Survival acceleration

TL;DR

This paper explores a novel relativistic effect where longer-lived excited atoms appear accelerated due to their decay dynamics, proposing an experiment to observe this phenomenon and calculating the resulting forces with relativistic corrections.

Contribution

It introduces the concept that longer-lived excited atoms can be accelerated, supported by a proposed experiment and relativistic calculations of the resulting forces.

Findings

Higher-momentum components decay more slowly due to time dilation

The atom experiences a force and acceleration from the non-emission of photons

Relativistic corrections are essential for accurate force calculations

Abstract

Relativistic time dilation implies that an accelerating excited atom would have its lifetime prolonged in the lab frame. In this paper, we demonstrate a complementary effect: Longer-lived excited atoms turn out to have been accelerated. We propose the following experiment. An excited atom is prepared in a superposition of momenta. Due to relativistic time dilation, in the lab frame, the decay rate of components with higher momentum is diminished. As time passes without the atom emitting a photon, higher-momentum components become more probable. This results in a time-dependent shift of the expectation value of momentum. Taking into account first-order relativistic corrections, we calculate the force and acceleration undergone by the atom due to the fact that it did not emit a photon.