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Researchers led by City College of New York physicist Pouyan Ghaemi report the development of a quantum algorithm with the potential to study a class of many-electron quantums system using quantum computers. Their paper, entitled “Creating and Manipulating a Laughlin-Type ν=1/3 Fractional Quantum Hall State on a Quantum Computer with Linear Depth Circuits,” appears in the December issue of PRX Quantum, a journal of the American Physical Society.

“Quantum physics is the fundamental theory of nature which leads to formation of molecules and the resulting matter around us,” said Ghaemi, assistant professor in CCNY’s Division of Science. “It is already known that when we have a macroscopic number of quantum particles, such as electrons in the metal, which interact with each other, novel phenomena such as superconductivity emerge.”

However, until now, according to Ghaemi, tools to study systems with large numbers of interacting quantum particles and their novel properties have been extremely limited.

Ira Pastor, ideaXme life sciences ambassador and CEO Bioquark interviews Dr. Michelle Francl the Frank B. Mallory Professor of Chemistry, at Bryn Mawr College, and an adjunct scholar of the Vatican Observatory.

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Continue reading “Tripping Over the Mysteries of the Universe: Molecules, Particles and People” »

A group of researchers led by Sir Andre Geim and Dr. Alexey Berdyugin at The University of Manchester have discovered and characterized a new family of quasiparticles named ‘Brown-Zak fermions’ in graphene-based superlattices.

The team achieved this breakthrough by aligning the atomic lattice of a graphene layer to that of an insulating boron nitride sheet, dramatically changing the properties of the graphene sheet.

The study follows years of successive advances in graphene-boron nitride superlattices which allowed the observation of a fractal pattern known as the Hofstadter’s butterfly—and today (Friday, November 13) the researchers report another highly surprising behavior of particles in such structures under applied magnetic field.

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.

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.

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 tantalum 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.

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 compounds, 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 reference frame 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 chemical 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.

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 nanographene; 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 hydrogen atoms from organic molecules of carbon and hydrogen, a process called dehydrogenation.

“Dehydrogenation takes place on a metal surface 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.”

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.