Enhancing precision of damping rate by PT symmetric Hamiltonian

  • Dong XieEmail author
  • Chunling Xu


We utilize quantum Fisher information to investigate the damping parameter precision of a dissipative qubit. PT symmetric non-Hermitian Hamiltonian is used to enhance the parameter precision in two models: one is direct PT symmetric quantum feedback; the other is that the damping rate is encoded into a effective PT symmetric non-Hermitian Hamiltonian conditioned on the absence of decay events. We find that compared with the case without feedback and with Hermitian quantum feedback, direct PT symmetric non-Hermitan quantum feedback can obtain better precision of damping rate. And in the second model, the result shows that the uncertainty of damping rate can be close to 0 at the exceptional point. We also obtain that non-maximal multiparticle entanglement can improve the precision to reach Heisenberg limit.


PT symmetric Hamiltonian Quantum Fisher information Estimation precision Damping rate 



This research was supported by the National Natural Science Foundation of China under Grant No. 11747008 and Guangxi Natural Science Foundation 2016GXNSFBA380227.


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Authors and Affiliations

  1. 1.College of ScienceGuilin University of Aerospace TechnologyGuilinPeople’s Republic of China

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