# Quantum metrology in local dissipative environments

## TL;DR

This paper investigates how local dissipative environments affect quantum metrology, showing that the Heisenberg limit can be asymptotically recovered through bound state formation, enabling practical quantum measurement enhancements.

## Contribution

It provides an exact analysis of local environment impacts on quantum metrology and demonstrates the recovery of the Heisenberg limit via bound state formation under long encoding times.

## Key findings

- Heisenberg limit is asymptotically recovered with finite probe atoms.
- Bound states between atoms and environment are crucial for metrology performance.
- Engineering system-environment interactions can enable practical quantum metrology.

## Abstract

Quantum metrology allows us to attain a measurement precision that surpasses the classically achievable limit by using quantum characters. The metrology precision is raised from the standard quantum limit (SQL) to the Heisenberg limit (HL) by using entanglement. However, it was reported that the HL returns to the SQL in the presence of local dephasing environments under the long encoding-time condition. We evaluate here the exact impacts of local dissipative environments on quantum metrology, based on the Ramsey interferometer. It is found that the HL is asymptotically recovered under the long encoding-time condition for a finite number of the probe atoms. Our analysis reveals that this is essentially due to the formation of a bound state between each atom and its environment. This provides an avenue for experimentation to implement quantum metrology under practical conditions via engineering of the formation of the system-environment bound state.