Hubbard–Stratonovich transformation

The Hubbard-Stratonovich transformation is a mathematical technique commonly used in theoretical physics, particularly in the fields of many-body physics and quantum field theory. It is used to simplify the analysis of interacting systems by transforming products of exponentials into more manageable forms involving auxiliary fields. ### Context In statistical mechanics and quantum field theory, one often encounters partition functions or path integrals involving quadratic forms, particularly in the context of fermionic or bosonic systems.