Quantum metrology with one-dimensional superradiant photonic states

TL;DR

This paper demonstrates that 1D superradiant photonic states generated by collectively excited quantum emitters can achieve quantum-enhanced metrology with Heisenberg scaling, and analyzes their robustness in experimental setups.

Contribution

It develops theoretical tools to compute Quantum Fisher Information for multimode states and shows superradiant states achieve Heisenberg scaling in 1D waveguides.

Findings

Superradiant photons in 1D waveguides achieve Heisenberg scaling.

Parity measurement saturates the quantum Fisher information.

States show robustness to experimental limitations.

Abstract

Photonic states with large and fixed photon numbers, such as Fock states, enable quantum-enhanced metrology but remain an experimentally elusive resource. A potentially simple, deterministic and scalable way to generate these states consists of fully exciting $N$ quantum emitters equally coupled to a common photonic reservoir, which leads to a collective decay known as Dicke superradiance. The emitted $N$-photon state turns out to be a highly entangled multimode state, and to characterise its metrological properties in this work we: (i) develop theoretical tools to compute the Quantum Fisher Information of general multimode photonic states; (ii) use it to show that Dicke superradiant photons in 1D waveguides achieve Heisenberg scaling, which can be saturated by a parity measurement; (iii) and study the robustness of these states to experimental limitations in state-of-art atom-waveguide QED setups.