Physics Note
Recommendation: 【Physics】 Physics Index
1. Celestial bodies
⑴ Alpha Centauri: 4.37 light-years from the Solar System.
2. Fluid Dynamics
⑴ Langevin dynamics: predicts molecular motion at each time step and can be run in reverse.
3. Baryon asymmetry problem
⑴ Sakharov’s condition
① baryon number violation
② C abd CP symmetry violation
③ departures from thermal equilibrium
4. Ising model
⑴ The Ising model (1920s) is a foundational physics model for ferromagnetism.
⑵ It consists of a lattice of spins (like tiny magnets) which can be in one of two states : +1 or -1.
⑶ Each spin interacts with its neighbors, tending to align to minimize overall energy.
⑷ Hopfield saw the parallels of Ising model and neurons
① neuron : spins
② synaptic weight : interaction strength
③ “My knowledge of the spin-glass lore and a little neurobiology led to the first paper in which I used the word neuron. … is the most cited paper I have ever written.” - John J. Hopfield
Input: 2024.09.23 13:57