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. 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. 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. Our findings can pave the way to a general quantitative description of out-of-equilibrium phase transitions driven by spontaneous parity-time symmetry breaking.

8 pages, 5 figures

References in corpus (8)

• Visualization of Branch Points in PT-Symmetric Waveguides
• Unidirectional Nonlinear PT-symmetric Optical Structures
• Physical realization of $\mathcal{P}\mathcal{T}$-symmetric potential scattering in a planar slab waveguide
• Mean-field dynamics of a non-Hermitian Bose-Hubbard dimer
• Bifurcation diagram and pattern formation in superconducting wires with electric currents
• PT-symmetric quantum mechanics
• Jarzynski equality in $\mathcal{P}\mathcal{T}$-symmetric quantum mechanics
• The resistive state in a superconducting wire: Bifurcation from the normal state

Cited by in corpus (32)

• Non-reciprocal phase transitions
• Non-Hermitian band topology and skin modes in active elastic media
• Experimental realization of Floquet PT-symmetric systems
• Exceptional magnetic sensitivity of PT-symmetric cavity magnon polaritons
• Perspective on Metallic Antiferromagnets
• Perspective: non-Hermitian physics in magnetic systems
• Bell-state generation for spin qubits via dissipative coupling
• Antiferromagnetism emerging in a ferromagnet with gain
• Relativistic theory of spin relaxation mechanisms in the Landau-Lifshitz-Gilbert equation of spin dynamics
• Steering magnonic dynamics and permeability at exceptional points in a parity-time symmetric waveguide
• Non-Hermitian bidirectional robust transport
• Non-Hermitian skin effect in magnetic systems
• Exceptional points in dissipatively coupled spin dynamics
• Realization and application of parity-time-symmetric oscillators in quantum regime
• Self-hybridization and tunable magnon-magnon coupling in van der Waals synthetic magnets
• Parity-time symmetry breaking in spin chains
• Nonreciprocal surface magnetoelastic dynamics
• Exceptional points as signatures of dynamical magnetic phase transitions
• Gain-Loss Coupled Systems
• Linear dynamics of classical spin as Möbius transformation
• Parameter estimation and quantum entanglement in PT symmetrical cavity magnonics system
• Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points
• On the K-theoretic classification of dynamically stable systems
• Non-Hermitian dynamics of a two-spin system with PT symmetry
• Stable solitons in a nearly PT-symmetric ferromagnet with spin-transfer torque
• Self-organization in the one-dimensional Landau-Lifshitz-Gilbert-Slonczewski equation with non-uniform anisotropy fields
• Influence of field-like torque in synchronization of spin torque oscillators
• Manipulating Quantum Spins by a Spin-Polarized Current: An Approach Based Upon PT-Symmetric Quantum Mechanics
• Negative Gilbert damping in cavity optomagnonics
• Spin-transfer torque driven localized spin excitations in the presence of field-like torque
• Semiclassical analysis of spin dynamics in the non-Hermitian Hubbard model
• Pursuing complex optical energy through Exceptional Points of Degeneracy (EPDs)