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Synthetic microparticles more intricate than some of the most complicated ones found in nature have been produced by a University of Michigan-led international team. They also investigated how that intricacy arises and devised a way to measure it.

The findings pave the way for more stable fluid-and-particle mixes, such as paints, and new ways to twist light—a prerequisite for holographic projectors.

The particles are composed of twisted spikes arranged into a ball a few microns, or millionths of a meter, across.

Error free qubits o.,o.

Physicists at MIT and elsewhere have observed evidence of Majorana fermions—particles that are theorized to also be their own antiparticle—on the surface of a common metal: gold. This is the first sighting of Majorana fermions on a platform that can potentially be scaled up. The results, published in the Proceedings of the National Academy of Sciences, are a major step toward isolating the particles as stable, error-proof qubits for quantum computing.

In particle physics, fermions are a class of elementary particles that includes electrons, protons, neutrons, and quarks, all of which make up the building blocks of matter. For the most part, these particles are considered Dirac fermions, after the English physicist Paul Dirac, who first predicted that all fermionic fundamental particles should have a counterpart, somewhere in the universe, in the form of an antiparticle—essentially, an identical twin of opposite charge.

Continue reading “First sighting of mysterious Majorana fermion on a common metal” »

O,.,o.

Since their invention in the 1930s, electron microscopes have helped scientists peer into the atomic structure of ordinary materials like steel, and even exotic graphene. But despite these advances, such imaging techniques cannot precisely map out the 3D atomic structure of materials in a liquid solution, such as a catalyst in a hydrogen fuel cell, or the electrolytes in your car’s battery.

Now, researchers at Berkeley Lab, in collaboration with the Institute for Basic Science in South Korea, Monash University in Australia, and UC Berkeley, have developed a technique that produces atomic-scale 3D images of nanoparticles tumbling in liquid between sheets of graphene, the thinnest material possible.

Continue reading “Scientists capture 3D images of nanoparticles, atom” »

In nuclear physics, like much of science, detailed theories alone aren’t always enough to unlock solid predictions. There are often too many pieces, interacting in complex ways, for researchers to follow the logic of a theory through to its end. It’s one reason there are still so many mysteries in nature, including how the universe’s basic building blocks coalesce and form stars and galaxies. The same is true in high-energy experiments, in which particles like protons smash together at incredible speeds to create extreme conditions similar to those just after the Big Bang.

Fortunately, scientists can often wield simulations to cut through the intricacies. A simulation represents the important aspects of one system—such as a plane, a town’s traffic flow or an atom—as part of another, more accessible system (like a computer program or a scale model). Researchers have used their creativity to make simulations cheaper, quicker or easier to work with than the formidable subjects they investigate—like proton collisions or black holes.

Simulations go beyond a matter of convenience; they are essential for tackling cases that are both too difficult to directly observe in experiments and too complex for scientists to tease out every logical conclusion from basic principles. Diverse research breakthroughs—from modeling the complex interactions of the molecules behind life to predicting the experimental signatures that ultimately allowed the identification of the Higgs boson—have resulted from the ingenious use of simulations.

Since the original work on Bose–Einstein condensation^1,2, the use of quantum degenerate gases of atoms has enabled the quantum emulation of important systems in condensed matter and nuclear physics, as well as the study of many-body states that have no analogue in other fields of physics³. Ultracold molecules in the micro- and nanokelvin regimes are expected to bring powerful capabilities to quantum emulation⁴ and quantum computing⁵, owing to their rich internal degrees of freedom compared to atoms, and to facilitate precision measurement and the study of quantum chemistry⁶. Quantum gases of ultracold atoms can be created using collision-based cooling schemes such as evaporative cooling, but thermalization and collisional cooling have not yet been realized for ultracold molecules. Other techniques, such as the use of supersonic jets and cryogenic buffer gases, have reached temperatures limited to above 10 millikelvin^7,8. Here we show cooling of NaLi molecules to micro- and nanokelvin temperatures through collisions with ultracold Na atoms, with both molecules and atoms prepared in their stretched hyperfine spin states. We find a lower bound on the ratio of elastic to inelastic molecule–atom collisions that is greater than 50—large enough to support sustained collisional cooling. By employing two stages of evaporation, we increase the phase-space density of the molecules by a factor of 20, achieving temperatures as low as 220 nanokelvin. The favourable collisional properties of the Na–NaLi system could enable the creation of deeply quantum degenerate dipolar molecules and raises the possibility of using stretched spin states in the cooling of other molecules.

You know the scene in “Akira” where Tetsuo rips a satellite space weapon out of orbit?

https://www.youtube.com/watch?v=pxh-IjxG2KY

Now the U.S. military wants to try something similar, according to Defense One. The Pentagon is requesting hundreds of millions of dollars to ramp up space-based weaponry including particle beams and space lasers that’ll fire downward at Earthly targets — a dark vision of the militarization of space.

Rydberg atoms, which are atoms in a highly excited state, have several unique and advantageous properties, including a particularly long lifetime and large sensitivities to external fields. These properties make them valuable for a variety of applications, for instance for the development of quantum technologies.

In order for Rydberg atoms to be effectively used in quantum technology, however, researchers first need to be able to trap them. While a number of studies have demonstrated the trapping of Rydberg atoms using magnetic, electric, or laser technology, the trapping times achieved so far have been relatively short, typically around 100μs.

Researchers at Laboratoire Kastler Brossel (LKB) have recently achieved a longer 2-D laser trapping time of circular Rydberg atoms of up to 10 ms. The method they employed, outlined in a paper published in Physical Review Letters, could open up exciting new possibilities for the development of quantum technology.

New particles sensitive to the strong interaction might be produced in abundance in the proton-proton collisions generated by the Large Hadron Collider (LHC) – provided that they aren’t too heavy. These particles could be the partners of gluons and quarks predicted by supersymmetry (SUSY), a proposed extension of the Standard Model of particle physics that would expand its predictive power to include much higher energies. In the simplest scenarios, these “gluinos” and “squarks” would be produced in pairs, and decay directly into quarks and a new stable neutral particle (the “neutralino”), which would not interact with the ATLAS detector. The neutralino could be the main constituent of dark matter.

The ATLAS Collaboration has been searching for such processes since the early days of LHC operation. Physicists have been studying collision events featuring “jets” of hadrons, where there is a large imbalance in the momenta of these jets in the plane perpendicular to the colliding protons (“missing transverse momentum,” E_T^miss). This missing momentum would be carried away by the undetectable neutralinos. So far, ATLAS searches have led to increasingly tighter constraints on the minimum possible masses of squarks and gluinos.

Is it possible to do better with more data? The probability of producing these heavy particles decreases exponentially with their masses, and thus repeating the previous analyses with a larger dataset only goes so far. New, sophisticated methods that help to better distinguish a SUSY signal from the background Standard Model events are needed to take these analyses further. Crucial improvements may come from increasing the efficiency for selecting signal events, improving the rejection of background processes, or looking into less-explored regions.

For years, scientists have looked for ways to cool molecules down to ultracold temperatures, at which point the molecules should slow to a crawl, allowing scientists to precisely control their quantum behavior. This could enable researchers to use molecules as complex bits for quantum computing, tuning individual molecules like tiny knobs to carry out multiple streams of calculations at a time.

While scientists have super-cooled atoms, doing the same for molecules, which are more complex in their behavior and structure, has proven to be a much bigger challenge.

Now MIT physicists have found a way to cool molecules of sodium lithium down to 200 billionths of a Kelvin, just a hair above absolute zero. They did so by applying a technique called collisional cooling, in which they immersed molecules of cold sodium lithium in a cloud of even colder sodium atoms. The ultracold atoms acted as a refrigerant to cool the molecules even further.