Entropic Reciprocity in Time-Reversed Young Interferometry
Abstract
We show that time-reversed Young interferometry reorganizes, rather than reverses, optical entropy. A fixed detector conditions the reciprocal source--detector Green function and produces a source-label probability distribution. Marginal entropies in the standard and time-reversed geometries are generally unequal; the reciprocal invariant is instead the mutual information between source and detector coordinates. Near a destructive response, the conditioned source-label entropy can decrease while Fisher information for small phase, tilt, or defocus perturbations increases. The result identifies time-reversed Young interferometry as a source-space information processor with no analogue in ordinary detector-plane fringe readout.
Cite
@article{arxiv.2605.01052,
title = {Entropic Reciprocity in Time-Reversed Young Interferometry},
author = {Jianming Wen},
journal= {arXiv preprint arXiv:2605.01052},
year = {2026}
}
Comments
This work provides an explicit definition on time reversal based on information theory