SAMOP 2023 – scientific programme
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QI: Fachverband Quanteninformation
QI 6: Poster I (joint session QI/Q)
QI 6.42: Poster
Monday, March 6, 2023, 16:30–19:00, Empore Lichthof
Luttinger's Theorem in the One-Dimensional tJ-model — •Annika Böhler1,2, Henning Schlömer1,2, and Fabian Grusdt1,2 — 1Ludwig-Maximilians University, Munich, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Munich, Germany
The Hubbard model in one dimension is known to exhibit spin charge separation, which has recently been observed in settings of ultracold fermions in optical lattices. Another signature of spin-charge separation in a lattice, that has not been directly observed thus far, is constituted by a change of the Fermi momentum. Luttinger's theorem relates the volume of the Fermi surface - and therefore the Fermi momentum - to the underlying particle density of the system. Here we discuss a proof of the theorem [M. Oshikawa, Phys. Rev. Lett. 84 (2000), 3370] in the presence of spin charge separation and evaluate whether it provides a tool to distinguish between qualitatively distinct spin-1/2 liquids and spinless chargon liquids via their different Fermi momenta. We show that Friedel oscillations of the density at the edge of a system can be used to directly observe the change of Fermi momentum, reflecting a qualitative change in the nature of charge carriers which we associate with an emergent U(1) symmetry corresponding to the total number of holes in the large-U limit of the Hubbard model.