Ideal clocks - a convenient fiction

TL;DR

This paper demonstrates that quantum clocks cannot measure proper time independently of acceleration effects, challenging the classical notion of ideal clocks by showing the influence of the Unruh effect on their time measurement.

Contribution

It reveals that quantum field theory prohibits truly ideal clocks and highlights the impact of acceleration-induced effects like the Unruh effect on time measurement.

Findings

Quantum clocks are affected by the Unruh effect during acceleration.

No device can measure proper time without acceleration influence.

The concept of an ideal clock is incompatible with quantum field theory.

Abstract

We show that no device built according to the rules of quantum field theory can measure proper time along its path. Highly accelerated quantum clocks experience the Unruh effect, which inevitably influences their time rate. This contradicts the concept of an ideal clock, whose rate should only depend on the instantaneous velocity.