Automated gadget discovery in the quantum domain

Abstract

In recent years, reinforcement learning (RL) has become increasingly successful in its application to the quantum domain and the process of scientific discovery in general. However, while RL algorithms learn to solve increasingly complex problems, interpreting the solutions they provide becomes ever more challenging. In this work, we gain insights into an RL agent’s learned behavior through a post-hoc analysis based on sequence mining and clustering. Specifically, frequent and compact subroutines, used by the agent to solve a given task, are distilled as gadgets and then grouped by various metrics. This process of gadget discovery develops in three stages: First, we use an RL agent to generate data, then, we employ a mining algorithm to extract gadgets and finally, the obtained gadgets are grouped by a density-based clustering algorithm. We demonstrate our method by applying it to two quantum-inspired RL environments. First, we consider simulated quantum optics experiments for the design of high-dimensional multipartite entangled states where the algorithm finds gadgets that correspond to modern interferometer setups. Second, we consider a circuit-based quantum computing environment where the algorithm discovers various gadgets for quantum information processing, such as quantum teleportation. This approach for analyzing the policy of a learned agent is agent and environment agnostic and can yield interesting insights into any agent’s policy.

A machine learning ride in the physics theme park: from quantum to biophysics

“…For instance, state preparation, a recurrent task in quantum computing, can be naturally framed as an RL problem [22,149,177,178]. Even more, ML algorithms contribute to the design of novel quantum algorithms and subroutines [179,180], as well as the reduction of the total number of gates in quantum circuits [181], which is critical for NISQ computers. However, many of these applications rely on quantum circuit simulators, such as those provided by quantum computing libraries like PennyLane [182] or Qiskit [183].…”