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Out of equilibrium correlation functions of quantum anisotropic XY models: one-particle excitations

Luigi Amico·Andreas Osterloh
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Abstract

We calculate exactly matrix elements between states that are not eigenstates of the quantum XY model for general anisotropy. Such quantities therefore describe non equilibrium properties of the system; the Hamiltonian does not contain any time dependence. These matrix elements are expressed as a sum of Pfaffians. For single particle excitations on the ground state the Pfaffians in the sum simplify to determinants.

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Luigi Amico, Andreas Osterloh. 2003-12-15. Out of equilibrium correlation functions of quantum anisotropic XY models: one-particle excitations. https://doi.org/10.1088/0305-4470%2F37%2F2%2F001

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