In Russia the first time measured the qubit

Laboratory MISA

Scientists from Russian Quantum Centre (RCC) and Laboratory of superconducting metamaterials MISA under the direction of Professor Alexei Ustinov for the first time in Russia produced a measurement of the qubit.

Unlike classical bits that can take only the values zero and one, qubit (Quantum bits) takes an infinite number of states, each of which is a "mixture" or a superposition of the two main (they are also denoted 0 and 1). The superposition given by a pair of complex numbers, each of which refers to the probability of detection of the qubit in one of the two ground states. 

Qubit in the Laboratory of superconducting materials has been implemented in the form of a metal ring with a diameter of several microns with cuts deposited on a semiconductor substrate. The ring was cooled mixture of helium-3 and helium-4 to a temperature of the order of several tens millikelvin — at a temperature metal which was formed qubit in the superconducting state. The role of zero and one performed a current flowing in a clockwise and counterclockwise, respectively.

The process of measuring the qubit represented the transmittance of microwave radiation through it and then measuring the phase shift of the radiation. The measurements have shown that the resulting system is indeed a two-qubit ground states. Has also been demonstrated in principle the possibility of a qubit in a superposition of two states at the same time.

According to scientists, the next stage of research will be the manipulation quantum state one, and then several qubits. Similar devices can be used to create so-called quantum computers — computers operating on the principle of quantum mechanics, deterministic logic than existing computers.

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In Russia set the stage for building a quantum computer

For the first time in Russia, a device that implements the quantum bit — qubit, and measured its state, it is necessary to build a quantum computer, the press service of the Russian Quantum Center.

The implementation of the qubit and the measurement of its state — a necessary step for building a quantum computer. This measurement was performed in the laboratory of the University of MIS in the project, carried out jointly with the research organization of the Russian Quantum Center (RCC). The study led by a member of the Scientific Council of the RCC Professor Alexei Ustinov.

At the moment, commercial supply of a quantum computer in the world carries only Canadian company D-Wave, so that Russia still has a chance to join in the global industry development of quantum computers. Its effectiveness has not yet been proven, but the prospects of its application exploring NASA, Google and others. In theory, quantum computers can speed up the payment in times of complex systems and decoding ciphers.

The first allows you to create new materials and accurately calculate the impact of the environment on them. The rapid opening of ciphers will radically change the current situation, as now cryptographically strong ciphers used to encode the state secrets is considered to be reliable. For their opening at the existing supercomputers requires a time comparable to the lifetime of the universe, but their quantum computers will be able to "solve" a matter of days.

Drawing parallels with modern computers, while Russia just mastering the element base of quantum computers, invents the "quantum transistor" for the construction of a "chip". Scientists MISA and RCCs have chosen to implement a qubit superconducting rings with a diameter of several micrometers with nanometer gaps in some places (called Josephson junctions). At precisely computed a weak magnetic field and cooled to extremely low temperatures millikelvins 20 (less than? 273 degrees Celsius), they acquire the quantum properties. Russian scientists were able to measure periodically varying the magnetic field signal qubit and its resonant frequency.

The main difference between the qubit from the "classical" bit is the ability to not only be able to either 1 or 0, but also in a superposition of these states. That is an element of a quantum computer can be simultaneously and at 0 and at 1, and the contribution of the states 1 and 0 can change over time. Russian scientists were able to measure the symmetric superposition of 0 and 1, the next task — to bring a superconducting qubit in arbitrarily selected the desired state.

In further to create a quantum computer will result in the qubits in some initial state, merge them into intricate system (the more qubits, "confused", the more powerful quantum computer) and to isolate these systems from the effects of external interference, according to the RCC. It will also continue to analyze the most effective basic elements for quantum computers.

 http://digit.ru/developme…t/20130701/402906469.html 

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