# mrmustard.physics¶

The physics module contains high-level functions for performing calculations on quantum objects. It allows for objects with different representations to be used seamlessly in the same calculation, e.g., fidelity(A, B) works whether A and B are in the Fock or Gaussian representation or a mix of both.

All the functions are automatically differentiated and can be used in conjunction with an optimization routine.

## Functions¶

 fidelity(A, B) Calculates the fidelity between two quantum states. Calculates the norm of a quantum state. Returns the normalized state. overlap(A, B) Calculates the overlap between two quantum states. Calculates the relative entropy between two quantum states. trace_distance(A, B) Calculates the trace distance between two quantum states. Calculates the Von Neumann entropy of a quantum state.

## Variables¶

 settings Settings class.