Stochastic thermodynamics of macrospins with fluctuating amplitude and direction

Abstract

We consider stochastic energy balance and entropy production (EP) in a generalized Langevin dynamics of macrospins, allowing for both amplitude and direction fluctuations, under external magnetic field. EP is calculated using Fokker-Planck equation, distinguishing between reversible and irreversible parts of probability currents. The system entropy increases due to irreversible non-equilibrium processes, and reduces as heat dissipates to surrounding environment. Using path probability distributions of time-forward trajectories and conjugate trajectories under time reversal, we obtain fluctuation theorems (FT) for total stochastic EP. We show that the choice of conjugate trajectories is crucial in obtaining entropy like quantities that obey FTs.

7 pages, no figure; version accepted for publication in Phys. Rev. E

References in corpus (7)

• A fluidized granular medium as an instance of the Fluctuation Theorem
• Distribution of Entropy Production for a Colloidal Particle in a Nonequilibrium Steady State
• Single Particle Stochastic Heat Engine
• Fluctuation relations for a driven Brownian particle
• Role of External Flow and Frame Invariance in Stochastic Thermodynamics
• Fluctuation Theorem for a Small Engine and Magnetization Switching by Spin Torque
• Feedback control of noise in spin valves by the spin-transfer torque

Cited by in corpus (6)

• The Theory of Spin Noise Spectroscopy: A Review
• Entropy production by active particles: Coupling of odd and even functions of velocity
• Macrospin in external magnetic field: Entropy production and fluctuation theorems
• Drift induced by dissipation
• Ultrafast Entropy Production in Non-Equilibrium Magnets
• Rotational diffusion under torque: Microscopic reversibility and excess entropy