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Archive for the ‘quantum physics’ category: Page 267

Dec 16, 2021

Reconstruction of Bloch wavefunctions of holes in a semiconductor

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

Abstract: A central goal of condensed-matter physics is to understand how the diverse electronic and optical properties of crystalline materials emerge from the wavelike motion of electrons through periodically arranged atoms. However, more than 90 years after Bloch derived the functional forms of electronic waves in crystals [1] (now known as Bloch wavefunctions), rapid scattering processes have so far prevented their direct experimental reconstruction. In high-order sideband generation [2–9], electrons and holes generated in semiconductors by a near-infrared laser are accelerated to a high kinetic energy by a strong terahertz field, and recollide to emit near-infrared sidebands before they are scattered. Here we reconstruct the Bloch wavefunctions of two types of hole in gallium arsenide at wavelengths much longer than the spacing between atoms by experimentally measuring sideband polarizations and introducing an elegant theory that ties those polarizations to quantum interference between different recollision pathways. These Bloch wavefunctions are compactly visualized on the surface of a sphere. High-order sideband generation can, in principle, be observed from any direct-gap semiconductor or insulator. We thus expect that the method introduced here can be used to reconstruct low-energy Bloch wavefunctions in many of these materials, enabling important insights into the origin and engineering of the electronic and optical properties of condensed matter.

From: Joseph Costello [view email].

Dec 15, 2021

Evidence for Parallel Universes — Max Tegmark / Serious Science

Posted by in categories: computing, cosmology, quantum physics, science

Physicist Max Tegmark on predictions that cannot be observed, explanation of Universe’ fine tuning, and quantum computer.

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Dec 15, 2021

Why China’s Advancements in Quantum Technology Worry Others

Posted by in categories: computing, encryption, military, quantum physics

The 41-year-old computing method can decode encrypted messages and help detect hidden military vehicles such as stealth aircraft.

Dec 15, 2021

Flawed Diamonds May Provide Perfect Interface for Quantum Computers — Faster and More Secure

Posted by in categories: computing, internet, quantum physics

Flaws in diamonds — atomic defects where carbon is replaced by nitrogen or another element — may offer a close-to-perfect interface for quantum computing 0, a proposed communications exchange that promises to be faster and more secure than current methods. There’s one major problem, though: these flaws, known as diamond nitrogen-vacancy centers, are controlled via magnetic field, which is incompatible with existing quantum devices. Imagine trying to connect an Altair, an early personal computer developed in 1974, to the internet via WiFi. It’s a difficult, but not impossible task. The two technologies speak different languages, so the first step is to help translate.

Researchers at Yokohama National University have developed an interface approach to control the diamond nitrogen-vacancy centers in a way that allows direct translation to quantum devices. They published their method today (December 15, 2021) in Communications Physics.

“To realize the quantum internet, a quantum interface is required to generate remote quantum entanglement by photons, which are a quantum communication medium,” said corresponding author Hideo Kosaka, professor in the Quantum Information Research Center, Institute of Advanced Sciences and in the Department of Physics, Graduate School of Engineering, both at Yokohama National University. “.

Dec 14, 2021

Quantum-circuit black hole lasers

Posted by in categories: cosmology, information science, quantum physics

A black hole laser in analogues of gravity amplifies Hawking radiation, which is unlikely to be measured in real black holes, and makes it observable. There have been proposals to realize such black hole lasers in various systems. However, no progress has been made in electric circuits for a long time, despite their many advantages such as high-precision electromagnetic wave detection. Here we propose a black hole laser in Josephson transmission lines incorporating metamaterial elements capable of producing Hawking-pair propagation modes and a Kerr nonlinearity due to the Josephson nonlinear inductance. A single dark soliton obeying the nonlinear Schrödinger equation produces a black hole-white hole horizon pair that acts as a laser cavity through a change in the refractive index due to the Kerr effect.

Dec 14, 2021

Ground-State Entanglement gives birth to Quantum Energy Teleportation

Posted by in categories: energy, quantum physics

Circa 2009 real teleportation not just in the quantum realm.


Ground-state entanglement induces emergence of negative-energy-density regions in quantum systems by squeezing zero-point oscillation, keeping total energy of the systems nonnegative. By use of the negativity of quantum energy density, protocols of quantum energy teleportation are proposed that transport energy to distant sites by local operations and classical communication. The energy is teleported without breaking any physical laws including causality and local energy conservation. Because intermediate subsystems of the energy transfer channel are not excited during the protocol execution, the protocol attains energy transportation without heat generation in the channel. We discuss the protocol focusing around qubit chains. In addition, we address a related problem of breaking ground-state entanglement by measurements.

Dec 14, 2021

Physicists create new state of matter from quantum soup of magnetically weird particles

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

The messy quantum soup of spin states allows for quantum entanglement across an entire material.

Dec 14, 2021

Can quantum effects in the brain explain consciousness?

Posted by in categories: neuroscience, quantum physics

New research reveals hints of quantum states in tiny proteins called microtubules inside brain cells. If the results stand up, the idea that consciousness is quantum might come in from the cold.

Dec 13, 2021

Generating quantum states of sound inside a microscopic device

Posted by in categories: particle physics, quantum physics

Scientists have made it possible to generate and control quantum states in different physical systems. This control allows scientists to develop powerful new quantum technologies. In addition, it offers a roadmap to test the foundations of quantum physics.

The main challenge is to create quantum states on a larger scale.

In collaboration with the University of Oxford, scientists at Imperial College London, the Niels Bohr Institute, the Max Planck Institute for the Science of Light, and Australian National University have generated and observed non-Gaussian states high-frequency sound waves comprising more than a trillion atoms. Certainly, they transformed a randomly fluctuating sound field in thermal equilibrium to a pattern thrumming with a more specific magnitude.

Dec 13, 2021

EK announces Special Edition water blocks for NVIDIA GeForce RTX 3070 Ti Founders Edition

Posted by in categories: computing, quantum physics

EK®, the leading computer cooling solutions provider, is proud to unveil its Special Edition high-performance GPU water blocks for the NVIDIA® GeForce® RTX™ 3,070 Ti Founders Edition graphics card. The EK-Quantum Vector FE RTX 3,070 Ti D-RGB comes in two versions – Silver and Black, both featuring the aluminum outer shell and backplate in the same color, as well as the Plexi window and terminal illuminated with addressable D-RGB LEDs.

This water block comes with multiple ports, allowing great versatility. The performance is one of the key elements of the design, which is why this block features a 30% larger fin area compared to other water blocks from the Vector family.