Recent work on quantum collapse models suggests that stochastic collapse dynamics can induce an intrinsic contribution to clock-time uncertainty, which can be interpreted as an effective fundamental (though extremely small) limit on clock precision. Here we investigate the operational consequences of such time uncertainty for reversibility and the thermodynamic arrow of time. We model fundamental time noise as a Brownian jitter of the effective time parameter in a driven quantum system and study its impact on Loschmidt echo, entropy production, and the depth of reversible control protocols. Using a minimal two-qubit model we show that even arbitrarily weak time noise leads to (i) a systematic decay of the Loschmidt echo, (ii) monotonic entropy growth under ensemble averaging, and (iii) a finite reversibility horizon Nc(Θ) that scales approximately as Nc ∝ Θ−1 with the time–noise strength Θ. We interpret these results in the framework of relational and operational time: fundamental time uncertainty manifests itself as a finite temporal budget of usable, low-entropy correlations and induces an intrinsic limit on the depth of reversible dynamics.
Yuliia Neziat (Mon,) studied this question.