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Category: particle physics

In 1934, theoretical physicist Eugene Wigner proposed a new type of crystal.

If the density of negatively charged electrons could be maintained below a certain level, the subatomic particles could be held in a repeating pattern to create a crystal of electrons; this idea came to be known as a Wigner crystal.

The first time a Wigner crystal was experimentally observed was in 1979, when researchers measured an electron-liquid to electron-crystal phase transition using helium; since then, such crystals have been detected numerous times.

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Most materials used for optical lighting applications need to produce a uniform illumination and require high mechanical and hydrophobic properties. However, they are rarely eco-friendly. Herein, a bio-based, polymer matrix-free, luminescent, and hydrophobic film with excellent mechanical properties for optical lighting purposes is demonstrated. A template is prepared by turning a wood veneer into porous scaffold from which most of the lignin and half of the hemicelluloses are removed. The infiltration of quantum dots (CdSe/ZnS) into the porous template prior to densification resulted in almost uniform luminescence (isotropic light scattering) and could be extended to various quantum dot particles, generating different light colors. In a subsequent step, the luminescent wood film is coated with hexadecyltrimethoxysilane (HDTMS) via chemical vapor deposition. The presence of the quantum dots coupled with the HDTMS coating renders the film hydrophobic (water contact angle ≈ 140°). This top-down process strongly eliminates lumen cavities and preserves the orientation of the original cellulose fibrils to create luminescent and polymer matrix-free films with high modulus and strength in the direction of fibers. The proposed optical lighting material could be attractive for interior designs (e.g., lamps and laminated cover panels), photonics, and laser devices.

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An international team of scientists have unveiled the world’s first production of a purified beam of neutron-rich, radioactive tantalum ions. This development could now allow for lab-based experiments on exploding stars helping scientists to answer long-held questions such as “where does gold come from?”

In a paper published in Physical Review Letters, the University of Surrey together with its partners detail how they used a new isotope-separation facility, called KISS, which is developed and operated by the Wako Nuclear Science Centre (WNSC) in the High Energy Accelerator Research Organization (KEK), Japan, to make beams of heavy isotopes.

The chemical element of tantalum is extremely difficult to vaporize, so the team had to capture radioactive tantalum atoms in high-pressure argon gas, ionizing the atoms with precisely tuned lasers. A single isotope of radioactive tantalum could then be selected for detailed investigation.

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Scientists have long sought a system for predicting the properties of materials based on their chemical composition. In particular, they set sights on the concept of a chemical space that places materials in a reference frame such that neighboring chemical elements and compounds plotted along its axes have similar properties. This idea was first proposed in 1984 by the British physicist, David G. Pettifor, who assigned a Mendeleev number (MN) to each element. Yet the meaning and origin of MNs were unclear. Scientists from the Skolkovo Institute of Science and Technology (Skoltech) puzzled out the physical meaning of the mysterious MNs and suggested calculating them based on the fundamental properties of atoms. They showed that both MNs and the chemical space built around them were more effective than empirical solutions proposed until then. Their research supported by a grant from the Russian Science Foundation’s (RSF) World-class Lab Research Presidential Program was presented in The Journal of Physical Chemistry C.

Systematizing the enormous variety of chemical , both known and hypothetical, and pinpointing those with a particularly interesting property is a tall order. Measuring the properties of all imaginable compounds in experiments or calculating them theoretically is downright impossible, which suggests that the search should be narrowed down to a smaller space.

David G. Pettifor put forward the idea of chemical space in the attempt to somehow organize the knowledge about material properties. The chemical space is basically a where elements are plotted along the axes in a certain sequence such that the neighboring elements, for instance, Na and K, have similar properties. The points within the space represent compounds, so that the neighbors, for example, NaCl and KCl, have similar properties, too. In this setting, one area is occupied by superhard materials and another by ultrasoft ones. Having the space at hand, one could create an algorithm for finding the best material among all possible compounds of all elements. To build their “smart” map, Skoltech scientists, Artem R. Oganov and Zahed Allahyari, came up with their own universal approach that boasts the highest predictive power as compared to the best-known methods.

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Nanographene is a material that could radically improve solar cells, fuel cells, LEDs and more. Typically, the synthesis of this material has been imprecise and difficult to control. For the first time, researchers have discovered a simple way to gain precise control over the fabrication of nanographene. In doing so, they have shed light on the previously unclear chemical processes involved in nanographene production.

Graphene, one-atom-thick sheets of carbon molecules, could revolutionize future technology. Units of graphene are known as ; these are tailored to specific functions, and as such, their fabrication process is more complicated than that of generic graphene. Nanographene is made by selectively removing from organic molecules of carbon and hydrogen, a process called dehydrogenation.

“Dehydrogenation takes place on a such as that of silver, gold or copper, which acts as a catalyst, a material that enables or speeds up a reaction,” said Assistant Professor Akitoshi Shiotari from the Department of Advanced Materials Science. “However, this surface is large relative to the target organic molecules. This contributes to the difficulty in crafting specific nanographene formations. We needed a better understanding of the catalytic process and a more precise way to control it.”

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The finding marks a major breakthrough in a search of almost 20 years, carried out in particle physics labs all over the world.

To understand what a tetraquark is and why the discovery is important, we need to step back in time to 1964, when particle physics was in the midst of a revolution. Beatlemania had just exploded, the Vietnam war was raging and two young radio astronomers in New Jersey had just discovered the strongest evidence ever for the Big Bang theory.

On the other side of the U.S., at the California Institute of Technology, and on the other side of the Atlantic, at CERN in Switzerland, two particle physicists were publishing two independent papers on the same subject. Both were about how to make sense of the enormous number of new particles that had been discovered over the past two decades.

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As the icy, ocean-filled moon Europa orbits Jupiter, it withstands a relentless pummeling of radiation. Jupiter zaps Europa’s surface night and day with electrons and other particles, bathing it in high-energy radiation. But as these particles pound the moon’s surface, they may also be doing something otherworldly: making Europa glow in the dark.

New research from scientists at NASA’s Jet Propulsion Laboratory in Southern California details for the first time what the glow would look like, and what it could reveal about the composition of ice on Europa’s . Different salty compounds react differently to the radiation and emit their own unique glimmer. To the naked eye, this glow would look sometimes slightly green, sometimes slightly blue or white and with varying degrees of brightness, depending on what material it is.

Scientists use a spectrometer to separate the light into wavelengths and connect the distinct “signatures,” or spectra, to different compositions of ice. Most observations using a spectrometer on a moon like Europa are taken using reflected sunlight on the moon’s dayside, but these new results illuminate what Europa would look like in the dark.

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Most efforts to combat the coronavirus have focused on public health measures and the race to develop a vaccine. However, a team from Columbia University, Cornell University, and others has developed something new: a nasal spray that attacks the virus directly. In a newly released study, the concoction was effective at deactivating the novel coronavirus before it could infect cells.

Like all viruses, SARS-CoV-2 (the causative agent of COVID-19) needs to enter a cell to reproduce. The virus injects its RNA genome and hijacks cellular machinery to make copies of itself, eventually killing the cell and spreading new virus particles to infect other cells. Gaining access to a cell requires a “key” that fits into a protein lock on the cell surface. In the case of SARS-CoV-2, we call that the spike protein, and that’s where the new nasal spray blocker attacks.

The spike protein “unzips” when it meets up with a cell, exposing two chains of amino acids (the building blocks of proteins). The spray contains a lipoprotein, which has a complementary strand of amino acids linked with a cholesterol particle. The lipoprotein inserts itself into the spike protein, sticking to one of the chains that would otherwise bind to a receptor and allow the virus to infect the cell. With that lipoprotein in the way, the virus is inactivated.

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Superconductors – materials in which electricity flows without any resistance whatsoever – could be extremely useful for future electronics. Now, engineers at the University of Tokyo have managed to create a superconductor out of a state of matter called a Bose-Einstein condensate (BEC) for the first time ever.

Sometimes called the fifth state of matter, behind the more commonly known solids, liquids, gases and plasmas, Bose-Einstein condensates are what happens when you cool a gas of bosons right down to almost the coldest temperature possible. Experiments have shown that at this point, quantum phenomena can be observed at the macro scale. Scientists have used BECs as a starting point to create exotic states of matter like supersolids, excitonium, quantum ball lightning, and fluids exhibiting negative mass.

“A BEC is a unique state of matter as it is not made from particles, but rather waves,” says Kozo Okazaki, lead author of the study. “As they cool down to near absolute zero, the atoms of certain materials become smeared out over space. This smearing increases until the atoms – now more like waves than particles – overlap, becoming indistinguishable from one another. The resulting matter behaves like it’s one single entity with new properties the preceding solid, liquid or gas states lacked.”

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Scientists have successfully teleported a three-dimensional quantum state. The international effort between Chinese and Austrian scientists could be crucial for the future of quantum computers.

The researchers, from Austrian Academy of Sciences, the University of Vienna, and University of Science and Technology of China, were able to teleport the quantum state of one photon to another distant state. The three-dimensional transportation is a huge leap forward. Previously, only two-dimensional quantum teleportation of qubits has been possible. By entering a third dimension, the scientists were able to transport a more advanced unit of quantum information known as a “qutrit.”

Quantum computing is different than what’s known as classical computing, which is what powers phones and laptops. These traditional devices store information in bits, which are represented with a binary 0 or 1. A good metaphor is to imagine a circle, where each 0 and 1 are on opposite points. In Quantum computing, which deals with atomic and subatomic particles, qubits can exist at both of those points as well as anywhere else in the circle.

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