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arXiv · 1208.0424

Quantum random walk : effect of quenching

Sanchari Goswami·Parongama Sen
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Abstract

We study the effect of quenching on a discrete quantum random walk by removing a detector placed at a position $x_D$ abruptly at time $t_R$ from its path. The results show that this may lead to an enhancement of the occurrence probability at $x_D$ provided the time of removal $t_R < t_{R}^{lim}$ where $t_{R}^{lim}$ scales as $x_D{^2}$. The ratio of the occurrence probabilities for a quenched walker ($t_R \neq 0$) and free walker ($t_R =0$) shows that it scales as $1/t_R$ at large values of $t_R$ independent of $x_D$. On the other hand if $t_R$ is fixed this ratio varies as $x_{D}^{2}$ for small $x_D$. The results are compared to the classical case. We also calculate the correlations as functions of both time and position.

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Sanchari Goswami, Parongama Sen. 2012-08-02. Quantum random walk : effect of quenching. https://doi.org/10.1103/physreva.86.022314

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