3 research outputs found
The role of interaction-induced tunneling in the dynamics of polar lattice bosons
Inter-site dipolar interactions induce, even in absence of disorder, an
intriguing non-ergodic dynamics for dipolar bosons in an optical lattice. We
show that the inherent dipole-induced density-dependent tunneling, typically
neglected, plays a crucial role in this dynamics. For shallow-enough lattices,
the delocalization stemming from the interaction-induced hopping overcomes the
localization induced by inter-site interactions. As a result, in stark contrast
to the more studied case of hard-core bosons, delocalization is
counter-intuitively strengthen when the dipolar strength increases.
Furthermore, the quasi-cancellation between bare and interaction-induced
tunneling may lead, near a lattice-depth-dependent value of the dipole
strength, to an exact decoupling of the Hilbert space between ergodic hard-core
states and strongly non-ergodic soft-core ones. Our results show that
interaction-induced hopping should play a crucial role in future experiments on
the dynamics of polar lattice gases.Comment: 10 pp. revised and extended versio
Scar States in Deconfined Lattice Gauge Theories
The weak ergodicity breaking induced by quantum many-body scars (QMBS)
represents an intriguing concept that has received great attention in recent
years due to its relation to unusual non-equilibrium behaviour. Here we reveal
that this phenomenon can occur in a previously unexplored regime of a lattice
gauge theory, where QMBS emerge due to the presence of an extensive number of
local constraints. In particular, by analyzing the gauged Kitaev model, we
provide an example where QMBS appear in a regime where charges are deconfined.
By means of both numerical and analytical approaches, we find a variety of
scarred states far away from the regime where the model is integrable. The
presence of these states is revealed both by tracing them directly from the
analytically reachable limit, as well as by quantum quenches showing persistent
oscillations for specific initial states.Comment: second modified version, comments welcom
Finite-size scaling analysis of the many-body localization transition in quasiperiodic spin chains
We analyze the finite-size scaling of the average gap ratio and the entanglement entropy across the many-body localization (MBL) transition in one dimensional Heisenberg spin chain with quasiperiodic (QP) potential. By using the recently introduced cost-function approach, we compare different scenarios for the transition using exact diagonalization of systems up to 22 lattice sites. Our findings suggest that the MBL transition in the QP Heisenberg chain belongs to the class of the Berezinskii-Kosterlitz-Thouless transition, the same as in the case of uniformly disordered systems as advocated in recent studies. Moreover, we observe that the critical disorder strength shows a clear sublinear drift with the system size as compared to the linear drift seen in random disordered models, suggesting that the finite-size effects in the MBL transition for the QP systems are less severe than that in the random disordered scenario. Moreover, deep in the ergodic regime, we find an unexpected double-peak structure of distribution of on-site magnetizations that can be traced back to the strong correlations present in the QP potential