Electromagnetic Wave Technology

In the ETH experiment, self-oscillations (blue-red) cause sound waves (green, orange, violet) to travel through the circulator only in one direction. Credit: Xin Zou

Researchers at ETH Zurich have managed to make sound waves travel only in one direction. In the future, this method could also be used in technical applications with electromagnetic waves.

Water, light and sound waves usually propagate in the same way forward as in a backward direction. As a consequence, when we are speaking to someone standing some distance away from us, that person can hear us as well as we can hear them. This is useful when having a conversation, but in some technical applications one would prefer the waves to be able to travel only in one direction—for instance, in order to avoid unwanted reflections of light or microwaves.

Ten years ago, researchers succeeded in suppressing sound wave propagation in the backward direction; however, this also attenuated the waves traveling forwards.       READ MORE...

Nanoscale Imaging Capabilities

Dynamic nuclear polarization (DNP) has revolutionized the field of nanoscale nuclear magnetic resonance (NMR), making it possible to study a wider range of materials, biomolecules and complex dynamic processes such as how proteins fold and change shape inside a cell.

A team of researchers at the University of Waterloo are combining pulsed DNP with nanoscale magnetic resonance force microscopy (MRFM) measurements to demonstrate that this process can be implemented on the nanoscale with high efficiency. The effort is overseen by Dr. Raffi Budakian, faculty member of the Institute for Quantum Computing and a professor in the Department of Physics and Astronomy, and his team consisting of Sahand Tabatabaei, Pritam Priyadarshi , Namanish Singh, Pardis Sahafi, and Dr. Daniel Tay.

"Large-Enhancement Nanoscale Dynamic Nuclear Polarization Near a Silicon Nanowire Surface" was published in Science Advances on Wednesday, August 21.          READ MORE...

Plasma Instabilities Observed

Whether between galaxies or within doughnut-shaped fusion devices known as tokamaks, the electrically charged fourth state of matter known as plasma regularly encounters powerful magnetic fields, changing shape and sloshing in space. 

Now, a new measurement technique using protons, subatomic particles that form the nuclei of atoms, has captured details of this sloshing for the first time, potentially providing insight into the formation of enormous plasma jets that stretch between the stars.

Scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) created detailed pictures of a magnetic field bending outward because of the pressure created by expanding plasma. 

As the plasma pushed on the magnetic field, bubbling and frothing known as magneto-Rayleigh Taylor instabilities arose at the boundaries, creating structures resembling columns and mushrooms.          READ MORE...

New Species of Extinct Walrus

A new discovery by a team of paleontologists, led by Dr. Mathieu Boisville (University of Tsukuba, Japan), has uncovered a new species of the extinct genus Ontocetus from the Lower Pleistocene deposits in the North Atlantic. 

This species, named Ontocetus posti, displays surprising similarities in feeding adaptations to the modern walrus (Odobenus rosmarus), highlighting an intriguing case of convergent evolution. The research is published in the journal PeerJ.         READ MORE...

The HIGGS Particle Keeps us Here

Tarantula nebula—a starforming region—seen by the James Webb Space Telescope. Credit: Nasa, ESA, CSA, STScI, Webb ERO Production Team, CC BY-SA

Although our universe may seem stable, having existed for a whopping 13.7 billion years, several experiments suggest that it is at risk—walking on the edge of a very dangerous cliff. And it's all down to the instability of a single fundamental particle: the Higgs boson.


In new research by me and my colleagues, just accepted for publication in Physical Letters B, we show that some models of the early universe, those which involve objects called light primordial black holes, are unlikely to be right because they would have triggered the Higgs boson to end the cosmos by now.

The Higgs boson is responsible for the mass and interactions of all the particles we know of. That's because particle masses are a consequence of elementary particles interacting with a field, dubbed the Higgs field. Because the Higgs boson exists, we know that the field exists.        READ MORE...

A photonic alloy with topological properties

Schematic diagram of a topological photonic alloy. The red star indicates the position of the line source, and the arrow indicates the direction of propagation of the chiral edge state. Credit: Qu et al.




Photonic alloys, alloy-like materials combining two or more photonic crystals, are promising candidates for the development of structures that control the propagation of electromagnetic waves, also known as waveguides. Despite their potential, these materials typically reflect light back in the direction where it originated.

This phenomenon, known as light backscattering, limits the transmission of data and energy, adversely impacting the materials' performance as waveguides. Reliably reducing or preventing light backscattering in photonic alloys will thus be a key milestone towards the practical use of these materials.

Researchers at Shanxi University and the Hong Kong University of Science and Technology recently fabricated a new photonic alloy with topological properties that enables the propagation of microwaves without light backscattering. This material, introduced in Physical Review Letters, could pave the way for the development of new topological photonic crystals.

"Our paper introduces a new concept: the topological photonic alloy as a nonperiodic topological material," Lei Zhang, co-author of the paper, told Phys.org. "We achieved this by combining non-magnetized and magnetized rods in a nonperiodic 2D photonic crystal configuration. This created photonic alloys that sustain chiral edge states in the microwave regime."            READ MORE...

Quantum Mechanics in Ultra Cold

There's a hot new BEC in town that has nothing to do with bacon, egg, and cheese. You won't find it at your local bodega, but in the coldest place in New York: the lab of Columbia physicist Sebastian Will, whose experimental group specializes in pushing atoms and molecules to temperatures just fractions of a degree above absolute zero.


Writing in Nature, the Will lab, supported by theoretical collaborator Tijs Karman at Radboud University in the Netherlands, has successfully created a unique quantum state of matter called a Bose-Einstein Condensate (BEC) out of molecules.

Their BEC, cooled to just five nanoKelvin, or about -459.66°F, and stable for a strikingly long two seconds, is made from sodium-cesium molecules. Like water molecules, these molecules are polar, meaning they carry both a positive and a negative charge. 

The imbalanced distribution of electric charge facilitates the long-range interactions that make for the most interesting physics, noted Will.     READ MORE...

Microbe Fingerprints

When you think of a criminal investigation, you might picture detectives meticulously collecting and analyzing evidence found at the scene: weapons, biological fluids, footprints and fingerprints. However, this is just the beginning of an attempt to reconstruct the events and individuals involved in the crime.


At the heart of the process lies the "principle of exchange" formulated by the French criminologist Edmond Locard in the early 1900s, which states that "every contact leaves a trace." The transfer of materials between the parties involved in a crime (the victim, the perpetrator, objects, the environment) forms the basis for reconstructing the events.

In Locard's time, these traces were typically things you could see with a magnifying glass or microscope, such as pollen, sand and fibers. However, such evidence is limited because much of it is not directly associated with a specific individual.     READ MORE...

Space Glass

Thanks to human ingenuity and zero gravity, we reap important benefits from science in space. Consider smart phones with built-in navigation systems and cameras.


Such transformational technologies seem to blend into the rhythm of our everyday lives overnight. But they emerged from years of discoveries and developments of materials that can withstand harsh environments outside our atmosphere. 

They evolve from decades of laying foundations in basic science to understand how atoms behave in different materials under different conditions.     READ MORE...

Archaeological Mystery Solved

Ancient symbols on a 2,700-year-old temple, which have baffled experts for more than a century, have been explained by Trinity Assyriologist Dr. Martin Worthington.

The sequence of "mystery symbols" was on view on temples at various locations in ancient city of Dūr-Šarrukīn, present-day Khorsabad, Iraq, which was ruled by Sargon II, king of Assyria (721–704 BC).

The sequence of five symbols—a lion, eagle, bull, fig tree and plow—was first made known to the modern world through drawings published by French excavators in the late nineteenth century. Since then, there has been a spate of ideas about what the symbols might mean.     READ MORE...

Exploring Exotic States of Matter

Proximity is key for many quantum phenomena, as interactions between atoms are stronger when the particles are close. In many quantum simulators, scientists arrange atoms as close together as possible to explore exotic states of matter and build new quantum materials.


They typically do this by cooling the atoms to a standstill, then using laser light to position the particles as close as 500 nanometers apart—a limit that is set by the wavelength of light. Now, MIT physicists have developed a technique that allows them to arrange atoms in much closer proximity, down to a mere 50 nanometers. For context, a red blood cell is about 1,000 nanometers wide.


The physicists have demonstrated the new approach in experiments with dysprosium, which is the most magnetic atom in nature. They used the new approach to manipulate two layers of dysprosium atoms and positioned the layers precisely 50 nanometers apart. At this extreme proximity, the magnetic interactions were 1,000 times stronger than if the layers were separated by 500 nanometers.     READ MORE...

The Entropy of Quantum Entanglement

Bartosz Regula from the RIKEN Center for Quantum Computing and Ludovico Lami from the University of Amsterdam have shown, through probabilistic calculations, that there is indeed, as had been hypothesized, a rule of entropy for the phenomenon of quantum entanglement.


This finding could help drive a better understanding of quantum entanglement, which is a key resource that underlies much of the power of future quantum computers. Little is currently understood about the optimal ways to make effective use of it, despite it being the focus of research in quantum information science for decades.


The second law of thermodynamics, which says that a system can never move to a state with lower entropy, or order, is one of the most fundamental laws of nature, and lies at the very heart of physics. It is what creates the "arrow of time," and tells us the remarkable fact that the dynamics of general physical systems, even extremely complex ones such as gases or black holes, are encapsulated by a single function, its entropy.     READ MORE...

Quantum Challenge Solved Underground

Radiation from space is a challenge for quantum computers as their computation time becomes limited by cosmic rays. Researchers from Chalmers University of Technology, Sweden, and University of Waterloo in Canada are now going deep underground in the search for a solution to this problem—in a two-kilometer-deep mine.

A recently discovered cause of errors in quantum computers is cosmic radiation. Highly charged particles from space disturb the sensitive qubits and cause them to lose their quantum state, as well as the ability to continue a calculation. 

But now quantum researchers from Sweden and Canada will join forces to find a solution to the problem—in the world's deepest located clean room, two kilometers underground.  READ MORE...

7,000-Year-Old Settlement

Together with cooperation partners from the Museum of Vojvodina in Novi Sad (Serbia), the National Museum Zrenjanin and the National Museum Pančevo, a team from the ROOTS Cluster of Excellence has discovered a previously unknown Late Neolithic settlement near the Tamiš River in Northeast Serbia.

"This discovery is of outstanding importance, as hardly any larger Late Neolithic settlements are known in the Serbian Banat region," says team leader Professor Dr. Martin Furholt from the Institute of Prehistoric and Protohistoric Archaeology at Kiel University.

Geophysics reveals a 13-hectare settlement structure
The newly discovered settlement is located near the modern village of Jarkovac in the province of Vojvodina. With the help of geophysical methods, the team was able to fully map its extent in March of this year. It covers an area of 11 to 13 hectares and is surrounded by four to six ditches.     READ MORE...

The Universe & Dark Matter

Physicists have long theorized that our universe may not be limited to what we can see. By observing gravitational forces on other galaxies, they've hypothesized the existence of "dark matter," which would be invisible to conventional forms of observation.


Pran Nath, the Matthews Distinguished University Professor of physics at Northeastern University, says that "95% of the universe is dark, is invisible to the eye."


"However, we know that the dark universe is there by [its] gravitational pull on stars," he says. Other than its gravity, dark matter has never seemed to have much effect on the visible universe.    READ MORE...

New Subatomic Particle Detected

The BESIII collaboration have reported the observation of an anomalous line shape around ppbar mass threshold in the J/ψ→γ3(π+π-) decay, which indicates the existence of a ppbar bound state. The paper was published online in Physical Review Letters.

The proximity in mass to 2mp is suggestive of nucleon-antinucleon bound states, an idea that has a long history. Before the birth of Quark Model, a nucleon-antinucleon bound state was already proposed by Prof. E. Fermi and Prof. C. N. Yang.

There is an accumulation of evidence for anomalous behavior in the proton-antiproton system near the ppbar mass threshold, e.g., J/ψ→γppabr , J/ψ→γπ+π-η' and the proton's effective form factor determined from e+e-→ppbar, exhibiting a narrow peak or a very steep falloff around the ppbar mass threshold, which inspired many speculations and renewed the interests on the nucleon-antinucleon bound state.     READ MORE...

Physics of Complex Fluids

The shearing of fluids—meaning the sliding of fluid layers over each other under shear forces—is an important concept in nature and in rheology, the science that studies the flow behavior of matter, including liquids and soft solids. 

Shear forces are lateral forces applied parallel to a material, inducing deformation or slippage between its layers.

Fluid shear experiments allow the characterization of important rheological properties such as viscosity (resistance to deformation or flow) and thixotropy (decrease in viscosity under the influence of shear), which are important in applications ranging from industrial processes to medicine. 

Studies on the shear behavior of viscoelastic fluids created by introducing polymers into Newtonian fluids have already been conducted in recent years.     READ MORE...

World's Most Powerful Laser

"Ready? Signal sent!" In the control room of a research center in Romania, engineer Antonia Toma activates the world's most powerful laser, which promises revolutionary advances in everything from the health sector to space.


The laser at the center, near the Romanian capital Bucharest, is operated by French company Thales, using Nobel prize-winning inventions.

France's Gerard Mourou and Donna Strickland of Canada won the 2018 Nobel Physics Prize for harnessing the power of lasers for advanced precision instruments in corrective eye surgery and in industry.

"The sharp beams of laser light have given us new opportunities for deepening our knowledge about the world and shaping it," said the Nobel Academy's citation.    READ MORE...

Device Acts Like Superconductivity Switch

In particle colliders that reveal the hidden secrets of the tiniest constituents of our universe, minute particles leave behind extremely faint electrical traces when they are generated in enormous collisions. Some detectors in these facilities use superconductivity—a phenomenon in which electricity is carried with zero resistance at low temperatures—to function.


For scientists to more accurately observe the behavior of these particles, these weak electrical signals, or currents, need to be multiplied by an instrument capable of turning a faint electrical flicker into a real jolt.     READ MORE...

Rich Countries Use More Resources

The extraction of the Earth's natural resources tripled in the past five decades, related to the massive build-up of infrastructure in many parts of the world and the high levels of material consumption, especially in upper-middle and high-income countries.


Material extraction is expected to rise by 60% by 2060 and could derail efforts to achieve not only global climate, biodiversity, and pollution targets but also economic prosperity and human well-being, according to a report published today by the UN Environment Program (UNEP)-hosted International Resource Panel.

The 2024 Global Resource Outlook, developed by the International Resource Panel with authors from around the globe and launched during the sixth session of the UN Environment Assembly, calls for sweeping policy changes to bring humanity to live within its means and reduce this projected growth in resource use by one third while growing the economy, improving well-being, and minimizing environmental impacts.     READ MORE...