A Programming Language Characterizing Quantum Polynomial Time

Abstract

AbstractWe introduce a first-order quantum programming language, named foq, whose terminating programs are reversible. We restrict foq to a strict and tractable subset, named pfoq, of terminating programs with bounded width, that provides a first programming language-based characterization of the quantum complexity class fbqp. We finally present a tractable semantics-preserving algorithm compiling a pfoq program to a quantum circuit of size polynomial in the number of input qubits.