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Archive for the ‘quantum physics’ category: Page 8

Dec 7, 2021

Quantum systems break the linearity of time

Posted by in categories: evolution, quantum physics

A new study suggests that systems governed by quantum mechanics do not show an exclusively linear evolution in time: in this way, they are sometimes able to unfold into the past and into the future simultaneously.

An international group of physicists concludes in a recent research published in the journal Communications Physics that quantum systems that evolve in one direction or another in time can also be found evolving in unison along both directions. This property shown by quantum systems in certain contexts breaks with the classical temporal conception, in which it is only possible to move forward or backward in time.

The work, carried out by scientists from the universities of Bristol (United Kingdom), Vienna (Austria), the Balearic Islands (Spain) and the Institute of Quantum Optics and Quantum Information (IQOQI-Vienna), shows that the limit between the time that going back and forth can be blurred in quantum mechanics. According to a press release from the University of Bristol, the new study forces us to rethink how the flow of time manifests itself in contexts in which quantum laws play a fundamental role.

Dec 7, 2021

China achieves crown of quantum supremacy

Posted by in categories: quantum physics, space

This website is dedicated to space and new developments in technology sector including new discoveries.

Dec 6, 2021

Quantum processor swapped in for a neural network

Posted by in categories: climatology, quantum physics, robotics/AI, satellites

To handle this, people have trained neural networks on regions where we have more complete weather data. Once trained, the system could be fed partial data and infer what the rest was likely to be. For example, the trained system can create a likely weather radar map using things like satellite cloud images and data on lightning strikes.

This is exactly the sort of thing that neural networks do well with: recognizing patterns and inferring correlations.

What drew the Rigetti team’s attention is the fact that neural networks also map well onto quantum processors. In a typical neural network, a layer of “neurons” performs operations before forwarding its results to the next layer. The network “learns” by altering the strength of the connections among units in different layers. On a quantum processor, each qubit can perform the equivalent of an operation. The qubits also share connections among themselves, and the strength of the connection can be adjusted. So, it’s possible to implement and train a neural network on a quantum processor.

Dec 5, 2021

Wolfgang Pauli’s *Philosophical* Position on Quantum Mechanics and Angels

Posted by in category: quantum physics

The Swiss-American theoretical physicist Wolfgang Pauli (1900–1958) once stated (in a 1954 letter to Max Born) the following often-quoted…

Dec 4, 2021

Pythagoras’ Revenge: Humans Didn’t Invent Mathematics, It’s What the Physical World Is Made Of

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

Graphene consists of a planar structure, with carbon atoms connected in a hexagonal shape that resembles a beehive. When graphene is reduced to several nanometers (nm) in size, it becomes a graphene quantum dot that exhibits fluorescent and semiconductor properties. Graphene quantum dots can be used in various applications as a novel material, including display screens, solar cells, secondary batteries, bioimaging, lighting, photocatalysis, and sensors. Interest in graphene quantum dots is growing, because recent research has demonstrated that controlling the proportion of heteroatoms (such as nitrogen, sulfur, and phosphorous) within the carbon structures of certain materials enhances their optical, electrical, and catalytic properties.

Dec 4, 2021

Development of a single-process platform for the manufacture of graphene quantum dots

Posted by in categories: chemistry, nanotechnology, particle physics, quantum physics, solar power, space, sustainability

Graphene consists of a planar structure, with carbon atoms connected in a hexagonal shape that resembles a beehive. When graphene is reduced to several nanometers (nm) in size, it becomes a graphene quantum dot that exhibits fluorescent and semiconductor properties. Graphene quantum dots can be used in various applications as a novel material, including display screens, solar cells, secondary batteries, bioimaging, lighting, photocatalysis, and sensors. Interest in graphene quantum dots is growing, because recent research has demonstrated that controlling the proportion of heteroatoms (such as nitrogen, sulfur, and phosphorous) within the carbon structures of certain materials enhances their optical, electrical, and catalytic properties.

The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) reported that the research team led by Dr. Byung-Joon Moon and Dr. Sukang Bae of the Functional Composite Materials Research Center have developed a technique to precisely control the bonding structure of single heteroatoms in the graphene quantum dot, which is a zero-dimensional carbon nanomaterial, through simple chemical reaction control; and that they identified the relevant reaction mechanisms.

With the aim of controlling heteroatom incorporation within the graphene quantum dot, researchers have previously investigated using additives that introduce the heteroatom into the dot after the dot itself has already been synthesized. The dot then had to be purified further, so this method added several steps to the overall fabrication process. Another method that was studied involved the simultaneous use of multiple organic precursors (which are the main ingredients for dot synthesis), along with the additives that contain the heteroatom. However, these methods had significant disadvantages, including reduced crystallinity in the final product and lower overall reaction yield, since several additional purification steps had to be implemented. Furthermore, in order to obtain quantum dots with the chemical compositions desired by manufacturers, various reaction conditions, such as the proportion of additives, would have to be optimized.

Dec 4, 2021

The supersymmetric bottom quark and its friends

Posted by in categories: alien life, particle physics, quantum physics

When it comes to quarks, those of the third generation (the top and bottom) are certainly the most fascinating and intriguing. Metaphorically, we would classify their social life as quite secluded, as they do not mix much with their relatives of the first and second generation. However, as the proper aristocrats of the particle physics world, they enjoy privileged and intense interactions with the Higgs field; it is the intensity of this interaction that eventually determines things like the quantum stability of our Universe. Their social life may also have a dark side, as they could be involved in interactions with dark matter.

This special status of third-generation quarks makes them key players in the search for phenomena not foreseen by the Standard Model. A new result released by the ATLAS Collaboration focuses on models of new phenomena that predict an enhanced yield of collision events with bottom quarks and invisible particles. A second new ATLAS search considers the possible presence of added tau leptons. Together, these results set strong constraints on the production of partners of the b-quarks and of possible dark-matter particles.

Dec 3, 2021

Physicists Observe Quantum Spin Liquid for First Time

Posted by in category: quantum physics

First theorized in 1973 by physicist Philip W. Anderson, quantum spin liquids are exotic phases of matter with topological order. They feature long-range quantum entanglement that can potentially be exploited to realize robust quantum computation. But the problem about this exotic state of matter has been its very existence: no one had ever seen it — at least, that had been the case for almost five decades.

“Instead, it’s all about magnets that never freeze and the way electrons in them spin.”

Dec 3, 2021

Physicists just gifted us ‘quantum spin liquid,’ a weird new state of matter

Posted by in categories: particle physics, quantum physics

This, combined with the esoteric rules of quantum mechanics, means that the spins are constantly in different positions at once. If you look at just a few particles, it’s hard to tell whether you have a quantum liquid or, if you do, what properties it has.

Quantum spin liquids were first theorized in 1973 by a physicist named Philip W. Anderson, and physicists have been trying to get their hands on this matter ever since. “Many different experiments…tried to create and observe this type of state. But this has actually turned out to be very challenging,” says Mikhail Lukin, a physicist at Harvard University and one of the paper authors.

The researchers at Harvard had a new tool in their arsenal: what they call a “programmable quantum simulator.” Essentially, it’s a machine that allows them to play with individual atoms. Using specifically focused laser beams, researchers can shuffle atoms around a two-dimensional grid like magnets on a whiteboard.

Dec 2, 2021

Novel quantum device design promises a regular flow of entangled electrons on demand

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

Quantum computer and many other quantum technologies rely on the generation of quantum-entangled pairs of electrons. However, the systems developed so far typically produce a noisy and random flow of entangled electrons, which hinders synchronized operations on the entangled particles. Now, researchers from Aalto University in Finland propose a way to produce a regular flow of spin-entangled electrons.

Their solution is based on a dynamically driven Cooper pair splitter. In a Cooper pair splitter, two near a superconductor are used to generate and separate a pair of entangled electrons known as a Cooper pair. When the Cooper pair splitter is driven with a static voltage, the result is a random and noisy process.

A by the Aalto team showed that driving the system dynamically with external gate voltages makes it possible to control the timing of the splitting process. As a result, exactly one pair of entangled electrons can be extracted during each splitting cycle, leading to a completely noiseless and regular flow of spin-entangled electrons.

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