[phys4phys] SCL & PolMoReMa Seminar: Veljko Janković, Thursday 6 November, 14:00

[Nenad Vukmirović]

Dear colleagues,

You are cordially invited to the seminar of the Scientific Computing 
Laboratory of the Center for the Study of Complex Systems and of the 
project Polaron Mobility in Model Systems and Real Materials 
(PolMoReMa). The seminar will be held on Thursday, 6 November 2025 at 
14:00 in the "Zvonko Marić" lecture hall of the Institute of Physics 
Belgrade. The talk entitled

Quantum dynamics of charge transport in the field of slow off-diagonal 
dynamic disorder

will be given by Dr Veljko Janković (Scientific Computing Laboratory, 
Institute of Physics Belgrade). The abstract of the talk:

The motion of a charge carrier in organic molecular crystals is mainly 
limited by its moderate coupling to slow and abundantly thermally 
excited intermolecular phonons [1]. Despite recent advances in fully 
quantum methods, computations of transport properties most often rely on 
Newtonian [2] or some effective phonon dynamics [3]. This holds true 
even for the one-dimensional Peierls model featuring a single phonon 
mode per lattice site [4].

In this second SCL & PolMoReMa seminar, we present our numerically exact 
hierarchical equations of motion (HEOM)-based framework to compute 
transport properties of the one-dimensional Peierls model [5,6]. The 
phonon-assisted current is handled using our explicit expression of HEOM 
auxiliary operators in terms of phonon creation and annihilation 
operators [5]. We find that the displaced Drude peak [3] is accompanied 
by an optical-conductivity enhancement below phonon frequency [6], which 
is not observed in experimental low-frequency signatures. Solving the 
dissipaton equations of motion for a more realistic model with a 
continuous distribution of phonon modes, we conclude that this 
enhancement is an artifact of the assumed delta-like density of phonon 
states [7].

This research is supported by the Science Fund of the Republic of 
Serbia, Grant No. 5468, Polaron Mobility in Model Systems and Real 
Materials – PolMoReMa.

[1] B. M. T. C. Peluso et al., Angew. Chem. Int. Ed. 2025, e202507566 
(2025).
[2] A. Troisi and G. Orlandi, Phys. Rev. Lett. 96, 086601 (2006).
[3] S. Fratini, D. Mayou, and S. Ciuchi, Adv. Funct. Mater. 26, 2292 (2016).
[4] J. E. Runeson, T. J. G. Drayton, and D. E. Manolopoulos, J. Chem. 
Phys. 161, 144102 (2024).
[5] V. Janković, Phys. Rev. B 112, 035111 (2025).
[6] V. Janković, Phys. Rev. B 112, 035112 (2025).
[7] V. Janković, arXiv:2508.14447 (2025).

Best regards,
Nenad Vukmirović

-- 
Dr Nenad Vukmirović
Research Professor
Scientific Computing Laboratory
Center for the Study of Complex Systems
Institute of Physics Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
URL: http://www.scl.rs/nenad