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Category: quantum physics – Page 895

Physicists from the Russian Quantum Center (RQC), MIPT, the Lebedev Physical Institute, and L’Institut d’Optique (Palaiseau, France) have devised a method for creating a special quantum entangled state. This state enables producing a high-precision ruler capable of measuring large distances to an accuracy of billionths of a metre. The results of the study have been published in Nature Communications (“Loss-tolerant state engineering for quantum-enhanced metrology via the reverse Hong–Ou–Mandel effect”).

“This technique will enable us to use quantum effects to increase the accuracy of measuring the distance between observers that are separated from one another by a medium with losses. In this type of medium, quantum features of light are easily destroyed,” says Alexander Lvovsky, a co-author of the paper, the head of the RQC scientific team that conducted the research, and a professor of the University of Calgary.

Alexander Ulanov in the Laboratory of quantum optics in RQC

Alexander Ulanov in the Laboratory of quantum optics in RQC.

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(Phys.org)—Inspired by natural selection and the concept of “survival of the fittest,” genetic algorithms are flexible optimization techniques that can find the best solution to a problem by repeatedly selecting for and breeding ever “fitter” generations of solutions.

Now for the first time, researchers Urtzi Las Heras et al. at the University of the Basque Country in Bilbao, Spain, have applied genetic algorithms to digital and shown that genetic algorithms can reduce quantum errors, and may even outperform existing optimization techniques. The research, which is published in a recent issue of Physical Review Letters, was led by Ikerbasque Prof. Enrique Solano and Dr. Mikel Sanz in the QUTIS group.

In general, quantum simulations can provide a clearer picture of the dynamics of systems that are impossible to understand using conventional computers due to their high degree of complexity. Whereas computers calculate the behavior of these systems, quantum simulations approximate or “simulate” the behavior.

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They’re calling this a 3 Axis Vector Nano Superconducting Quantum Interference Device which is pretty exciting because it enables the ability to make smaller and cheaper devices for measuring light, such as optical sensors and photodetectors which are and will grow in demand especially with some of the AI technology that is and will be developed. Optical sensors are used to read the gestures/ expressions of a face which are important in security, AI technology, etc. Just hope the cost savings is passed on.

(Phys.org)—Researchers have fabricated a silicon optical antenna that is somewhat like an extremely small, special kind of prism. This is because when a red light shines on the optical antenna, the light turns right, but when the light is another color such as orange, it turns left.

This unusual property, which is called “bidirectional color scattering,” enables the optical antenna to function effectively as a passive wavelength router for visible . The device could have applications for innovative light sensors, light-matter manipulation, and optical communication.

The new optical antenna was developed by a team of researchers, Jiaqi Li et al., at imec (Interuniversity MicroElectronics Center) and the University of Leuven (KU Leuven), both in Leuven, Belgium. Their work is published in a recent issue of Nano Letters.

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Excellent story and highlights how Quantum computers may provide a way to overcome the obstacles around particle physics because QC can simulate certain aspects of elementary particle physics in a well-controlled quantum system.

Physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, building a bridge between high-energy theory and atomic physics. In the journal Nature, Rainer Blatt’s and Peter Zoller’s research teams describe how they simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer.

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Entanglement purification, a vital enabler for practical quantum networks, has been shown to be feasible with secluded nuclear memories in diamond.

Quantum devices can team up to perform a task collectively, but only if they share that most “spooky” of all quantum phenomena: entanglement. Remote devices have been successfully entangled in order to investigate entanglement itself [1], but the entanglement’s quality is too low for practical applications. The solution, known as entanglement purification [2], has seemed daunting to implement in a real device. Now new research [3] shows that even quite simple quantum components—nanostructures in diamond—have the potential to store and upgrade entanglement. The result relies on hiding information in almost-inaccessible nuclear memories, and may be a key step toward the era of practical quantum networks.

The concept of an interlinked network is absolutely fundamental to conventional technologies. It applies not only to distributed systems like the internet, but also to individual devices like laptops, which contain a hierarchy of interlinked components. For quantum technologies to fulfill their potential, we will want them to have the flexibility and scalability that come from embracing the network paradigm.

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Quantum physics applies Hilbert spaces as the realm in which quantum physical research is done. However, the Hilbert spaces contain nothing that prevents universe from turning into complete chaos. Quantum physics requires extra mechanisms that ensure sufficient coherence.

Reality has built-in principles. If you understand these built-in principles, then these principles teach a lesson.

The foundation of reality already supports the built-in principles. A foundation must have a simple structure and that structure must be easily comprehensible. It must install restrictions such that extension of the foundation runs according predetermined lines that preserve sufficient coherence, such that the installed principles are keeping their validity. This makes the discovery of the foundation a complicated affair, because not every simple structure will provide these requirements. Still a sensible candidate for such foundation was discovered eighty years ago. It is a relational structure and it discovery was reported in 1936. The structure implements a law of reality. That law cannot be phrased in the form of a formula, because the relational structure only contains unnamed elements and it defines tolerated relations between these elements. Thus the relational structure does not contain numbers that could be used as variables in the formula.

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Oh no; China has slipped by a month.

Launch of the world’s first quantum communications satellite will take place in August, the leader of China’s space science program has said.

Dr Wu Ji of the National Space Science Centre (NSSC) under the Chinese Academy of Sciences (CAS), told reporters in Beijing while updating on space science missions (link in Chinese).

The pioneering QUantum Experiments at Space Scale (QUESS) mission, part of China’s ambitious space science agenda, was expected to launch from Jiuquan Satellite Launch Centre in July, but has now slipped.

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Using numerical modelling, researchers from Russia, the US, and China have discovered previously unknown features of rutile TiO2, which is a promising photocatalyst. The calculations were performed at an MIPT laboratory on the supercomputer Rurik. A paper detailing the results has been published in the journal Physical Chemistry Chemical Physics.

It’s all on the surface

Special substances called catalysts are needed to accelerate or induce certain chemical reactions. Titanium dioxide (TiO2) is a good photocatalyst—when exposed to light, it effectively breaks down water molecules as well as hazardous organic contaminants. TiO2 is naturally found in the form of rutile and other minerals. One of the two most active surfaces of rutile R-TiO2 is a surface that is denoted as (011). The photocatalytic activity is linked to the way in which oxygen and titanium atoms are arranged on the surface. This is why it is important to understand which forms the surface of rutile can take.

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A high-tech version of an old-fashioned balance scale at the National Institute of Standards and Technology (NIST) has just brought scientists a critical step closer toward a new and improved definition of the kilogram. The scale, called the NIST-4 watt balance, has conducted its first measurement of a fundamental physical quantity called Planck’s constant to within 34 parts per billion — demonstrating the scale is accurate enough to assist the international community with the redefinition of the kilogram, an event slated for 2018.

The redefinition-which is not intended to alter the value of the kilogram’s mass, but rather to define it in terms of unchanging fundamental constants of nature-will have little noticeable effect on everyday life. But it will remove a nagging uncertainty in the official kilogram’s mass, owing to its potential to change slightly in value over time, such as when someone touches the metal artifact that currently defines it.

Planck’s constant lies at the heart of quantum mechanics, the theory that is used to describe physics at the scale of the atom and smaller. Quantum mechanics began in 1900 when Max Planck described how objects radiate energy in tiny packets known as “quanta.” The amount of energy is proportional to a very small quantity called h, known as Planck’s constant, which subsequently shows up in almost all equations in quantum mechanics. The value of h — according to NIST’s new measurement — is 6.62606983×10−34 kg?m2/s, with an uncertainty of plus or minus 22 in the last two digits.

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