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Archive for the ‘quantum physics’ category: Page 590

Oct 1, 2019

Quantum Superposition Record: 2000 Atoms in Two Places at Once

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

The quantum superposition principle has been tested on a scale as never before in a new study by scientists at the University of Vienna in collaboration with the University of Basel. Hot, complex molecules composed of nearly two thousand atoms were brought into a quantum superposition and made to interfere. By confirming this phenomenon – “the heart of quantum mechanics”, in Richard Feynman’s words – on a new mass scale, improved constraints on alternative theories to quantum mechanics have been placed. The work was published in Nature Physics on September 23, 2019.

Quantum to classical?

The superposition principle is a hallmark of quantum theory which emerges from one of the most fundamental equations of quantum mechanics, the Schrödinger equation. It describes particles in the framework of wave functions, which, much like water waves on the surface of a pond, can exhibit interference effects. But in contrast to water waves, which are a collective behavior of many interacting water molecules, quantum waves can also be associated with isolated single particles.

Oct 1, 2019

Non-abelian Aharonov-Bohm experiment done at long last

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

For the first time, physicists in the US have confirmed a decades-old theory regarding the breaking of time-reversal symmetry in gauge fields. Marin Soljacic at the Massachusetts Institute of Technology and an international team of researchers have made this first demonstration of the “non-Abelian Aharonov-Bohm effect” in two optics experiments. With improvements, their techniques could find use in optoelectronics and fault-tolerant quantum computers.

First emerging in Maxwell’s famous equations for classical electrodynamics, a gauge theory is a description of the physics of fields. Gauge theories have since become an important part of physicists’ descriptions of the dynamics of elementary particles – notably the theory of quantum electrodynamics.

A salient feature of a gauge theory is that the physics it describes does not change when certain transformations are made to the underlying equations describing the system. An example is the addition of a constant scalar potential or a “curl-free” vector potential to Maxwell’s equations. Mathematically, this does not change the electric and magnetic fields that act on a charged particle such as an electron – and therefore the behaviour of the electron – so Maxwell’s theory is gauge invariant.

Oct 1, 2019

How AI will transform healthcare (and can it fix the US healthcare system?)

Posted by in categories: finance, internet, quantum physics, robotics/AI

This thorough review focuses on the impact of AI, 5G, and edge computing on the healthcare sector in the 2020s as well as a look at quantum computing’s potential impact on AI, healthcare, and financial services.

Sep 30, 2019

A ten-qubit solid-state spin register with remarkable quantum memory

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

In years to come, quantum computers and quantum networks might be able to tackle tasks that are inaccessible to traditional computer systems. For instance, they could be used to simulate complex matter or enable fundamentally secure communications.

The elementary building blocks of quantum information systems are known as qubits. For to become a tangible reality, researchers will need to identify strategies to control many qubits with very high precision rates.

Spins of individual particles in solids, such as electrons and nuclei have recently shown great promise for the development of quantum networks. While some researchers were able to demonstrate an elementary control of these qubits, so far, no one has reported entangled quantum states containing more than three spins.

Sep 29, 2019

Focus: “Quantum Foam” Scrubs Away Gigantic Cosmic Energy

Posted by in categories: energy, quantum physics

Theory suggests that empty space is filled with enormous energy, but according to a new proposal this energy may be hidden because its effects cancel at the tiniest scales.

Sep 28, 2019

This New Chip Could Bridge The Gap Between Classical And Quantum Computing

Posted by in categories: computing, quantum physics

Quantum computers exist today, although they’re limited, cut-down versions of what we hope fully blown quantum computers are going to be able to do in the future.

But now, researchers have developed hardware for a ‘probabilistic computer’ – a device that might be able to bridge the gap between genuine quantum computers and the standard PCs and Macs we have today.

The special trick that a probabilistic computer can do is to solve quantum problems without actually going quantum, as it were. It does this using a p-bit, which the team behind this research describes as a “poor man’s qubit”.

Sep 28, 2019

Quantum Internet Is One Step Closer to Reality With U.S. Army Research Breakthrough

Posted by in categories: internet, military, quantum physics

Research Triangle Park, N.C. — A U.S. Army research result brings the quantum internet a step closer. Such an internet could offer the military security, sensing, and timekeeping capabilities not possible with traditional networking approaches.

The U.S. Army’s Combat Capability Development’s Army Research Laboratory’s Center for Distributed Quantum Information, funded and managed by the lab’s Army Research Office, saw researchers at the University of Innsbruck achieve a record for the transfer of quantum entanglement between matter and light — a distance of 50 kilometers using fiber optic cables.

Entanglement is a correlation that can be created between quantum entities such as qubits. When two qubits are entangled and a measurement is made on one, it will affect the outcome of a measurement made on the other, even if that second qubit is physically far away.

Sep 26, 2019

Leonard Susskind: Quantum Mechanics, String Theory and Black Holes

Posted by in categories: cosmology, quantum physics, robotics/AI

https://www.youtube.com/watch?v=s78hvV3QLUE

Leonard Susskind is a professor of theoretical physics at Stanford University, and founding director of the Stanford Institute for Theoretical Physics. He is widely regarded as one of the fathers of string theory and in general as one of the greatest physicists of our time both as a researcher and an educator. This conversation is part of the Artificial Intelligence podcast.

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Sep 26, 2019

Project brings quantum internet closer to reality

Posted by in categories: internet, military, quantum physics

A U.S. Army research result brings the quantum internet a step closer. Such an internet could offer the military security, sensing and timekeeping capabilities not possible with traditional networking approaches.

The U.S. Army’s Combat Capability Development’s Army Research Laboratory’s Center for Distributed Quantum Information, funded and managed by the lab’s Army Research Office, saw researchers at the University of Innsbruck achieve a record for the transfer of quantum entanglement between matter and light—a distance of 50 kilometers using fiber optic cables.

Entanglement is a correlation that can be created between quantum entities such as qubits. When two qubits are entangled and a measurement is made on one, it will affect the outcome of a measurement made on the other, even if that second qubit is physically far away.

Sep 26, 2019

A different kind of gravitational wave detector

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

Hidden deep in a basement at Stanford stands a 10-meter-tall tube, wrapped in a metal cage and draped in wires. A barrier separates it from the main room, beyond which the cylinder spans three stories to an apparatus holding ultra-cold atoms ready to shoot upward. Tables stocked with lasers to fire at the atoms—and analyze how they respond to forces such as gravity—fill the rest of the laboratory.

The tube is an , a custom-built device designed to study the wave nature of . According to quantum mechanics, atoms exist simultaneously as particles and waves. The Stanford instrument represents a model for an ambitious new instrument ten times its size that could be deployed to detect gravitational waves—minute ripples in spacetime created by energy dissipating from moving astronomical objects. The instrument also could shed light on another mystery of the universe: dark matter.

Stanford experimental physicists Jason Hogan and Mark Kasevich never intended for their device to be implemented this way. When Hogan began his graduate studies in Kasevich’s lab, he focused instead on testing gravity’s effects on atoms. But conversations with theoretical physicist Savas Dimopoulos, a professor of physics, and his graduate students—often lured downstairs by an espresso machine housed directly across the hall from Kasevich’s office—led them to start thinking about its utility as a highly .