[institut] [phys4phys] SCL & PolMoReMa Seminar: Suzana Miladić, Thursday 27 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, 27 November 2025 at 
14:00 in the library reading room "Dr Dragan Popović" of the Institute 
of Physics Belgrade. The talk entitled

QMC study of transport in Holstein polaron model

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

Organic semiconductors are emerging materials that are shaping modern 
technologies (OLEDs, OFETs, OPVs). Their low cost, mechanical 
flexibility, and tunable properties make them highly promising for a 
wide range of applications. However, realizing their full potential 
requires a detailed understanding of charge transport in these materials.

In this work, we investigate transport within the Holstein polaron 
model—a simple yet representative framework for organic molecular 
semiconductors. We develop a path-integral Quantum Monte Carlo method 
for computing current–current correlation functions and the dc mobility 
in the 1D Holstein model [1]. By carefully choosing the basis for the 
trace expansion in path integral, we suppress the dynamical sign problem 
and are able to evaluate correlation functions over long real-time 
intervals with small errors.

Using the Kubo formula, we extract the dc mobility either through direct 
integration of real-time correlation functions or via analytic 
continuation that combines real- and imaginary-time data. This approach 
yields highly precise results for dc mobility across a broad parameter 
range. The numerically exact results obtained here provide a great 
benchmark for evaluating the validity of commonly used transport 
theories, which rely on approximations appropriate only in extreme cases 
(strong or weak electron–phonon coupling, very low or high temperature).

By comparing our numerical results to the predictions of each transport 
theory, we are able to map out the parameter ranges—defined by 
temperature, electron–phonon interaction strength, and phonon 
frequency—over which small-polaron hopping, polaron band transport, or 
conventional band transport offers an accurate description of charge 
transport. This allows us to construct a transport-regime diagram for 
the 1D Holstein model, offering better insights into its transport 
behavior [2].

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] S. Miladić and N. Vukmirović, Phys. Rev. B 107, 184315 (2023).
[2] S. Miladić and N. Vukmirović, Phys. Rev. B 112, 054314 (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



_______________________________________________
phys4phys mailing list
phys4phys at mail.ipb.ac.rs
https://mail.ipb.ac.rs/mailman/listinfo/phys4phys