Temperature effects on high-harmonic generation in one-dimensional Mott insulators

High-harmonic generation (HHG) has recently attracted attention not only as a source of ultrashort laser pulses but also as a probe for extracting information of material from the HHG spectrum. In particular, a lot of studies on HHG are performed in strongly correlated systems, where many-body excitations and correlation effects play an essential role in their optical responses due to the coupling among multiple degrees of freedom such as charge, spin, and orbital. Since temperature affects correlations through changes in the excitation distribution, investigating the temperature dependence of HHG spectra is important for understanding the mechanisms of HHG in strongly correlated systems. We investigate the laser-induced response of a one-dimensional Mott insulator at finite temperatures using the infinite time-evolving block decimation (iTEBD) method. We have found that the response intensity decreases uniformly over the entire frequency range as the temperature increases. This result indicates that, in the temperature range considered, the characteristic energy scales of excitations are not significantly affected. We discuss the mechanism of the temperature effects on HHG spectra in detail through the subcycle analysis.