Fluctuating Nature of Light-Enhanced <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>d</mml:mi></mml:math>-Wave Superconductivity: A Time-Dependent Variational Non-Gaussian Exact Diagonalization Study
Yao Wang, Tao Shi, Cheng-Chien Chen
Abstract
Engineering quantum phases using light is a novel route to designing functional materials, where lightinduced superconductivity is a successful example. Although this phenomenon has been realized experimentally, especially for the high-T c cuprates, the underlying mechanism remains mysterious. Using the recently developed variational non-Gaussian exact diagonalization method, we investigate a particular type of photoenhanced superconductivity by suppressing a competing charge order in a strongly correlated electron-electron and electron-phonon system. We find that the d-wave superconductivity pairing correlation can be enhanced by a pulsed laser, consistent with recent experiments based on gap characterizations. However, we also find that the pairing correlation length is heavily suppressed by the pump pulse, indicating that light-enhanced superconductivity may be of fluctuating nature. Our findings also imply a general behavior of nonequilibrium states with competing orders, beyond the description of a mean-field framework.