Make a matrix representation of a singular bosonic ladder operator

in the Fock space.

Since the bosonic operator lies 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. ladder_type (int): This is a nonzero integer. 0 indicates a lowering operator, 1 a raising operator. 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.