Quantum Computing Provides Exponential Regret Improvement in Episodic Reinforcement Learning
In this paper, we investigate the problem of episodic reinforcement learning with quantum oracles for state evolution. To this end, we propose an Upper Confidence Bound (UCB) based quantum algorithmic framework to facilitate learning of a finite-horizon MDP. Our quantum algorithm achieves an exponential improvement in regret as compared to the classical counterparts, achieving a regret of ๐ช(1) as compared to ๐ช(โ(K)) [๐ช(ยท) hides logarithmic terms.], K being the number of training episodes. In order to achieve this advantage, we exploit efficient quantum mean estimation technique that provides quadratic improvement in the number of i.i.d. samples needed to estimate the mean of sub-Gaussian random variables as compared to classical mean estimation. This improvement is a key to the significant regret improvement in quantum reinforcement learning. We provide proof-of-concept experiments on various RL environments that in turn demonstrate performance gains of the proposed algorithmic framework.
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