QuantumOpticsBase.jl provides the base functionality for QuantumOptics.jl. For the main project, see https://github.com/qojulia/QuantumOptics.jl or the website of the @qojulia organization http://qojulia.org. Specifically, QuantumOpticsBase implements basic types such as different bases, states and operators defined on these bases, and fundamental operations (such as multiplication) on these states/operators.