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Category: computing – Page 7

Magnetic ‘sweet spots’ enable optimal operation of hole spin qubits

Quantum computers, systems that process information leveraging quantum mechanical effects, could reliably tackle various computational problems that cannot be solved by classical computers. These systems process information in the form of qubits, units of information that can exist in two states at once (0 and 1).

Hole spins, the intrinsic angular momentum of holes (i.e., missing electrons in semiconductors that can be trapped in nanoscale regions called quantum dots), have been widely used as qubits. These spins can be controlled using electric fields, as they are strongly influenced by a quantum effect known as spin-orbit coupling, which links the motion of particles to their magnetism.

Unfortunately, due to this spin-orbit coupling, hole spin qubits are also known to be highly vulnerable to noise, including random electrical disturbances that can prompt decoherence. This in turn can result in the loss of valuable quantum information.

Neuropsychiatric symptoms in cognitive decline and Alzheimer’s disease: biomarker discovery using plasma proteomics

Placental toxicology progress!

Commonly used in vitro and in vivo placental models capture key placental functions and toxicity mechanisms, but have significant limitations.

The physiological relevance of placental models varies, with a general hierarchy of simple in vitro complex in vitro/ organ-on-chip in vivo, but species-of origin considerations may alter their relevance to human physiology.

Cellular, rodent, human, and computational modeling systems provide insights into placental transport, physiology, and toxicology linked to maternal–fetal health.

Recent advances in 3D culture and microfluidic technologies offer more physiologically relevant models for studying the placenta.

Mathematical modeling approaches can integrate mechanistic physiological data and exposure assessments to define key toxicokinetic parameters.

Environmental chemical concentrations and omic data obtained from placental tissues can link toxicant influences on placental function to adverse birth outcomes.

Continue reading “Neuropsychiatric symptoms in cognitive decline and Alzheimer’s disease: biomarker discovery using plasma proteomics” | >

Why Jupiter and Saturn Have Different Polar Vortices

“Our study shows that, depending on the interior properties and the softness of the bottom of the vortex, this will influence the kind of fluid pattern you observe at the surface,” said Dr. Wanying Kang.

What processes are responsible for shaping Jupiter and Saturn’s polar weather? This is what a recent study published in the Proceedings of the National Academy of Sciences hopes to address as a team of scientists from the Massachusetts Institute of Technology (MIT) investigated how the polar vortex structures on Jupiter and Saturn could provide key insight into the interiors of both planets. This study has the potential to help scientists better understand the complex processes on gas giant planets, which could serve as analogs for gas giant exoplanets.

For the study, the researchers used a series of computer models to simulate how the vortex patterns on Jupiter and Saturn are produced. The motivation for this study comes from several years of spacecraft images and observations that clearly show both planets exhibiting very different polar vortex patterns. Until now, researchers have been stumped regarding the processes responsible for two different patterns on each planet. In the end, the researchers discovered that the planet’s interior composition is responsible for the polar vortex patterns. For example, Jupiter’s interior is comprised of light materials, resulting in a large area of smaller vortices. In contrast, Saturn’s interior is comprised of denser materials, resulting in one large vortex.

Bionic LiDAR system achieves beyond-retinal resolution through adaptive focusing

In a recent study, researchers from China have developed a chip-scale LiDAR system that mimics the human eye’s foveation by dynamically concentrating high-resolution sensing on regions of interest (ROIs) while maintaining broad awareness across the full field of view.

The study is published in the journal Nature Communications.

LiDAR systems power machine vision in self-driving cars, drones, and robots by firing laser beams to map 3D scenes with millimeter precision. The eye packs its densest sensors in the fovea (sharp central vision spot) and shifts gaze to what’s important. By contrast, most LiDARs use rigid parallel beams or scans that spread uniform (often coarse) resolution everywhere. Boosting detail means adding more channels uniformly, which explodes costs, power, and complexity.

Massive black hole mystery unlocked by researchers

It’s one of astronomy’s great mysteries: how did black holes get so big, so massive, so quickly. An answer to this cosmic conundrum has now been provided by researchers at Ireland’s Maynooth University (MU) and reported today in Nature Astronomy.

“We found that the chaotic conditions that existed in the early universe triggered early, smaller black holes to grow into the super-massive black holes we see later following a feeding frenzy which devoured material all around them,” says Daxal Mehta, a Ph.D. candidate in Maynooth University’s Department of Physics, who led the research.

“We revealed, using state-of-the-art computer simulations, that the first generation of black holes—those born just a few hundred million years after the Big Bang—grew incredibly fast, into tens of thousands of times the size of our sun.”

New insight into light-matter thermalization could advance neutral-atom quantum computing

Light and matter can remain at separate temperatures even while interacting with each other for long periods, according to new research that could help scale up an emerging quantum computing approach in which photons and atoms play a central role.

In a theoretical study published in Physical Review Letters, a University at Buffalo-led team reports that interacting photons and atoms don’t always rapidly reach thermal equilibrium as expected.

Thermal equilibrium is the process by which interacting particles exchange energy before settling at the same temperature, and it typically happens quickly when trapped light repeatedly interacts with matter. Under the right circumstances, however, physicists found that photons and atoms can instead settle at different—and in some cases opposite—temperatures for extended periods.

Innovative optical atomic clock could combine single-ion accuracy with multi-ion stability

For many years, cesium atomic clocks have been reliably keeping time around the world. But the future belongs to even more accurate clocks: optical atomic clocks. In a few years’ time, they could change the definition of the base unit second in the International System of Units (SI). It is still completely open, which of the various optical clocks will serve as the basis for this.

The large number of optical clocks that the Physikalisch-Technische Bundesanstalt (PTB), as a leading institute in this field, has realized could be joined by another type: an optical multi-ion clock with ytterbium-173 ions. It could combine the high accuracy of individual ions with the improved stability of several ions. This is the result of a cooperation between PTB and the Thai metrology institute NIMT.

The team led by Tanja Mehlstäubler reports on this in the current issue of the journal Physical Review Letters. The results are also interesting for quantum computing and, with a new look inside the atom, for fundamental research.

New cryogenic vacuum chamber cuts noise for quantum ion trapping

Even very slight environmental noise, such as microscopic vibrations or magnetic field fluctuations a hundred times smaller than Earth’s magnetic field, can be catastrophic for quantum computing experiments with trapped ions.

To address that challenge, researchers at the Georgia Tech Research Institute (GTRI) have developed an improved cryogenic vacuum chamber that helps reduce some common noise sources by isolating ions from vibrations and shielding them from magnetic field fluctuations. The new chamber also incorporates an improved imaging system and a radio frequency (RF) coil that can be used to drive ion transitions from within the chamber.

“There’s a lot of excitement around quantum computing today, and trapped ions are just one of the research platforms available, each with their own benefits and drawbacks,” explained Darian Hartsell, a GTRI research scientist who leads the project. “We are trying to mitigate multiple sources of noise in this chamber and make other improvements with one robust new design.”

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