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SUMMARY:Simulation of quantum circuits with tensor networks - Pan Zhang\, 
 Institute of Theoretical Physics\, Chinese Academy of Sciences
DTSTART:20221020T131500Z
DTEND:20221020T141500Z
UID:TALK183923@talks.cam.ac.uk
CONTACT:Damian Pitalua-Garcia
DESCRIPTION:In this talk\, I will introduce two tensor-network methods tar
 geting the sampling problem of the Sycamore circuits. The first method com
 putes amplitudes and probabilities for a large number of correlated bitstr
 ings. The obtained results verify the Porter-Thomas distribution of the la
 rge and deep quantum circuits of Google and can be used for spoofing the l
 inear cross entropy benchmark of quantum supremacy using a post-sampling a
 pproach. The second method can be used to generate one million uncorrelate
 d bitstrings which are sampled from a final distribution of the Sycamore c
 ircuit with 53 qubits and 20 cycles. With the approximate state having fid
 elity of roughly 0.0037. The whole computation has cost about 15 hours on 
 a computational cluster with 512 GPUs. If our algorithm could be implement
 ed with high efficiency on a modern supercomputer with ExaFLOPS performanc
 e\, we estimate that ideally\, the simulation would cost a few dozens of s
 econds\, which is faster than Google's quantum hardware.
LOCATION:Zoom
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