Exact results for nonlinear Drude weights in the spin-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mfrac><mml:mn>1</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math> XXZ chain

Abstract

While the linear Drude weight in quantum many-body systems has been studied extensively, its nonlinear counterparts -- called nonlinear Drude weights (NLDWs) -- remain largely unexplored. Here, the authors present the first exact results for the NLDWs of the spin-$\frac{1}{2}$ XXZ chain, a paradigmatic quantum many-body system. Their exact results based on the Bethe ansatz reveal that the NLDWs diverge with the system size in certain parameter regions. Also, the analytical expressions for the NLDWs are obtained when they converge.

Topics & Concepts