Physics Magazine

Twisted Bilayers Are Hard to Pin Down Simulations have shown that the 2D sheets in twisted bilayers such as graphene can slide past one another even at small twists and under extreme compression. 

If the two sheets of a graphene bilayer are aligned, they’ll stick together. But for certain twist angles, one sheet can move freely over the other. Researchers have now found that this friction-free state is remarkably robust.

Viscous Stars Can Reflect Gravitational Waves like Black Holes Do A neutron star’s viscosity determines how the star interacts with gravitational waves, a behavior that could be useful to the study of neutron-star interiors.

Researchers have figured out how future gravitational-wave measurements could enable researchers to extract information about the internal structure of neutron stars.

Polymers Tame Turbulent Flow New experiments show that adding polymers to a fluid can reduce energy dissipation by suppressing small eddies.

Adding polymers to a liquid speeds up its flow through a pipe by reducing the frictional drag at the pipe’s inner surface. Now researchers have found that the polymers also suppress eddy formation and thus reduce the loss of flow energy to heat.

Interface Forces Leak Through Graphene Coatings Experiments clarify the degree to which a graphene coating can reduce the strength of van der Waals interactions with a surface.

How much does a layer of graphene screen van der Waals forces emanating from the material below? Researchers now have a clear answer.

Rethinking Our Place in the Universe The new map of the Universe’s expansion history released by the DESI Collaboration offers hints at a breakdown of the standard model of cosmology.

The Dark Energy Spectroscopic Instrument has created a cosmic map of unprecedented scale. Its newly published findings, combined with those from other observations, suggest that dark energy changes over time.

How a Molecular Motor Minimizes Energy Waste Turning a biologically important molecular motor at a constant rate saves energy, according to experiments.

Within every cell is a molecular motor, adenosine triphosphate synthase, which churns out energy-rich molecules for fueling the cell’s activity. By artificially cranking the motor, researchers have discovered that maintaining a fixed rotation rate minimizes energy loss.

A Smooth Plasmon Accelerator Researchers have shown experimentally that ultraintense lasers can drive high-amplitude surface plasma waves without the need for intricate structures.

Launching surface plasma waves (SPWs) in a metal foil used to require the patterning of a nanoscopic diffraction grating, which can be costly to make and lead to energy losses. Now researchers have demonstrated SPW generation without the need for gratings or other components.

Dark-Matter Sensitivity Improved with a Xenon Still The most troublesome contaminant in dark-matter searches that use xenon can be removed using a centuries-old concept.

For the XENONnT Collaboration, the most significant dark-matter-impostor (background) events come from decays of tiny amounts of radioactive radon. Using a whiskey-still-like system, the team has now reduced the amount of radon so much that its effect is comparable to that of solar neutrinos.

Cosmic Handedness Might Show Up in Galaxy Spins Cosmological simulations show that a left–right asymmetry in the early Universe could leave a mark in the distribution of galaxy rotations.

Parity violation in the infant universe could show up billions of years later in the distribution of galaxy rotations across the sky, researchers predict.

Charge Transfer Happens Too Fast to See A new experiment on static electricity casts doubt on previous ones.

Researchers have discovered why contact electrification—commonly known as static electricity—is poorly understood: The charge dynamics are too fast for some previous studies to be meaningful.

Criticality in Nature’s Strongest Force Experiments at the Relativistic Heavy Ion Collider give the first hints of a critical point in the hot quark–gluon “soup” that is thought to have pervaded the infant Universe.

Theory predicts that at large densities and moderately high temperatures a critical point exists where a clear distinction between gas-like hadrons and liquid-like quark–gluon soup vanishes. Hints of this critical point appear in new data from RHIC.

Building Blocks for Microwave Quantum Communication A certain superconducting device can entangle separate microwave signals, enabling reliable quantum teleportation and entanglement swapping.

Components for continuous-variable quantum communication based on optical light have already made their debuts. Now researchers have extended those demonstrations to microwave radiation. This work could help long-distance quantum communication and scalable quantum computing.

Active Matter Breaks like an Amorphous Plastic Shearing a dusty plasma with a laser shows how vibrational modes lead to weak points in an amorphous active system.

When stressed, amorphous materials undergo plastic transformations aided by low-frequency vibrational modes. Now researchers have found the same association in an entirely separate class of materials: active matter.

Superradiance Without Entanglement Scientists have shown that entanglement plays no role in a form of collective light emission called Dicke superradiance, settling a long-standing debate.

In 1954, physicist Robert Dicke predicted that a group of atoms could collectively emit an intense burst of radiation. Does the effect involve quantum entanglement? New work has confirmed previous suggestions that the answer is no.

New Material Solves Three Problems The polymer glass is easily processed and is also resistant both to small deformations and to cracking.

Researchers have shown that adding nanoparticles to plexiglass can increase both strength and toughness. The nanoparticles also decrease the melt viscosity, opening a path to easier manufacturing of a wide class of improved polymer materials.

New Suspect for Neutrino Signals Black holes born in the early Universe could account for the recently observed ultrahigh-energy astrophysical neutrinos.

The origin of ultrahigh-energy neutrinos is one of the greatest mysteries in astrophysics. Now theorists have shown that these particles could have been produced in the explosive deaths of primordial black holes.

Theorists have analyzed the case of a small emitter subjected to a periodic light field. Under the right circumstances, the emitter produces negative radiated power, a counterintuitive effect that defies the traditional concept of light emission.

Pasta Physics Scoops Up an Ig Nobel Prize A group of Italian physicists was awarded the Ig Nobel Prize in Physics for their study of the phase diagram of a cheesy sauce renowned in Italy.

How do you prevent cacio e pepe sauce from congealing? A thoroughly researched answer earned its authors a prize!

Predicting Sea Waves More Effectively Researchers have developed an improved technique for making wave-height predictions that mitigate gaps in data coverage and encompass rare, dangerously high waves.

Researchers have developed an algorithm that uses radar data to predict wave motion in rough seas a few minutes in advance. The problem is challenging because big nearby waves block the view and because big waves are nonlinear.

Experiments Refute Dark Matter Claim Two direct-detection experiments see no evidence of a signal reported by their predecessor.

A new study combining data from two dark-matter experiments has failed to find variability on the scale of Earth’s orbital period, casting doubt on a previous experiment that attributed annual variability to the presence of dark matter.

Bilayer Graphene Slides into Action Sliding one layer of bilayer graphene over the other provides a powerful way to tune the material’s electronic properties.

The electronic properties of twisted bilayer graphene can be tailored by adjusting the angle between the two layers. Now researchers have shown they can achieve similar results by sliding one sheet over the other without rotation.

Recreating Iceberg Flips in a Lab Experiments with small, floating slabs of ice have revealed melting-induced shape changes that may explain why icebergs sometimes flip over.

A new experiment that flipped iceberg analogues in the lab suggests that changes in shape due to melting determine if and how an iceberg tips over. The results could help improve climate models by providing a better picture of ice dynamics in the oceans.

Extending Spatial Light Modulation into the Ultraviolet An array of tiny spring-loaded mirrors creates intricate patterns of UV light for trapping and manipulating cold atoms.

Thanks to spatial light modulators (SLMs), any and all of thousands of optically trapped atoms can be moved back and forth in less than a millisecond. Now Researchers have demonstrated an SLM that works in the UV range.

Landmark Black Hole Test Marks Decade of Gravitational-Wave Discoveries The clearest black hole merger signal ever measured has allowed researchers to test the Kerr nature of black holes and validate Stephen Hawking’s black hole area theorem.

A new LIGO observation of merging black holes has confirmed a theorem formulated in 1971 by Stephen Hawking, which asserts that the total surface area of black hole horizons cannot decrease in time.

Dark Charge Could Make Exploding Black Holes More Common Primordial black holes could be stabilized by a dark, electromagnetic-like interaction, delaying their violent end until the present day.  

Black holes evaporate by emitting Hawking radiation. The process, which ends in the black hole exploding, is so slow that lightweight primordial black holes could be dying only now. Beyond-standard-model physics could hasten the process, boosting our chances of seeing a black hole explosion.

Diamond Defects Drive Dynamics A minuscule diamond containing billions of impurities can be induced to produce enough force to bend a cantilever.

Researchers have shown how defects called nitrogen vacancy centers can generate a spin-dependent force that is strong enough to bend a cantilever. The force might offer insights into the interplay between quantum physics and classical physics.

Envisioning a Neutrino Laser A Bose-Einstein condensate of radioactive atoms could turn into a source of intense, coherent, and directional neutrino beams, according to a theoretical proposal.

Researchers propose that a “neutrino laser” could be built from a Bose-Einstein condensate of radioactive atoms. The scheme would generate an intense, coherent beam of neutrinos that could be a transformative tool for neutrino studies and, consequently, for fundamental physics.

Salt Loss Dictates Sea-Ice Structure Experiments on freezing saltwater have teased apart flow dynamics inside ice pores, offering a possible boost to climate models’ predictive power.

Researchers have identified a physical process that’s been missing in models of how sea ice changes as it ages. Salt expelled from young ice decreases the ice's porosity over time, which, in turn, affects fluid flow, heat transfer, and other processes.

How to Switch an Antiferromagnet Two main mechanisms can flip the orientation of antiferromagnetic domains. Researchers have determined when one prevails over the other.

Once thought merely interesting, antiferromagnets are promising materials for applications—provided researchers can figure out how to toggle their magnetization.

Removing Classical Inputs from Quantum Gravity Tests Researchers suggest that unambiguous signals of quantum gravity could appear in future tabletop experiments with gravitationally interacting objects.

Some proposed tests for the quantumness of gravity could potentially give the same results as classical Newtonian gravity. Now researchers have devised a more definitive test.