# Changelog

Stay up to date with the latest Boulder Opal release notes

## Boulder Opal 18.2.0

May 16, 2022

### What’s new

- We've added simpler ways to create common operations of quantum mechanics:
- The new operation number_operator creates the number operator in the Fock space.
- The operation pauli_matrix now can also create the raising and lowering matrices.

- We've added the operation ms_phases_multitone to calculate the phases produced by a Mølmer–Sørensen gate created with a multitone global beam.
- We've added the unified graph operation hermitian_part for taking the Hermitian part of any of the data types used in our graphs (Tensors, PWCs, or STFs).
- You can now pass any kind of SciPy sparse matrix format to graph operations that use sparse matrices, such as density_matrix_evolution_pwc.

## Boulder Opal 18.1.0

April 26, 2022

### What’s new

- We've added new graph operations to create Pauli operators.
- pauli_matrix creates Pauli matrices.
- pauli_kronecker_product creates products of Pauli matrices in composite systems.

## Boulder Opal 18.0.0

April 14, 2022

### Breaking changes

- We’ve removed support for Python 3.6.

### What’s new

- We’ve added support for Python 3.10.
- We’ve added new graph operations to work with quantum harmonic oscillator-like systems. You can use them to easily create states and operators in Fock spaces.
- creation_operator generate creation operators for truncated Fock spaces.
- annihilation_operator generate annihilation operators for truncated Fock spaces.
- fock_state generates a basis state in a Fock basis.
- coherent_state generates a coherent state.

- The
`cut_off_frequency`

parameter in the sinc_convolution_kernel node is now deprecated and will be removed in the future. Please use`cutoff_frequency`

instead.