Charge stiffness and long-range correlation in the optically induced $\eta$-pairing state of the one-dimensional Hubbard model

TL;DR

This paper demonstrates that optical excitation of the one-dimensional Hubbard model can induce a state with superconducting-like properties, such as non-zero charge stiffness and long-range pairing correlations, through the creation of $ta$-pairing states.

Contribution

It reveals that optical pumping can generate $ta$-pairing states with superconducting features in the Hubbard model, a novel mechanism for inducing superconductivity-like behavior.

Findings

Optical excitation induces $ta$-pairing eigenstates with non-zero charge stiffness.

The induced pairing correlation decays very slowly with system size.

Charge stiffness is directly linked to $ta$-pairing correlations.

Abstract

We show that optical excitation of the Mott insulating phase of the one-dimensional Hubbard model can create a state possessing two of the hallmarks of superconductivity: a nonvanishing charge stiffness and long-ranged pairing correlation. By employing the exact diagonalization method, we find that the superposition of the $\eta$-pairing eigenstates induced by the optical pump exhibits a nonvanishing charge stiffness and a pairing correlation that decays very slowly with system size in sharp contrast to the behavior of an ensemble of thermally excited eigenstates, which has a vanishing charge stiffness and no long-ranged pairing correlations. We show that the charge stiffness is indeed directly associated with the $\eta$-pairing correlation in the Hubbard model. Our finding demonstrates that optical pumping can actually lead to superconducting-like properties on the basis of the $\eta$-pairing states.