Spatial Correlation in Matter Wave Interference as a Measure of Decoherence, Dephasing and Entropy

摘要

The loss of contrast in double-slit electron-diffraction due to dephasing anddecoherence processes is studied. It is shown that the spatial correlationfunction of diffraction patterns can be used to distinguish between dephasingand decoherence. This establishes a measure of time-reversibility that does notrequire the determination of coherence terms of the density matrix, while vonNeumann entropy, another measure of time-reversibility, does require coherenceterms. This technique is exciting in view of the need to understand and controlthe detrimental experimental effects of contrast loss and for fundamentalstudies on the transition from the classical to the quantum regime.