The wavefunction of two identical bosons remains invariant under particle exchange - a fundamental quantum symmetry that underlies Bose-Einstein statistics. We report the direct experimental observation of bosonic exchange symmetry in the temporal wavefunction of photon pairs generated via spontaneous four-wave mixing in a three-level cold atomic ensemble. The measured two-photon temporal correlations show excellent agreement with theoretical predictions based on symmetrized bosonic wavefunctions. In addition, we perform time-resolved two-photon interference to reconstruct the complex temporal wavefunction. Both the amplitude and phase profiles exhibit clear symmetry under photon exchange, providing a direct confirmation of bosonic exchange symmetry in the time domain.
@article{arxiv.2507.04134,
title = {Revealing Bosonic Exchange Symmetry in Two-Photon Temporal Wavefunction},
author = {Yefeng Mei and Yue Jiang and Shengwang Du},
journal= {arXiv preprint arXiv:2507.04134},
year = {2026}
}