Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: quantum physics – Page 489

University of Queensland scientists have cracked a problem that’s frustrated chemists and physicists for years, potentially leading to a new age of powerful, efficient, and environmentally friendly technologies.

Using , Professor Ben Powell from UQ’s School of Mathematics and Physics has discovered a “recipe” which allows molecular switches to work at room temperature.

“Switches are materials that can shift between two or more states, such as on and off or 0 and 1, and are the basis of all digital technologies,” Professor Powell said. “This discovery paves the way for smaller and more powerful and energy efficient technologies. You can expect batteries will last longer and computers to run faster.”

Read more | >

Researchers from the Institute of Laser Physics at Universität Hamburg have succeeded for the first time in realizing a time crystal that spontaneously breaks continuous time translation symmetry. They report their observation in a study published online by the journal Science on Thursday, 9 June, 2022.

The idea of a time crystal goes back to Nobel laureate Franck Wilczek, who first proposed the phenomenon. Similar to water spontaneously turning into ice around the , thereby breaking the of the system, the time translation symmetry in a dynamical many-body system spontaneously breaks when a time crystal is formed.

In recent years, researchers have already observed discrete or Floquet time crystals in periodically driven closed and open quantum systems. “In all previous experiments, however, the continuous-time translation symmetry is broken by a time-periodic drive,” says Dr. Hans Keßler from Prof. Andreas Hemmerich’s group at the Cluster of Excellence CUI: Advanced Imaging of Matter. “The challenge for us was to realize a system that spontaneously breaks the continuous time translation symmetry.”

Read more | >

View insights.

A collection of 16 qubits has been organized in such a way that they may be able to operate any computation without error. It is an important step toward constructing quantum computers that outperform standard ones.

When completing any task, a quantum computer consisting of charged atoms can detect its own faults. Because conventional computers constantly detect and rectify their own flaws, quantum computers will need to do the same in order to fully outperform them. Nevertheless, quantum effects can cause errors to propagate rapidly through the qubits, or quantum bits, that comprise these devices.

Lukas Postler and his team from the Austria’s University of Innsbruck have created a quantum computer that can perform any calculation without error.

Read more | >

Machine learning can get a boost from quantum physics.

On certain types of machine learning tasks, quantum computers have an exponential advantage over standard computation, scientists report in the June 10 Science. The researchers proved that, according to quantum math, the advantage applies when using machine learning to understand quantum systems. And the team showed that the advantage holds up in real-world tests.

“People are very excited about the potential of using quantum technology to improve our learning ability,” says theoretical physicist and computer scientist Hsin-Yuan Huang of Caltech. But it wasn’t entirely clear if machine learning could benefit from quantum physics in practice.

Read more | >

A recent experiment detailed in the journal Nature is challenging our picture of how electrons behave in quantum materials. Using stacked layers of a material called tungsten ditelluride, researchers have observed electrons in two-dimensions behaving as if they were in a single dimension—and in the process have created what the researchers assert is a new electronic state of matter.

“This is really a whole new horizon,” said Sanfeng Wu, assistant professor of physics at Princeton University and the senior author of the paper. “We were able to create a new electronic phase with this experiment—basically, a new type of metallic state.”

Our current understanding of the behavior of interacting in metals can be described by a theory that works well with two-and three-dimensional systems, but breaks down when describing the interaction of electrons in a single dimension.

Read more | >

An interdisciplinary team led by Boston College physicists has discovered a new particle—or previously undetectable quantum excitation—known as the axial Higgs mode, a magnetic relative of the mass-defining Higgs Boson particle, the team reports in the online edition of the journal Nature.

The detection a decade ago of the long-sought Higgs Boson became central to the understanding of mass. Unlike its parent, axial Higgs mode has a , and that requires a more complex form of the theory to explain its properties, said Boston College Professor of Physics Kenneth Burch, a lead co-author of the report “Axial Higgs Mode Detected by Quantum Pathway Interference in RTe3.”

Theories that predicted the existence of such a mode have been invoked to explain “,” the nearly invisible material that makes up much of the universe, but only reveals itself via gravity, Burch said.

Read more | >

Quantum sensing is poised to revolutionize today’s sensors, significantly boosting the performance they can achieve. More precise, faster, and reliable measurements of physical quantities can have a transformative effect on every area of science and technology, including our daily lives. However, most of these schemes are based on special entangled or squeezed states of light or matter that are difficult to detect. It is a significantly challenging task to harness the full power of quantum-limited sensors and deploy them in real-world scenarios.

A team of physicists at the Universities of Bristol, Bath, and Warwick have found a way to operate mass manufacturable photonic sensors at the quantum limit. They have shown that it is possible to perform high-precision measurements of critical physical properties without the need for sophisticated quantum states of light and detection schemes.

Using ring resonators is a key to this breakthrough discovery. The ring resonators are tiny racetrack structures that guide light in a loop and maximize its interaction with the sample under study. Importantly, ring resonators can be mass-produced in the same way chips in computers and cell phones are.

Read more | >

Using a network of vibrating nano-strings controlled with light, researchers from AMOLF have made sound waves move in a specific irreversible direction and attenuated or amplified the waves in a controlled manner for the first time. This gives rise to a lasing effect for sound. To their surprise, they discovered new mechanisms, so-called “geometric phases,” with which they can manipulate and transmit sound in systems where that was thought to be impossible. “This opens the way to new types of (meta)materials with properties that we do not yet know from existing materials,” says group leader Ewold Verhagen who, together with shared first authors Javier del Pino and Jesse Slim, publishes the surprising results on June 2 in Nature.

The response of electrons and other charged particles to magnetic fields leads to many unique phenomena in materials. “For a long time, we have wanted to know whether an effect similar to a magnetic field on electrons could be achieved on , which has no charge,” says Verhagen. “The influence of a magnetic field on electrons has a wide impact: for example, an electron in a magnetic field cannot move along the same path in the opposite direction. This principle lies at the basis of various exotic phenomena at the nanometer scale, such as the quantum Hall effect and the functioning of topological insulators (materials that conduct current perfectly at their edges and not in their bulk). For many applications, it would be useful if we could achieve the same for vibrations and sound waves and therefore break the symmetry of their propagation, so it is not time-reversal symmetric anymore.”

Read more | >

A group of photonics researchers at Tampere University have introduced a novel method to control a light beam with another beam through a unique plasmonic metasurface in a linear medium at ultra-low power. This simple linear switching method makes nanophotonic devices such as optical computing and communication systems more sustainable, requiring low intensity of light.

All– is the modulation of signal light due to control light in such a way that it possesses the on/off conversion function. In general, a can be modulated with another intense laser beam in the presence of a nonlinear medium.

The switching method developed by the researchers is fundamentally based on the quantum optical phenomenon known as Enhancement of Index of Refraction (EIR).

Read more | >