Optical distinguishability of MOTT insulators in time vs frequency domain
The understanding of electronic properties of materials on a short time scale is vital for the improvement of the devices on which our modern civilization relies. One phenomena help ing push the limits of ultrafast measurement is High Harmonic Generation (HHG) which has been at the forefront of attosecond physics since its discovery and is a prime tool for studying electronic dynamics. One class of materials that demonstrate HHG are Mott in sulators whose electronic properties are of great interest given their stronglycorrelated na ture. Here, we use the paradigmatic representation of Mott insulators, the halffilled Fermi Hubbard model, to investigate the potential of using HHG response to distinguish these materials. We develop an analytical argument based on the Magnus expansion approxima tion to evolution by the Schrodinger equation that indicates decreased distinguishability of Mott insulators as lattice spacing, a, and the strength of the driving field, F0, increase rel ative to the frequency, ω0. This argument is then bolstered through numerical simulations of different systems and subsequent comparison of their responses in both the time and fre quency domain. Ultimately, we demonstrate reduced resolution of Mott insulators in both domains when the dimensionless parameter g ≡ aF0/ω0 is large, though the time domain provides higher distinguishability. Conductors are exempted from these trends, becoming much more distinguishable in the frequency domain at high g.