# Measurement of the neutron lifetime and inverse quantum Zeno effect

## TL;DR

This paper investigates how measurement processes can influence neutron decay rates, proposing that the inverse quantum Zeno effect could be detectable in ultracold neutron traps but not in beam experiments, and discusses implications for neutron lifetime measurements.

## Contribution

It introduces the idea that the inverse quantum Zeno effect can be observed in neutron decay experiments with traps, providing a new perspective on neutron lifetime measurement discrepancies.

## Key findings

- Inverse quantum Zeno effect detectable at percent level in ultracold neutron traps.
- Neutron lifetime measurements in beam experiments are insensitive to the inverse quantum Zeno effect.
- Proposes a correlation between neutron number in traps and decay rate.

## Abstract

Quantum mechanics predicts that the decay rate of unstable systems could be effectively modified by the process of the measurement of the survival probability. Depending on the intrinsic properties of the unstable system and the experimental setup for the observation, one could obtain the so called (direct) quantum Zeno and inverse quantum Zeno effects corresponding to a slowing down or a speeding up of the decay, respectively. We argue that the inverse quantum Zeno effect is in principle detectable at a percent level for the neutron decay in experiments with trapped ultracold neutrons. Conversely, this effect is basically undetectable in experiments in which the neutron lifetime is measured by measuring the decays of beams of neutrons. As a test of our claim, we propose a simple qualitative correlation between the number of neutrons in the trap and the neutron lifetime: the larger the number, the faster the decay. Finally we discuss also the presently available measurements of the neutron lifetime and address the issue of the possible discrepancy that has been reported among the results obtained by the different experimental techniques.