Exciton transfer dynamics and quantum diffusion in a lattice of two level systems: Interplay between transport and coherent population transfer dynamics

Rajesh Dutta; Biman Bagchi

Home/Archive/arXiv

arXiv · 1608.04494

Exciton transfer dynamics and quantum diffusion in a lattice of two level systems: Interplay between transport and coherent population transfer dynamics

Rajesh Dutta·Biman Bagchi

View original source ↗Read source document ↗Export metadata ↓

Abstract

We study excitation transfer dynamics in a lattice of two level systems characterized by dynamic disorder. The diagonal and off-diagonal energy disorders arise from the coupling of system and bath. We consider both the same and the independent bath limits. In case of independent bath all diagonal and off-diagonal bath coupling elements fluctuate independently of each other and the dynamics is complicated. We obtain the time dependent population distribution by solving quantum stochastic Liouville equation (QSLE) derived by Kubo. The main result of our study is both the population transfer dynamics and the mean square displacement of the exciton behave the similar way in the same and independent bath cases in the Markovian limit. However, these two baths can give rise to markedly different behavior in the non-Markovian limit where coherent transport becomes important. There are also several additional new results as follows. (i) Exciton migration remains coherent all the time for an average, non-zero off-diagonal coupling value J for the same bath case while it becomes incoherent for independent bath case in the Markovian limit. (ii) An oscillatory behavior of the population transfer dynamics supports the coherent mode of transfer of exciton. (iii) Agreement with available analytical expression of mean squared displacement is good in the Markovian limit for independent bath case with off-diagonal fluctuation but only qualitative in the non-Markovian limit for which no complete analytical solution is available. (iv) Transition from coherent to incoherent transport is observed in the independent bath case with diagonal fluctuation when the bath is made progressively more Markovian. (v) The correlation time of the bath plays a unique role in dictating the diffusive spread that is not anticipated in a Markovian treatment.

Explore related subjects

cond-mat.stat-mech physics.chem-ph

Keep this discovery

BibTeX RIS

Rajesh Dutta, Biman Bagchi. 2016-08-16. Exciton transfer dynamics and quantum diffusion in a lattice of two level systems: Interplay between transport and coherent population transfer dynamics. https://arxiv.org/abs/1608.04494

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Universal sampling of spin systems across quenched disorder

Statistical physics extracts macroscopic laws by averaging over the many microscopic degrees of freedom of a system. Disordered systems demand a second and far harder average, one over the quenched randomness itself. The classic analytical routes, the replica and cavity methods, become uncontrolled outside mean-field or tree-like limits, and conventional numerical algorithms like parallel tempering require expensive, independent equilibration for every disorder realization. In this work, we introduce a universal neural variational framework that amortizes inference across the disorder ensemble, eliminating both the need for per-instance Markov chain equilibration and the cost of retraining instance-specific variational ansatzes. Built on an encoder-decoder Transformer architecture, after training once, it produces an explicit approximation to the Boltzmann distribution given previously unseen disorder realizations without further optimization. We validate this framework on 2D Edwards-Anderson models, and apply it to the random-bond Ising model, successfully capturing the Binder cumulant crossings near the Nishimori multicritical point. These results shift the object of variational inference from the single instance to the disorder ensemble, opening a route to frustrated many-body systems where instance-by-instance computation is prohibitive.

cond-mat.stat-mech↗

arXiv2026

Information-Theoretic Characterization of Macroscopic Chaos Emerging from the Chemical Master Equation

Open chemical reaction networks exhibit stochastic concentration dynamics at finite system sizes, whereas their macroscopic limit is governed by deterministic rate equations that can display chaos. In this Letter, we show theoretically that a rate of information loss constructed from two-time mutual information recovers the Kolmogorov-Sinai entropy in the deterministic limit. We verify this result through numerical simulations of a Markov jump process for a three-species system involving seven reactions.

cond-mat.stat-mech↗

arXiv2026

Orientational order on non-orientable domains

We study the statistical properties of passive and active many-body systems with orientational degrees of freedom on non-orientable domains. By rephrasing topological constraints as non-local symmetry relations on an orientable double-cover, we show that non-orientability eliminates global rotational soft modes without acting like an external field. In a passive XY model, this results in topological caging, where orientational fluctuations that exhibit conventional diffusive behavior on a torus saturate on a Klein bottle to a finite value that we compute exactly in the thermodynamic limit. In models of active self-propelled particles with orientational degrees of freedom, topological caging persists despite continuously changing interaction neighborhoods. In an active Ising spin model, non-orientability enforces the coexistence of ordered anti-parallel domains with vanishing global polar order, a state that is absent on orientable domains.

cond-mat.stat-mech↗