrations of a supersolid made of atoms and light

  The 20th century was marked by the discovery of exotic states of matter. First, liquid helium was observed to flow without friction at extremely low temperatures, a phase now known as superfluid. Soon after, it was also discovered that under appropriate external conditions, some materials can conduct electricity without resistance; these materials were therefore named superconductors.

• Prototype cassettes mark key step toward new CMS high-granularity calorimeter

  In beehives on the CERN site, a buzzing team of bees collaborates to build hexagon after hexagon of honeycomb—a shape that allows the most honey for a given amount of beeswax to be stored. Working nearby, a team of similarly committed scientists has recently pieced together some more high-tech hexagons to form the first prototype "cassette" for the new CMS endcap calorimeters.

• Mapping 'figure 8' Fermi surfaces to pinpoint future chiral conductors

  One of the biggest problems facing modern microelectronics is that computer chips can no longer be made arbitrarily smaller and more efficient. Materials used to date, such as copper, are reaching their limits because their resistivity increases dramatically when they become too small. Chiral materials could provide a solution here. These materials behave like left and right hands: they look almost identical and are mirror images of each other, but cannot be made to match.

• Scientists develop high-performance Hg-based crystal for mid-far infrared birefringence

  Mid- and far-infrared birefringent crystals are key functional materials for polarization control, laser technologies, and infrared photonics. However, existing materials generally suffer from limited infrared transparency, an intrinsic trade-off between large birefringence and wide transmission windows, and challenges in optical characterization due to restricted crystal dimensions.

• Novel quantum refrigerator benefits from problematic noise

  For quantum computers to function, they must be kept at extremely low temperatures. However, today's cooling systems also generate noise that interferes with the fragile quantum information they are meant to protect. Now, researchers at Chalmers University of Technology in Sweden have developed an entirely new type of quantum refrigerator, which is partly driven by the noise itself. This refrigerator enables very precise control over heat and energy flows and could play an important role in scaling up quantum technology.

• Gravitational wave signal tests Einstein's theory of general relativity

  For those who watch gravitational waves roll in from the universe, GW250114 is a big one. It's the clearest gravitational wave signal from a binary black hole merger to date, and it gives researchers an opportunity to test Albert Einstein's theory of gravity, known as general relativity.

• 2D discrete time crystals realized on a quantum computer for the first time

  Physical systems become inherently more complicated and difficult to produce in a lab as the number of dimensions they exist in increases—even more so in quantum systems. While discrete time crystals (DTCs) had been previously demonstrated in one dimension, two-dimensional DTCs were known to exist only theoretically. But now, a new study, published in Nature Communications, has demonstrated the existence of a DTC in a two-dimensional system using a 144-qubit quantum processor.

• Is time a fundamental part of reality? A quiet revolution in physics suggests not

  Time feels like the most basic feature of reality. Seconds tick, days pass and everything from planetary motion to human memory seems to unfold along a single, irreversible direction. We are born and we die, in exactly that order. We plan our lives around time, measure it obsessively and experience it as an unbroken flow from past to future. It feels so obvious that time moves forward that questioning it can seem almost pointless.

• Programmable terahertz vortices enable dual electric and magnetic skyrmion modes

  Researchers have created an optical device that can generate both electric and magnetic vortex-ring-like light patterns. These structured light vortices, known as skyrmions, are highly stable and resistant to disturbances, making them promising for reliably encoding information in wireless applications.

• Measuring the quantum extent of a single molecule confined to a nanodroplet

  There is no measurement that can directly observe the wave function of a quantum mechanical system, but the wave function is still enormously useful as its (complex) square represents the probability density of the system or elements of the system. But for a confined system, the wave function can be inferred.

• Atomic spins set quantum fluid in motion: Experimental realization of the Einstein–de Haas effect

  The Einstein–de Haas effect, which links the spin of electrons to macroscopic rotation, has now been demonstrated in a quantum fluid by researchers at Science Tokyo. The team observed this effect in a Bose–Einstein condensate of europium atoms, showing that a change in magnetization causes the coherent transfer of angular momentum from atomic spins to fluid motion, thereby experimentally demonstrating that angular momentum is conserved at the quantum level.

• Novel 'XFELO' laser system produces razor-sharp X-ray light

  A team of engineers and scientists has shown for the first time that a hard-X-ray cavity can provide net X-ray gain, with X-ray pulses being circulated between crystal mirrors and amplified in the process, much like happens with an optical laser. The result of the proof-of-concept at European XFEL is a particularly coherent, laser-like light of a quality that is unprecedented in the hard X-ray spectrum.

• Establishing design principles for achieving ultralow thermal conductivity via controlled chemical disorder

  A major challenge in thermal-management and thermal-insulation technologies, across multiple industries, is the lack of materials that simultaneously offer low thermal conductivity, mechanical robustness, and scalable fabrication routes.

• Novel ferroelectric ultraviolet photodetector achieves near-10,000-fold speed increase

  Researchers from the Institute of Metal Research (IMR) of the Chinese Academy of Sciences have developed a new ferroelectric ultraviolet photodetector material that overcomes the long-standing performance limitations of conventional photodetectors.

• Quantum batteries could quadruple qubit capacity while reducing energy infrastructure requirements

  Scientists have unveiled a new approach to powering quantum computers using quantum batteries—a breakthrough that could make future computers faster, more reliable, and more energy efficient.

• Superfluids are supposed to flow indefinitely. Physicists just watched one stop moving

  Ordinary matter, when cooled, transitions from a gas into a liquid. Cool it further still, and it freezes into a solid. Quantum matter, however, can behave very differently. In the early 20th century, researchers discovered that when helium is cooled, it transitions from a seemingly ordinary gas into a so-called superfluid. Superfluids flow without losing any energy, among other quantum quirks, like an ability to climb out of containers.