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发帖数: 782 | 1 http://physics.aps.org/articles/v6/139
A Year of Quantum Victories—But No Quantum Computer Yet
Do we have quantum computers, and are they better than conventional ones?
The Canadian company D-Wave Systems reported that they had successfully
tackled a hard-to-solve problem on their putative quantum computer. But many
scientists would argue there is no evidence that the device, made of ～100
superconducting elements, can be called a quantum computer or that it
outperforms classical computers. While quantum computing may still be some
years in the future, in 2013 researchers reported a number of victories
against obstacles to quantum information and communication protocols. In
quantum cryptography, code makers regained the upper hand against code
breakers, when two independent research teams demonstrated a new encryption
method that may provide the ultimate security against hackers. Two other
reports showed how entanglement, the essential ingredient that gives quantum
technologies an advantage over classical methods, can be protected from
noise and dissipation. A team at the Massachusetts Institute of Technology,
Cambridge, showed that in a secure quantum communication channel, the
benefits of entanglement can be harnessed even after its breakup induced by
noise. And researchers at the Free University of Berlin, Germany, the Niels
Bohr Institute, Denmark, and the Technical University of Munich, Germany,
suggested that, thanks to a technique called quantum illumination,
dissipative processes can be put to use to engineer more robust quantum
states. |
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