An Effective Model of Fluctuating Stripes and Topological Deconfinement in Cuprates

The recent achievement of ultra-low temperatures in quantum simulators has expanded the accessible parameter regimes of the Fermi–Hubbard model, opening the door to previously unexplored regions of strongly correlated physics. In particular, breakthrough experiments using quantum gas microscopes now provide access to new observables that make it possible to directly tackle and probe effective theories of fluctuating stripes and gain insights into the intriguing, yet not fully understood, properties of this phase.

High-temperature superconductivity in cuprates remains one of the central open questions in condensed matter physics. Despite decades of research, the origin of superconductivity and the nature of the pseudogap phase that precedes it are still not fully understood. The cuprate phase diagram features a complex interplay between antiferromagnetism, charge and spin orders (such as stripes) and a unified theoretical picture has not been achieved yet.

In this talk, we focus on the pseudogap regime and explore a recent theoretical framework involving fluctuating, string-like domain walls embedded in a background with hidden antiferromagnetic order. In this picture, the AFM background breaks SU(2) spin symmetry, while the ends of these fluctuating strings act as topological defects. We argue that the onset of the pseudogap at temperature T* can be understood as a deconfinement transition of these topological charges.

To investigate this idea, we construct a classical effective theory at finite temperature, incorporating percolation-inspired observables (POPs) and U(1) order parameters to probe the confinement dynamics. Our results reveal deep connections between topological order, confinement phenomena, and broken symmetries in the cuprates, offering new insights into the microscopic physics underlying the pseudogap phase and its relation to high-Tc superconductivity.