We consider the problem of de termining the initial state of integrable quantum field theory quenches in terms of the post-quench eigenstates. The corresponding overlaps are a fu ndamental input to most exact methods to treat in tegrable quantum quenches. We construct and examin e an infinite integral equation hierarchy based o n the form factor bootstrap\, proposed earlier as a set of conditions determining the overlaps. Usi ng quenches of the mass and interaction in Sinh-G ordon theory as a concrete example\, we present th eoretical arguments that the state has the squeez ed coherent form expected for integrable quenches \, and supporting an Ansatz for the solution of th e hierarchy. Moreover we also develop an iterativ e method to solve numerically the lowest equation of the hierarchy. The iterative solution along wi th extensive numerical checks performed using the next equation of the hierarchy provides a strong numerical evidence that the proposed Ansatz gives a very good approximation for the solution.

Related Links

- http://www.sciencedirect.com/science/ar ticle/pii/S0550321315004095 - Nuclear Physics B902 (2016) 508-547 \;