Authors: George Rajna
From stationary to flying qubits at speeds never reached before…. This feat, achieved by a team from Polytechnique Montréal and France's Centre national de la recherche scientifique (CNRS), brings us a little closer to the era when information is transmitted via quantum principles.  But University of Utah electrical and computer engineering associate professor Rajesh Menon and his team have developed a cloaking device for microscopic photonic integrated devices—the building blocks of photonic computer chips that run on light instead of electrical current—in an effort to make future chips smaller, faster and consume much less power.  In 1959 renowned physicist Richard Feynman, in his talk "Plenty of Room at the Bottom," spoke of a future in which tiny machines could perform huge feats. Like many forward-looking concepts, his molecule and atom-sized world remained for years in the realm of science fiction.  The race towards quantum computing is heating up. Faster, brighter, more exacting – these are all terms that could be applied as much to the actual science as to the research effort going on in labs around the globe.  For the first time, scientists now have succeeded in placing a complete quantum optical structure on a chip, as outlined Nature Photonics. This fulfills one condition for the use of photonic circuits in optical quantum computers.  The intricately sculpted device made by Paul Barclay and his team of physicists is so tiny it can only be seen under a microscope. But their diamond microdisk could lead to huge advances in computing, telecommunications, and other fields.  Researchers from the Institute for Quantum Computing at the University of Waterloo and the National Research Council of Canada (NRC) have, for the first time, converted the color and bandwidth of ultrafast single photons using a room-temperature quantum memory in diamond.  One promising approach for scalable quantum computing is to use an all-optical architecture, in which the qubits are represented by photons and manipulated by mirrors and beam splitters. So far, researchers have demonstrated this method, called Linear Optical Quantum Computing, on a very small scale by performing operations using just a few photons. In an attempt to scale up this method to larger numbers of photons, researchers in a new study have developed a way to fully integrate single-photon sources inside optical circuits, creating integrated quantum circuits that may allow for scalable optical quantum computation.  Spin-momentum locking might be applied to spin photonics, which could hypothetically harness the spin of photons in devices and circuits. Whereas microchips use electrons to perform computations and process information, photons are limited primarily to communications, transmitting data over optical fiber. However, using the spin of light waves could make possible devices that integrate electrons and photons to perform logic and memory operations.  Researchers at the University of Ottawa observed that twisted light in a vacuum travels slower than the universal physical constant established as the speed of light by Einstein's theory of relativity. Twisted light, which turns around its axis of travel much like a corkscrew, holds great potential for storing information for quantum computing and communications applications.  We demonstrated the feasibility and the potential of a new approach to making a quantum computer. In our approach, we replace the qubits with qumodes. Our method is advantageous because the number of qumodes can be extremely large. This is the case, for instance, in hundred–thousand mode, octave-spanning optical frequency combs of carrier-envelope phase-locked classical femtosecond lasers.  IBM scientists today unveiled two critical advances towards the realization of a practical quantum computer. For the first time, they showed the ability to detect and measure both kinds of quantum errors simultaneously, as well as demonstrated a new, square quantum bit circuit design that is the only physical architecture that could successfully scale to larger dimensions.  Physicists at the Universities of Bonn and Cambridge have succeeded in linking two completely different quantum systems to one another. In doing so, they have taken an important step forward on the way to a quantum computer. To accomplish their feat the researchers used a method that seems to function as well in the quantum world as it does for us people: teamwork. The results have now been published in the "Physical Review Letters".  While physicists are continually looking for ways to unify the theory of relativity, which describes large-scale phenomena, with quantum theory, which describes small-scale phenomena, computer scientists are searching for technologies to build the quantum computer.
Comments: 31 Pages.
[v1] 2016-11-11 07:14:53
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