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Category: computing

Microfluidic chip reveals how living glioblastoma slices resist chemotherapy

Combining microchip engineering techniques with cutting-edge gene profiling, scientists at Columbia University have developed a new way to study drug responses in living slices of human brain tumor cells. The system, using a type of chip called a microfluidic device, has already revealed new details about how these aggressive tumors resist chemotherapy drugs and could help researchers develop more effective treatments.

The work grew from earlier efforts to study glioblastoma tumors removed from patients during surgery. “These samples that we’re getting from our colleagues who resect these tumors clinically, they’re alive, and we can actually do experiments directly on those surgical samples,” says Peter Sims, Ph.D., associate professor of systems biology at Columbia and senior author on the new study, which appears in the journal Lab on a Chip.

New memory chip survives temperatures hotter than lava

The electronics inside your phone, your car, and every satellite currently orbiting Earth share one critical weakness: heat. Push them past about 200 degrees Celsius and they start to fail. For decades, that thermal ceiling has been one of the hardest walls in engineering. Now a team at the University of Southern California may have just found a way around it.

In a study published in Science, researchers led by Joshua Yang, Arthur B. Freeman Chair Professor at the Ming Hsieh Department of Electrical and Computer Engineering of the USC Viterbi School of Engineering and the USC School of Advanced Computing, report a new type of electronic memory device that kept working reliably at 700 degrees Celsius, hotter than molten lava and far beyond anything previously achieved in its class. The device showed no signs of reaching its limit. Seven hundred degrees was simply as hot as their testing equipment could go.

“You may call it a revolution,” Yang said. “It is the best high-temperature memory ever demonstrated.”

Put a nanodiamond under intense pressure and it becomes flexible

Diamond is among the hardest naturally occurring substances on Earth, but if you shrink it down to the nanoscale, it is surprisingly elastic. And that could be useful for a host of applications such as quantum computing. In a paper published in the journal Physical Review X, Chongxin Shan at Zhengzhou University in China and colleagues studied diamonds as small as four nanometers across to see how they respond to pressure.

Scientists already know that nanodiamonds, which are thousands of times smaller than a grain of sand, can survive being stretched or squeezed in ways that destroy a regular diamond. But nobody knew how.

So the team placed individual nanodiamonds (ranging from 4 to 13 nanometers across) inside a transmission electron microscope between two diamond indenters and compressed them. These were connected to a sensor that measured how strongly each nanodiamond resisted being squeezed while a high-resolution camera imaged diamond atoms as they moved. The researchers backed up their observations with computer simulations.

Laser bursts flip nanoscale magnetic vortices at blistering speeds, opening a path to brain-like spintronics

Spintronics are devices that operate leveraging the spin, an intrinsic form of angular momentum, of electrons. The ability to switch magnetic states is central to the functioning of these devices, as it ultimately allows them to represent binary digits (i.e., “0” and “1”) when processing or storing information.

Some of these devices rely on magnetic vortices, nanoscale whirlpool-like patterns of magnetization that influence the alignment of spins. These vortices possess a property known as helicity, which is essentially the direction in which they rotate.

Reliably switching the helicity of magnetic vortices could open new possibilities for both neuromorphic computing systems, devices that mimic the brain’s neural organization, and multi-state memories. So far, however, this has proved challenging, mainly because it requires a synchronized wave-like rotation of spins without disrupting the geometric structure of vortices.

Pressure-tuned quantum spin liquid-like behavior observed in material Y-kapellasite

A quantum spin liquid is a phase of matter in which the magnetic moments in a material do not align or freeze, even at temperatures close to absolute zero (i.e., at 0 K). The experimental realization of this highly dynamic state could have important implications for the development of quantum computers and other technologies that operate leveraging quantum mechanical effects.

Previous studies have collected evidence that a quantum spin liquid phase emerges in various materials, including herbertsmithite, α-RuCl3, and EtMe3Sb[Pd(dmit)2]2. However, so far none of these materials have been conclusively confirmed to host this state.

Researchers at University Paris-Saclay-CNRS, University of Stuttgart and other institutes in Europe gathered evidence of quantum spin liquid-like behavior in a recently discovered material called Y-kapellasite. Their paper, published in Physical Review Letters, shows that this material is a promising experimental platform for studying exotic states of matter, particularly those driven by quantum magnetism.

ATLAS acts as a cosmic-ray laboratory with first measurement of proton–oxygen collisions

Tens of kilometers above Earth’s surface, high-energy particles from outer space constantly strike the atmosphere, creating showers of energetic secondary particles that rain down from the sky. Approximately one of these particles passes through your head every second, but the “cosmic rays” that produce them are still not fully understood. In a recent paper posted to the arXiv preprint server, the ATLAS Collaboration describes how its first measurement of proton–oxygen collisions at the LHC could help us learn more about them.

Cosmic rays were discovered over a century ago by physicist Victor Hess in experiments conducted aboard hot-air balloons. Today, astrophysicists use detectors on the ground to image cosmic-ray showers and computer simulations of the showers to understand that data.

However, these simulations depend on properties of the strong force—one of the fundamental forces of the universe—which is difficult to accurately model. Current simulations disagree with one another, making it difficult for astrophysicists to interpret their measurements of cosmic rays.

Universal Quantum Computing as a Markov Chain

Let’s say you have a probabilistic computer with a single bit of memory. Some algorithms on the computer will stochastically flip the single bit of memory such that its new value will be uniformly distributed with a 50% chance of being 0 and a 50% chance of being 1. Other programs will place it into a degenerate distribution, meaning it either has 100% chance of being 0 every time you run the program, or other programs will produce 1 100% of the time.

A magician tells you to run one of the programs in one of the two categories of your choosing and then copy the computer’s memory state onto a thumb drive and hand it to him. You pick one, run the program, copy the bit of the memory to your thumb drive, then hand it to the magician. The magician then does something with the thumb drive you cannot see, then looks up at you and tell you exactly what category the program you ran to produce that bit came from.

Curious, you repeat this many times over: you run a program from one of the two categories (degenerate or uniform), copy the bit value produced from the algorithm, and then hand the thumb drive to the magician. Each and every time he always correctly guesses which category of program was ran to produce it.

A long-sought quantum computing milestone arrives as fermionic atom gates top 99% accuracy

Two independent research teams have each demonstrated collisional quantum gates using fermionic atoms: a long-sought milestone in quantum computing where logic operations are performed through the direct physical overlap of atoms, rather than forcing them into fragile, highly excited states.

The studies have been published simultaneously in Nature: the first led by Petar Bojović at the Max Planck Institute for Quantum Optics in Garching, Germany, and the second by Yann Kiefer and colleagues at ETH Zurich, Switzerland.

Two paths to scalable quantum computing: Optical links between fridges and higher-temperature qubits

Superconducting qubits—bits of quantum information—have been widely considered a promising technology for moving quantum computing forward. But there’s still much work to be done before they can be brought out of a near absolute zero temperature environment. The lab of Professor Hong Tang has recently published two studies that advance the technology.

To solve practical problems, quantum processors need a lot of qubits—up to thousands to millions. Such a large number of qubits requires significantly complex wiring and a way to store them at a temperature colder than deep space. This is complicated by the physical size of the cryogenic devices, known as dilution refrigerators, that maintain qubits at a temperature just above absolute zero. In a study published in Nature Photonics, Tang’s research team has found a way around this obstacle.

A flexible and cost-effective solution is to build a quantum network by connecting qubits inside separate refrigerators. Connecting qubits with standard coaxial cables, however, wouldn’t work if those cables were kept in a room temperature environment. And storing them all in one very cold room would be near impossible. Even under an optimistic assumption of 1,000 qubits per refrigerator, scaling to 1 million qubits would require linking 1,000 refrigerators—an arrangement that is physically impractical within a single room.

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