Controlling quantum chaos via Parrondo strategies on noisy intermediate-scale quantum hardware
Aditi Rath, Dinesh Kumar Panda, Colin Benjamin
TL;DR
This work addresses how to observe and control quantum chaos on NISQ hardware by implementing discrete-time quantum walks on cyclic graphs and applying Parrondo's paradox to induce order from chaos. The authors develop a QFT-based diagonalization of the shift operator to realize efficient circuits for DTQW on both even (4-cycle) and odd (3-cycle) cycles and verify Parrondo sequences (AABB...) that transition chaotic walks into periodic ones. On three IBM devices, 4-cycle DTQW achieves high fidelity (>$98\%$) up to 25 steps, confirming the chaos-to-order transition in practice, while 3-cycle walks suffer from depth-related noise; dynamical decoupling improves 3-cycle fidelity to the $75$–$95\%$ range but cannot fully overcome gate-depth limitations. This study provides a practical route to harness controlled chaotic dynamics on real quantum hardware, with implications for quantum algorithms and cryptographic protocols based on quantum walks.
Abstract
Advancements in Noisy Intermediate-Scale Quantum (NISQ) computing are steadily pushing these systems toward outperforming classical supercomputers on specific, well-defined computational tasks. In this work, we explore and control quantum chaos in NISQ systems using discrete-time quantum walks (DTQW) on cyclic graphs. To efficiently implement quantum walks on NISQ hardware, we employ the quantum Fourier transform (QFT) to diagonalize the conditional shift operator, optimizing circuit depth and fidelity. We experimentally realize the transition from quantum chaos to order via DTQW dynamics on both odd and even cyclic graphs, specifically 3- and 4-cycle graphs, using the counterintuitive Parrondo's paradox strategy across three different NISQ devices. While the 4-cycle graphs exhibit high-fidelity quantum evolution, the 3-cycle implementation shows significant fidelity improvement when augmented with dynamical decoupling pulses. Our results demonstrate a practical approach to probing and harnessing controlled chaotic dynamics on real quantum hardware, laying the groundwork for future quantum algorithms and cryptographic protocols based on quantum walks.
