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Archive for the ‘quantum physics’ category: Page 496

Jul 1, 2019

Finally, Proof That Quantum Computing Can Boost Machine Learning

Posted by in categories: information science, quantum physics, robotics/AI

Quantum supremacy sounds like something out of a Marvel movie. But for scientists working at the forefront of quantum computing, the hope—and hype—of this fundamentally different method of processing information is very real. Thanks to the quirky properties of quantum mechanics (here’s a nifty primer), quantum computers have the potential to massively speed up certain types of problems, particularly those that simulate nature.

Scientists are especially enthralled with the idea of marrying the quantum world with machine learning. Despite all their achievements, our silicon learning buddies remain handicapped: machine learning algorithms and traditional CPUs don’t play well, partly because the greedy algorithms tax classical computing hardware.

Add in a dose of quantum computing, however, and machine learning could potentially process complex problems beyond current abilities at a fraction of the time.

Jul 1, 2019

Theoretical physicists unveil one of the most ubiquitous and elusive concepts in chemistry

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

Oxidation numbers have so far eluded any rigorous quantum mechanical definition. A new SISSA study, published in Nature Physics, provides such a definition based on the theory of topological quantum numbers, which was honored with the 2016 Nobel Prize in Physics, awarded to Thouless, Haldane and Kosterlitz. This result, combined with recent advances in the theory of transport achieved at SISSA, paves the way to an accurate, yet tractable, numerical simulation of a broad class of materials that are important in energy-related technologies and planetary sciences.

Every undergraduate student in the natural sciences learns how to associate an integer oxidation number to a chemical species participating in a reaction. Unfortunately, the very concept of oxidation state has thus far eluded a rigorous quantum mechanical definition, so that no method was known until now to compute oxidation numbers from the fundamental laws of nature, let alone demonstrate that their use in the simulation of charge transport does not spoil the quality of numerical simulations. At the same time, the evaluation of electric currents in ionic conductors, which is required to model their transport properties, is presently based on a cumbersome quantum-mechanical approach that severely limits the feasibility of large-scale computer simulations. Scientists have lately noticed that a simplified model where each atom carries a charge equal to its oxidation number may give results in surprising good agreement with rigorous but much more expensive approaches.

Jul 1, 2019

Study unveils new supersymmetry anomalies in superconformal quantum field theories

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

Researchers at the University of Southampton and the Korea Institute for Advanced Study have recently showed that supersymmetry is anomalous in N=1 superconformal quantum field theories (SCFTs) with an anomalous R symmetry. The anomaly described in their paper, published in Physical Review Letters, was previously observed in holographic SCFTs at strong coupling, yet their work confirms that it is already present in the simplest free STFCs.

“Supersymmetry is a symmetry that relates particles with integer and half-integer spin, and has played a central role in many advances in since its discovery,” Kostas Skenderis, one of the researchers who carried out the study, told Phys.org. “It has been used as a means to understand the behavior of strongly interacting where our usual theoretical tools () are not applicable, as well as in some of the main candidates for beyond the Standard Model physics.”

Supersymmetry underlies the mathematical consistency of string theory, which is the most complete theory of gravity proposed so far. A quantum anomaly, such as that observed by the researchers, is essentially the failure of a symmetry to be preserved at a quantum level. These anomalies typically come in two types: “bad” ones, which render string theory mathematically inconsistent and “healthy” ones, which capture important quantum properties of the theory.

Jul 1, 2019

How to Turn a Quantum Computer Into the Ultimate Randomness Generator

Posted by in categories: computing, quantum physics

Pure, verifiable randomness is hard to come by. Two proposals show how to make quantum computers into randomness factories.

Jun 30, 2019

Laser Interferometry and Gravitational Wave Astronomy

Posted by in categories: futurism, quantum physics

The Division focuses on the detection of gravitational waves and the development of gravitational-wave astronomy. This comprises the development and operation of large gravitational-wave detectors on the ground as well as in space, but also a full range of supporting laboratory experiments in quantum optics and laser physics.

According to Einstein´s theory of General Relativity, accelerated masses produce gravitational waves – perturbations of spacetime propagating at the speed of light through the universe, unhindered by intervening mass. The direct observation of gravitational waves on September 14, 2015 added a new sense to our perception of the Universe.

In the future, we will for the first time listen to the Universe.

Jun 30, 2019

Scientists achieve teleportation breakthrough

Posted by in categories: innovation, quantum physics

Japanese researchers carry out quantum teleportation within a diamond.

Jun 30, 2019

Quantum Computing Vs. Blockchain: Impact on Cryptography

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

Quantum computers will not kill blockchain, but they might trigger fundamental changes in underlying cryptography.

Jun 29, 2019

How quantum brain biology can rescue conscious free will

Posted by in categories: biological, computing, information science, neuroscience, quantum physics

Conscious “free will” is problematic because brain mechanisms causing consciousness are unknown, measurable brain activity correlating with conscious perception apparently occurs too late for real-time conscious response, consciousness thus being considered “epiphenomenal illusion,” and determinism, i.e., our actions and the world around us seem algorithmic and inevitable. The Penrose–Hameroff theory of “orchestrated objective reduction (Orch OR)” identifies discrete conscious moments with quantum computations in microtubules inside brain neurons, e.g., 40/s in concert with gamma synchrony EEG. Microtubules organize neuronal interiors and regulate synapses. In Orch OR, microtubule quantum computations occur in integration phases in dendrites and cell bodies of integrate-and-fire brain neurons connected and synchronized by gap junctions, allowing entanglement of microtubules among many neurons. Quantum computations in entangled microtubules terminate by Penrose “objective reduction (OR),” a proposal for quantum state reduction and conscious moments linked to fundamental spacetime geometry. Each OR reduction selects microtubule states which can trigger axonal firings, and control behavior. The quantum computations are “orchestrated” by synaptic inputs and memory (thus “Orch OR”). If correct, Orch OR can account for conscious causal agency, resolving problem 1. Regarding problem 2, Orch OR can cause temporal non-locality, sending quantum information backward in classical time, enabling conscious control of behavior. Three lines of evidence for brain backward time effects are presented. Regarding problem 3, Penrose OR (and Orch OR) invokes non-computable influences from information embedded in spacetime geometry, potentially avoiding algorithmic determinism. In summary, Orch OR can account for real-time conscious causal agency, avoiding the need for consciousness to be seen as epiphenomenal illusion. Orch OR can rescue conscious free will.

Keywords: microtubules, free will, consciousness, Penrose-Hameroff Orch OR, volition, quantum computing, gap junctions, gamma synchrony.

We have the sense of conscious control of our voluntary behaviors, of free will, of our mental processes exerting causal actions in the physical world. But such control is difficult to scientifically explain for three reasons:

Jun 28, 2019

Optimal quantum computation linked to gravity

Posted by in categories: computing, quantum physics

Information and gravity may seem like completely different things, but one thing they have in common is that they can both be described in the framework of geometry. Building on this connection, a new paper suggests that the rules for optimal quantum computation are set by gravity.

Physicists Paweł Caputa at Kyoto University and Javier Magan at the Instituto Balseiro, Centro Atómico de Bariloche in Argentina have published their paper on the link between and gravity in a recent issue of Physical Review Letters.

In the field of , one of the main ideas is minimizing the cost (in terms of computational resources) to solve a problem. In 2006, Michael Nielsen demonstrated that, when viewed in the context of differential geometry, computational costs can be estimated by distances. This means that minimizing computational costs is equivalent to finding minimal “geodesics,” which are the shortest possible distances between two points on a curved surface.

Jun 28, 2019

Physicists Discover Entirely New Quantum States When Graphene Meets Itself

Posted by in categories: nanotechnology, quantum physics

The super-thin ’wonder material’ graphene has been shaking up science for years with its amazing properties, but things get really interesting when you stack this 2D nanomaterial up against itself.

In new experiments, physicists in the US have found that when graphene is assembled in a double-layer vertical stack – with two adjacent sheets of the material that are almost touching – the proximity produces quantum states that haven’t been observed before.

These newly measured states, resulting from complex interactions of electrons between the two graphene layers, are examples of what’s called the fractional quantum Hall effect – and it’s just the latest example of how physical science gets weird when materials effectively only occupy two dimensions.