Steady off-diagonal long-range order state in a half-filled dimerized Hubbard chain induced by a resonant pulsed field

TL;DR

This paper demonstrates that a resonant pulsed field can induce a steady superconducting state with off-diagonal long-range order in a dimerized Hubbard chain, revealing a new non-equilibrium pathway to exotic quantum states.

Contribution

It introduces a novel mechanism where resonant external fields induce superconductivity via η-pairing in a Mott insulator, absent in the ground state.

Findings

Resonant pulsed fields generate a charge density wave state from a valence bond solid.

The induced superconducting state exhibits off-diagonal long-range order.

The non-equilibrium steady state is characterized by η-pairing and suppressed decay of excitations.

Abstract

We show that a resonant pulsed field can induce a steady superconducting state even in the deep Mott insulating phase of the dimerized Hubbard model. The superconductivity found here in the non-equilibrium steady state is due to the $\eta $-pairing mechanism, characterized by the existence of the off-diagonal long-range order (ODLRO), and is absent in the ground-state phase diagram. The key of the scheme lies in the generation of the field-induced charge density wave (CDW) state that is from the valence bond solid. The dynamics of this state resides in the highly-excited subspace of dimerized Hubbard model and is dominated by a $\eta $-spin ferromagnetic model. The decay of such long-living excitation is suppressed because of energy conservation. We also develop a dynamical method to detect the ODLRO of the non-equilibrium steady state. Our finding demonstrates that the non-equilibrium many-body dynamics induced by the interplay between the resonant external field and electron-electron interaction is an alternative pathway to access a new exotic quantum state, and also provides an alternative mechanism for enhancing superconductivity.