A linear response framework for simulating bosonic and fermionic correlation functions illustrated on quantum computers

Understand

Response functions are a fundamental aspect of physics; they represent the link between experimental observations and the underlying quantum many-body state.

• However, this link is often under-appreciated, as the Lehmann formalism for obtaining response functions in linear response has no direct link to experiment.
• Within the context of quantum computing, and by using a linear response framework, we restore this link by making the experiment an inextricable part of the quantum simulation.
• This method can be frequency- and momentum-selective, avoids limitations on operators that can be directly measured, and is ancilla-free.