A quantum state is a mathematical description of the properties and behaviour of a quantum system, such as an atom, a photon, or an electron. A quantum state can be represented by a vector, a matrix, or a wave function, depending on the context and the type of system. A quantum state can change over time according to the laws of quantum mechanics, such as the Schrödinger equation or the Heisenberg uncertainty principle. A quantum state can also be measured by an observer, which may result in a collapse of the state to one of its possible outcomes.
