The death of spin

F. Alberto Grünbaum, Luc Vinet, Alexei S. Zhedanov

This paper underscores the intimate connection between the quantum walks generated by certain semi-infinite spin chain Hamiltonians and classical birth and death processes. It is observed that transition amplitudes between single excitation states of the spin chains have an expression in terms of orthogonal polynomials which is analogous to the Karlin-McGregor representation formula of the transition probability functions for classes of birth and death processes. As an application, we present a characterization of spin systems for which the probability to return to the point of origin at some time is 1 or almost 1.

D. Gershoni

Sergei M. Guriev, Daniel S. Treisman

Zhao-Ming Wang, Shao Bin, Zou Jian

We investigate the entanglement transfer in two parallel 1D spin chains of a quantum spin network, and show that the perfect entanglement transfer can be realized at some special times. In addition, the so-called `sudden death' phenomenon of entanglement is found in the spin network system.

M. C. Aronson

Xiaoguang Wang, Adam Miranowicz, Yu-xi Liu +2 more

In order to witness multipartite correlations beyond pairwise entanglement, spin-squeezing parameters are analytically calculated for a spin ensemble in a collective initial state under three different decoherence channels. It is shown that, in analogy to pairwise entanglement, the spin squeezing described by different parameters can suddenly become zero at different vanishing times. This finding shows the general occurrence of sudden vanishing phenomena of quantum correlations in many-body systems, which here is referred to as spin-squeezing sudden death (SSSD). It is shown that the SSSD usually occurs due to decoherence and that SSSD never occurs for some initial states in the amplitude-damping channel. We also analytically obtain the vanishing times of spin squeezing.