Oral: Enhancing Sensitivity of Solid-State Quantum Sensor with Exceptional Points

In non-Hermitian Hamiltonians, exceptional points (EPs) arise when eigenvalues and eigenvectors coalesce. The presence of EPs enables unique dynamics that support applications such as unidirectional invisibility, robust mode switching, and enhanced sensing [1, 2, 3]. More specifically, sensing near EPs enhances the response of the energy levels to the external electromagnetic fields [1,3], increasing the potential of quantum sensors. In this work, we investigate the enhancement of the sensitivity via EPs for a single solid-state quantum sensor (e.g., rare-earth ions and NV centers) and contrast it to traditional sensing techniques. Nevertheless, the increased response to external fields also increases the relaxation and dephasing time, thus harming the quantum sensor sensitivity. Therefore, we also assess the regimes for an actual increase in the signal-to-noise ratio. This work aims to guide the use of EPs for superior solid-state sensing capabilities with enhanced sensitivity and improved signal-to-noise ratio.

1 Chen et al. "Exceptional points enhance sensing in an optical microcavity" Nat vol 548, pg 192–196 (2017)

2 Pick et al. "Robust mode conversion in NV centers using exceptional points" Phys. Rev. Research 1, 013015 (2019)

3 Hodaei et al. "Enhanced sensitivity at higher-order exceptional points." Nat 548, 187 (2017).