Quantum Walker in Presence of a Moving Detector

TL;DR

This paper investigates how a moving detector influences a one-dimensional quantum random walk, revealing quantum effects, scaling behaviors, and limiting cases that connect to classical walk variants.

Contribution

It introduces a detailed analysis of a quantum walk with a moving detector, highlighting quantum effects and scaling laws not previously explored.

Findings

Occupation probability at detector position is enhanced for small n

Scaling behavior of occupation probability ratio is proportional to x_D^2/n^2

Limiting behaviors connect to infinite, semi-infinite, and quenched quantum walks

Abstract

In this work, we study the effect of a moving detector on a discrete time one dimensional Quantum Random Walk where the movement is realized in the form of hopping/shifts. The occupation probability $f(x,t;n,s)$ is estimated as the number of detection $n$ and amount of shift $s$ vary. It is seen that the occupation probability at the initial position $x_D$ of the detector is enhanced when $n$ is small which is a quantum mechanical effect but decreases when $n$ is large. The ratio of occupation probabilities of our walk to that of an Infinite walk shows a scaling behavior of $\frac{x_D^2}{n^2}$. It shows a definite scaling behavior with amount of shifts $s$ also. The limiting behaviors of the walk are observed when $x_D$ is large, $n$ is large and $s$ is large and the walker for these cases approach the Infinite Walk, The Semi Infinite Walk and the Quenched Quantum Walk respectively.