Condensed Matter Theory Seminar | January 08, 14:00

Subdiffusive dynamics and critical quantum correlations in a disorder-free localized Kitaev honeycomb model out of equilibrium

Guo-Yi Zhu

The Kitaev honeycomb model is well-known to host a quantum spin liquid at zero temperature, exhibiting topological order and fractionalization of spin into emergent Majorana fermion minimally coupled with Z2 gauge field. The exact solvability of this model stems from the conservation of local gauge fluxes, which also has dramatic impact upon the nonequilibrium dynamics when the system is brought out of equilibrium and isolated from any environment. The latter issue has been widely studied in the quest of emergent ergodicity in generic quantum manybody systems, or ergodicity breaking in manybody localization or other mechanisms. In this talk, I will show that the homogeneous Kitaev model exhibits the phenomenon of disorder-free localization, where the fractionalized Majorana fermion is partially localized by the Z2 gauge flux disorder dynamically generated in a highly excited state. As a result, the system exhibits exotic quench dynamics that is neither MBL nor ergodic: (1) algebraic lightcone of dimer correlation spreading; (2) algebraic decaying critical correlation in late time steady state; (3) algebraic growth of projective bipartite entanglement entropy to a volume law. Further, I will show numerical evidence that the long time feature is stable against solvability breaking perturbation. Our results may possibly imply nontrivial dimer correlation for Kitaev spin liquids at finite temperature.


MPI-PKS, Dresden
https://uni-koeln.zoom.us/j/93649501617?pwd=UVFUT2thakZ4U2N2VlpWazNDb1FRUT09
Contact: Simon Trebst