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arXiv · 1610.01540

Universal front propagation in the quantum Ising chain with domain-wall initial states

Viktor Eisler·Florian Maislinger·Hans Gerd Evertz
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Abstract

We study the melting of domain walls in the ferromagnetic phase of the transverse Ising chain, created by flipping the order-parameter spins along one-half of the chain. If the initial state is excited by a local operator in terms of Jordan-Wigner fermions, the resulting longitudinal magnetization profiles have a universal character. Namely, after proper rescalings, the profiles in the noncritical Ising chain become identical to those obtained for a critical free-fermion chain starting from a step-like initial state. The relation holds exactly in the entire ferromagnetic phase of the Ising chain and can even be extended to the zero-field XY model by a duality argument. In contrast, for domain-wall excitations that are highly non-local in the fermionic variables, the universality of the magnetization profiles is lost. Nevertheless, for both cases we observe that the entanglement entropy asymptotically saturates at the ground-state value, suggesting a simple form of the steady state.

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Viktor Eisler, Florian Maislinger, Hans Gerd Evertz. 2016-10-05. Universal front propagation in the quantum Ising chain with domain-wall initial states. https://doi.org/10.21468/scipostphys.1.2.014

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