Engineering Quantum Many-Body Scars through Lattice Geometry

TL;DR

This paper demonstrates that lattice geometry alone can induce and stabilize quantum many-body scars, enabling persistent non-ergodic dynamics in engineered quantum systems.

Contribution

It shows how transforming lattice geometry into a triangle-decorated structure induces and enhances quantum many-body scars without fine-tuning initial states.

Findings

Pronounced fidelity revivals observed in the modified lattice.

Slow entanglement growth indicating non-ergodic behavior.

Overlap with weakly entangled eigenstates increases due to geometry.

Abstract

Quantum many-body scars enable persistent non-ergodic dynamics in otherwise thermalizing systems, yet their stabilization typically relies on fine-tuned initial states or engineered Hamiltonian perturbations. Here we show that lattice geometry alone can serve as a powerful and experimentally accessible control knob for inducing and enhancing scarring. By transforming a one-dimensional chain into a quasi-one-dimensional triangle-decorated lattice, we find that the fully polarized state -- normally thermalizing in the PXP model -- exhibits pronounced fidelity revivals, slow entanglement growth, and strong overlap with a tower of weakly entangled eigenstates. We trace this behavior to a geometry-induced restructuring of the constrained Hilbert space, whereby the adjacency graph decomposes into hypercube subgraphs that enforce coherent population transfer and stabilize an emergent approximate $\mathrm{su}(2)$ algebra. We propose a direct implementation in programmable arrays of tweezer-trapped Rydberg atoms, where the triangle-decorated geometry can be realized using spatial light modulators and the resulting scarring dynamics probed via time-resolved measurements of excitation density. Our results establish lattice connectivity as a design principle for engineering non-ergodic dynamics in constrained quantum systems.