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Title: Parity-time symmetry breaking in magnetic systems

Abstract

The understanding of out-of-equilibrium physics, especially dynamic instabilities and dynamic phase transitions, is one of the major challenges of contemporary science, spanning the broadest wealth of research areas that range from quantum optics to living organisms. By focusing on nonequilibrium dynamics of an open dissipative spin system, we introduce a non-Hermitian Hamiltonian approach, in which non-Hermiticity reflects dissipation and deviation from equilibrium. The imaginary part of the proposed spin Hamiltonian describes the effects of Gilbert damping and applied Slonczewski spin-transfer torque. In the classical limit, our approach reproduces Landau-Lifshitz-Gilbert-Slonczewski dynamics of a large macrospin. Here, we reveal the spin-transfer torque-driven parity-time symmetry-breaking phase transition corresponding to a transition from precessional to exponentially damped spin dynamics. Micromagnetic simulations for nanoscale ferromagnetic disks demonstrate the predicted effect. These findings can pave the way to a general quantitative description of out-of-equilibrium phase transitions driven by spontaneous parity-time symmetry breaking.

Authors:
 [1];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1356846
Alternate Identifier(s):
OSTI ID: 1262455
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Citation Formats

Galda, Alexey, and Vinokur, Valerii M. Parity-time symmetry breaking in magnetic systems. United States: N. p., 2016. Web. doi:10.1103/PhysRevB.94.020408.
Galda, Alexey, & Vinokur, Valerii M. Parity-time symmetry breaking in magnetic systems. United States. doi:10.1103/PhysRevB.94.020408.
Galda, Alexey, and Vinokur, Valerii M. Thu . "Parity-time symmetry breaking in magnetic systems". United States. doi:10.1103/PhysRevB.94.020408. https://www.osti.gov/servlets/purl/1356846.
@article{osti_1356846,
title = {Parity-time symmetry breaking in magnetic systems},
author = {Galda, Alexey and Vinokur, Valerii M.},
abstractNote = {The understanding of out-of-equilibrium physics, especially dynamic instabilities and dynamic phase transitions, is one of the major challenges of contemporary science, spanning the broadest wealth of research areas that range from quantum optics to living organisms. By focusing on nonequilibrium dynamics of an open dissipative spin system, we introduce a non-Hermitian Hamiltonian approach, in which non-Hermiticity reflects dissipation and deviation from equilibrium. The imaginary part of the proposed spin Hamiltonian describes the effects of Gilbert damping and applied Slonczewski spin-transfer torque. In the classical limit, our approach reproduces Landau-Lifshitz-Gilbert-Slonczewski dynamics of a large macrospin. Here, we reveal the spin-transfer torque-driven parity-time symmetry-breaking phase transition corresponding to a transition from precessional to exponentially damped spin dynamics. Micromagnetic simulations for nanoscale ferromagnetic disks demonstrate the predicted effect. These findings can pave the way to a general quantitative description of out-of-equilibrium phase transitions driven by spontaneous parity-time symmetry breaking.},
doi = {10.1103/PhysRevB.94.020408},
journal = {Physical Review B},
issn = {2469-9950},
number = 2,
volume = 94,
place = {United States},
year = {2016},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 5 works
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