Quantum metrology enhanced by coherence-induced driving in a cavity-QED setup

Abstract

Entangled states are beneficial for quantum metrology, but difficult to prepare and maintain. To tackle this issue, we here propose a quantum metrology scheme in a cavity QED setup to achieve the Heisenberg limit without preparing entangled states. In our scheme, a series of identical two-level atoms randomly pass through and interact with the cavity mode. We show that the initial atomic coherence will induce an effective driving to the cavity field, whose steady state is an incoherent superposition of orthogonal states, with the superposition probabilities being dependent on the atom-cavity coupling strength. By measuring the average photon number of the cavity in the steady state, we demonstrate that the root-mean-square of the fluctuation of the atom-cavity coupling strength is proportional to 1/N 2 c (N c is the effective atom number interacting with the photon in the cavity during its lifetime). It implies that we have achieved the Heisenberg limit in our quantum metrology process. We also discuss the experimental feasibility of our theoretical proposal. Our findings may find potential applications in quantum metrology technology.

Understanding and Improving Critical Metrology. Quenching Superradiant Light-Matter Systems Beyond the Critical Point

“…The rich ensuing dynamics in turn open up possibilities to use these systems to simulate fundamental solid-state physical systems and explore non-equilibrium many-body phenomena beyond the scope of conventional condensed matter systems [3]. Moreover, due to the presence of non-classical correlations and the feasibility of non-destructive monitoring of these systems through photons leaking from the cavity mirrors, they serve as an ideal platform for precise measurements of unknown physical parameters beyond the standard quantum limit [4][5][6][7][8][9][10][11][12]. Therefore, quantum-gas cavity QED systems may lead to the development of new paradigms in quantum metrology.…”

Understanding and Improving Critical Metrology. Quenching Superradiant Light-Matter Systems Beyond the Critical Point

“…The rich ensuing dynamics in turn open up possibilities to use these systems to simulate fundamental solid-state physical systems and explore non-equilibrium many-body phenomena beyond the scope of conventional condensed matter systems [3]. Moreover, due to the presence of non-classical correlations and the feasibility of non-destructive monitoring of these systems through photons leaking from the cavity mirrors, they serve as an ideal platform for precise measurements of unknown physical parameters beyond the standard quantum limit [4][5][6][7][8][9][10][11][12]. Therefore, quantum-gas cavity quantum electrodynamics systems may lead to the development of new paradigms in quantum metrology.…”