Ultimate Decoherence Border for Matter-Wave Interferometry

Abstract

Stochastic backgrounds of gravitational waves are intrinsic fluctuations of spacetime which lead to an unavoidable decoherence mechanism. This mechanism manifests itself as a degradation of the contrast of quantum interferences. It defines an ultimate decoherence border for matter-wave interferometry using larger and larger molecules. We give a quantitative characterization of this border in terms of figures involving the gravitational environment as well as the sensitivity of the interferometer to gravitational waves. The known level of gravitational noise determines the maximal size of the molecular probe for which interferences may remain observable. We discuss the relevance of this result in the context of ongoing progresses towards more and more sensitive matter-wave interferometry.

Quantum gravitational decoherence of light and matter

“…Decoherence plays a central role in quantum-to-classical transition, a main question in the foundation of quantum mechanics, through unavoidable entanglements between the quantum system and the environment, leading to the loss of coherence between the system's superposition states and, hence, the appearance of a classical mixture [3,4]. Gravitationally induced decoherence could, therefore, set a limit for precision measurements and astronomical observations providing a strong motivation to investigate its full nature and detailed mechanisms [5][6][7][8][9][10].…”

GAUGE: the GrAnd Unification and Gravity Explorer

“…It depends on whether the decoherence effect is due to, e.g. Newtonian gravitational interaction [48,51] or stochastic gravitational waves [50] or zeropoint gravitational fluctuations [51] which also takes into account nonlinear gravitational effects. Furthermore, for cooled and hence indistinguishable quantum particles the form factor A is expected to increase quadratically with the particle number N. In the approach of [51], this factor depends on a UV cutoff frequency w p /l with a phenomenological parameter λ given by:…”

“…However, quantum decoherence due to gravitational vacuum fluctuations does not require modifying the boundary conditions of gravity and could be tested using matter wave interferometry under ultra quiet conditions. A number of models exploring quantum and stochastic gravitational decoherence have recently been considered [48][49][50][51]. These phenomenological models predict decoherence in terms of the loss of visibility in matter wave interferometry of the form…”

The effect of dissipation on quantum transmission resonance

“…collisions to external molecules [7] or internal vibrations resulting in thermal photon radiations [8], play a key role for the quantum-to-classical transition of "free" particle. Even the gravitational waves were suggested to become a source of decoherence of matter waves [9]. Thus, macroscopic transmission resonance originated from quantum interference of macroscopic object also provides an alternative platform to that of quantum tunneling for testing the validity of quantum mechanics on a macroscopic scale.…”