A variational quantum-classical ansatz to study quantum systems

In recent years, simulations of quantum chemical and physical systems has been successfully carried out on quantum hardware.

However, given that quantum resources are still limited in size and coherence times, these demonstrations have focused on small molecular and spin systems.

To scale up to more complex applications, it is highly desirable to introduce novel approaches that combine quantum algorithms with classical computational methods and keep quantum resources under control.

In this talk we present our recent results on the simulation of quantum systems using a variational mixed quantum-classical ansatz.

We illustrate observables evaluation and analyze the cost in terms of quantum-classical computational time.

Finally, we show applications to different types of physical systems, such as spin chains and molecular electronic structures.