QFitter - A Quantum Fitting Framework Applied to Effective Field Theories

The use of experimental data to constrain the values of the Wilson coefficients of an Effective Field Theory (EFT) involves the minimization of a $\chi^2$ function that may contain local minima. Classical optimization algorithms can become trapped in these minima, preventing the determination of the global minimum. The quantum annealing framework has the potential to overcome this limitation and reliably find the global minimum of non-convex functions. We present QFitter, a method that uses quantum annealing to perform EFT fits. With concrete examples, we show that QFitter can be used to fit sets of at least 8 coefficients, including their quadratic contributions, using a state-of-the-art quantum annealer. An arbitrary number of observables can be included without changing the required number of qubits. We provide an example in which $\chi^2$ is non-convex, and show that QFitter is able to find the global minimum more accurately than its classical alternatives