Quantum-enhanced multiparameter estimation in multiarm interferometers

Understand

Quantum metrology is the state-of-the-art measurement technology.

• It uses quantum resources to enhance the sensitivity of phase estimation beyond what reachable within classical physics.
• While single parameter estimation theory has been widely investigated, much less is known about the simultaneous estimation of multiple phases, which finds key applications in imaging and sensing.
• In this manuscript we provide conditions of useful entanglement (among multimode particles, qudits) for multiphase estimation and adapt them to multiarm Mach-Zehnder interferometry.