Variational Quantum Circuit-Based Reinforcement Learning for Dynamic Portfolio Optimization
Vincent Gurgul, Ying Chen, Stefan Lessmann
TL;DR
This work investigates dynamic portfolio optimization with quantum reinforcement learning by deploying a fully quantum RL framework based on Variational Quantum Circuits. It encodes market data via an extended amplitude map, uses PQCs for both the actor and critic, and derives portfolio weights from Pauli-Z readouts with gradient updates via the parameter-shift rule. Empirical results on real-world data show that QRL models with only 30–60 trainable parameters can match or exceed the performance of classical Deep RL models that require orders of magnitude more parameters, although end-to-end latency is currently dominated by cloud infrastructure. The study highlights a compelling potential for QRL in high-dimensional, non-stationary finance, while acknowledging that practical deployment awaits reductions in quantum hardware access overheads; the work also provides open-source code for reproducibility.
Abstract
This paper presents a Quantum Reinforcement Learning (QRL) solution to the dynamic portfolio optimization problem based on Variational Quantum Circuits. The implemented QRL approaches are quantum analogues of the classical neural-network-based Deep Deterministic Policy Gradient and Deep Q-Network algorithms. Through an empirical evaluation on real-world financial data, we show that our quantum agents achieve risk-adjusted performance comparable to, and in some cases exceeding, that of classical Deep RL models with several orders of magnitude more parameters. However, while quantum circuit execution is inherently fast at the hardware level, practical deployment on cloud-based quantum systems introduces substantial latency, making end-to-end runtime currently dominated by infrastructural overhead and limiting practical applicability. Taken together, our results suggest that QRL is theoretically competitive with state-of-the-art classical reinforcement learning and may become practically advantageous as deployment overheads diminish. This positions QRL as a promising paradigm for dynamic decision-making in complex, high-dimensional, and non-stationary environments such as financial markets. The complete codebase is released as open source at: https://github.com/VincentGurgul/qrl-dpo-public
