Experimental observation of the 'wave particle' duality of matter provides some explanation for the exploration of theories that incorporate wave-like behavior. In 1926 Erwin Schrödinger introduced his eponymous equation which permits a probabilistic view of quantum phenomena. Mathematical operators applied to a wave function (an object that encodes all the information of the system) result in the prediction of observable properties. His initial applications considered an electron in a Coulombic potential, the harmonic oscillator, and the rigid rotor .