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Archive for the ‘quantum physics’ category: Page 446

Aug 26, 2019

New theory draws connections between Planckian metals and black holes

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

Two researchers at Harvard University, Aavishkar A. Patel and Subir Sachdev, have recently presented a new theory of a Planckian metal that could shed light on previously unknown aspects of quantum physics. Their paper, published in Physical Review Letters, introduces a lattice model of fermions that describes a Planckian metal at low temperatures (Tà 0).

Metals contain numerous , which carry . When physicists consider the electrical resistance of metals, they generally perceive it as arising when the flow of current-carrying electrons is interrupted or degraded due to electrons scattering off impurities or off the crystal lattice in the metal.

“This picture, put forth by Drude in 1900, gives an equation for the electrical resistance in terms of how much time electrons spend moving freely between successive collisions,” Patel told Phys.org. “The length of this time interval between collisions, called the ‘,’ or ‘electron liftetime,’ is typically long enough in most common metals for the electrons to be defined as distinct, mobile objects to a microscopic observer, and the Drude picture works remarkably well.”

Aug 25, 2019

Researchers observe spontaneous occurrence of skyrmions in atomically thin cobalt films

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

Since their experimental discovery, magnetic skyrmions—tiny magnetic knots—have moved into the focus of research. Scientists from Hamburg and Kiel have now been able to show that individual magnetic skyrmions with a diameter of only a few nanometers can be stabilized in magnetic metal films even without an external magnetic field. They report on their discovery in the journal Nature Communications.

The existence of magnetic skyrmions as particle-like objects was predicted 30 years ago by , but could only be proven experimentally in 2013. Skyrmions with a diameter from micrometers to a few nanometers were discovered in different magnetic material systems. Although they can be generated on a surface of a few atoms and manipulated with , they show a high stability against external influences. This makes them for future data storage or logic devices. In order to be competitive for technological applications, however, skyrmions must not only be very small, but also stable without an applied magnetic field.

Researchers at the universities of Hamburg and Kiel have now taken an important step in this direction. On the basis of quantum mechanical numerical calculations carried out on the supercomputers of the North-German Supercomputing Alliance (HLRN), the physicists from Kiel were able to predict that individual skyrmions with a diameter of only a few nanometers would appear in an atomically thin, ferromagnetic cobalt film (see Fig. 1). “The stability of the magnetic knots in these films is due to an unusual competition between different magnetic interactions,” says Sebastian Meyer, Ph.D. student in Prof. Stefan Heinze’s research group at the Kiel University.

Aug 25, 2019

Researchers Demonstrate The World’s First Quantum Radar

Posted by in categories: computing, encryption, quantum physics

Yes, we know that sometimes it feels like they just tack the word quantum on new technology and call it a day like we are all living in the Marvel Cinematic Universe. Nevertheless, quantum technology is very real and is just as exciting. Our better understanding of the quantum world and handle on the principals will help us improve everything from computing to encryption.

Aug 23, 2019

Quantum radar has been demonstrated for the first time

Posted by in categories: computing, encryption, quantum physics

One of the advantages of the quantum revolution is the ability to sense the world in a new way. The general idea is to use the special properties of quantum mechanics to make measurements or produce images that are otherwise impossible.

Much of this work is done with photons. But as far as the electromagnetic spectrum is concerned, the quantum revolution has been a little one-sided. Almost all the advances in quantum computing, cryptography, teleportation, and so on have involved visible or near-visible light.

Aug 23, 2019

Complex quantum teleportation achieved for the first time

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

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Austrian and Chinese scientists have succeeded in teleporting three-dimensional quantum states for the first time. High-dimensional teleportation could play an important role in future quantum computers.

Researchers from the Austrian Academy of Sciences and the University of Vienna have experimentally demonstrated what was previously only a theoretical possibility. Together with quantum physicists from the University of Science and Technology of China, they have succeeded in teleporting complex high-dimensional quantum states. The research teams report this international first in the journal Physical Review Letters.

Continue reading “Complex quantum teleportation achieved for the first time” »

Aug 22, 2019

Quantum computers to become portable

Posted by in categories: computing, quantum physics, transportation

Together with the University of Innsbruck, the ETH Zurich and Interactive Fully Electrical Vehicles SRL, Infineon Austria is researching specific questions on the commercial use of quantum computers. With new innovations in design and manufacturing, the partners from universities and industry want to develop affordable components for quantum computers.

Aug 22, 2019

Practical anonymous communication protocol developed for quantum networks

Posted by in categories: internet, quantum physics

The ability to securely transmit information over the internet is extremely important, but most of the time, eavesdroppers can still generally determine who the sender and receiver are. In some highly confidential situations, it is important that the sender’s and receiver’s identities remain anonymous.

Over the past couple of decades, researchers have been developing protocols for anonymously transmitting messages over classical networks, but similar protocols for are still in much earlier stages of development. The anonymity methods that have been proposed for quantum networks so far face challenges such as implementation difficulties or require that strong assumptions be made about the resources, making them impractical for use in the .

In a new paper, Anupama Unnikrishnan, Ian MacFarlane, Richard Yi, Eleni Diamanti, Damian Markham, and Iordanis Kerenidis, from the University of Oxford, MIT, Sorbonne University, the University of Paris and CNRS, have proposed the first practical for anonymous communication in quantum networks.

Aug 21, 2019

The World’s First MRI of a SINGLE Atom Is Here, and It Could Revolutionize Imaging

Posted by in categories: computing, neuroscience, quantum physics

Magnetic resonance imaging is nothing new, but scientists were able to perform an MRI on a single atom. But how?
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Scientists recently captured the smallest MRI ever while scanning an individual atom. The technique successfully reached a breakthrough level of resolution in the world of microscopy, the detailed MRI can reveal single atoms as well as different types of atoms based on their magnetic interactions.

Continue reading “The World’s First MRI of a SINGLE Atom Is Here, and It Could Revolutionize Imaging” »

Aug 21, 2019

Cambridge Quantum Random Key Generation and Encryption

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

Cambridge Quantum Computing has a demo of its quantum key security generation at Ironbridgeapi.com.

Aug 21, 2019

Quantum physicists have teleported ‘qutrits’ for the first time

Posted by in category: quantum physics

Y.-H. Luo et al. Quantum teleportation in high dimensions. Physical Review Letters. Vol. 123, August 16, 2019. doi:10.1103/PhysRevLett.123.070505.