Fig. 4.
Spectra at different temperatures around Tc, calculated from DMFT for the dimer Hubbard model. Spectra calculated with parameters t⊥ = 0.2, U = 3.1 (a–c) and t⊥ = 0.5, U = 2.405 (d–f) as a function of energy normalized to the half-bandwidth D. The temperatures (normalized to Tc) of each curve for small t⊥/U (a–c) are shown to the left of panel (a). The temperatures used for large t⊥/U (d–f) are shown to the left of panel (d). The local density of states (LDOS) at different temperatures as a function of energy is shown for small t⊥/U (a) and large t⊥/U (d). The black line is the LDOS at T = 0. The sharp peak in the T = 0 LDOS in (d) is due to the formation of an intra-dimer singlet at very low temperatures (see text for details). The real part of the optical conductivity at different temperatures is shown for small t⊥/U (b) and large t⊥/U (e). All conductivities are normalized to the DC conductivity at the highest temperature shown (i.e., the DC conductivity of the metallic state). The calculated near-field signal at different temperatures as a function of frequency is shown for small t⊥/U (c) and large t⊥/U (f). The vertical gray lines in all figures indicate the THz (dashed) and MIR (dotted) frequencies used for calculating histograms in Fig. 5