Spatial entanglement between two quantum walkers with exchange symmetric coins

Ibrahim Yahaya Muhammad, Tanapat Deesuwan, Sikarin Yoo-Kong, Suwat Tangwancharoen, Monsit Tanasittikosol

Published 2022-03-02Version 1

We investigate the dynamics of the spatial entanglement between two initially independent walkers that perform discrete-time quantum walk with respect to symmetric and anti-symmetric initial coin states. By considering the symmetry associated with the setting and post-selecting the states of the two coins accordingly, we show that, for the anti-symmetric initial coin state, the entanglement corresponding to all the anti-symmetric results are always constant, while that corresponding to the symmetric result is underdamped-like with period of oscillation ($T$) being inversely proportional to the coin operator parameter ($\theta$). The results are the opposite way around for the case of symmetric initial coin states. We also discover that the underdamped-like behaviour of the spatial entanglement show up in the cases of both initial coin states when the post-selected results have no symmetry. Our findings reveal some interesting aspects of symmetry and entanglement dynamics in quantum walk, which may be useful for applications in quantum communication and other quantum technology.