Universal behavior of the Shannon mutual information in nonintegrable self-dual quantum chains

An existing conjecture states that the Shannon mutual information contained in the ground-state wave function of conformally invariant quantum chains, on periodic lattices, has a leading finite-size scaling behavior that, similarly as the von Neumann entanglement entropy, depends on the value of the central charge of the underlying conformal field theory describing the physical properties. This conjecture applies whenever the ground-statewave function is expressed in some special basis (conformal basis). Its formulation comes mainly from numerical evidences on exactly integrable quantum chains. In this paper, the above conjecture was tested for several general nonintegrable quantum chains. We introduce new families of self-dual Z(Q) symmetric quantum chains (Q = 2,3,...). These quantum chains contain nearest-neighbor as well next-nearest-neighbor interactions (coupling constant p). In the cases Q = 2 and Q = 3, they are extensions of the standard quantum Ising and three-state Potts chains, respectively. For Q = 4 and Q >= 5, they are extensions of the Ashkin-Teller and Z(Q) parafermionic quantum chains. Our studies indicate that these models are interesting on their own. They are critical, conformally invariant, and share the same universality class in a continuous critical line. Moreover, our numerical analysis for Q = 2-8 indicate that the Shannon mutual information exhibits the conjectured behavior irrespective if the conformally invariant quantum chain is exactly integrable or not. For completeness we also calculated, for these new families of quantum chains, the two existing generalizations of the Shannon mutual information, which are based on the Renyi entropy and on the Renyi divergence.