[institut] Reminder: IPB Colloquium: Branislav Nikolić, Wednesday, 18 March 12:00

[Nenad Vukmirović]

Dear colleagues,

This is a reminder about the IPB Colloquium taking place today.

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




-------- Forwarded Message --------
Subject: 	[institut] [phys4phys] IPB Colloquium: Branislav Nikolić, 
Wednesday, 18 March 12:00
Date: 	Thu, 12 Mar 2026 13:35:29 +0100
From: 	Nenad Vukmirovic <nenad.vukmirovic at ipb.ac.rs>
To: 	phys4phys at ipb.ac.rs



Dear colleagues,

You are cordially invited to the IPB COLLOQUIUM which will be held on 
Wednesday, 18 March 2026 at 12:00 in the “Zvonko Marić” lecture hall of 
the Institute of Physics Belgrade. The talk entitled

Driven-dissipative spin systems in spintronics, magnonics and quantum 
computing

will be given by Prof. Branislav Nikolić (University of Delaware, USA). 
The abstract of the talk:

The driven-dissipative many-body systems remain one of the most 
challenging unsolved problems of quantum physics. When “body” is spin, 
such as of electrons or of engineered ones like qubits, these many-body 
systems underlie spintronics, magnonics and quantum computing 
technologies. In this talk, I will first explain conditions [1] under 
which quantum spins interacting with a dissipative environment can 
transition toward classical dynamics governed by the celebrated 
Landau-Lifshitz-Gilbert (LLG) equation. The extended LLG equation for 
classical spin dynamics, which includes non-Markovian and spatially 
nonlocal damping of quantum origin, can be rigorously derived from 
Schwinger-Keldysh quantum field theory (SKFT) [2] by integrating out 
fermionic or bosonic bath and by neglecting quantum fluctuations of spin 
fields. Its application [3] to magnons explains recent experiments [4] 
where quantum sensing has measured 100-fold increase of magnon damping 
in yttrium iron garnet (one of the key materials in magnonics) due to 
metallic overlayer. It also explains [5] how to properly bring light 
into the LLG equation and predict optically excited magnons. In the case 
of fully quantum spin dynamics, by combining SKFT with two-particle 
irreducible effective (2PI) action formalism and 1/N expansion, both of 
which have been developed originally in elementary particle physics, we 
describe [6] time evolution of spin in archetypical open quantum 
system⸺the spin-boson model (that is also of great importance for 
understanding decoherence of idle superconducting qubits). Despite only 
a class of Feynman diagrams being resummed to infinite order by 2PI, 
where those diagrams are generated by expansion in 1/N (N in the number 
of Schwinger bosons to which spin is mapped) instead of expansion in the 
system-bath coupling, our SKFT can track numerically exact non-Markovian 
simulations from tensor networks (TN) methods. It also provides access 
to longer times and higher spatial dimensions where TN fail due to the 
emergence of “entanglement barrier.” These newly developed methods make 
it possible to understand, for the first time, fate of entanglement in 
open quantum spin liquids [7].

References
[1] F. Garcia-Gaitan and B. K. Nikolić, Phys. Rev. B 109, L180408 (2024).
[2] F. Reyes-Osorio and B. K. Nikolić, Phys. Rev. B 109, 024413 (2024).
[3] F. Reyes-Osorio and B. K. Nikolić, Phys. Rev. B 110, 214432 (2024).
[4] I. Bertelli et. al., Adv. Quantum Technol. 4, 2100094 (2021).
[5] F. Reyes-Osorio and B. K. Nikolić, Phys. Rev. Lett. 135, 246701 (2025).
[6] F. Reyes-Osorio, F. Garcia-Gaitan, D. J. Strachan, P. Plecháč, S. R. 
Clark, and B. K. Nikolić, Rep. Prog. Phys. 89, 018002 (2026).
[7] F. Garcia-Gaitan and B. K. Nikolić, https://arxiv.org/abs/2510.02256 
(2025).

Branislav K. Nikolić is a Full Professor of Physics at the University of 
Delaware and a Senior Visiting Scientist at RIKEN in Japan. He received 
his Ph.D. in theoretical condensed matter physics from Stony Brook 
University, and a B.Sc. degree from the University of Belgrade, Serbia. 
He was visiting Professor at the University of Regensburg, National 
Taiwan University, Centre de Physique Théorique de Grenoble-Alpes and 
Beijing Normal University. His research focuses on nonequilibrium 
quantum many-body and field theory, computational quantum transport, 
multiscale quantum-classical approaches, and high-performance scientific 
computing, including applications to technologically relevant problems 
in spintronics, magnonics, quantum information, nanoelectronics, 
thermoelectrics and nano-bio interface.

Best regards,
Nenad Vukmirović

--
Dr Nenad Vukmirović
Research Professor
Institute of Physics Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
URL: http://www.scl.rs/nenad

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