TY - JOUR
T1 - Round complexity in the local transformations of quantum and classical states
AU - Chitambar, Eric
AU - Hsieh, Min Hsiu
N1 - Funding Information:
We thank Benjamin Fortescue for fruitful discussions on multi-round key distillation. E.C. is supported by the National Science Foundation (NSF) Early CAREER Award No. 1352326. M.H. is supported by an ARC Future Fellowship under Grant FT140100574.
Publisher Copyright:
© 2017 The Author(s).
PY - 2017/12/1
Y1 - 2017/12/1
N2 - In distributed quantum and classical information processing, spatially separated parties operate locally on their respective subsystems, but coordinate their actions through multiple exchanges of public communication. With interaction, the parties can perform more tasks. But how the exact number and order of exchanges enhances their operational capabilities is not well understood. Here we consider the minimum number of communication rounds needed to perform the locality-constrained tasks of entanglement transformation and its classical analog of secrecy manipulation. We provide an explicit construction of both quantum and classical state transformations which, for any given r, can be achieved using r rounds of classical communication exchanges, but no fewer. To show this, we build on the common structure underlying both resource theories of quantum entanglement and classical secret key. Our results reveal that highly complex communication protocols are indeed necessary to fully harness the information-theoretic resources contained in general quantum and classical states.
AB - In distributed quantum and classical information processing, spatially separated parties operate locally on their respective subsystems, but coordinate their actions through multiple exchanges of public communication. With interaction, the parties can perform more tasks. But how the exact number and order of exchanges enhances their operational capabilities is not well understood. Here we consider the minimum number of communication rounds needed to perform the locality-constrained tasks of entanglement transformation and its classical analog of secrecy manipulation. We provide an explicit construction of both quantum and classical state transformations which, for any given r, can be achieved using r rounds of classical communication exchanges, but no fewer. To show this, we build on the common structure underlying both resource theories of quantum entanglement and classical secret key. Our results reveal that highly complex communication protocols are indeed necessary to fully harness the information-theoretic resources contained in general quantum and classical states.
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U2 - 10.1038/s41467-017-01887-5
DO - 10.1038/s41467-017-01887-5
M3 - Article
C2 - 29233989
AN - SCOPUS:85037813206
SN - 2041-1723
VL - 8
JO - Nature communications
JF - Nature communications
IS - 1
M1 - 2086
ER -