Month: September 2017

How Hamiltonians vary under coordinate changes

How Hamiltonians vary under coordinate changes

TL;DR – Hamiltonians are not invariant: they change as the time component of a covector (i.e. covariant component) in phase space. In the previous post we saw how momentum varies as covariant components and that keeps the Hamiltonian equations unchanged under coordinate transformations. We have also seen, though, that under coordinate transformations that mix time …

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Relativity and the mathropologist

Relativity and the mathropologist

TL;DR – The laws of physics are the same for all observers because nature couldn’t care less what coordinate system we use. I recently met someone who had some slight misconceptions about the principle of relativity. “Is it true that time and space are relative concepts?” “That contemporary events for you may not be contemporary …

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