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Category: particle physics – Page 521

Coming Soon to a Processor Near You: Atom-Thick Transistors

Devices made with 2D semiconductors might start to appear sooner than you expected.

If there’s one thing about Moore’s Law that’s obvious to anyone, it’s that transistors have been made smaller and smaller as the years went on. Scientists and engineers have taken that trend to an almost absurd limit during the past decade, creating devices that are made of one-atom-thick layers of material.

The most famous of these materials is, of course, graphene, a hexagonal honeycomb-shaped sheet of carbon with outstanding conductivity for both heat and electricity, odd optical abilities, and incredible mechanical strength. But as a substance with which to make transistors, graphene hasn’t really delivered. With no natural bandgap—the property that makes a semiconductor a semiconductor—it’s just not built for the job.

Instead, scientists and engineers have been exploring the universe of transition metal dichalcogenides, which all have the chemical formula MX2. These are made up of one of more than a dozen transition metals (M) along with one of the three chalcogenides (X): sulfur, selenium, or tellurium. Tungsten disulfide, molybdenum diselenide, and a few others can be made in single-atom layers that (unlike graphene) are natural semiconductors. These materials offer the enticing prospect that we will be able to scale down transistors all the way to atom-thin components long after today’s silicon technology has run its course.

Keeping Track of the World’s Highest-Intensity Neutrino Beam

Essentially neutrino lasers could take out missiles and also hack missiles or nukes rendering them inert in defense practices.

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Scientists at the Fermi National Accelerator Laboratory (Fermilab) are working on research projects that aim to answer fundamental physics questions. How did the universe begin? What are dark matter and dark energy? What is the mass hierarchy of neutrinos? Are there other undiscovered particles beyond the currently known Standard Model of Particle Physics?

A Clock that Will Last Forever

Circa 2012

Imagine a clock that will keep perfect time forever or a device that opens new dimensions into quantum phenomena such as emergence and entanglement.

Imagine a clock that will keep perfect time forever, even after the heat-death of the universe. This is the “wow” factor behind a device known as a “space-time crystal,” a four-dimensional crystal that has periodic structure in time as well as space. However, there are also practical and important scientific reasons for constructing a space-time crystal. With such a 4D crystal, scientists would have a new and more effective means by which to study how complex physical properties and behaviors emerge from the collective interactions of large numbers of individual particles, the so-called many-body problem of physics. A space-time crystal could also be used to study phenomena in the quantum world, such as entanglement, in which an action on one particle impacts another particle even if the two particles are separated by vast distances.

A space-time crystal, however, has only existed as a concept in the minds of theoretical scientists with no serious idea as to how to actually build one – until now. An international team of scientists led by researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has proposed the experimental design of a space-time crystal based on an electric-field ion trap and the Coulomb repulsion of particles that carry the same electrical charge.

Microresonator Measures and Images Nanoparticles with High Degree of Sensitivity

#biophotonics #photonics

ONNA, Japan, Jan. 13, 2020 — Scientists at the Okinawa Institute of Science and Technology (OIST) Graduate University have developed a light-based device that can act as a biosensor, detecting biological substances in materials, such as harmful pathogens in food. The scientists said that their tool, an optical microresonator, is 280× more sensitive than current industry-standard biosensors, which can detect only cumulative effects of groups of particles, not individual molecules.

Precise measurements find a crack in universal physics

The concept of universal physics is intriguing, as it enables researchers to relate physical phenomena in a variety of systems, irrespective of their varying characteristics and complexities. Ultracold atomic systems are often perceived as ideal platforms for exploring universal physics, owing to the precise control of experimental parameters (such as the interaction strength, temperature, density, quantum states, dimensionality, and the trapping potential) that might be harder to tune in more conventional systems. In fact, ultracold atomic systems have been used to better understand a myriad of complex physical behavior, including those topics in cosmology, particle, nuclear, molecular physics, and most notably, in condensed matter physics, where the complexities of many-body quantum phenomena are more difficult to investigate using more traditional approaches.

Understanding the applicability and the robustness of universal is thus of great interest. Researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder have carried out a study, recently featured in Physical Review Letters, aimed at testing the limits to universality in an ultracold system.

“Unlike in other physical systems, the beauty of ultracold systems is that at times we are able to scrap the importance of the periodic table and demonstrate the similar phenomenon with any chosen atomic species (be it potassium, rubidium, lithium, strontium, etc.),” Roman Chapurin, one of the researchers who carried out the study, told Phys.org. “Universal behavior is independent of the microscopic details. Understanding the limitations of universal phenomenon is of great interest.”

Atomic tuning on cobalt enables an eightfold increase of hydrogen peroxide production

IBS scientists and their colleagues have recently report an ultimate electrocatalyst that addresses all of the issues that trouble H2O2 production. This new catalyst comprising the optimal Co-N4 molecules incorporated in nitrogen-doped graphene, Co1-NG(O), exhibits a record-high electrocatalytic reactivity, producing up to 8 times higher than the amount of H2O2 that can be generated from rather expensive noble metal-based electrocatalysts.

Just as we take a shower to wash away dirt and other particles, semiconductors also require a cleaning process. However, its cleaning goes to extremes to ensure even trace contaminants “leave no trace.” After all the chip fabrication materials are applied to a silicon wafer, a strict cleaning process is taken to remove residual particles. If this high-purity cleaning and particle-removal step goes wrong, electrical connections in the chip are likely to suffer from it. With ever-miniaturized gadgets on the market, the purity standards of the electronics industry reach a level equivalent to finding a needle in a desert.

That explains why (H2O2), a major electronic cleaning chemical, is one of the most valuable chemical feedstocks that underpins the chip-making industry. Despite the ever-growing importance of H2O2, its industry has been left with an energy-intensive and multi-step method known as the anthraquinone process. This is an environmentally unfriendly process which involves the hydrogenation step using expensive palladium catalysts. Alternatively, H2O2 can be synthesized directly from H2 and O2 gas, although the reactivity is still very poor and it requires high pressure. Another eco-friendly method is to electrochemically reduce oxygen to H2O2 a via 2-electron pathway. Recently, noble metal-based electrocatalysts (for example, Au-Pd, Pt-Hg, and Pd-Hg) have been demonstrated to show H2O2 productivity although such expensive investments have seen low returns that fail to meet the scalable industry needs.