Transient Dynamics of Open Quantum Systems using the Multiparticle Holstein Hamiltonian

Polarons are key quasiparticles that govern the electronic and optical properties of organic semiconducting polymers and molecular aggregates. Understanding the dissipative dynamics of polarons is crucial for elucidating how quantum systems evolve in realistic environments, with applications spanning quantum technologies, condensed matter physics, and chemical/biological systems [1]. In this work, we investigate the dissipative dynamics of polarons in a one-dimensional linear chain coupled to a bath of harmonic oscillators, with a focus on understanding the phenomenon of decoherence [2]. We employ an efficient quantum dynamical approach based on unitary time evolution, where the dynamics is governed by the exponential of Holstein-style vibronic Hamiltonians diagonalized using a multiparticle basis set. To explore environment-induced effects, we systematically increase the dimensionality of the bath and observe a clear trend of coherence and purity decay in the system [3,4]. The subsystem purity is obtained by computing the trace over the bath degrees of freedom of the total time-evolved density matrix [5]. Our model system begins with a dimer, initially excited at one site, coupled to a bath of harmonic oscillators, enabling controlled investigation of system-bath interactions and their impact on quantum coherence and charge carrier mobility [6].

References:

[1] R. Ghosh and F. C. Spano, Acc. Chem. Res. 53, 2201-2211 (2020).

[2] M. A. Schlosshauer, Decoherence and the Quantum-To-Classical Transition (Springer, 2017).

[3] O. Prezhdo and P. Rossky, Phys. Rev. Lett. 81, 5294 (1998).

[4] B. Guo and I. Franco, J. Phys. Chem. Lett. 8, 4289 (2017).

[5] M. Werther and F. Grossmann, Phys. Rev. B. 101, 174315 (2020).

[6] T. Li, Y. Yan, Q. Shi, J. Chem. Phys. 160, 111102 (2024).