Make a matrix representation of a singular quadrature

operator in the Fock space.

Since the bosonic operators lie in an infinite Fock space, a truncation value needs to be provide so that a sparse matrix of finite size can be returned.

n_modes (int): Number of modes in the system Hilbert space. mode (int): The mode the ladder operator targets. quadrature (str): 'q' for the canonical position operator, 'p' for the canonical moment]um operator. hbar (float): the value of hbar to use in the definition of the canonical commutation relation [q_i, pj] = \delta{ij} i hbar. trunc (int): The size at which the Fock space should be truncated when returning the matrix representing the ladder operator.

The corresponding trunc x trunc Scipy sparse matrix.