Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session E28: Experiment and Theory of Quantum Input-output Networks
8:00 AM–11:00 AM,
Tuesday, March 6, 2018
LACC Room: 405
Sponsoring Unit: DQI
Chair: Kevin Young, Sandia Natl Labs
Abstract: E28.00009 : Quantum Fisher Information of non-Hermitian sensing near exceptional points
10:24 AM–10:36 AM
Exceptional points are points in the parameter space of a non-hermitian system when two eigenvectors of the hamiltonian coalesce. Eigenvalue change of the non-hermitian system near exceptional points can have abnormal dependence on external perturbation, which is recently proposed and demonstrated as a way to enhance the sensitivity of resonant frequency shifts to small external signal. However, physical realization of non-hermitian system unavoidably introduces noises accompanying loss and gain to a hermitian system, which may potentially decrease the signal-to-noise ratio. To understand the combined effect of exceptional points on both sensitivity and signal-to-noise ratio, we computed the quantum fisher information of typical non-hermitian sensing processes, whose inverse give us a lower bound of the estimation error. Our work provides not only a fundamental bound for the sensing limit using exceptional points, but also a design tool to achieve the same scaling as the fundamental sensing limit.
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