Wednesday, December 9, 2015

Quantum computing: the quest for the Grail Digital – JDN

The quantum computer Allows to leverage existing computing performance, quantum computing could be one of the solutions at the end of Moore’s Law. There remain many obstacles.

The notion of quantum computer was born in 1970 and 1980. It was driven by the American physicist David Wineland – which has also received the Nobel Prize in physics for his research in this area . Behind this concept include the idea that quantum phenomena could be used to multiply the computing power of conventional machines. While today’s computers use the bit as a fundamental unit, the quantum computer, he leans on a value called the qubit (or quantum bit). A value that would not only be expressed through 1 and 0, but by a superposition of both.



Beyond the limits of Moore’s Law

d ware
D-Wave would be the first company to have commercialized a quantum computer. But researchers have questioned the quantum nature of its machines. © capure JDN

The speed calculation is seen thus increase exponentially, the machine is capable of simultaneously processing multiple states at once. The power measurement of the qubit? It is 2 to the power N (N being the number of qubits in the processor). Thus, a binary machine resting on a 6-bit architecture may create one of 64 (2 to the power of 6) possible combinations (000000, 000001, 000010 …). The qubit can be a superposition of 0 and 1, might tend suddenly to 64 states. Quantum computing and would bypass the limits of Moore’s Law, that the complexity of semiconductor double-entry every year at constant prices – as with miniaturization ceiling which by definition is not endless.

But how then create an information qubit? Very schematically, the operation of a qubit (that can be compared to an artificial atom) based on various phenomena of nuclear physics. This is also the reason why the quantum computer is said. It indeed refers to quantum physics that describes the behavior of atoms and particles. What are these nuclear phenomena? A qubit can be created based for example on the polarization of a photon (and the measurement of the polarization plane) or on the energy level of an atom, angular momentum or “spin” or revolution of the electron around him.

How to spend bit qubit? That is the question …

There are several techniques to create qubits. With superconductors, they can be embedded on electronic circuitry with semiconductor made from already known methods, borrowed from nanoelectronics

One major obstacle.: the system must remain completely isolated from the calculation time

It remains a significant technical hurdle before operating a quantum computer. The system during the calculation phase, must be completely isolated from any thermal or magnetic interference. Because of nuclear physics that puts the music, the qubit is sensitive to disturbance, such as electromagnetic fields. Researchers call time “decoherence” the period during which the system remains well isolated, the integrity of its quantum properties then being complete.

The design problems are also very numerous. Beyond the creation of a qubit, in particular must also be able to create sensors for measuring the information carried by the qubit. This involves mastering the parameters of the magnetic flux (intensity and spatial distribution), which is complex.



Google launched research to quantum computer

Several actors have started in the 2000s in the race to build a quantum computer. The American company D-Wave Systems is the first. It announced in 2007 managing to build a prototype, without presenting it to the scientific community – for reasons of confidentiality. 1 qubit, this computer presented as functioning in cryogenic medium, however, was limited to certain optimization quantum operations. Presenting a roadmap for achieving the 512 qubits, D-Wave Systems announced it has been able to design a chip with 128 qubits in 2009. The same year, the start-up sign an agreement of co-innovation with Google. This is the first time the software giant then communicates on the subject. In 2011, D-Wave is sold to Lockheed Martin and the company, the brand continues, has since launched the marketing of a quantum computer.



smart quantum
Puce designed by IBM harboring three qubits. © IBM

In May 2013, Google announced briskly launching a research laboratory focused exclusively on quantum computing: Quantum Artificial Intelligence Lab. Objective: to offer a new way to machine learning and combinatorial computing to improve the efficiency of predictive models. Google in particular evokes the grand societal challenges of the modern world: climate, health and diet. Hosted by NASA, the laboratory has a quantum computer … A second generation D-Wave Systems (2X) based on an architecture of qubits 1097.



Questions remain unanswered

The Mountain View group is no longer the only software giant became interested in quantum computing. Others have followed suit. This is particularly the case of IBM. End of 2013, the activity of the American Research Group presented the results of a prototype. Using the quantum phenomenon of Bose-Einstein condensates, it is made of luminescent polymers, and could afford to build highly energy efficient lasers and ultrafast optical switches. “These are critical components for building energy-efficient systems capable of processing massive volumes of data in big data,” said IBM. Microsoft also, a research project was also launched (in 2015). But also at Intel. The founder has announced an investment of $ 50 million on the subject in September 2015, in very clear perspective override the boundaries of Moore’s Law.

It remains a debate between the researchers, and some seriously question the authenticity of the quantum processes of D-Wave Systems. Some IBM engineers (the TJ Watson Research Laboratory) have expressed doubts about the ability of these machines to go beyond conventional computer performance. So far, experts struggled to prove that this advance is real. To answer these questions, the R & amp teams; D of the main groups involved in research on quantum computing is set to work. Google has published a comparative study in December 2015 which tends to prove the capabilities of quantum computers (see article: A quantum computer would be 100 million times faster than a conventional computer)

. the quantum computer endowed with consciousness

France is also present in this race for quantum computing. Since 2000, CEA is working on the subject. The Centre for Atomic Energy has developed a silicon chip-based nanojunctions to manage the qubit. Since then, the search continued through several experiments. Often openly criticized by the scientific community, some researchers, including French, also devised the next step. Simon Thorpe, CNRS research director at CERCO (brain and cognition research center) in Toulouse, do not hesitate to affirm the existence of a link between consciousness and quantum physics, with particular reference to the work of American researchers Stuart Hameroff and Roger Penrose. From there to discuss a future quantum computer that would be endowed with consciousness … Simon Thorpe asks that possibility for the future (see his presentation on a conference given in 2013).

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