- 2818 - BOSONS AND FERMIONS - are particle physics words for “electrons and photons“. Fermions and Bosons are two different types of fundamental particles that make up our world. ALL “observed” elementary particles are either fermions or bosons.
--------------- 2818 - BOSONS AND FERMIONS - are electrons and photons ?
- ALL observed elementary particles are either fermions or bosons. There are more than these familiar ones we know as electrons and photons.
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- Bosons got their name from Satyendra Nath Bose and Albert Einstein. The light photon is the most common boson. Bosons are particles that transmit interactions between particles. They are called “force carriers“. photons are force carriers.
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- The photon is the force carrier for all electromagnetic radiation. Gluons and W Z bosons are the carriers for the Strong and Weak nuclear forces. Bose and Einstein developed the mathematics for studying the behavior of bosons. The math is called the Bose-Einstein statistics.
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- Fermions got their name from Enrico Fermi and Paul Dirac. These two physicists developed the math, Fermi-Dirac statistics. Different math was required because fermions are forbidden from occupying the same energy level at the same time. This is called the Pauli Exclusion Principle.
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- Because fermions are excluded from the same energy levels, or, occupying the same state, they form the rigidity or stiffness that is the constituents of ordinary matter. Electrons are fermions and because they orbit different energy levels in the atom they form the 100 different elements in the Periodic Table.
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- Bosons, photons, can occupy the same energy level and occupy the same place in space. Two flashlight beams of photons can overlap, but you can not do that with two wooden poles. You can build a birdhouse out of fermions, but, not out of photons.
- “Spin” is the angular momentum of a particle when it is not moving. For example, the spin of an electron is what gives a permanent magnet its magnetism. All particles have either integer spin or ½ integer spin in multiples of Planck’s Constant of Action.
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The Constant of Action of one wavelength is 1.05 * 10^-34 joule-seconds. Integer spin means a phase change of 360 degrees, or one wavelength, and is equal to 1. “½ integer” spin means a phase change of 180 degrees rotation or ½ wavelength equal to -1. Different math is needed to deal with these differences.
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------------------------- Bosons can have spins of 1,2,3, etc
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------------------------- Fermions can have spins of ½, 3/2, 5/2, etc
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- Bosons and Fermions are very small particles. Think of photons and electrons. And, you have to use the math of Quantum Mechanics to deal with them. Small particles enter the realm of wave-particle duality. All particles become waves when they get to atomic sizes and it is impossible to know their position and their momentum at the same time.
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- All calculations for position and momentum become “probabilities“. Probabilities come from statistics. In 1920 Bose developed the statistics for the photons. In 1924 Einstein developed the statistics for atoms. Bose-Einstein statistics work only for bosons, particles that have integer spins and are not subject to the Pauli Exclusion Principle.
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- In 1926 Fermi and Dirac developed the statistics for fermions that have ½ integer spins and do obey the Pauli exclusion principle. Both maths deal with statistical distributions of particles over their energy level states when they are in thermal equilibrium.
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- Both the Fermi-Dirac and the Bose-Einstein statistics become the same as the Maxwell-Boltzmann statistics with dealing with particles at high temperatures and low concentrations, low densities.
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- So, the way all this math breaks out, Maxwell-Boltzman statistics are useful for studying gases. Fermi-Dirac statistics are useful for studying electrons in solids, such as semi-conductors and electronics. Bose-Einstein statistics are useful for studying light waves. Just so you see some of the math:
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------------- Ni = gi / [e^(ei - mu) / k*T + or - 1 ]
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------------- k is Boltzman’s constant = 1.38*10^-23 joule / Kelvin
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------------- T is temperature in Kelvin
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------------- mu is permeability of a vacuum = 4*pi*10^-7 Tesla * meter / Ampere
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------------- but enough of this stuff.
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- So, what does all this stuff have to do with astronomy? It is the fermions in a Neutron Star that obey the Pauli - Exclusion Principle and refuse to occupy the same state. In the way according to the Fermi-Dirac statistics the fermions create a Degeneracy Pressure that keeps the massive star form collapsing due to gravity.
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- So, we have a White Dwarf or a Neutron Star. If gravity gets too large and overcomes the calculated Degeneracy Pressure than the star collapses further creating a Black Hole. In order to understand this big stuff, you have to learn about the little stuff.
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------------------------------ There are 5 bosons: --------------------------------------
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----------- photon ---------- electromagnetic force
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---------- gluon ------------ strong nuclear force
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----------- W+ - boson ----- weak nuclear force
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------------ Z boson -------- weak nuclear force
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----------- Higgs boson --- responsible for mass, but not yet discovered.
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---------------------------------- There are 12 fermions: -----------------------------------
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---------- electron neutrino
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---------- electron
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---------- muon neutrino
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---------- muon
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---------- tau neutrino
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---------- tau
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----------- up quark
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---------- down quark
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----------- charm quark
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----------- strange quark
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------------ top quark
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------------ bottom quark
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- And now you know all about fermions and bosons. You are ready to become a particle physicist. Stay tuned there is still more to learn.
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- September 8, 2020 977 2818
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--------------------- --- September 9, 2020 --------------------------------------
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