  Understanding and predicting the properties of solid-state materials from
first-principles has been a great challenge for decades. Owing to the recent
advances in quantum technologies, quantum computations offer a promising way to
achieve this goal. Here, we demonstrate the first-principles calculation of a
quasiparticle band structure on actual quantum computers. This is achieved by
hybrid quantum-classical algorithms in conjunction with qubit-reduction and
error-mitigation techniques. Our demonstration will pave the way to practical
applications of quantum computers.
