DISORDER OPERATORS, QUANTUM DOUBLES, AND HAAG DUALITY IN 1 + 1 DIMENSIONS

Guangzhao Zhou, Dingchang Xian

Victor V. Albert, David Aasen, Wenqing Xu +3 more

Michael Keyl, Taku Matsui, Dirk-M. Schlingemann +1 more

In this note, we consider quantum spin chains and their translationally invariant pure states. We prove Haag duality for quasilocal observables localized in semi-infinite intervals (-∞ , 0] and [1, ∞) when the von Neumann algebra generated by observables localized in [0, ∞) is non-type I.

Taku Matsui

Tai Kai Ng

We show in this paper an interesting relation between elementary and topological excitations in the antiferromagnetic and d-wave superconducting phases of the t–J model at two dimensions. The topological spin and charge excitations in one phase have the same dynamics as elementary excitations in the other phase, except the appearance of energy gaps. Moreover, the transition from one phase to another can be described as a quantum disordering transition associated with the topological excitations. Based on the above picture, a plausible phase diagram of t–J model is constructed.

Enrique Rico Ortega