2,667 research outputs found
Quantum jumps on Anderson attractors
In a closed single-particle quantum system, spatial disorder induces Anderson
localization of eigenstates and halts wave propagation. The phenomenon is
vulnerable to interaction with environment and decoherence, that is believed to
restore normal diffusion. We demonstrate that for a class of experimentally
feasible non-Hermitian dissipators, which admit signatures of localization in
asymptotic states, quantum particle opts between diffusive and ballistic
regimes, depending on the phase parameter of dissipators, with sticking about
localization centers. In diffusive regime, statistics of quantum jumps is
non-Poissonian and has a power-law interval, a footprint of intermittent
locking in Anderson modes. Ballistic propagation reflects dispersion of an
ordered lattice and introduces a new timescale for jumps with non-monotonous
probability distribution. Hermitian dephasing dissipation makes localization
features vanish, and Poissonian jump statistics along with normal diffusion are
recovered.Comment: 6 pages, 5 figure
Signatures of many-body localization in steady states of open quantum systems
Many-body localization (MBL) is a result of the balance between
interference-based Anderson localization and many-body interactions in an
ultra-high dimensional Fock space. It is usually expected that dissipation is
blurring interference and destroying that balance so that the asymptotic state
of a system with an MBL Hamiltonian does not bear localization signatures. We
demonstrate, within the framework of the Lindblad formalism, that the system
can be brought into a steady state with non-vanishing MBL signatures. We use a
set of dissipative operators acting on pairs of connected sites (or spins), and
show that the difference between ergodic and MBL Hamiltonians is encoded in the
imbalance, entanglement entropy, and level spacing characteristics of the
density operator. An MBL system which is exposed to the combined impact of
local dephasing and pairwise dissipation evinces localization signatures
hitherto absent in the dephasing-outshaped steady state.Comment: 6 pages, 3 figure
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