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

Mrinal Kanti Giri^1,2*, Pochung Chen^1,3

¹Department of Physics, NTHU, Hsinchu, Taiwan
²School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore
³Frontier Center for Theory, Computation, and Data Science, NTHU, Hsinchu, Taiwan

* Presenter:Mrinal Kanti Giri, email:mrinalphy333@gmail.com

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. Starting from single-particle dynamics, we observe two distinct behaviours: strong localization in ABF lattices and delocalization in FB lattices. By integrating FB and ABF lattices within one-dimensional structures, we demonstrate a mechanism to regulate 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.

Keywords: quantum computation, quantum control, quantum simulation, tensor network, Flat band dynamics