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Category: quantum physics – Page 272

Scientists at the Niels Bohr Institute, in cooperation with the University of Münster and Ruhr-Universität Bochum, developed new technology capable of processing the enormous amounts of information quantum systems generate. They’ve successfully linked deterministic single-photon.

A photon is a particle of light. It is the basic unit of light and other electromagnetic radiation, and is responsible for the electromagnetic force, one of the four fundamental forces of nature. Photons have no mass, but they do have energy and momentum. They travel at the speed of light in a vacuum, and can have different wavelengths, which correspond to different colors of light. Photons can also have different energies, which correspond to different frequencies of light.

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Researchers have created a quantum superposition state in a semiconductor nanostructure that might serve as a basis for quantum computing. The trick: two optical laser pulses that act as a single terahertz laser pulse.

A German-Chinese research team has successfully created a quantum bit in a semiconductor nanostructure. Using a special energy transition, the researchers created a state in a quantum dot—a tiny area of the semiconductor—in which an electron hole simultaneously possessed two different energy levels. Such superposition states are fundamental for quantum computing.

However, excitation of the state would require a large-scale free-electron that can emit light in the terahertz range. Additionally, this wavelength is too long to focus the beam on the tiny quantum dot. The German-Chinese team has now achieved the excitation with two finely tuned short-wavelength optical .

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Looking only at their subatomic particles, most materials can be placed into one of two categories.

Metals—like copper and iron—have free-flowing electrons that allow them to conduct electricity, while —like glass and rubbe r— keep their electrons tightly bound and therefore do not conduct electricity.

Insulators can turn into metals when hit with an intense electric field, offering tantalizing possibilities for microelectronics and supercomputing, but the behind this phenomenon called resistive switching is not well understood.

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A team of scientists studied the single-system version of multipartite Bell nonlocality, and observed the highest degree of quantum contextuality in a single system. Their work was published in Physical Review Letters.

Physical Review Letters (PRL) is a peer-reviewed scientific journal published by the American Physical Society. It is one of the most prestigious and influential journals in physics, with a high impact factor and a reputation for publishing groundbreaking research in all areas of physics, from particle physics to condensed matter physics and beyond. PRL is known for its rigorous standards and short article format, with a maximum length of four pages, making it an important venue for rapid communication of new findings and ideas in the physics community.

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A scalable system for controlling quantum bits demonstrates a very low error rate, which is essential for making practical devices.

A major obstacle to the development of practical quantum computers is the difficulty of scaling up—making a device with large numbers of quantum bits (qubits) that also gives accurate results in the presence of environmental noise. Now researchers report a significant improvement in the accuracy of a technology that is already known to be much easier to scale up than conventional techniques [1]. This alternative technology uses units of magnetic flux called flux quanta to control conventional superconducting qubits. The reduction in the error rate came from physically separating the control circuits from the qubits. With further refinement, the flux-quanta technology could provide a superior pathway to practical quantum computation.

Many current efforts to carry out quantum logic operations—the basic units of computation—use short microwave pulses to control the qubits. Currently, however, this technology is difficult to scale up beyond 1,000 qubits. But the presence of environmental noise requires error-correction methods that rely on large numbers of qubits, perhaps a million or more, for an effective error-correcting system that performs useful computations, according to some estimates.

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A team led by Prof. Li Chuanfeng and Prof. Xu Jinshi from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), collaborating with Prof. Chen Jingling from Nankai University and Prof. Adán Cabello from the University of Seville, studied the single-system version of multipartite Bell nonlocality, and observed the highest degree of quantum contextuality in single system. Their work was published in Physical Review Letters.

Quantum contextuality refers to the phenomenon that the measurements of quantum observables cannot be simply considered as revealing preexisting properties. It is a distinctive feature in and a crucial resource for quantum computation. Contextuality defies noncontextuality hidden-variable theories and is closely linked to .

In multipartite systems, quantum arises as the result of the contradiction between quantum contextuality and noncontextuality hidden-variable theories. The extent of nonlocality can be measured by the violation of Bell and previous researches showed that the violation increases exponentially with the number of quantum bits involved. However, while single-particle high-dimensional system offers more possibilities for measurements compared to multipartite systems, the quest to enhance contextual correlation’s robustness remains an ongoing challenge.

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Abstract: I do not share the feeling that consciousness (whatever this means) cannot be understood in the context of the known physical laws. So far we do not understand it well, but neither do we fully understand thunderstorms, for that matter. I offer three small contributions in the direction of a direct naturalistic account of consciousness: (i) a purely physical account of agency and the openness of the future, which traces the source of information to past low entropy; (ii) a purely physical basis for a simple notion of “meaning”; and (iii) a suggestion that current understanding of quantum matter (without need of panpsychism) weakens the apparent hiatus between the mental and the physical.

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Imagine shrinking light down to the size of a tiny water molecule, unlocking a world of quantum possibilities. This has been a long-held dream in the realms of light science and technology. Recent advancements have brought us closer to achieving this incredible feat, as researchers from Zhejiang University have made groundbreaking progress in confining light to subnanometer scales.

Traditionally, there have been two approaches to localize light beyond its typical diffraction limit: dielectric confinement and plasmonic confinement. However, challenges such as precision fabrication and optical loss have hindered the confinement of optical fields to sub-10 nanometer (nm) or even 1-nm levels. But now, a new waveguiding scheme reported in Advanced Photonics promises to unlock the potential of subnanometer optical fields.

Picture this: Light travels from a regular , embarking on a transformative journey through a fiber taper, and finds its destination in a coupled-nanowire-pair (CNP). Within the CNP, the light morphs into a remarkable nano-slit mode, generating a confined optical field that can be as tiny as a mere fraction of a nanometer (approximately 0.3 nm). With an astonishing efficiency of up to 95% and a high peak-to-background ratio, this novel approach offers a whole new world of possibilities.

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Similar to Interstellar, Oppenheimer (now in theaters) finds Christopher Nolan at his most abstract, with the director working overtime to ascribe a visual language to concepts just beyond our comprehension.

It wasn’t enough to simply make a biopic about the father of the atomic bomb — he needed to take us inside the extraordinary theoretical mind of J. Robert Oppenheimer (played in the film by Cillian Murphy) and show us the Big Bang-like birth of quantum physics and how it directly led to the creation of the atomic bomb.

RELATED: Oppenheimer’s Atomic Bombs Marked a New Geologic Age of Humans.

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