Quantum Systems: A Mathematical Journey from Few to Many Particles

Quantum, kinetic and hydrodynamic descriptions on spin transfer torque

Xu Yang

University of California, Santa Barbara


Spin-transfer torque is an effect in which the orientation of a magnetic layer in a magnetic tunnel junction or spin valve can be modified using a spin-polarized current. In this talk we aim to discuss the inner connections of physical models at different scales for the description of spin transfer torque. Specifically, we connect the quantum to kinetic with the help of Wigner transform, and kinetic to diffusion by a specific parabolic scaling. Numerical examples will also be present to illustrate the applicability and limit of different models.