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Archive for the ‘quantum physics’ category: Page 778

Jun 24, 2016

A new form of hybrid photodetectors with quantum dots and graphene

Posted by in categories: computing, quantum physics

Glad to see others finding value in using Q-Dots with Graphene.


The development of photodetectors has been a matter of considerable interest in the past decades since their applications are essential to many different fields including cameras, medical devices, safety equipment, optical communication devices or even surveying instruments, among others.

Many efforts have been focused towards optoelectronic research in trying to create low cost photodetectors with high sensitivity, high quantum efficiency, high gain and fast photoresponse. This is of paramount importance especially in the short wave infrared which currently is addressed by very expensive III-V InGaAs photodetectors. The development of two main classes of photodetectors, photodiodes and phototransistors, have partially been able to accomplish these goals because even though they both have many outstanding properties, none seem to fulfill all of these requirements. While photodiodes are much faster than phototransistors, phototransistors have a higher gain and do not require low noise preamplifiers for their use.

To overcome these limitations, ICFO researchers Ivan Nikitskiy, Stijn Goossens, Dominik Kufer, Tania Lasanta, Gabriele Navickaite, led by ICREA professors at ICFO Frank Koppens and Gerasimos Konstantatos, have been able to develop a hybrid photodetector capable of attaining concomitantly better performance features in terms of speed, quantum efficiency and linear dynamic range, operating not only in the visible but also in the near infrared (NIR: 700-1400nm) and SWIR range (1400-3000nm). At the same time this technology is based upon materials that can be monolithically integrated with Si CMOS electronics as well as flexible electronic platforms. The results of this work have been recently published in Nature Communications.

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Jun 23, 2016

A Brief Explanation of Planck’s Constant and the Birth of Quantum Physics

Posted by in category: quantum physics

Planck’s constant put the “quantum” in “quantum mechanics.”

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Jun 23, 2016

Physicists create a high-precision ‘quantum ruler’

Posted by in categories: engineering, quantum physics

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

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Jun 23, 2016

Genetic algorithms can improve quantum simulations

Posted by in categories: computing, genetics, information science, quantum physics

(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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Jun 22, 2016

Optical antenna scatters different colors of light in different directions

Posted by in categories: quantum physics, robotics/AI, security

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.

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Jun 22, 2016

Quantum computer makes first high-energy physics simulation

Posted by in categories: computing, quantum physics

Cool beans.


The technique would help address problems that classical computers can’t handle.

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Jun 22, 2016

Particle zoo in a quantum computer

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

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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Jun 22, 2016

Viewpoint: Hiding a Quantum Cache in Diamonds

Posted by in categories: computing, internet, nanotechnology, quantum physics

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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Jun 21, 2016

Mechanisms that keep reality coherent

Posted by in category: quantum physics

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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Jun 21, 2016

China’s pioneering quantum satellite launch slips to August

Posted by in categories: quantum physics, satellites

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).

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