Superuniversality from disorder at two-dimensional topological phase transitions
University of Oxford (2020)
Abstract:
Data were produced by stochastic series expansion Monte Carlo simulations.Topology and symmetry-protected domain wall conduction in quantum Hall nematics
Physical review B: Condensed matter and materials physics American Physical Society 100:16-15 (2019) 165103
Signatures of information scrambling in the dynamics of the entanglement spectrum
Physical review B: Condensed Matter and Materials Physics American Physical Sociey 100 (2019) 125115
Abstract:
We examine the time evolution of the entanglement spectrum of a small subsystem of a nonintegrable spin chain following a quench from a product state. We identify signatures in this entanglement spectrum of the distinct dynamical velocities (related to entanglement and operator spreading) that control thermalization. We show that the onset of level repulsion in the entanglement spectrum occurs on different timescales depending on the “entanglement energy”, and that this dependence reflects the shape of the operator front. Level repulsion spreads across the entire entanglement spectrum on a timescale that is parametrically shorter than that for full thermalization of the subsystem. This timescale is also close to when the mutual information between individual spins at the ends of the subsystem reaches its maximum. We provide an analytical understanding of this phenomenon and show supporting numerical data for both random unitary circuits and a microscopic Hamiltonian.Quantum Brownian motion in a quasiperiodic potential
Physical review B: Condensed matter and materials physics American Physical Society 100:6 (2019) 060301
Abstract:
We consider a quantum particle subject to Ohmic dissipation, moving in a bichromatic quasiperiodic potential. In a periodic potential the particle undergoes a zero-temperature localization-delocalization transition as dissipation strength is decreased. We show that the delocalized phase is absent in the quasiperiodic case, even when the deviation from periodicity is infinitesimal. Using the renormalization group, we determine how the effective localization length depends on the dissipation. We show that a similar problem can emerge in the strong-coupling limit of a mobile impurity moving in a periodic lattice and immersed in a one-dimensional quantum gas.Quantum Hall valley nematics
Journal of Physics: Condensed Matter IOP Publishing 31:27 (2019) 273001