Quantum it describes a fundamental aspect of energy not just restricted to photons. In the attempt to bring theory into agreement with experiment, Max Planck postulated that electromagnetic energy is absorbed or emitted in discrete packets, or quanta. Quantum In physics, a quantum (plural: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a physical property may be "quantized" is referred to as "the hypothesis of quantization". This means that the magnitude of the physical property can take on only discrete values consisting of integer multiples of one quantum. For example,
European Physical Journal D European Physical Journal D The European Physical Journal D: Atomic, Molecular, Optical and Plasma Physics is an academic journal recognized by the European Physical Society, presenting new and original research results. The main areas covered are: The range of topics covered in these areas is extensive, from Molecular Interaction and Reactivity to Spectroscopy and Thermodynamics of Clusters, from Atomic Optics to Bose-Einstein Condensation to Femtochemistry. The EPJ D arose from various predecessors: "Il Nuovo Cimento (Section D)", "Journal de Physique", and "Zeitschrift für Physik D". Prior to 1998, this journal was named "Zeitschrift für Physik D: Atoms, Molecules and Clusters".