Quantum metrology beyond Heisenberg limit with entangled matter wave solitons

TL;DR

This paper demonstrates that entangled matter wave solitons in Bose-Einstein condensates can achieve measurement precision beyond the Heisenberg limit by utilizing nonlinear phase shifts in quantum interferometry.

Contribution

It introduces a method to surpass the Heisenberg limit in phase measurements using macroscopic entangled solitons and nonlinear phase shifts in matter wave interferometry.

Findings

Macroscopic non-classical states are formed from matter wave solitons.

Heisenberg limit can be surpassed using nonlinear phase shifts.

Measurement of scattering length and hopping parameter with enhanced precision.

Abstract

By considering matter wave bright solitons from weakly coupled Bose-Einstein condensates trapped in a double-well potential, we study the formation of macroscopic non-classical states, including Schr\"odinger-cat superposition states and maximally path entangled $N00N$-states. With these macroscopic states, we examine Mach-Zehnder interferometer in the context of parity measurements, in order to obtain Heisenberg limit accuracy for linear phase shift measurement. We reveal that the ratio between two-body scattering length and intra-well hopping parameter can be measured with the scaling beyond this limit by using nonlinear phase shift with interacting quantum solitons.