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Category: particle physics – Page 483

Researchers have successfully used sound waves to control quantum information in a single electron, a significant step towards efficient, robust quantum computers made from semiconductors.

The international team, including researchers from the University of Cambridge, sent high-frequency across a modified to direct the behaviour of a , with efficiencies in excess of 99 percent. The results are reported in the journal Nature Communications.

A quantum computer would be able to solve previously unsolvable computational problems by taking advantage of the strange behaviour of particles at the subatomic scale, and such as entanglement and superposition. However, precisely controlling the behaviour of quantum particles is a mammoth task.

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Searching for new substances and developing new techniques in the chemical industry: tasks that are often accelerated using computer simulations of molecules or reactions. But even supercomputers quickly reach their limits. Now researchers at the Max Planck Institute of Quantum Optics in Garching (MPQ) have developed an alternative, analogue approach. An international team around Javier Argüello-Luengo, Ph.D. candidate at the Institute of Photonic Sciences (ICFO), Ignacio Cirac, Director and Head of the Theory Department at the MPQ, Peter Zoller, Director at the Institute of Quantum Optics and Quantum Information in Innsbruck (IQOQI), and others have designed the first blueprint for a quantum simulator that mimics the quantum chemistry of molecules. Like an architectural model can be used to test the statics of a future building, a molecule simulator can support investigating the properties of molecules. The results are now published in the scientific journal Nature.

Using hydrogen, the simplest of all , as an example, the global team of physicists from Garching, Barcelona, Madrid, Beijing and Innsbruck theoretically demonstrate that the quantum simulator can reproduce the behaviour of a real molecule’s . In their work, they also show how experimental physicists can build such a simulator step by step. “Our results offer a new approach to the investigation of phenomena appearing in quantum chemistry,” says Javier Argüello-Luengo. This is highly interesting for chemists because classical computers notoriously struggle to simulate chemical compounds, as molecules obey the laws of quantum physics. An electron in its shell, for example, can rotate to the left and right simultaneously. In a compound of many particles, such as a molecule, the number of these parallel possibilities multiplies. Because each electron interacts with each other, the complexity quickly becomes impossible to handle.

As a way out, in 1982, the American physicist Richard Feynman suggested the following: We should simulate quantum systems by reconstructing them as simplified models in the laboratory from , which are inherently quantum, and therefore implying a parallelism of the possibilities by default. Today, quantum simulators are already in use, for example to imitate crystals. They have a regular, three-dimensional atomic lattice which is imitated by several intersecting , the “optical lattice.” The intersection points form something like wells in an egg carton into which the are filled. The interaction between the atoms can be controlled by amplifying or attenuating the rays. This way researchers gain a variable model in which they can study atomic behavior very precisely.

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Swedish and Chinese scientists have developed organic solar cells optimised to convert ambient indoor light to electricity. The power they produce is low, but is probably enough to feed the millions of products that the internet of things will bring online.

As the internet of things expands, it is expected that we will need to have millions of products online, both in public spaces and in homes. Many of these will be the multitude of sensors to detect and measure moisture, particle concentrations, temperature and other parameters. For this reason, the demand for small and cheap sources of renewable energy is increasing rapidly, in order to reduce the need for frequent and expensive battery replacements.

This is where organic solar cells come in. Not only are they flexible, cheap to manufacture and suitable for manufacture as large surfaces in a printing press, they have one further advantage: the light-absorbing layer consists of a mixture of donor and acceptor materials, which gives considerable flexibility in tuning the solar cells such that they are optimised for different spectra – for light of different wavelengths.

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BERLIN, August 21, 2019 (Newswire.com) — The Neutrino Energy Group cooperates with a worldwide team of scientists and various international research centers, which deal with application research, the conversion of invisible radiation spectra of the sun, among other things the neutrinos (high-energy particles, which ceaselessly reach the earth) in electric power.

Is renewable energy hurting consumers?

During the last decade or so, consumers around the world have been encouraged to install solar panels on top of their houses. In certain climates, these rooftop photovoltaic installations can more than cover the electrical needs of an individual home, and many solar-equipped houses feature photovoltaic systems that wire directly into the grid. At times when the home has excess solar-generated electricity left over, this energy feeds back into the grid and helps out with the electricity needs of other energy company customers.

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Semiconductors are the basic building blocks of today’s digital, electronic age, providing us a multitude of devices that benefit our modern life, including computer, smartphones and other mobile devices. Improvements in semiconductor functionality and performance are likewise enabling next-generation applications of semiconductors for computing, sensing and energy conversion. Yet researchers have long struggled with limitations in our ability to fully understand the electronic charges inside semiconductor devices and advanced semiconductor materials, limiting our ability to drive further advances.

In a new study in the journal Nature, an IBM Research-led collaboration describes an exciting breakthrough in a 140-year-old mystery in physics—one that enables us to unlock the physical characteristics of semiconductors in much greater detail and aid in the development of new and improved materials.

To truly understand the physics of semiconductors, we first need to know the fundamental properties of the inside the materials, whether those particles are positive or negative, their speed under an applied electric field and how densely they are packed in the material. Physicist Edwin Hall found a way to determine those properties in 1879, when he discovered that a magnetic field will deflect the movement of electronic charges inside a conductor and that the amount of deflection can be measured as a voltage perpendicular to the flow of charge as shown in Fig. 1a. This voltage, known as the Hall voltage, unlocks essential information about the charge carriers in a semiconductor, including whether they are negative electrons or positive quasi-particles called “holes,” how fast they move in an or their “mobility” (µ) and their density (n) inside the semiconductor.

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CERN’s colossal complex of accelerators is in the midst of a two-year shutdown for upgrade work. But that doesn’t mean all experiments at the Laboratory have ceased to operate. The CLOUD experiment, for example, has just started a data run that will last until the end of November.

The CLOUD experiment studies how ions produced by high-energy particles called cosmic rays affect aerosol particles, clouds and the climate. It uses a special cloud chamber and a beam of particles from the Proton Synchrotron to provide an artificial source of cosmic rays. For this run, however, the cosmic rays are instead natural high-energy particles from cosmic objects such as exploding stars.

“Cosmic rays, whether natural or artificial, leave a trail of ions in the chamber,” explains CLOUD spokesperson Jasper Kirkby, “but the Proton Synchrotron provides cosmic rays that can be adjusted over the full range of ionisation rates occurring in the troposphere, which comprises the lowest ten kilometres of the atmosphere. That said, we can also make progress with the steady flux of natural cosmic rays that make it into our chamber, and this is what we’re doing now.”

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Circa 2010

Ultra-fast pulses from a powerful laser can create droplets of water out of thin air, according to a new study. With the right conditions and large enough droplets, the researchers say, the technique could be used to make rain on demand.

Rain forms when water condenses around tiny particles in the atmosphere. Most of the time, dust or pollen do the job, but humans have long attempted to speed the process by seeding clouds with chemicals like silver iodide. Those chemicals provide the so-called “condensation nuclei” that trigger the consolidation of water into raindrops.

Unfortunately, such methods are difficult and could have environmental side effects, said Jérôme Kasparian, an optical physicist at the University of Geneva, Switzerland who was on the team that demonstrated the laser-triggered condensation. The study was published online May 2 in the journal Nature Photonics.

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Scientists have observed a quantum vibration at normal room temperature for the first time, a phenomenon that usually requires ultra-cold, carefully calibrated conditions – bringing us another step closer to understanding the behaviour of quantum mechanics in common materials.

The team was able to spot a phonon, a quantum particle of vibration generated from high-frequency laser pulses, in a piece of diamond. These phonons are notoriously hard to detect, partly because of their sensitivity to heat.

What makes observing a phonon so important is that it shows a vibration acting as a single unit of energy (as described by quantum mechanics), as well as a wave (as described by classical physics). At room temperature in open air conditions, it brings quantum behaviour “closer to our daily life” in the words of the researchers.

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