Paper: arXiv 2611.03891

Authors: Renáta Rusnáková, Eugen Šlapak, Gaurav K. Pandey, Juraj Gazda

Abstract

Quantum reservoir computing (QRC) processes temporal information through quantum dynamics, but it remains unclear whether small QRC models can forecast real data competitively with classical models and whether their predictions survive the transfer from ideal simulation to noisy hardware. We address both questions for a six-qubit gate-based reservoir that forecasts next-day motor-insurance claim counts. Five reservoir candidates were selected and frozen using hardware-native interaction graphs, Trotterized Ising dynamics, memory and measurement-robustness criteria, circuit cost, and calibrated-noise screening. On 232 held-out test days, the ideal candidates reached root-mean-square errors (RMSEs) of 5.66-6.12 claims/day, compared with 5.36 for ridge regression. For four of the five, the difference from ridge was not significant under a 95% block bootstrap, and their accuracy was comparable with classical recurrent and reservoir baselines. On the 156-qubit IBM Kingston processor, we ran 63 evaluations in 21 paired rounds, comparing hardware-aware, random-native, and Qiskit optimization level 1 layouts. Hardware-aware placement gave lower RMSE than Qiskit in every round, with a maximum transfer distortion of 7.59 claims/day (11.84 for Qiskit), and avoided the severe transfer failures seen for some random layouts. Most of the hardware distortion appeared as a systematic forecast shift, which a short hardware probe on training inputs detected before the test runs. Longer replay windows raised circuit cost without a consistent gain in forecasting accuracy or hardware transfer. Small QRC models can thus reach competitive accuracy on this task, and hardware-aware layout selection makes their transfer to IBM Kingston more consistent.

Complexity vs Empirical Score

  • Math Complexity: 6.5/10
  • Empirical Rigor: 8.0/10
  • Quadrant: Holy Grail — high math complexity, high empirical rigor

Why this score: The paper demonstrates strong empirical rigor through extensive hardware testing and comparison with classical models on real-world data. Its novelty lies in the hardware-aware design for QRC in a practical financial forecasting context, addressing critical challenges in quantum computing applications.

Research Flowchart

  flowchart TD
    A[Research Goal: QRC Competitiveness & Hardware Transfer?] --> B{Methodology: 6-Qubit Gate-Based Reservoir Design};
    B --> C[Data: Next-Day Motor Insurance Claim Counts (232 Test Days)];
    C --> D{Computational Process: Candidate Selection, Ideal Sim, Hardware Runs};
    D --> E[Outcomes: RMSE Comparison (QRC vs. Classical), Hardware Transfer Distortion];
    E --> F{Key Findings: Small QRC Models Competitive; Hardware-Aware Layout Improves Transfer};