Density Operators for Quantum Module in sympy.physics.quantum

by Guru Devanla for SymPy

The goal of this project is to add an implementation of density matrix and related functionality to the sympy.physics.quantum module. This functionality should extend the quantum module to support density operators for arbitrary quantum systems and for qubit related operations. The density matrix implementation would include functionality to represent density matrices in different bases, make them work with states and tensor products of states. We will also implement a specialized density operator to deal with n-bit qubits. The density operator will also include methods to measure expectations, entropy/entanglements and also perform partial trace operations on of tensors states or just qubits. One other offshoot effect of this goal would be to implement a generic Trace expression.