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Archive for the ‘quantum physics’ category: Page 723

Dec 26, 2016

The Science and Engineering of Quantum Dot Lasers

Posted by in categories: engineering, quantum physics, science

Since their development in 1960, lasers have become an indispensable tool supporting our modern society, finding use in fields such as medicine, information, and industry. Thanks to their compact size and energy efficiency, semiconductor lasers are now one of the most important classes of laser, making possible a diverse range of applications. However, the threshold current of a typical semiconductor laser—the minimum electrical current required to induce lasing—increases with temperature. This is one of a number of disadvantages that can be overcome by using quantum dot lasers. Professor Yasuhiko Arakawa of the Institute of Industrial Science at the University of Tokyo has been researching quantum dot lasers for about 35 years, from their conception to commercialization.

An electron trapped in a microscopic box

Sunlight is composed of light of various colors. The property that determines the color of light is its wavelength, or in other words, the distance between two successive wave peaks or troughs. The location of the peaks and troughs in the waveform is known as its phase. As a laser emits light waves in a uniform phase at the same wavelength, the light can be transmitted as a beam over long distances at high intensity.

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Dec 26, 2016

Ultra-Small Nanocavity Advances Technology for Quantum-Based Data Encryption

Posted by in categories: encryption, nanotechnology, quantum physics

What’s next? Nanocavities in a diamond for small devices.


Researchers have developed a new type of light-enhancing optical cavity that is only 200 nanometers tall and 100 nanometers across. Their new nanoscale system represents a step toward brighter single-photon sources, which could help propel quantum-based encryption techniques under development.

Quantum encryption techniques, which are seen as likely to be central to future data encryption methods, use individual photons as an extremely secure way to encode data. A limitation of these techniques has been the ability to emit photons at high rates. “One of the most important figures of merit for single-photon sources is brightness — or collected photons per second — because the brighter it is, the more data you can transmit securely with quantum encryption,” said Yousif Kelaita of Stanford University.

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Dec 25, 2016

Physicists Achieve Quantum Teleportation of Photon Over 25 Kilometers

Posted by in categories: particle physics, quantum physics

For the first time, a team of physicists have successfully teleported a quantum state of a photon to a crystal over 25 kilometers away through a fiber optic cable. This effectively showed that the photon’s quantum state, not its composition, is important to the teleportation process. The team was led by Nicolas Gisin of the University of Geneva and the results were published in the journal Nature Photonics. With this new paper, Gisin’s team has successfully squashed the previous record they set a decade ago by teleporting a quantum state of a proton 6 kilometers.

The quantum state of the photon is able to preserve information under extreme conditions, including the difference between traveling as light or becoming stored in the crystal like matter. The photon’s state acts as information that can be teleported along great distances using the optical fiber, and can be stored within the crystal. This was achieved due to a phenomenon in quantum mechanics known as entanglement, where two particles have a correlation, despite the fact that they aren’t touching and transmitting information to one another.

To test this and ensure what they were observing was actually happening, one photon was stored in a crystal while the other was sent along optical fiber, over a distance of 25 kilometers. The photon that was sent along the optical fiber collides with a third photon, which was assumed to destroy them both. However, the information from the first photon was transferred to the third photon in the collision, like the transfer of energy when one billiard ball hits another. The information from the third photon came back to the crystal where it could be measured to ensure the information was preserved between the first and the second.

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Dec 25, 2016

Russia offers technology to keep hackers at bay

Posted by in categories: cybercrime/malcode, encryption, finance, government, neuroscience, quantum physics

Russian Quantum Center (RQC) said that it is ready to collaborate with India and offer its quantum technology that will prevent hackers from breaking into bank accounts. RQC plans to offer ‘quantum cryptography’ that could propel India to the forefront of hack proof communication in sectors such as banking and national and homeland security.

“We are ready to work with Indian colleagues. It (the technology) can’t be bought from the United States as it deals with the government and security,” said Ruslan Yunusov, chief executive at RQC, in an interview.

Established by Russia’s largest global technology hub, Skolkovo in 2010, RQC conducts scientific research that could lead to a new class of technologies. These include developing ‘unbreakable cryptography’ for the banks and the government organisations. It also involves research in areas such as materials with superior properties and new systems for ultrasensitive imaging of the brain. The research is mostly funded by the government money.

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Dec 25, 2016

The Edge of Physics: Do Gravitons Really Exist?

Posted by in categories: particle physics, quantum physics

Einstein’s theory of relativity described gravity as the distortion of space and time—which bend and stretch based on the masses of objects within them as well as the energy released from the phenomena. A few years later however, we gained awareness of the confusing world of quantum physics as physicists discovered the existence of very small particles—which were later found to affect even the biggest, most powerful phenomena in the universe.

This led to the discovery of force-carrier particles, or bosons, behind three of the fundamental forces governing the universe: the electromagnetic field has photons, the strong nuclear force has gluons, and the weak force is carried by W and Z bosons. This leaves gravity out. Physicists hypothesize that, if the other three fundamental forces have a corresponding quantum theory, there must be a particle behind gravity too.

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Dec 25, 2016

Jülich Installs New QPACE3 Supercomputer for Quantum Chromodynamics

Posted by in categories: augmented reality, cosmology, particle physics, quantum physics, robotics/AI, supercomputing

A new supercomputer has been deployed at the Jülich Supercomputing Center (JSC) in Germany. Called QPACE3, the new 447 Teraflop machine is named for “QCD Parallel Computing on the Cell.”

QPACE3 is being used by the University of Regensburg for a joint research project with the University of Wuppertal and the Jülich Supercomputing Center for numerical simulations of quantum chromodynamics (QCD), which is one of the fundamental theories of elementary particle physics. Such simulations serve, among other things, to understand the state of the universe shortly after the Big Bang, for which a very high computing power is required.

The demand for high performance computers to solve complex applications has risen exponentially, but unfortunately so has their consumption of power. Many supercomputers require more than a megawatt of electricity to operate and annual electricity costs can easily run into millions of Euros. The energy supply is therefore a significant part of the operating costs of a data center. According to recent analyst studies, this represents the second-largest factor in addition to personnel and maintenance costs. The upcoming boom with (3D) video streaming, augmented reality, image recognition and artificial intelligence is driving up the demand for data center capabilities, thereby placing new challenges in the power supply sector.

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Dec 25, 2016

Quantum Computing Update: Coherent Electron-Photon Coupling Achieved, May Help Build Scalable Devices

Posted by in categories: computing, quantum physics

Over 6 months ago we reported the electron-photon coupling discovery which makes scalable QC possibly. This article provides some additional content around the experiment.


The silicon-based device, created by researchers at Princeton University, could eventually help build viable and robust quantum computers.

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Dec 22, 2016

News in brief: Groupon grief; Apple encryption delay; post-quantum crypto

Posted by in categories: encryption, mobile phones, quantum physics, security

Your daily round-up of some of the other security stories in the news

Groupon grief – was it password reuse?

The Telegraph reports that crooks have hijacked a number of Groupon accounts and used them to purchase expensive items like games consoles, iPhones and holidays. Some victims have suffered thousands of pounds of losses.

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Dec 22, 2016

2017 sneak peek: What the new year holds for science

Posted by in categories: quantum physics, science

She forgot one on QC; 2017 marks the year that Google shares with us the worlds 1st quantum device.


Expect researchers to glimpse an event horizon, continue striving for quantum supremacy and brace themselves for a political hangover.

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Dec 22, 2016

The sound of quantum vacuum

Posted by in categories: media & arts, quantum physics

Quantum mechanics dictates sensitivity limits in the measurements of displacement, velocity and acceleration. A recent experiment at the Niels Bohr Institute probes these limits, analyzing how quantum fluctuations set a sensor membrane into motion in the process of a measurement. The membrane is an accurate model for future ultraprecise quantum sensors, whose complex nature may even hold the key to overcome fundamental quantum limits. The results are published in the scientific journal, Proceedings of the National Academy of Sciences.

Vibrating strings and membranes are at the heart of many musical instruments. Plucking a string excites it to vibrations, at a frequency determined by its length and tension. Apart from the fundamental frequency — corresponding to the musical note — the string also vibrates at higher frequencies. These overtones influence how we perceive the ‘sound’ of the instrument, and allow us to tell a guitar from a violin. Similarly, beating a drumhead excites vibrations at a number of frequencies simultaneously.

These matters are not different when scaling down, from the half-meter bass drum in a classic orchestra to the half-millimeter-sized membrane studied recently at the Niels Bohr Institute. And yet, some things are not the same at all: using sophisticated optical measurement techniques, a team lead by Professor Albert Schliesser could show that the membrane’s vibrations, including all its overtones, follow the strange laws of quantum mechanics. In their experiment, these quantum laws implied that the mere attempt to precisely measure the membrane vibrations sets it into motion. As if looking at a drum already made it hum!

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