Photon Spin

Did you know light polarization (the thing that makes you Oakleys amazing) is actually due to a quantum mechanical property known as spin? You might vaguely remember something about electron spin from high school chemistry - photon spin is the same! The only difference is photon has a spin of 1 and an electron as ha 1/2 spin. This means that you can put as many photons as you want in one place but you can only put two electrons in one place (pauli exclusion principle)

Modern Physics

Steps of Modern Physics

____________Lagrangian Mechanics

____________/__________ \

Quantum Mechanics ------- Special Relativity

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Quantum Field Theory (QFT) --- General Relativity

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_________________String Theory

What is entropy?

Entropy is a measurement of randomness.

Statistically, entropy (represented by S) is the logarithm of the number of microstates that describe a macrostate. For this specific formula to work, the probability that a system is in each state should be equal.

An example: the entropy of a binary system such as a coin or electron would be log(2) because there are two microstates: a head and a tail.

Technically,

S = k ln W

ln is the natural log and k is some constant which has units of J/K