Heat transfer physics Heat transfer physics Heat transfer physics describes the kinetics of energy storage, transport, and energy transformation by principal energy carriers: phonons (lattice vibration waves), electrons, fluid particles, and photons. Heat is energy stored in temperature-dependent motion of particles including electrons, atomic nuclei, individual atoms, and molecules. Heat is transferred to and from matter by the principal energy carriers. The state of energy stored within matter, or transported by the carriers, is described by a combination of classical and quantum statistical mechanics. The energy is also transformed (converted) among various carriers. The heat transfer processes (or kinetics) are governed by the
Cluster (physics) Cluster (physics) In physics, the term clusters denotes small, multiatom particles. As a rule of thumb, any particle of somewhere between 3 and 3×10 atoms is considered a cluster. Two-atom particles are sometimes considered clusters as well. A two atom particle may also be a molecule. The term can also refer to the organization of protons and neutrons within an atomic nucleus, e.g. the alpha particle (also known as "α-cluster"), consisting of two protons and two neutrons (as in a helium nucleus). Although first reports of cluster species date back already to the 1940s, cluster science emerged as a separate