Quantum computing is the realm of computer science devoted to the notion that inter-atomic quantum properties can ultimately be utilized as functional logic gates and networked to perform computational algorithms as an alternative to much larger, more cumbersome and slower silicon circuitry.
John Timmer writes for Ars Technica: "A quantum computer isn't like our existing computers, where electrons
flow through a series of switches. Instead, a carefully prepared quantum
system is allowed to evolve, and it is then measured. The system only
provides us with an answer because we can map different answers to all
the possible states that the system can end up in. Because quantum
systems evolve very quickly, it should be possible for these systems to
arrive at an answer much faster than a typical computer."
Researchers from Australia have created a simple circuit using a technique called boson sampling, which samples bosons scattered by photons in controllable probability distributions.
"There is extremely strong evidence to support that Boson Sampling
cannot be simulated efficiently on a classical computer, so
demonstrating the Boson Sampling algorithm in the lab with a real
quantum computer is strong evidence to show that one can indeed harness a
computational advantage with quantum physics," [Matthew Broome, from Australia's University of Queensland told Ars].
Boson sampling is, as noted in the abstract, "sampling the output distributions of n [amount of] bosons
scattered by some linear-optical unitary process. Here, we test the
central premise of boson sampling, experimentally
verifying that 3-photon scattering amplitudes
are given by the permanents of submatrices generated from a unitary
describing
a 6-mode integrated optical circuit. We find the
protocol to be robust, working even with the unavoidable effects of
photon
loss, non-ideal sources, and imperfect
detection. Scaling this to large numbers of photons will be a much
simpler task than
building a universal quantum computer."
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