band, conduction: (Context: condensed matter physics) The conduction band is the energy band which contains higher-valued energy levels. Electrons in the conduction band are loosely bound to the atoms and can generally be thought of as bound to the material rather than to an atom.

band, energy: (Context: condensed matter physics) Electrons orbit the nucleus of an atom in specific orbits determined by the quantization of their angular momentum. Each specific orbit has an associated energy. Since the orbits are discrete, the available energies are discrete. When atoms are brought together to form a material, the available energy levels adjust to accommodate the neighboring atoms. The energy levels tend to adjust into separated groups of energy levels called "energy bands." This is not inherently a spacial separation; rather it is a difference in the energy values which are available to the electrons. In fact, the electron can jump between bands and does so by gaining or losing energy. The jump is in energy-space, not in real-space. Although this jump does allow the electron to move through a different region of real-space, it is the change in energy which is the jump, not the motion in real-space. In this case, the electrons are said to be jumping across the energy gap. (See also conduction band and valence band)

band, valence: (Context: condensed matter physics) The valence band is the energy band which contains lower-valued energy levels. Electrons in the valence band are tightly bound to the atoms.

baryon: These particles are not fundamental. These are made up of quarks. Baryons are a sub-category of hadrons; that is to say, all baryons are hadrons, but not all hadrons are baryons. A baryon is made up of three constituent quarks. These may or may not be the same flavor. The colors of the three quarks must combine to leave the hadron uncharged with respect to the strong interaction. It could still be electrically or otherwise charged.

basis:

black body radiation: Objects which absorb all colors except green, which is reflected, look green. This is also true of blue (or whatever color) objects. Objects which can absorb all colors, thus appear black. Hence, a "black body" is one which absorbs all frequencies of light. Furthermore, objects which are heated will glow. The color of the glow will correspond to the temperature of the object - red is warm, yellow is hot, white is very hot, blue is extremely hot; the range goes well past the visible frequencies of light. In fact, every object has some ambiant temperature and therefore glows. (People glow in the infrared, hence the usefulness of IR gogles for night-vision.) Black Body radiation is this correspondance between the color of the glow and the temperature of the object. The use of a black body as described above idealizes the situation, removing complications which can arise if the object cannot absorb ambient light. For example, visible light does not heat a window but UV light can (because glass absorbs UV but not visible light). This effect was one of the clues that classical physics was incomplete, heralding the birth of quantum mechanics. It was first mathematically modeled by Planck with the claim that the energy in the absorbed light was quantized. (For more information, see the off-site explanation)

boson: Particles which have integral spin angular momentum are shown to behave differently than particles with half-integral spin angular momentum. Statistical mechanics can be used to describe the particles. The statistical rules which express how bosons interact are called Bose-Einstein statistics. The fundamental bosons which are found in nature are gauge bosons.

boson, gauge: These bosons mediate the fundamental forces.