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Spin Drag and Spin-Charge Separation in Cold Fermi Gases

Marco Polini·Giovanni Vignale
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Abstract

Low-energy spin and charge excitations of one-dimensional interacting fermions are completely decoupled and propagate with different velocities. These modes however can decay due to several possible mechanisms. In this paper we expose a new facet of spin-charge separation: not only the speeds but also the damping rates of spin and charge excitations are different. While the propagation of long-wavelength charge excitations is essentially ballistic, spin propagation is intrinsically damped and diffusive. We suggest that cold Fermi gases trapped inside a tight atomic waveguide offer the opportunity to measure the spin-drag relaxation rate that controls the broadening of a spin packet.

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Marco Polini, Giovanni Vignale. 2007-02-20. Spin Drag and Spin-Charge Separation in Cold Fermi Gases. https://doi.org/10.1103/physrevlett.98.266403

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