paper

Many-body effects on high-harmonic generation in Hubbard ladders

arXiv:2407.01936 · doi:10.1103/PhysRevLett.134.096504

Abstract

We show how many-body effects associated with background spin dynamics control the high-harmonic generation (HHG) in Mott insulators by analyzing the two-leg ladder Hubbard model. Spin dynamics activated by the interchain hopping drastically modifies the HHG features. When two chains are decoupled (), HHG originates from the dynamics of coherent doublon-holon pairs because of spin-charge separation. With increasing , the doublon-holon pairs lose their coherence due to their interchain hopping and resultant spin-strings. Furthermore, the HHG signal from spin-polarons -- charges dressed by spin clouds -- leads to an additional plateau in the HHG spectrum. For large , we identify unconventional HHG processes involving elementary excitations -- two polarons and one magnon. Our results demonstrate the nontrivial nature of HHG in strongly correlated systems, and its qualitative differences to conventional semiconductors.

6pages, 4 figures + 12 pages, 11 figures

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