Proximity of the Superconducting Dome and the Quantum Critical Point in the Two-Dimensional Hubbard Model

TL;DR

This paper investigates how the superconducting transition temperature relates to quantum criticality in the 2D Hubbard model, revealing enhanced $T_c$ near the quantum critical point due to changes in pairing susceptibility.

Contribution

It demonstrates that at optimal doping, the pairing susceptibility exhibits power-law behavior, leading to increased $T_c$, and proposes experimental verification of these findings.

Findings

Power-law behavior of pairing susceptibility at optimal doping

Enhanced $T_c$ near the quantum critical point

Proposal for experimental tests

Abstract

We use the dynamical cluster approximation to understand the proximity of the superconducting dome to the quantum critical point in the two-dimensional Hubbard model. In a BCS formalism, $T_c$ may be enhanced through an increase in the d-wave pairing interaction ($V_d$) or the bare pairing susceptibility ($\chi_{0d}$). At optimal doping, where $V_d$ is revealed to be featureless, we find a power-law behavior of $\chi_{0d}(\omega=0)$, replacing the BCS log, and strongly enhanced $T_c$. We suggest experiments to verify our predictions.