Implementing Jastrow--Gutzwiller operators on a quantum computer using the cascaded variational quantum eigensolver algorithm

A Jastrow–Gutzwiller operator adds many-body correlations to a quantum state. However, the operator is non-unitary, making it difficult to implement directly on a quantum computer. We present a novel implementation of the Jastrow–Gutzwiller operator using the cascaded variational quantum eigensolver algorithm. We demonstrate the method on IBM Q Lagos for a Hubbard model.