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arXiv · 2509.21813

Low-energy photoexcitations inside the Mott gap in doped Hubbard and t-J ladders

Sumal Chandra·Kazuya Shinjo·Shigetoshi Sota·Seiji Yunoki·Takami Tohyama
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Abstract

We investigate changes in the optical conductivity of doped Mott insulators by tuning ultrashort pump pulses to target either the Drude or low-energy absorption regions. Using a hole-doped two-leg Hubbard ladder and a four-leg t-J ladders, we calculate the optical conductivity after pump by employing the time-dependent density matrix renormalization group. We find that a monocycle electric field pulse tuned to the Drude absorption reduces the Drude weight, accompanied by a slight enhancement in the mid-infrared (mid-IR) spectral weight. However, this enhancement diminishes as the pulse intensity increases. In contrast, a pump pulse tuned to the mid-IR absorption only affects the Drude weight. This behavior arises because the mid-IR absorption originates from magnetic excitations that do not couple directly to photons. These predictions can be tested experimentally by applying ultrashort low-energy pump pulses to cuprate materials.

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Sumal Chandra, Kazuya Shinjo, Shigetoshi Sota, Seiji Yunoki, Takami Tohyama. 2025-09-26. Low-energy photoexcitations inside the Mott gap in doped Hubbard and t-J ladders. https://doi.org/10.1103/pt16-43yd

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