Clocks and fisher information
Ping Chen, Shunlong Luo
THEORETICAL AND MATHEMATICAL PHYSICS | SPRINGER | Published : 2010
In a broad sense, any parametric family of quantum states can be viewed as a quantum clock. The time, which is the parameter, is encoded in the corresponding quantum states. The quality of such a clock depends on how precisely we can distinguish the states or, equivalently, estimate the parameter. In view of the quantum Cramér-Rao inequalities, the quality of quantum clocks can be characterized by the quantum Fisher information. We address the issue of quantum clock synchronization in terms of quantum Fisher information and demonstrate its fundamental difference from the classical paradigm. The key point is the superadditivity of Fisher information, which always holds in the classical case b..View full abstract
Awarded by NSFC
Awarded by Science Fund for Creative Research Groups
Awarded by Key Lab of Random Complex Structures and Data Science, Chinese Academy of Sciences
This work was supported by the NSFC (Grant No. 10771208), the Science Fund for Creative Research Groups (Grant No. 10721101), and the Key Lab of Random Complex Structures and Data Science, Chinese Academy of Sciences (Grant No. 2008DP173182).