Internal decoherence in nano-object interferometry due to phonons

Understand

We discuss the coherent splitting and recombining of a nanoparticle in a mesoscopic "closed-loop" Stern-Gerlach interferometer in which the observable is the spin of a single impurity embedded in the particle.

• This spin, when interacting with a pulsed magnetic gradient, generates the force on the particle.
• We calculate the internal decoherence which arises as the displaced impurity excites internal degrees of freedom (phonons) that may provide Welcher Weg information and preclude interference.
• We estimate the constraints this decoherence channel puts on future interference experiments with massive objects.