# ReQWIRE: Reasoning about Reversible Quantum Circuits

## TL;DR

This paper introduces ReQWIRE, a framework for verifying that ancilla qubits in quantum circuits are correctly returned to their initial state before being discarded, enhancing correctness and enabling verified compilation.

## Contribution

It provides novel methods for verifying ancillae disposal in quantum circuits and implements a verified compiler from classical functions to quantum oracles.

## Key findings

- Developed verification techniques for ancillae in quantum circuits
- Implemented a verified compiler for classical to quantum functions
- Enhanced correctness assurance in quantum circuit programming

## Abstract

Common quantum algorithms make heavy use of ancillae: scratch qubits that are initialized at some state and later returned to that state and discarded. Existing quantum circuit languages let programmers assert that a qubit has been returned to the |0> state before it is discarded, allowing for a range of optimizations. However, existing languages do not provide the tools to verify these assertions, introducing a potential source of errors. In this paper we present methods for verifying that ancillae are discarded in the desired state, and use these methods to implement a verified compiler from classical functions to quantum oracles.