Temporally localized quantum operations on continuous-wave thermal light
Abstract
Previous work showed that thermal light with a blackbody spectrum cannot be decomposed into a mixture of independent localized pulses. However, we find that in the weak-source limit and under the assumption of a flat spectrum, the first non-vacuum term in the state expansion does form a mixture of such pulses. This decomposition is essential for quantum-enhanced astronomical interferometry, which typically operates on localized pulses even though stellar light is inherently continuous-wave. We present a quantum derivation of the van Cittert-Zernike theorem that incorporates finite bandwidth, thereby justifying the operations on localized pulses while processing continuous-wave thermal light. For general spectra in the weak-source limit, we establish a criterion under which correlations between pulses can be safely neglected. When this criterion is not met, we provide a corrected strategy that accurately accounts for both the spectral profile and the detector-defined pulse shape.
Cite
@article{arxiv.2412.17223,
title = {Temporally localized quantum operations on continuous-wave thermal light},
author = {Yunkai Wang and Yujie Zhang and Virginia O. Lorenz},
journal= {arXiv preprint arXiv:2412.17223},
year = {2025}
}