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Archive for the ‘quantum physics’ category: Page 566

May 18, 2020

Efficient, ‘green’ quantum-dot solar cells exploit defects

Posted by in categories: quantum physics, solar power, sustainability

Novel quantum dot solar cells developed at Los Alamos National Laboratory match the efficiency of existing quantum-dot based devices, but without lead or other toxic elements that most solar cells of this type rely on.

“This quantum-dot approach shows great promise for a new type of toxic-element-free, inexpensive that exhibit remarkable defect tolerance,” said Victor Klimov, a physicist specializing in semiconductor nanocrystals at Los Alamos and lead author of the report featured on the cover of the journal Nature Energy.

Not only did the researchers demonstrate highly efficient devices, they also revealed the mechanism underlying their remarkable defect tolerance. Instead of impeding photovoltaic performance, the defect states in copper indium selenide quantum dots actually assist the photoconversion process.

May 18, 2020

Two Studies Just Revealed How Twisted Graphene Gets Even Weirder at a ‘Magic Angle’

Posted by in categories: computing, quantum physics

Graphene has already proven itself to be a weird and wonderful material in many different ways, but its properties get even more unusual and exotic when it’s twisted – and two new studies have given scientists a much closer look at this intriguing phenomenon.

When two sheets of graphene are put together at slightly different angles, the resulting material becomes either very effective at conducting electricity, or very effective at blocking it. It’s known as ‘magic-angle’ twisted graphene, and knowing more about how and why this happens could lead to advances in high-temperature superconductors and quantum computing.

Now for the first time, scientists have mapped out a twisted graphene structure in its entirety, and at a very high resolution. They’ve also been able to get ‘graphene twistronics’ working with four layers of graphene as well as just two.

May 17, 2020

DARPA Kicks Off Program to Advance Quantum Computing

Posted by in categories: computing, quantum physics

DARPA has selected seven university and industry teams for the first phase of the Optimization with Noisy Intermediate-Scale Quantum devices (ONISQ) program. Phase 1 of the program began in March and will last 18 months.

ONISQ aims to exploit quantum information processing before universal fault-tolerant quantum computers are realized, which isn’t expected for many years. The program is pursuing a hybrid concept that combines intermediate-sized quantum devices (hundreds to thousands of quantum bits, or qubits) with classical computing systems to solve a particularly challenging set of problems known as combinatorial optimization.

ONISQ seeks to demonstrate a quantitative advantage of quantum information processing by leapfrogging the performance of classical-only systems in solving optimization challenges. If successful, ONISQ could be applied to optimization problems of interest to defense and commercial industry, such as global logistics management, electronics manufacturing, and protein-folding.

May 17, 2020

First Observation of a Pauli Quantum Crystal

Posted by in category: quantum physics

Quantum physicists predicted the Pauli exclusion principle should create spectacular crystals. Now they’ve found them for the first time.

May 17, 2020

Samsung Galaxy A Quantum announced with quantum encryption technology

Posted by in categories: encryption, internet, mobile phones, quantum physics, security

Samsung and South Korean carrier SK Telecom today announced a new 5G smartphone dubbed Galaxy A Quantum.

The Samsung Galaxy A Quantum is the world’s first 5G smartphone equipped with a quantum random number generator (QRNG) chipset, which is developed by SK Telecom’s Switzerland-based subsidiary ID Quantique.

The QRNG chipset is the SKT IDQ S2Q000 and it enhances the security of the phone’s data by using quantum encryption technology to generate random numbers and create unpredictable secure keys.

May 17, 2020

Quantum Brakes to Learn About the Forces Within Molecules

Posted by in categories: particle physics, quantum physics

Physicists have measured the flight times of electrons emitted from a specific atom in a molecule upon excitation with laser light. This has enabled them to measure the influence of the molecule itself on the kinetics of emission.

Photoemission – the release of electrons in response to excitation by light – is one of the most fundamental processes in the microcosm. The kinetic energy of the emitted electron is characteristic for the atom concerned, and depends on the wavelength of the light employed. But how long does the process take? And does it always take the same amount of time, irrespective of whether the electron is emitted from an individual atom or from an atom that is part of a molecule? An international team of researchers led by laser physicists in the Laboratory for Attosecond Physics (LAP) at LMU Munich and the Max Planck Institute of Quantum Optics (MPQ) in Garching has now probed the influence of the molecule on photoemission time.

The theoretical description of photoemission in 1905 by Albert Einstein marked a breakthrough in quantum physics, and the details of the process are of continuing interest in the world of science and beyond. How the motions of an elementary quantum particle such as the electron are affected within a molecular environment has a significant bearing on our understanding of the process of photoemission and the forces that hold molecules together.

May 16, 2020

José Cordeiro — THE DEATH OF DEATH (Longevity #0001)

Posted by in categories: cryonics, life extension, quantum physics, Ray Kurzweil, robotics/AI, singularity, transhumanism

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May 16, 2020

Samsung Surprise As World’s First Smartphone With Quantum Technology Launches May 22

Posted by in categories: mobile phones, quantum physics

A Samsung Galaxy smartphone incorporating quantum technology is due to launch in Korea next week.

May 16, 2020

Microwave quantum illumination using a digital receiver

Posted by in categories: biotech/medical, encryption, internet, quantum physics

Quantum illumination uses entangled signal-idler photon pairs to boost the detection efficiency of low-reflectivity objects in environments with bright thermal noise. Its advantage is particularly evident at low signal powers, a promising feature for applications such as noninvasive biomedical scanning or low-power short-range radar. Here, we experimentally investigate the concept of quantum illumination at microwave frequencies. We generate entangled fields to illuminate a room-temperature object at a distance of 1 m in a free-space detection setup. We implement a digital phase-conjugate receiver based on linear quadrature measurements that outperforms a symmetric classical noise radar in the same conditions, despite the entanglement-breaking signal path. Starting from experimental data, we also simulate the case of perfect idler photon number detection, which results in a quantum advantage compared with the relative classical benchmark. Our results highlight the opportunities and challenges in the way toward a first room-temperature application of microwave quantum circuits.

Quantum sensing is well developed for photonic applications (1) in line with other advanced areas of quantum information (25). Quantum optics has been, so far, the most natural and convenient setting for implementing the majority of protocols in quantum communication, cryptography, and metrology (6). The situation is different at longer wavelengths, such as tetrahertz or microwaves, for which the current variety of quantum technologies is more limited and confined to cryogenic environments. With the exception of superconducting quantum processing (7), no microwave quanta are typically used for applications such as sensing and communication. For these tasks, high-energy and low-loss optical and telecom frequency signals represent the first choice and form the communication backbone in the future vision of a hybrid quantum internet (810).

Despite this general picture, there are applications of quantum sensing that are naturally embedded in the microwave regime. This is exactly the case with quantum illumination (QI) (11–17) for its remarkable robustness to background noise, which, at room temperature, amounts to ∼103 thermal quanta per mode at a few gigahertz. In QI, the aim is to detect a low-reflectivity object in the presence of very bright thermal noise. This is accomplished by probing the target with less than one entangled photon per mode, in a stealthy noninvasive fashion, which is impossible to reproduce with classical means. In the Gaussian QI protocol (12), the light is prepared in a two-mode squeezed vacuum state with the signal mode sent to probe the target, while the idler mode is kept at the receiver.

May 16, 2020

Army Researchers Advance Toward Quantum Computing at Room Temperature

Posted by in categories: computing, military, quantum physics

Army researchers predict quantum computer circuits that will no longer need extremely cold temperatures to function could become a reality after about a decade.

For years, solid-state quantum technology that operates at room temperature seemed remote. While the application of transparent crystals with optical nonlinearities had emerged as the most likely route to this milestone, the plausibility of such a system always remained in question.

Now, Army scientists have officially confirmed the validity of this approach. Dr. Kurt Jacobs, of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, working alongside Dr. Mikkel Heuck and Prof. Dirk Englund, of the Massachusetts Institute of Technology, became the first to demonstrate the feasibility of a quantum logic gate comprised of photonic circuits and optical crystals.