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Archive for the ‘quantum physics’ category: Page 336

Jan 9, 2021

Inside the Air Force Research Laboratory’s Quantum Lab

Posted by in categories: engineering, quantum physics

Basic science, practical engineering — and an attempt to focus on the most productive lines of effort.

Jan 9, 2021

Using the SYK model to examine the fast-charging process of quantum batteries

Posted by in categories: cosmology, quantum physics

The Sachdev-Ye-Kitaev (SYK) model, an exactly solvable model devised by Subir Sachdev and Jinwu Ye, has recently proved useful for understanding the characteristics of different types of matter. As it describes quantum matter without quasiparticles and is simultaneously a holographic version of a quantum black hole, it has so far been adopted by both condensed matter and high-energy physicists.

Researchers at University of Pisa and the Italian Institute of Technology (IIT) have recently used the SYK model to examine the charging protocols of quantum batteries. Their paper, published in Physical Review Letters, offers evidence of the potential of quantum mechanical resources for boosting the charging process of batteries.

“Previous theoretical studies laid down the idea that entanglement can be used to greatly speed up the charging process of a quantum battery,” Davide Rossini and Gian Marcello Andolina, two of the researchers who carried out the study, told Phys.org, via email. “However, a concrete solid-state model displaying such fast charging was missing, until now.”

Jan 8, 2021

Researchers realize efficient generation of high-dimensional quantum teleportation

Posted by in categories: quantum physics, security

In a study published in Physical Review Letters, a team led by academician Guo Guangcan from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) has made progress in high dimensional quantum teleportation. The researchers demonstrated the teleportation of high-dimensional states in a three-dimensional six-photon system.

To transmit unknown quantum states from one location to another, quantum teleportation is one of the key technologies to realize long-distance transmission.

Compared with two-dimensional systems, high-dimensional system quantum networks have the advantages of higher channel capacity and better security. In recent years more and more researchers of the quantum information field have been working on generating efficient generation of high-dimensional quantum teleportation to achieve efficient high-dimensional quantum networks.

Jan 8, 2021

The World’s First Quantum Phase Battery Is Here

Posted by in categories: computing, nanotechnology, quantum physics

O,.o circa 2020.


Their quantum phase battery consists of an n-doped InAs nanowire forming the core of the battery (the pile) and Al superconducting leads as poles. It is charged by applying an external magnetic field, which then can be switched off.

Cristina Sanz-Fernández and Claudio Guarcello, also from CFM, adapted the theory to simulate the experimental findings.

Continue reading “The World’s First Quantum Phase Battery Is Here” »

Jan 8, 2021

Birds Have a Mysterious ‘Quantum Sense’. For The First Time, Scientists Saw It in Action

Posted by in categories: chemistry, quantum physics

Looks like living cells may have a lot more surprises to offer. 😃


Seeing our world through the eyes of a migratory bird would be a rather spooky experience. Something about their visual system allows them to ‘see’ our planet’s magnetic field, a clever trick of quantum physics and biochemistry that helps them navigate vast distances.

Now, for the first time ever, scientists from the University of Tokyo have directly observed a key reaction hypothesised to be behind birds’, and many other creatures’, talents for sensing the direction of the planet’s poles.

Continue reading “Birds Have a Mysterious ‘Quantum Sense’. For The First Time, Scientists Saw It in Action” »

Jan 7, 2021

Researchers question fundamental study on the Kondo effect

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

The Kondo effect influences the electrical resistance of metals at low temperatures and generates complex electronic and magnetic orders. Novel concepts for data storage and processing, such as using quantum dots, are based on this. In 1998, researchers from the United States published spectroscopic studies on the Kondo effect using scanning tunneling microscopy, which are considered ground-breaking and have triggered countless others of a similar kind. Many of these studies may have to be re-examined now that Jülich researchers have shown that the Kondo effect cannot be proven beyond doubt by this method. Instead, another phenomenon is creating precisely the spectroscopic ‘fingerprint’ that was previously attributed to the Kondo effect.

Normally the resistance of metals decreases as the temperature drops. The Kondo effect causes it to rise again below a threshold value typical to the material in question, the so-called Kondo temperature. This phenomenon occurs when magnetic foreign atoms, such as iron, contaminate non-magnetic host metals, such as copper. Simply put, when a current flows, the atomic nuclei are engulfed by electrons. The iron atoms have a quantum mechanical magnetic moment. This causes the electrons in the vicinity to align their spin antiparallel to the moment of the atom at low temperatures and to hang around the cobalt atom like a cloud on a mountaintop. This hinders the flow of the electrons—the electrical resistance then increases. In physics, this is known as entanglement, the strong coupling of the moment of the impurity with the spins of the surrounding electrons.

Jan 7, 2021

2020’s Biggest Breakthroughs in Math and Computer Science

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

For mathematicians and computer scientists, 2020 was full of discipline-spanning discoveries and celebrations of creativity. We’d like to take a moment to recognize some of these achievements.

1. A landmark proof simply titled MIP = RE” establishes that quantum computers calculating with entangled qubits can theoretically verify the answers to an enormous set of problems. Along the way, the five computer scientists who authored the proof also answered two other major questions: Tsirelson’s problem in physics, about models of particle entanglement, and a problem in pure mathematics called the Connes embedding conjecture.

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Jan 7, 2021

Quantum Nanodevice Can Be Both a Heat Engine and Refrigerator at the Same Time

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

A multitasking nanomachine that can act as a heat engine and a refrigerator at the same time has been created by RIKEN engineers. The device is one of the first to test how quantum effects, which govern the behavior of particles on the smallest scale, might one day be exploited to enhance the performance of nanotechnologies.

Conventional heat engines and refrigerators work by connecting two pools of fluid. Compressing one pool causes its fluid to heat up, while rapidly expanding the other pool cools its fluid. If these operations are done in a periodic cycle, the pools will exchange energy and the system can be used as either a heat engine or a fridge.

It would be impossible to set up a macroscale machine that does both tasks simultaneously—nor would engineers want to, says Keiji Ono of the RIKEN Advanced Device Laboratory. “Combining a traditional heat engine with a refrigerator would make it a completely useless machine,” he says. “It wouldn’t know what to do.”

Jan 6, 2021

Physicists observe competition between magnetic orders

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

They are as thin as a hair, only a hundred thousand times thinner—so-called two-dimensional materials, consisting of a single layer of atoms, have been booming in research for years. They became known to a wider audience when two Russian-British scientists were awarded the Nobel Prize in Physics in 2010 for the discovery of graphene, a building block of graphite. The special feature of such materials is that they possess novel properties that can only be explained with the help of the laws of quantum mechanics and that may be relevant for enhanced technologies. Researchers at the University of Bonn (Germany) have now used ultracold atoms to gain new insights into previously unknown quantum phenomena. They found out that the magnetic orders between two coupled thin films of atoms compete with each other. The study has been published in the journal Nature.

Quantum systems realize very unique states of matter originating from the world of nanostructures. They facilitate a wide variety of new technological applications, e.g. contributing to secure data encryption, introducing ever smaller and faster technical devices and even enabling the development of a quantum computer. In the future, such a computer could solve problems which conventional computers cannot solve at all or only over a long period of time.

How unusual quantum phenomena arise is still far from being fully understood. To shed light on this, a team of physicists led by Prof. Michael Köhl at the Matter and Light for Quantum Computing Cluster of Excellence at the University of Bonn are using so-called quantum simulators, which mimic the interaction of several quantum particles—something that cannot be done with conventional methods. Even state-of-the-art computer models cannot calculate complex processes such as magnetism and electricity down to the last detail.

Jan 6, 2021

Breaking through the resolution barrier with quantum-limited precision

Posted by in category: quantum physics

Researchers at Paderborn University have developed a new method of distance measurement for systems such as GPS, which achieves more precise results than ever before. Using quantum physics, the team led by Leibniz Prize winner Professor Christine Silberhorn has successfully overcome the so-called resolution limit, which causes the ‘noise’ we may see in photos, for example. Their findings have just been published in the academic journal Physical Review X Quantum (PRX Quantum).

Physicist Dr. Benjamin Brecht explains the problem of the resolution limit: “In laser distance measurements a detector registers two light pulses of different intensities with a . The more precise the time measurement is, the more accurately the distance can be determined. Providing the time separation between the pulses is greater than the length of the pulses, this works well.” Problems arise, however, as Brecht explains, if the pulses overlap: “Then you can no longer measure the time difference using conventional methods. This is known as the ‘resolution limit’ and is a well-known effect in photos. Very small structures or textures can no longer be resolved. That’s the same problem—just with position rather than time.”

A further challenge, according to Brecht, is to determine the different intensities of two light pulses, simultaneously with their time difference and the arrival time. But this is exactly what the researchers have managed to do—” with quantum-limited precision,” adds Brecht. Working with partners from the Czech Republic and Spain, the Paderborn physicists were even able to measure these values when the pulses overlapped by 90 per cent. Brecht says: “This is far beyond the resolution limit. The precision of the measurement is 10000 times better. Using methods from quantum information theory, we can find new forms of measurement which overcome the limitations of established methods.”