In solid state physics, band theory is the theory of the behavior of the electrons in solids. Solid-state physics, the largest branch of condensed matter physics, is the study of rigid matter, or solids. ... Properties The electron is a subatomic particle. ... A solid is a state of matter, characterized by a definite volume and a definite shape (i. ...

Band theory is an outgrowth of the concept of energy levels. It makes the assumption that the energy levels of a solid are so numerous as to be indistinct. For macroscopic solids, this assumption is very reasonable. First, the separation between energy levels in a solid is comparable with the energy that electrons constantly exchange with phonons (atomic vibrations). Second, it is comparable with the energy uncertainty due to the Heisenberg uncertainty principle, for reasonably long intervals of time. In physics and quantum chemistry, an energy level is a quantized energy of a bound quantum mechanical state. ... A phonon is a quantized mode of vibration occurring in a rigid crystal lattice, such as the atomic lattice of a solid. ... Properties For alternative meanings see atom (disambiguation). ... See Oscillator (disambiguation) for particular types of oscillation and oscillators. ... In quantum physics, the Heisenberg uncertainty principle, sometimes called the Heisenberg indeterminacy principle, expresses a limitation on accuracy of (nearly) simultaneous measurement of observables such as the position and the momentum of a particle. ...