Parametrically-enhanced quantum sensing with effective non-Hermitian lattice dynamics

Systems whose dynamics are described by a non-Hermitian effective Hamiltonian have been suggested as platforms for improved sensing. Several experiments have already demonstrated the utility of exceptional points, a uniquely non-Hermitian feature, in setups consisting of a few resonant modes [1-3]. The phenomena exhibited by coupled multi-mode non-Hermitian systems, such as the non-Hermitian skin effect [4] and the existence of abnormally large susceptibilities, are also promising sensing resources. Here, we show how to harness the unusual lattice physics to build quantum sensing platforms with remarkable properties. In particular, the quantum Fisher information of our measurement scheme grows exponentially with system size, even when bounding the number of photons used for the measurement. This is achieved without coupling to dissipative baths or postselection. Our setup is realizable in a number of experimental platforms, including superconducting quantum circuits and quantum optical setups.

[1] Hodaei, H. et al,. Nature 548, 187–191 (2017)
[2] Chen, W., Kaya Özdemir, S., Zhao, G., Wiersig, J. & Yang, L. Nature 548, 192–196 (2017)
[3] Naghiloo, M., Abbasi, M., Joglekar, Y. N. & Murch, K. W. Nat. Phys. (2019)
[4] S. Yao and Z. Wang, Phys. Rev. Lett. 121, 086803 (2018).