Quasilocal conservation laws from semicyclic irreducible representations of Uq(sl2) in XXZ spin-1/2 chains
Lenart Zadnik (Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia)
; Marko Medenjak (Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia); Tomaž Prosen (Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia)
We construct quasilocal conserved charges in the gapless ( |Δ|≤1 ) regime of the Heisenberg XXZ spin-1/2 chain, using semicyclic irreducible representations of Uq(sl2) . These representations are characterized by a periodic action of ladder operators, which act as generators of the aforementioned algebra. Unlike previously constructed conserved charges, the new ones do not preserve magnetization, i.e. they do not possess the U(1) symmetry of the Hamiltonian. The possibility of application in relaxation dynamics resulting from U(1) -breaking quantum quenches is discussed.
