TY - JOUR
T1 - Ultimate Limits for Multiple Quantum Channel Discrimination
AU - Zhuang, Quntao
AU - Pirandola, Stefano
N1 - Funding Information:
Q. Z. acknowledges funding from Army Research Office under Grant No. W911NF-19-1-0418, Office of Naval Research under Grant No. N00014-19-1-2189, Defense Advanced Research Projects Agency (DARPA) under Young Faculty Award (YFA) Grant No. N660012014029, and University of Arizona. S. P. acknowledges funding from the European Union’s Horizon 2020 Research and Innovation Action under Grant Agreement No. 862644 (Quantum readout techniques and technologies, QUARTET).
Funding Information:
Q.Z. acknowledges funding from Army Research Office under Grant No.?W911NF-19-1-0418, Office of Naval Research under Grant No.?N00014-19-1-2189, Defense Advanced Research Projects Agency (DARPA) under Young Faculty Award (YFA) Grant No.?N660012014029, and University of Arizona. S.P. acknowledges funding from the European Union?s Horizon 2020 Research and Innovation Action under Grant Agreement No.?862644 (Quantum readout techniques and technologies, QUARTET).
Publisher Copyright:
© 2020 authors. Published by the American Physical Society.
PY - 2020/8/21
Y1 - 2020/8/21
N2 - Quantum hypothesis testing is a central task in the entire field of quantum information theory. Understanding its ultimate limits will give insight into a wide range of quantum protocols and applications, from sensing to communication. Although the limits of hypothesis testing between quantum states have been completely clarified by the pioneering works of Helstrom in the 1970s, the more difficult problem of hypothesis testing with quantum channels, i.e., channel discrimination, is less understood. This is mainly due to the complications coming from the use of input entanglement and the possibility of employing adaptive strategies. In this Letter, we establish a lower limit for the ultimate error probability affecting the discrimination of an arbitrary number of quantum channels. We also show that this lower bound is achievable when the channels have certain symmetries. As an example, we apply our results to the problem of channel position finding, where the goal is to identify the location of a target channel among multiple background channels. In this general setting, we find that the use of entanglement offers a great advantage over strategies without entanglement, with nontrivial implications for data readout, target detection, and quantum spectroscopy.
AB - Quantum hypothesis testing is a central task in the entire field of quantum information theory. Understanding its ultimate limits will give insight into a wide range of quantum protocols and applications, from sensing to communication. Although the limits of hypothesis testing between quantum states have been completely clarified by the pioneering works of Helstrom in the 1970s, the more difficult problem of hypothesis testing with quantum channels, i.e., channel discrimination, is less understood. This is mainly due to the complications coming from the use of input entanglement and the possibility of employing adaptive strategies. In this Letter, we establish a lower limit for the ultimate error probability affecting the discrimination of an arbitrary number of quantum channels. We also show that this lower bound is achievable when the channels have certain symmetries. As an example, we apply our results to the problem of channel position finding, where the goal is to identify the location of a target channel among multiple background channels. In this general setting, we find that the use of entanglement offers a great advantage over strategies without entanglement, with nontrivial implications for data readout, target detection, and quantum spectroscopy.
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U2 - 10.1103/PhysRevLett.125.080505
DO - 10.1103/PhysRevLett.125.080505
M3 - Article
C2 - 32909798
AN - SCOPUS:85090818253
VL - 125
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 8
M1 - 080505
ER -