Quantum arrival time measurement and backflow effect

TL;DR

This paper investigates the quantum arrival time measurement, focusing on the backflow effect where current density becomes negative, and compares different operational distributions through a model detector.

Contribution

It provides a detailed analysis of the backflow effect in quantum arrival time measurements and compares various proposed distributions using a model detector.

Findings

Identification of the backflow regime and its properties

Comparison of operational arrival time distributions

Discussion of counterintuitive negative current densities

Abstract

The current density for a freely evolving state without negative momentum components can temporarily be negative. The operational arrival time distribution, defined by the absorption rate of an ideal detector, is calculated for a model detector and compared with recently proposed distributions. Counterintuitive features of the backflow regime are discussed.