Two-particle correlated interference in reflection: extending the quantum-classical boundary via a macroscopic quantum superposition insensitive to decoherence

摘要

Reflection of a microscopic particle from a mesoscopic/macroscopic `mirror'generates two-body correlated interference from the incident and reflectedparticle substates and their associated mirror substates. The microscopicmomentum exchanged generates two mirror substates which interfere to producefringes which do not vanish as the mirror mass increases. The smalldisplacement between these mirror states can yield negligible environmentaldecoherence times. Mirror coherence lengths impose constraints on the extent ofthis interference, which are mitigated using interference of the two-bodystates associated with the particle reflecting from both of the two surfaces ofa slab of matter in a manner analogous to the classical interference of a pulseof light reflecting from a `thin film'. This two-body correlated interferenceis modeled as a particle traversing a finite well with both the particle andwell treated quantum mechanically. Such a treatment predicts the expected`thin-film' interference but only as a special case of a more general result.It is also shown that measurements on only the reflected particle (yielding amarginal probability density function) can act as a probe to reveal the quantumstate of the macroscopic reflector. For equal masses, coherence of the particlesubstate is transferred to the mirror substate, a quantum manifestation of afamiliar classical result.