# At what time does a quantum experiment have a result?

## TL;DR

This paper introduces a method to define quantum observables for the time of occurrence, enabling proper probabilistic predictions without relying on instantaneous measurements, and discusses implications for the quantum Zeno effect.

## Contribution

It presents a novel approach to defining time observables in quantum mechanics that avoids problematic assumptions of previous methods.

## Key findings

- Provides a generalized POVM for the time of detection
- Addresses the interpretation of quantum Zeno experiments
- Avoids the need for instantaneous projective measurements

## Abstract

This paper provides a general method for defining a generalized quantum observable (or POVM) that supplies properly normalized conditional probabilities for the time of occurrence (i.e., of detection). This method treats the time of occurrence as a probabilistic variable whose value is to be determined by experiment and predicted by the Born rule. This avoids the problematic assumption that a question about the time at which an event occurs must be answered through instantaneous measurements of a projector by an observer, common to both Rovelli (1998) and Oppenheim et al. (2000). I also address the interpretation of experiments purporting to demonstrate the quantum Zeno effect, used by Oppenheim et al. (2000) to justify an inherent uncertainty for measurements of times.