# First Experimental Proof For Super-Fast Quantum Algorithm Published

It's only three lines of simple math for a human, but a small victory for a quantum computer. Researchers in China report in Physical Review Letters that they can solve two linear equations by manipulating four entangled photons. Their demonstration-the rough equivalent of solving for x and y in the equations 4x+3y=6 and 3x+2y=3-is the first proof that a quantum algorithm proposed in 2009, which promised exponential speed-up compared to one run on a normal CPU, can be implemented in the lab.

Few quantum algorithms are actually faster than their classical counterparts. The most famous example in which quantum mechanics wins is an algorithm for factoring large numbers proposed by mathematician Peter Shor in 1994. But four years ago, theorists showed that a quantum algorithm for solving a set of linear equations could also be exponentially faster that any classical algorithm, provided you only needed to know probabilistic information about the solution-and not the exact solution itself.

*Jessica Thomas*

*Paper:*

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*Experimental Quantum Computing to Solve Systems of Linear Equations*

X.-D. Cai, C. Weedbrook, Z.-E. Su, M.-C. Chen, Mile Gu, M.-J. Zhu, Li Li, Nai-Le Liu, Chao-Yang Lu, and Jian-Wei Pan

Phys. Rev. Lett. 110, 230501 (2013), Published June 6, 2013

X.-D. Cai, C. Weedbrook, Z.-E. Su, M.-C. Chen, Mile Gu, M.-J. Zhu, Li Li, Nai-Le Liu, Chao-Yang Lu, and Jian-Wei Pan

Phys. Rev. Lett. 110, 230501 (2013), Published June 6, 2013

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