April 14 has been designated World Quantum Day in honour of Planck’s Constant which can be rounded to h~ 4.14×10−15 eV·s (and some folks write April 14 as 4/14*). Planck’s constant comes up a lot in quantum mechanics; for instance a photon’s energy is h times its frequency). So I thought I would share Feynman Bauhaus.
🧵1/n
Interesting fact of the day: Since a photon is its own anti-particle both matter and antimatter emit the exact same kind of light. They can still annihilate each other, they are just so weakly interacting such annihilation has never been experimentally observed, and we dont expect it ever will be, at least not anytime soon.
#PhysicsFactlet
A quantum simple pendulum.
The pendulum position is spread out, with opacity here being proportional to the probability that the pendulum is at that position at a given time. The average position of the quantum dynamics is the same as the classical pendulum dynamics (Ehrenfest theorem).
Technicalities: I used the Crank-Nicholson method to evolve the system in time. This is a 1D problem, and the only variable I considered was the angle, with the initial state being a Gaussian.
@j_bertolotti By the way, this is a fun example, thanks for sharing! Especially as it behaves differently to a harmonic oscillator. I don't have Mathematica though, so have had to try to reproduce your code using Python.