A physicist, biologist and a chemist were going to the ocean for the first time. The physicist saw the ocean and was fascinated by the waves. He said he wanted to do some research on the fluid dynamics of the waves and walked into the ocean. Obviously he was drowned and never returned. The biologist said he wanted to do research on the flora and fauna inside the ocean and walked inside the ocean. He too, never returned. The chemist waited for a long time and afterwards, wrote the observation, “The physicist and the biologist are soluble in ocean water”.
The fields of biology and physics have long been regarded as being on nearly opposite sides of the scientific field. Biology has been revolutionized by the discoveries of natural selection, DNA and cellular chemistry. Physicists study matter in its nearly unlimited variety of condensed states from liquids to crystalline solids (class of solids that have regular or nearly regular crystalline
structures), from chemically-synthesized nanostructures ( objects that have a physical dimension smaller than 100 nanometers) to superconductors ( materials that have no resistance to the flow of electricity) , from carbon nanotubes to liquid crystals… and so on!
Microscopic observation of the trapped clouds of bosonic and fermionic atoms have led to developments and progress in these fields.
All fundamental particles in nature can be divided into one of two categories: Fermions or Bosons.
|Fermions||half-integral spin||only one per state||Examples:
electrons, protons, neutrons, quarks, neutrinos
|Bosons||integral spin||Many can occupy the same state||Examples:
photons, 4He atoms, gluons
Bosons have intrinsic angular momenta in integral units of . Many bosons can occupy a single quantum state. Any object which is comprised of an even number of fermions is a boson, while any particle which is comprised of an odd number of fermions is a fermion. Only one fermion can exist in a given quantum state. This is known as the Pauli exclusion principle.
According to Pauli’s exclusion principle: “In an atom no two electrons can have the same set of four quantum numbers.”
Pauli’s exclusion principle can also be stated as: “An orbital can not accomodate more than two electrons i.e. maximum number of electrons that an orbital can accomodate is two.”