Orbital computing: An amazing atomic-level tech for future computers | ExtremeTech

Orbital computing: An amazing atomic-level tech for future computers | ExtremeTech: He calls the idea “orbital computing” since the bit... would be the orbits of electrons around the nucleus of an atom. The goal is to be able to probe the electron clouds of single atoms using terahertz waves of just the right size.

In materials like these, the macroscopic properties (like conductance) are controlled mainly by electron orbits known as “d-orbitals.” The state of these d-orbitals can be readily observed with X-rays, and they can be controlled as easily as adjusting the temperature. But temperature or other gross manipulations are relatively slow ways to try to read or write data, compact bunches of T-rays does the trick much better.

'Accelerator on a chip' demonstrated

'Accelerator on a chip' demonstrated: ...electrons are first accelerated to near light-speed in a conventional accelerator. Then they are focused into a tiny, half-micron-high channel within a fused silica glass chip just half a millimeter long. The channel had been patterned with precisely spaced nanoscale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.

New evidence to aid search for charge 'stripes' in superconductors

New evidence to aid search for charge 'stripes' in superconductors: ...uncovering the detailed relationship between these stripe patterns and the appearance or disappearance of superconductivity is extremely difficult, particularly because the stripes that may accompany superconductivity are very likely moving, or fluctuating.


The scientists ground up crystals of the test material into a fine powder and placed samples of it in line with a beam of neutrons...


With increasing temperature, the scientists found that while the aspect ratio of the crystal structure changed, the displacements from average structure persisted, leading them to conclude by inference that the striped pattern of charge density also remained, even though it was no longer static.

"This is the first powder diffraction scattering evidence for fluctuating charge stripes above the temperature where we see static order..."

Team finds new way to use X-rays to probe properties of solid materials

Team finds new way to use X-rays to probe properties of solid materials: The energy and power density of incoming laser light can get so high that photons actually work together and nonlinear effects result from their interaction with matter. This results in materials greatly enhancing certain colors of light. In other words, if you irradiate a crystal with green light, the light that gets irradiated is actually red. This color can be precisely correlated with the structural properties of the material that is being analyzed.
Now, Alexander F�hlisch from the HZB and his team were able to observe through a series of experiments at Hamburg's short-pulse X-ray laser FLASH that these types of effects can also be achieved using soft X-rays and that this method works on solids as well. "Normally, inelastic scattering processes using soft X-rays are ineffective," explains Martin Beye, the study's primary author: "Our experiment allowed us to document how inelastic X-ray scattering can be intelligently intensified. Just like a laser, the different photons are actually working together and amplifying each other and we end up with a very high measurement signal."

One-of-a-kind spectrometer reads vibrations between atoms to find structures of molecules

One-of-a-kind spectrometer reads vibrations between atoms to find structures of molecules:

By measuring the vibrations between atoms using femtosecond-long laser pulses, the Rice lab of chemist Junrong Zheng is able to discern the positions of atoms within molecules without the restrictions imposed by X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) imaging.
The technique can capture the structure of molecules at room temperature or very low or high temperatures and in many kinds of samples...

 "The atoms in every molecule are always vibrating, and each bond between atoms vibrates at a certain frequency, and in a certain direction," he said. "We found that if we can measure the direction of one vibration and then another, then we can know the angle between these two vibrations – and therefore the angle between the bonds."
He said the researchers begin with the chemical formula and already know, through Fourier transform infrared spectroscopy, how many vibrational frequencies are contained in a given molecule. "Then we measure each vibrational mode, one by one. Once we get all the cross-angles, we can translate this to a model," he said.

Physicists Build Super-Powerful Tabletop Particle Accelerator | Popular Science

Physicists Build Super-Powerful Tabletop Particle Accelerator | Popular Science: "We have accelerated about half a billion electrons to 2 gigaelectronvolts over a distance of about 1 inch," Mike Downer, professor of physics says in a statement. "Until now that degree of energy and focus has required a conventional accelerator that stretches more than the length of two football fields. It's a downsizing of a factor of approximately 10,000..."

In order to create electrons of the energy level required to produce these X-rays, the team employed laser-plasma acceleration, which involves firing a brief but intensely powerful laser pulse into a puff of gas, using the Texas Petawatt Laser. Though the method was conceived of in the 1970s, a lack of sufficiently powerful lasers to perform it has kept scientists limited at 1 GeV accelerators.

Giant, Heavy and Hollow: Physicists Create Extreme Atoms

Giant, Heavy and Hollow: Physicists Create Extreme Atoms: “If you tune your X-rays properly, you can pick which shell you want to empty out first,” says Young. “Being able to control the inner-shell dynamics is very cool.” The current record for this kind of atom-hollowing was reported last November by a group at the Center for Free-electron Laser Science in Hamburg, Germany, which used the SLAC laser to strip away, from the inside out, the 36 inner electrons of a 54-electron-strong xenon atom...

In 2008, researchers led by Dunning reported that they had managed to squeeze the normally spread-out electron into a tight packet that briefly orbited the nucleus. Last year, they added radio waves that enabled that motion to be maintained indefinitely. “It only took a century, but we recreated Bohr's atom,” says Dunning proudly...

By 2002, two collaborations had been able to make as many as 50,000 atoms of antihydrogen, but the atoms quickly annihilated on the walls of their container. It took until 2010 before researchers at ALPHA showed how to trap the atoms using three magnets with a combined field sufficient to restrain antihydrogen, with its tiny magnetic moment. At that time, the antimatter was held for just 170 milliseconds, and only about one atom was trapped for every eight times the group ran the 20–30 minute experiment, says Hangst. But the team has improved its equipment to trap one atom per experiment, and hold it for about 1,000 seconds...

Laser empties atoms from the inside out

Laser empties atoms from the inside out: ...it is possible to remove the two most deeply bound electrons from atoms, emptying the inner most quantum shell and leading to a distinctive plasma state...


"At such extraordinary intensities electrons move at close to the speed of light and as they move they create perhaps the most intense X-rays ever observed on Earth. These X-rays empty the atoms from the inside out..."


The analysis showed the mechanism for hollow atom generation was not due to the collision of electrons or driven by the laser photons, but was driven by the resulting radiation field from the interaction.

New physics in iridium compounds

New physics in iridium compounds: The researchers looked at the electronic structure of Sr3CuIrO6, a compound in which the iridium atoms are surrounded by oxygen atoms in a slightly distorted octahedron.

Such a system is typically modeled by assuming that the octahedron is perfectly regular and thus the orbital degree of freedom is being quenched in certain ways. If the shape is not perfect, then the layout of the electron cloud is deformed, but previous research groups have assumed that minor irregularities made little difference and could be ignored. In this case, the structure of Sr3CuIrO6 is close to the ideal.

When the Brookhaven-led group gathered data on the actual structure, however, they found that the irregularity makes a noticeable and important change to the wave function, which thus deforms the orbitals of the active electrons, as shown in the graphic. When the spin couples to the orbitals, the effect cannot be ignored.

Tabletop X-rays light up : Nature News & Comment

Tabletop X-rays light up : Nature News: The tabletop sources rely on a technique called high-harmonic generation, in which laser light is passed through a medium that converts it to light of shorter wavelengths and higher frequencies. Shine a ruby laser into a quartz crystal, for example, and a beam of ultraviolet light comes out — albeit dimmer, but still focused like a laser beam.

Murnane and Kapteyn have pushed high-harmonic generation to its limits, with a system that uses an infrared laser as the source and pressurized helium gas as the medium. The laser creates a strong electric field, which draws electrons away from the helium atoms, allowing the electrons to absorb energy from the electric field. When they slam back in to the helium atoms, they release that absorbed energy as shorter-wavelength photons — but only about one photon comes out for every 5,000 infrared photons that are put in.