Interplay between Anderson and Stark Localization in 2D Lattices

Kolovsky, Andrey R.

doi:10.1103/physrevlett.101.190602

Cited by 14 publications

(11 citation statements)

References 20 publications

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“…( 3)] can be viewed as a distance traveled by a carrier within the time-interval (0, t). For noninteracting case ∆E(t) < 4 and r(t) < 4/F , which is the Stark localization length [22]. Here, we have found that r(t 1 ) ∼ L confirming that the finitesize effects originate from heating of the spin background when carrier repeatedly encircles the ladder.…”

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confidence: 72%

Nonequilibrium Quantum Dynamics of a Charge Carrier Doped into a Mott Insulator

et al. 2011

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We study real-time dynamics of a charge carrier introduced into undoped Mott insulator propagating under a constant electric field F on the t-J ladder and square lattice. We calculate quasistationary current. In both systems adiabatic regime is observed followed by the positive differential resistivity (PDR) at moderate fields where carrier mobility is determined. Quantitative differences between ladder and 2-dimensional (2D) system emerge when at large fields both systems enter negative differential resistivity (NDR) regime. In the ladder system Bloch-like oscillations prevail, while in 2D the current remains finite, proportional to 1/F . The crossover between PDR and NDR regime in 2D is accompanied by a change of the spatial structure of the propagating spin polaron. [12,13] and the relaxation of correlated systems after the photoexcitations [14,15], represent the well-studied examples of nonequilibrium phenomena which are important both for fundamental understanding of strongly correlated systems as well as for their potential applications.Most of theoretical studies so far considered the breakdown of undoped MI, when threshold value of the electric field exceeds experimental value [9] by a few orders of magnitude (see discussion in Ref. [11]). It indicates that other transport mechanism becomes active at energies much lower than the Mott-Hubbard gap. In this Letter we inveqstigate a nonequilibrium response of a charge carrier doped into the insulator and driven by an uniform electric field F . Understanding of this subject on one hand widens our knowledge of a charge carrier doped into the antiferromagnetic (AFM) background [16,17], on the other, it represents a fundamental problem of a quantum particle moving in a dissipative medium [18].Having in mind strongly correlated systems, we investigate the t-J model where the particle driven by a constant electric field dissipates the energy by inelastic scattering on spin degrees of freedom. We use numerical approaches to treat t-J model at zero temperature on two different system geometries, i.e., a ladder with periodic boundary conditions and an infinite 2-dimensional (2D)

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confidence: 72%

Nonequilibrium Quantum Dynamics of a Charge Carrier Doped into a Mott Insulator

et al. 2011

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“…Systematic variations in site energies or coupling strengths can also cause localization [31], with the well-known instance of Bloch oscillations and Stark localization deriving from a linear bias in site energies [32]. Both systematic and random variations in site energies remove the symmetry necessary for Bloch's theorem, so it is not surprising that their combination leads to localization as well [33,34]. Adding disorder into the graph structure also usually causes localization [35] (although such disorder can also reduce localization if it makes an already disordered graph more connected [36]).…”

Section: Coherent Dynamicsmentioning

confidence: 99%

Limits of quantum speedup in photosynthetic light harvesting

2010

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It has been suggested that excitation transport in photosynthetic light harvesting complexes features speedups analogous to those found in quantum algorithms. Here we compare the dynamics in these light harvesting systems to the dynamics of quantum walks, in order to elucidate the limits of such quantum speedups. For the Fenna-Matthews-Olson (FMO) complex of green sulfur bacteria, we show that while there is indeed speedup at short times, this is short lived (70 fs) despite longer lived (ps) quantum coherence. Remarkably, this time scale is independent of the details of the decoherence model. More generally, we show that the distinguishing features of light-harvesting complexes not only limit the extent of quantum speedup but also reduce rates of diffusive transport. These results suggest that quantum coherent effects in biological systems are optimized for efficiency or robustness rather than the more elusive goal of quantum speedup.

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“…In this paper, we want to extend the spectral analysis to the case of two-dimensional BHMs with strong interparticle interactions. The dynamics of two-dimensional tight-binding systems was studied before in the noninteracting case [17], or in the specific case of a four mode interacting system [18]. Analyzing different minimal models of up to a 3x3 square lattice, we will see how the geometry of the lattice and the number of permitted couplings (i.e.…”

Section: Introductionmentioning

confidence: 99%

Spectral analysis of two-dimensional Bose-Hubbard models

Fischer¹,

Hoffmann²,

Wimberger³

2016

Phys. Rev. A

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One-dimensional Bose-Hubbard models are well known to obey a transition from regular to quantum-chaotic spectral statistics. We are extending this concept to relatively simple twodimensional many-body models. Also in two dimensions a transition from regular to chaotic spectral statistics is found and discussed. In particular, we analyze the dependence of the spectral properties on the bond number of the two-dimensional lattices and the applied boundary conditions. For maximal connectivity, the systems behave most regularly in agreement with the applicability of mean-field approaches in the limit of many nearest neighbor couplings at each site.

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Interplay between Anderson and Stark Localization in 2D Lattices

Cited by 14 publications

References 20 publications

Nonequilibrium Quantum Dynamics of a Charge Carrier Doped into a Mott Insulator

Nonequilibrium Quantum Dynamics of a Charge Carrier Doped into a Mott Insulator

Limits of quantum speedup in photosynthetic light harvesting

Spectral analysis of two-dimensional Bose-Hubbard models

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