bitter waters

In quantum mechanics, the state of a physical system is described by the so-called wave function (or the "wavefunction").  What is the wavefunction?  The attempts by Schrödinger, who first introduced the wavefunction, and others to interpret it as a scalar potential of some physical field or as de Broglie wave (as in particle-wave dualism) were not successful.  In 1926, Max Born noticed that the square of the amplitude of the wavefunction of a particle in a given region gives the probability of finding the particle in this region of configuration space.  He suggested that the wavefunction represented not a physical reality but rather our knowledge of the quantum state of an object. The wavefunction represents our knowledge of all possible quantum-mechanical states of an object.  In other words, the quantum-mechanical state of a physical [...]