Digital Quantum Simulation of Flat-Band and All-Bands-Flat Dynamics for Tunable Quantum Transport

TL;DR

This paper demonstrates high-fidelity digital quantum simulations of flat-band systems using tensor-network circuit compression, revealing controllable quantum transport and localization phenomena with potential applications in quantum technology.

Contribution

It introduces an advanced tensor-network-based circuit compression method for simulating flat-band systems on NISQ devices, enabling exploration of quantum transport control.

Findings

Strong localization observed in ABF lattices.

Delocalization in FB lattices demonstrated.

Controllable quantum transport achieved with hybrid structures.

Abstract

Flat-band systems offer a uniquely powerful tool for quantum control in dynamics due to their characteristic feature of having a dispersionless energy band. Simulating such highly sensitive systems on current digital quantum computers is a challenging task, due to the intrinsic limitations of the noisy intermediate-scale quantum (NISQ) devices. Here we present high-fidelity digital quantum simulations of flat-band (FB) and all-bands-flat (ABF) lattices, using an advanced tensor-network-based circuit compression method. With the compressed quantum circuits, we first explore single-particle dynamics and observe two distinct behaviours: strong localization in ABF lattices and delocalization in FB lattices. By integrating FB and ABF lattices into a one-dimensional hybrid structure, we achieve controllable quantum transport, where the ABF lattice acts as a quantum switch. Extending to two-particle dynamics, we show that transport remains controllable by tuning the hopping amplitude alone, even in the presence of interactions. These results establish flat-band engineered systems as a promising pathway for scalable control of quantum transport in emerging quantum technologies, with potential applications in qubit isolation, particle trapping, and state transfer.