posted on Sep, 29 2011 @ 08:48 AM
The quantum computer is no longer a fantasy of science. He could emerge soon thanks to the work of a Japanese-Quebec team that has managed to develop
the centerpiece of the computer of the future from a semiconductor material commonly used in industry. Physicists worked for a decade to create
quantum computers, which "actively using the postulates of quantum mechanics" [this branch of physics that describes the phenomena at the atomic and
subatomic scale]. "The quantum computer will to develop high-performance algorithms, capable of factoring large numbers (about ten digits), for
example, which can only be done by computers today, at least let them calculate the age as long as the universe, "says Michel Pioro-Ladrière
Department of Physics, University of Sherbrooke, but said that data encryption in our Internet banking is done through an algorithm based on the
factorization of large numbers. A quantum computer would then "communicate on the Internet so completely safe." A quantum computer could also
simulate the quantum behavior of drug molecules in the body, "which takes a lot of time with current supercomputers," gives the example of the
specialist, which currently totals an experimental laboratory for Quantum Computing . 'All modern computers use the electron charge to carry the
current. For our part, we use the electron spin. By turning on itself, generates the electron, because of his office, a small magnet that points up or
down. The fact that it does not point in opposite directions allows us to use it as a bit of information (quantum bits, or qubits, in this case),
which in conventional computers consists of 0 or 1 " , noted physicist, who currently stands an experimental laboratory for quantum computing. During
his postdoctoral fellowship in Japan, it has manufactured using standard semiconductor device consists of two juxtaposed boxes each containing a spin
"we get to handle and coupled in a very precise and controlled," said he, pointing out that he manages to manipulate individual spins using
microaimants it deposits on the surface of device. And it is by changing the voltage applied to the device happens to change the degree of coupling
between the spins of two boxes, "a crucial operation in quantum mechanics." This double box, in fact composed of two juxtaposed boxes containing
each one electron spin, is "the minimum required to form the" proof of concept "of a quantum computer that will contain a multitude of boxes. We
have succeeded in showing that we can juxtapose in several, "says M. Pioro-Ladrière, whose findings are published in the latest edition of Physical
Review Letters. Much work still remains much work to do, admits the researcher. For a quantum system is, it is necessary that the qubits are in a
quantum state, where the qubit is either in state 0 or in state 1, but in both states at once, that is called "superposition of quantum states."
"For a quantum computer, perform all calculations is lost before the superposition of states, called coherence, qubits that lose when they interact
with their environment. Gradually, as time elapses, the qubits become classical bits, and you lose all power quantum, "says the physicist, who attack
the problem on two fronts. The time required to manipulate the spin of an electron, the reverse example, is currently too long compared to the
coherence time. "To increase the speed of operation, we will play in the design of microaimants. We believe that by changing their geometry and
location, we can move from one nanosecond to 100 nanoseconds, "he says. The second approach is to increase the coherence time. The researcher
believes to achieve this by using purified materials, which would "get rid of parasites spins of the nuclei of thousands of atoms contained in the
quantum dot and turning on themselves loom ahead and create the decoherence. " "But if we manage to exceed a critical threshold in the coherence
time, the computer will, once lost coherence, decoherence due to correct an algorithm, and thus to perpetuate quantum computing forever. We will not
need infinite coherence time, there would simply reach a critical threshold, the time it takes to perform a basic operation, "adds the researcher.
"If our research leads, we will have 'microelectronics industry behind us to begin the manufacture of large-scale quantum computers, "says an
enthusiastic researcher.