Pseudogap phase as fluctuating pair density wave

TL;DR

This paper uses advanced tensor network methods to identify a fluctuating pair density wave state in the $t$-$J$ model, offering a potential explanation for the pseudogap phase in high-temperature cuprate superconductors.

Contribution

It introduces a novel fluctuating PDW state in the $t$-$J$ model, expanding the understanding of possible pseudogap phase candidates beyond known states.

Findings

Discovered a fluctuating PDW state with wave vector $(\,\pi,\,\pi)$

The PDW state has energy comparable or lower than the $d$-wave state

The PDW state weakly breaks $C_4$ symmetry

Abstract

The physical nature of pseudogap phase is one of the most important and intriguing problems towards understanding the key mechanism of high temperature superconductivity in cuprates. Theoretically, the square-lattice $t$-$J$ model is widely believed to be the simplest toy model that captures the essential physics of cuprate superconductors. We employ the Grassmann tensor product state approach to investigate uniform states in the underdoped ($\delta \lesssim 0.1$) region. In addition to the previously known uniform $d$-wave state, we discover a strongly fluctuating pair density wave (PDW) state with wave vector $Q = (\pi, \pi)$. This fluctuating PDW state weakly breaks the $C_4$ rotational symmetry of the square lattice and has a lower or comparable energy to the $d$-wave state (depending on doping and the $t/J$ ratio), making it a promising candidate state for describing the pseudogap phase.