Quantum clocks are more precise than classical ones

TL;DR

This paper demonstrates that quantum clocks can achieve quadratically higher precision than classical clocks of the same size by leveraging information-theoretic principles.

Contribution

It establishes a fundamental quantum advantage in clock precision based on information-theoretic analysis, showing quadratic improvement over classical clocks.

Findings

Quantum clocks outperform classical clocks in precision.

The advantage scales quadratically with clock size.

Information-theoretic analysis underpins the quantum advantage.

Abstract

A clock is, from an information-theoretic perspective, a system that emits information about time. One may therefore ask whether the theory of information imposes any constraints on the maximum precision of clocks. Here we show a quantum-over-classical advantage for clocks or, more precisely, the task of generating information about what time it is. The argument is based on information-theoretic considerations: we analyse how the precision of a clock scales with its size, measured in terms of the number of bits that could be stored in it. We find that a quantum clock can achieve a quadratically improved precision compared to a purely classical one of the same size.