Is the Conventional Picture of Coherence Time Complete? Dark Matter Recoherence

TL;DR

This paper introduces a generalized coherence time for ultralight dark matter, revealing a recoherence phenomenon that can greatly extend the effective observation window, enhancing detection sensitivity.

Contribution

It uncovers the recoherence effect in ULDM due to gravitational potential energy levels, extending the coherence time beyond traditional estimates.

Findings

Recoherence causes divergence in coherence time at long durations.

Extended coherence times improve dark matter detection sensitivity.

Dark matter dynamics are influenced by gravitational potential energy levels.

Abstract

The local solar gravitational potential forms a basin for ultralight dark matter (ULDM), with discrete energy levels. Even if barely populated, it introduces a new characteristic timescale in DM dynamics. This necessitates a generalization of the notion of coherence time. We find that, at long times, the phenomenon of recoherence emerges, whereby a subcomponent of ULDM exhibits a formally divergent coherence time. The fact that this generalized coherence time can significantly exceed the naive estimate implies an enhanced sensitivity for dark matter searches that accumulate data over extended observation periods.