Menu

Blog

Page 3922

Nov 9, 2022

Truly chiral phonons observed in three-dimensional materials for the first time

Posted by in categories: particle physics, space

Chirality is the breaking of reflection and inversion symmetries. Simply put, it is when an object’s mirror images cannot be superimposed over each other. A common example are your two hands—while mirror images of each other, they can never overlap. Chirality appears at all levels in nature and is ubiquitous.

In addition to static , chirality can also occur due to dynamic motion including rotation. With this in mind, we can distinguish true and false chirality. A system is truly chiral if—when translating—space inversion does not equate to time reversal combined with a proper spatial rotation.

Phonons are quanta (or small packets) of energy associated with the vibration of atoms in a . Recently, phonons with chiral properties have been theorized and experimentally discovered in two-dimensional (2D) materials such as tungsten diselenide. The discovered chiral phonons are rotating—yet not propagating—atomic motions. But, truly chiral phonons would be atomic motions that are both rotating and propagating, and these have never been observed in three-dimensional (3D) bulk systems.

Nov 9, 2022

Using vibrations to control a swarm of tiny robots

Posted by in categories: biotech/medical, robotics/AI

Vibrating tiny robots could revolutionize research.

Individual robots can work collectively as to create major advances in everything from construction to surveillance, but microrobots’ small scale is ideal for drug delivery, disease diagnosis, and even surgeries.

Despite their potential, microrobots’ size often means they have limited sensing, communication, motility, and computation abilities, but new research from the Georgia Institute of Technology enhances their ability to collaborate efficiently. The work offers a new system to control swarms of 300 3-millimeter microbristle robots’ (microbots) ability to aggregate and disperse controllably without onboard sensing.

Nov 9, 2022

A high-speed sequential deposition strategy to fabricate photoactive layers for organic cells

Posted by in categories: solar power, sustainability

Organic photovoltaics, solar energy devices based on organic semiconductors, have so far achieved very promising results in experimental settings, both in terms of efficiency and stability. However, engineers have not yet devised reliable strategies to fabricate these devices on a large-scale at a reasonable cost.

Researchers at Wuhan University in China have recently identified an approach that could facilitate the rapid fabrication of photoactive layers for , without compromising the cells’ efficiency and stability. Their proposed strategy, introduced in a paper published in Nature Energy, is based on sequential deposition, a method often used to deposit organic semiconductors and perovskite films on substrates.

“To realize the commercialization of organic photovoltaics (OPVs), the golden triangle of power conversion efficiency (PCE), stability, and cost should be considered simultaneously,” Jie Min, one of the researchers who carried out the study, told TechXplore.

Nov 9, 2022

AI helps optimize power electronic converters

Posted by in category: robotics/AI

A new and more efficient way of modeling and designing power electronic converters using artificial intelligence (AI) has been created by a team of experts from Cardiff University and the Compound Semiconductor Applications (CSA) Catapult.

The method has reduced design times for technology by up to 78% compared to traditional approaches and was used to create a device with an efficiency of over 98%.

The team’s findings have been published in the IEEE Open Journal of Power Electronics and IEEE Transactions on Power Electronics.

Nov 9, 2022

Paving the Way for Satellite Quantum Communications

Posted by in categories: computing, encryption, quantum physics, satellites, security

A series of demonstrations by Micius—a low-orbit satellite with quantum capabilities—lays the groundwork for a satellite-based quantum communication network.

Few things have captured the scientific imagination quite like the vastness of space and the promise of quantum technology. Micius—the Chinese Academy of Science’s quantum communications satellite launched in 2016—has connected these two inspiring domains, producing a string of exciting first demonstrations in quantum space communications. Reviewing the efforts leading up to the satellite launch and the major outcomes of the mission, Jian-Wei Pan and colleagues at the University of Science and Technology of China provide a perspective on what the future of quantum space communications may look like [1]. The success of this quantum-satellite mission proves the viability of several space-based quantum communications protocols, providing a solid foundation for future improvements that may lead to an Earth-spanning quantum communications network (Fig. 1).

Photons, the quanta of light, are wonderful carriers of quantum information because they are easy to manipulate and travel extremely fast. They can be created in a desired quantum state or as the output of some quantum sensor or quantum computer. Quantum entanglement between multiple photons—the nonclassical correlation between their quantum states—can be amazingly useful in quantum communications protocols such as quantum key distribution (QKD), a cryptography approach that can theoretically guarantee absolute information security. QKD schemes have been demonstrated on distances of a few hundreds of kilometers—sufficient to cover communications networks between cities. But increasing their range, eventually to the global scale, is a formidable challenge.

Nov 9, 2022

Chirping toward a Quantum RAM

Posted by in categories: computing, information science, mobile phones, nanotechnology, quantum physics

A new quantum random-access memory device reads and writes information using a chirped electromagnetic pulse and a superconducting resonator, making it significantly more hardware-efficient than previous devices.

Random-access memory (or RAM) is an integral part of a computer, acting as a short-term memory bank from which information can be quickly recalled. Applications on your phone or computer use RAM so that you can switch between tasks in the blink of an eye. Researchers working on building future quantum computers hope that such systems might one day operate with analogous quantum RAM elements, which they envision could speed up the execution of a quantum algorithm [1, 2] or increase the density of information storable in a quantum processor. Now James O’Sullivan of the London Centre for Nanotechnology and colleagues have taken an important step toward making quantum RAM a reality, demonstrating a hardware-efficient approach that uses chirped microwave pulses to store and retrieve quantum information in atomic spins [3].

Just like quantum computers, experimental demonstrations of quantum memory devices are in their early days. One leading chip-based platform for quantum computation uses circuits made from superconducting metals. In this system, the central processing is done with superconducting qubits, which send and receive information via microwave photons. At present, however, there exists no quantum memory device that can reliably store these photons for long times. Luckily, scientists have a few ideas.

Nov 9, 2022

Magnetic Field Heats Up Fusion

Posted by in categories: futurism, nuclear energy

A magnetic field can significantly boost the performance of a large-scale fusion experiment that may lead to a future source of clean power.

Nuclear fusion could provide a clean power source, but one of the technological challenges is maintaining the fuel at a high enough temperature for a long enough time. In a technique called inertial confinement fusion (ICF)—where lasers initiate the nuclear reaction—a magnetic field has been shown to improve heating. Now researchers have shown that a magnetic field can also help in a large-scale experiment with a more complicated design that produces far more energy [1]. The applied field increased the fuel’s temperature by 40% and tripled the fusion reaction’s efficiency. The work provides a step toward increasing the robustness and energy output of the fusion reaction and provides the first proof of concept of magnetization-assisted fusion in a large-scale experiment.

In the simplest version of ICF, synchronized laser pulses hit a capsule filled with cold hydrogen fuel, causing it to implode. The implosion heats the fuel and creates a spot of burning plasma (see Viewpoint: Fusion Turns Up the Heat). The “hot spot” serves as a spark that initiates burning throughout the fuel, driving a self-sustaining fusion reaction that releases energy. However, these implosions can fail to generate significant fusion energy if the fuel pellet has small imperfections on its surface or if the lasers are not perfectly timed. But if the fuel could be heated to temperatures higher than was possible in recent experiments, there would be more margin for error, which could alleviate the sensitivity to such details.

Nov 9, 2022

Birth of Turbulence Captured for a Quantum Gas

Posted by in categories: evolution, particle physics, quantum physics

The observation of the onset of turbulence in a gas of bosons allows researchers to explore how turbulence comes to life.

Despite over a century of trying, physicists have yet to develop a complete theory of turbulence—the complex, chaotic motion of a fluid. Now Maciej Gałka of the University of Cambridge and colleagues have taken a step in that direction by witnessing the onset of turbulence in a quantum gas and observing its evolution over roughly 100 ms [1]. The finding could help scientists answer open questions in turbulence, which is observed in systems ranging from ocean waves to star interiors.

Nov 9, 2022

Exploring open ended intelligence using patternist philosophy

Posted by in category: futurism

Share your videos with friends, family, and the world.

Nov 9, 2022

A miniature universe shows particles may emerge out of empty space

Posted by in categories: particle physics, quantum physics

An analogue of a tiny, expanding universe has been created out of extremely cold potassium atoms. It could be used to help us understand cosmic phenomena that are exceedingly difficult to directly detect, such as pairs of particles that may be created out of empty space as the universe expands.

Markus Oberthaler at Heidelberg University in Germany and his colleagues cooled more than 20,000 potassium atoms in a vacuum, using lasers to slow them down and lower their temperature to about 60 nanokelvin, or 60 billionths of a degree kelvin above absolute zero.

At this temperature, the atoms formed a cloud about the width of a human hair and, instead of freezing, they became a quantum, fluid-like phase of matter called a Bose-Einstein condensate. Atoms in this phase can be controlled by shining light on them – using a tiny projector, the researchers precisely set the atoms’ density, arrangement in space and the forces they exert on each other.