Quantum mechanics is a _linear theory_ meaning that it models physical systems in terms of [linear transformations](Linear%20map.md) of [quantum systems.](Quantum%20systems.md) %%Find a way to explain this linearity. This linearity can be thought of in terms of the fact that quantum mechanics is a wave theory as well%% # Linear operators in quantum mechanics Here we list types of [linear operators](linear%20operator) in quantum mechanics. * [observables](Observable.md) * [unitary operators](Unitary%20transformations%20in%20quantum%20mechanics.md#Unitary%20operators%20in%20quantum%20mechanics) * [density operators](density%20matrix.md) .md#^bff927) #QuantumMechanics/MathematicalFoundations