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Category: computing – Page 23

Caltech Team Sets Record with 6,100-Qubit Array

Quantum computers will need large numbers of qubits to tackle challenging problems in physics, chemistry, and beyond. Unlike classical bits, qubits can exist in two states at once—a phenomenon called superposition. This quirk of quantum physics gives quantum computers the potential to perform certain complex calculations better than their classical counterparts, but it also means the qubits are fragile. To compensate, researchers are building quantum computers with extra, redundant qubits to correct any errors. That is why robust quantum computers will require hundreds of thousands of qubits.

Now, in a step toward this vision, Caltech physicists have created the largest qubit array ever assembled: 6,100 neutral-atom qubits trapped in a grid by lasers. Previous arrays of this kind contained only hundreds of qubits.

This milestone comes amid a rapidly growing race to scale up quantum computers. There are several approaches in development, including those based on superconducting circuits, trapped ions, and neutral atoms, as used in the new study.

The neutral-atom platform shows promise for scaling up quantum computers.

How Bose-Einstein condensates replicate Shapiro steps

The microscopic processes taking place in superconductors are difficult to observe directly. Researchers at the RPTU University of Kaiserslautern-Landau have therefore implemented a quantum simulation of the Josephson effect: They separated two Bose-Einstein condensates (BECs) by means of an extremely thin optical barrier.

The characteristic Shapiro steps were observed in the atomic system. The research was published in the journal Science.

Two superconductors separated by a wafer-thin insulating layer—that’s how simple a Josephson junction looks. But despite its simple structure, it harbors a quantum mechanical effect that is now one of the most important tools of modern technology: Josephson contacts form the heart of many quantum computers and enable high-precision measurements—such as the measurement of very weak magnetic fields.

Pinpointing the glow of a single atom to advance quantum emitter engineering

Researchers have discovered how to design and place single-photon sources at the atomic scale inside ultrathin 2D materials, lighting the path for future quantum innovations.

Like perfectly controlled light switches, quantum emitters can turn on the flow of single particles of light, called photons, one at a time. These tiny switches—the “bits” of many quantum technologies—are created by atomic-scale defects in materials.

Their ability to produce light with such precision makes them essential for the future of quantum technologies, including quantum computing, secure communication and ultraprecise sensing. But finding and controlling these atomic light switches has been a major scientific challenge—until now.

Scientists Uncover How Tiny “Nanopores” Learn Like the Brain

Scientists found that nanopores’ electrical charges control how ions flow and when pores temporarily shut down. The discovery could allow engineers to design nanopores that “learn” like synapses for next-generation computing.

Pore-forming proteins appear across many forms of life. In humans, they help protect the body by supporting immune defenses. In bacteria, they often function as toxins that create openings in cell membranes. These natural pores regulate the movement of ions and molecules, and their precise control over molecular transport has made them valuable in biotechnology, including DNA sequencing and molecular sensing.

Unpredictable Behavior in Ion Flow.

Epitaxial multilayer MoS2 wafers promise high-performance transistors

Two-dimensional (2D) semiconductors, such as molybdenum disulfide (MoS2), enable unprecedented opportunities to solve the bottleneck of transistor scaling and to build novel logic circuits with faster speeds, lower power consumption, flexibility and transparency, benefiting from their ultra-thin thickness, dangling-bond-free flat surface and excellent gate controllability.

Tremendous efforts have been devoted to exploring the scaled-up potentials of MoS2, including both wafer-scale synthesis of high-quality materials and large-area devices. For instance, four-inch wafer-scale monolayer MoS2 with large domain sizes (up to ~300 μm) and record-high electronic quality (average field-effect mobility of ~80 cm2·V-1 ·s-1) has already been demonstrated via van der Waals epitaxial growth.

In terms of a further improvement of the electronic quality of the large-scale monolayer MoS2, structural imperfections should be eliminated as much as possible; however, there is not much space left for monolayer MoS2 after ten years of synthesis optimizations in this field. Another key direction is to switch to multilayer MoS2, e.g., bilayers and trilayers, since they have intrinsically higher electronic quality than monolayers and thus are conducive to higher-performance devices and logic circuits. However, due to the fundamental limitation of thermodynamics, it is still a great challenge to realize wafer-scale multilayer MoS2 with high-quality and large-scale uniformity.

Real-life ‘quantum molycircuits’ using exotic nanotubes

Molybdenum disulfide MoS2 is a groundbreaking material for electronics applications. As a two-dimensional layer similar to graphene, it is an excellent semiconductor, and can even become intrinsically superconducting under the right conditions. It’s not particularly surprising that science fiction authors have already been speculating about molycircs, fictional computer circuits built from MoS2, for years—and that physicists and engineers are directing huge research efforts at this material.

Researchers at the University of Regensburg, have many years of expertise with diverse quantum materials—in particular also with carbon nanotubes, tube-like macromolecules made from carbon atoms alone.

“It was an obvious next step to now focus on MoS2 and its fascinating properties,” said Dr. Andreas K. Hüttel, head of the research group Nanotube Electronics and Nanomechanics in Regensburg. In cooperation with Prof. Dr. Maja Remškar, Jožef Stefan Institut Ljubljana, a specialist in the crystalline growth of nanomaterials, his research group started working on based on MoS2 nanotubes.

New method realize ohmic contacts in n-type MoS₂ transistors at cryogenic temperatures

Semiconducting transition metal dichalcogenides (TMDs) are a class of layered materials exhibiting unique optoelectronic properties that could be leveraged to develop transistors, sensors and other nanoelectronics. Despite their advantages, creating robust ohmic contacts that connect a metal electrode in transistors to semiconducting TMDs at cryogenic temperatures has proved challenging.

This has so far limited the use of these materials for either studying or developing nanoelectronics that operate at low temperatures.

In a paper in Nature Electronics, researchers at the Liaoning Academy of Materials, Shanxi University and other institutes introduced a new technique for realizing ohmic contacts to the TMD molybdenum disulfide (MoS2) at , and found that in those transistors can be surprisingly high.

Earth’s atmosphere may help support human life on the moon

The moon’s surface may be more than just a dusty, barren landscape. Over billions of years, tiny particles from Earth’s atmosphere have landed in the lunar soil, creating a possible source of life-sustaining substances for future astronauts. But scientists have only recently begun to understand how these particles make the long journey from Earth to the moon and how long the process has been taking place.

New research from the University of Rochester, published in Communications Earth & Environment, shows that Earth’s magnetic field may actually help guide atmospheric particles—carried by solar wind—into space, instead of blocking them. Because Earth’s magnetic field has existed for billions of years, this process could have steadily moved particles from Earth to the moon over very long periods of time.

“By combining data from particles preserved in lunar soil with computational modeling of how solar wind interacts with Earth’s atmosphere, we can trace the history of Earth’s atmosphere and its magnetic field,” says Eric Blackman, a professor in the Department of Physics and Astronomy and a distinguished scientist at URochester’s Laboratory for Laser Energetics (LLE).

Chip-scale magnetometer uses light for high-precision magnetic sensing

Researchers have developed a precision magnetometer based on a special material that changes optical properties in response to a magnetic field. The device, which is integrated onto a chip, could benefit space missions, navigation and biomedical applications.

High-precision magnetometers are used to measure the strength and direction of magnetic fields for various applications. However, many of today’s magnetometers must operate at extremely low temperatures—close to 0 kelvin—or require relatively large and heavy apparatus, which significantly restricts their practicality.

“Our device operates at room temperature and can be fully integrated onto a chip,” said Paolo Pintus from the University of California, Santa Barbara (UCSB) and the University of Cagliari, Italy, co-principal investigator for the study. “The light weight and low power consumption of this magnetometer make it ideal for use on small satellites, where it could enable studies of the magnetic areas around planets or aid in characterizing foreign metallic objects in space.”

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