SciPost Phys. Core 3, 002 (2020) ·
published 31 July 2020

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We study the limit of Dseries minimal models when the central charge tends
to a generic irrational value $c\in (\infty, 1)$. We find that the limit
theory's diagonal threepoint structure constant differs from that of Liouville
theory by a distribution factor, which is given by a divergent Verlinde
formula. Nevertheless, correlation functions that involve both nondiagonal and
diagonal fields are smooth functions of the diagonal fields' conformal
dimensions. The limit theory is a nontrivial example of a nondiagonal,
nonrational, solved twodimensional conformal field theory.
Sergio Enrique Tapias Arze, Pieter W. Claeys, Isaac Pérez Castillo, JeanSébastien Caux
SciPost Phys. Core 3, 001 (2020) ·
published 22 July 2020

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We consider the dynamics of an XY spin chain subjected to an external transverse field which is periodically quenched between two values. By deriving an exact expression of the Floquet Hamiltonian for this outofequilibrium protocol with arbitrary driving frequencies, we show how, after an unfolding of the Floquet spectrum, the parameter space of the system is characterized by alternations between local and nonlocal regions, corresponding respectively to the absence and presence of Floquet resonances. The boundary lines between regions are obtained analytically from avoided crossings in the Floquet quasienergies and are observable as phase transitions in the synchronized state. The transient behaviour of dynamical averages of local observables similarly undergoes a transition, showing either a rapid convergence towards the synchronized state in the local regime, or a rather slow one exhibiting persistent oscillations in the nonlocal regime, where explicit decay coefficients are presented.