Universal spin dynamics in two-dimensional Fermi gases

Abstract

Harnessing spins as information carriers has emerged as an elegant extension to the transport of electrical charges. The coherence of such spin transport in spintronic circuits is determined b. The lifetime of spin excitations and by spin diffusion. Fermionic quantum gases allo. The study of spin transport from first principles because interactions can be precisely tailored an. The dynamics is on directly observable timescales. In particular, at unitarity, spin transport is dictated by diffusion an. The spin diffusivity is expected to reach a universal, quantum-limited value of the order of the reduced Planck constant ħ divided b. The mass m. Here, we study a two-dimensional Fermi gas after a quench into a metastable, transversely polarized state. Usin. The spin-echo technique, for strong interactions, we measur. The lowest transverse spin diffusion constant so far 0.25(3) ħ/m. For weak interactions, we observe a collective transverse spin-wave mode that exhibits mode softening when approachin. The strongly interacting regime. © 2013 Macmillan Publishers Limited. All rights reserved.