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Liquid water molecules are inherently asymmetric: New insight into the bonds between water molecules

Icebergs float on water because the underlying liquid water has a higher density than the iceberg. Liquid water itself has its highest density at 4°C—one of the so-called anomalies of water, i.e. properties of liquids that are rarely observed for other liquids.

The origins of these anomalies have long been the subject of scientific research. Researchers at the Max Planck Institute for Polymer Research have now discovered another piece to the puzzle to explain the special behavior of water.

Many of the anomalous properties of water can be traced to the special interactions between the individual —the so-called hydrogen bonds. Each water molecule can donate two of these bonds—one from each hydrogen atom—and accept two of them from other, neighboring molecules.

Observing gain-induced group delay between multiphoton pulses generated in a spontaneous down-conversion source

Spontaneous parametric down-conversion (SPDC) and spontaneous four-wave mixing are powerful nonlinear optical processes that can produce multi-photon beams of light with unique quantum properties. These processes could be leveraged to create various quantum technologies, including computer processors and sensors that leverage quantum mechanical effects.

Researchers at the National Research Council of Canada and École Polytechnique de Montréal recently carried out a study observing the effects emerging in the SPDC process. Their paper, published in Physical Review Letters, reports the observation of a gain-induced group delay in multi-photon pulses generated in SPDC.

“The inspiration for this paper came from studying a process called SPDC,” Nicolás Quesada, senior author of the paper, told Phys.org. “This is a mouthful to say that certain materials are able to take a violet photon (the particle light is made of) and transform it into two red photons.

Neutron Stars Illuminate the Hidden Physics of Quark Superconductivity

Requiring consistency between the physics of neutron stars and quark matter leads to the first astrophysical constraint on this exotic phase of matter.

Recent research uses neutron star measurements to place empirical limits on the strength of color superconducting pairing in quark matter, revealing new insights into the physics of the densest visible matter in the universe through astronomical observations.

Color Superconductivity

Physicists propose a quantum–optomechanical solution to dark-matter detection

An interdisciplinary collaboration between condensed-matter, quantum-optics and particle physicists has the potential to crack the search for low-mass dark matter. The proposed quantum detector builds on EQUS studies of elementary excitations in superfluid helium and advances in opto-mechanics.

Led by EQUS Research Fellow Dr. Chris Baker (UQ), study proposes direct detection of low-mass dark matter via its interactions with confined in an optomechanical cavity.

Optomechanical dark matter instrument for direct detection” was published in Physical Review D in August 2024.

Quantum Scientists Just Made a Major Breakthrough Using 31 Superconducting Qubits

Scientists have achieved unprecedented control over quantum transport using a 31-qubit superconducting processor, opening new possibilities for next-generation electronics and thermal management. This approach allows researchers to observe and manipulate quantum particles with extraordinary precision, potentially revolutionizing how we develop future technologies.

The research, led by teams from Singapore and China, marks a significant advance in understanding how particles, energy, and information flow at the quantum level. This breakthrough could accelerate development of more efficient nanoelectronics and thermal management systems.

3D scans of giant hailstones reveal surprising discoveries that could help predict future storms

Hailstones are formed during thunderstorms, when raindrops are propelled into very cold parts of a cloud, where they freeze. Once the particles are heavy enough, gravity pulls them back towards Earth. As they plummet, they grow into hailstones, which can cause injury to people and significant damage to homes and cars.

Scientists have been studying how hailstones grow since the 1960s but doing so meant breaking them in the process. To better understand the anatomy and growth of hailstones, researchers in Catalonia have used computed tomography (CT) scans to examine the giant hailstones that hit the north-east of the Iberian Peninsula during an exceptionally strong thunderstorm in the summer of 2022.

“We show that the CT scanning technique enables the observation of the internal structure of the hailstones without breaking the samples,” said Carme Farnell Barqué, a researcher at the Meteorological Service of Catalonia and lead author of the study published in Frontiers in Environmental Science.

X-ray data-enhanced computational method can determine crystal structures of multiphase materials

A joint research team led by Yuuki Kubo and Shiji Tsuneyuki of the University of Tokyo has developed a new computational method that can efficiently determine the crystal structures of multiphase materials, powders that contain more than one type of crystal structures. The method can predict the structure directly from powder X-ray diffraction patterns, the patterns of X-rays passing through crystals roughly the same size as instant coffee particles.

Unlike conventional methods, this approach does not require the use of “lattice constants” and can be applied to existing experimental data that could not be analyzed until now. Thus, the new method is a crucial asset for discovering new material phases and developing new materials. The findings are published in The Journal of Chemical Physics.

Many materials can have several crystal structures, “phases,” even in the same solid state. Determining the underlying crystal structures of materials is essential for understanding their properties and formulating strategies to develop new materials. However, conventional methods make calculations using the “lattice constant,” a property of the crystal being investigated.

Researchers reveal the mechanism of runaway electron generation in tokamak fusion reactors

A research team has clarified the mechanism behind the generation of runaway electrons during the startup phase of a tokamak fusion reactor. The paper, “Binary Nature of Collisions Facilitates Runaway Electron Generation in Weakly Ionized Plasmas,” was published in the journal Physical Review Letters.

Nuclear energy refers to a power generation method that harnesses the energy of an artificial sun created on Earth, using resources extracted from seawater. To achieve this, technology capable of confining high-temperature plasma exceeding 100 million degrees for extended periods in a fusion is essential.

A tokamak is an artificial sun system in the shape of a torus, with no beginning or end, where magnetic fields are applied to confine particles.

Scientists reveal superconductivity secrets of an iron-based material

Scientists at the University of California, Irvine have uncovered the atomic-scale mechanics that enhance superconductivity in an iron-based material, a finding published recently in Nature.

Using advanced spectroscopy instruments housed in the UC Irvine Materials Research Institute, the researchers were able to image atom vibrations and thereby observe new phonons—quasiparticles that carry thermal energy—at the interface of an iron selenide (FeSe) ultrathin film layered on a (STO) substrate.

“Primarily emerging from the out-of-plane vibrations of oxygen atoms at the interface and in apical oxygens in STO, these phonons couple with electrons due to the spatial overlap of electron and phonon wave functions at the interface,” said lead author Xiaoqing Pan, UC Irvine Distinguished Professor of materials science and engineering, Henry Samueli Endowed Chair in Engineering and IMRI director.

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