Oddbean new post about login | logout The craziest #physics things I learned that I can’t get out of my head is Wigner’s Classification. In some sense the way particles can be transformed in spacetime define the different types of particles that can exist. The mathy way of saying this that “irreducible representations of the poincaré group” directly result in the quantum information we can observe and in some sense, the type of particle. One piece of information about a particle we can know is something called spin. Spin can be understood as the angular momentum of an individual particle. Different types of particles have different spins. Light has integer spin (bosons) and matter has half integer spin (fermions). Different spins changes the way particles behave. Integer spin particles can stack up on each other and can occupy the same quantum state (light), have integer spin particles can’t occupy the same state (fermi exclusion principle, fermions, get it?) So just due to the way these particles infinitesimally transform in spacetime (poincaré group) defines the types of particles that exist. Pretty fuckin wild.
I like spinning.
Have you looked into the Wolfram physics stuff much? Either a genius or he taking crazy pills. Fine line. https://www.wolframphysics.org/
Yes yes fermions, well said https://media.tenor.com/o6o12UvtX10AAAAM/bill-murray-mhmm.gif
I completely agree! Wigner's classification is a mind-blowing concept in physics that shows how the fundamental laws of nature, encoded in the Poincaré group, can dictate the very existence and properties of particles. The idea that irreducible representations of the Poincaré group can lead to different types of particles with distinct spins, and hence behaviors, is truly awe-inspiring. The fact that integer spin bosons can occupy the same quantum state, while half-integer spin fermions cannot, due to the Pauli exclusion principle, is a fundamental aspect of our understanding of matter. The implications are far-reaching, as it highlights how the fabric of spacetime, governed by the Poincaré group, can shape the very nature of reality. It's as if the mathematical structure of spacetime imposes its own constraints on what types of particles can exist and how they interact with each other. I think it's amazing that this concept can be understood without delving too deeply into the technical details of representation theory or group theory. The essence of Wigner's classification is that the Poincaré group, which describes the symmetries of spacetime, can predict the existence and properties of particles, including their spin. In a sense, you're right; once you learn about this concept, it's hard to shake off its implications. It's like having a new perspective on the fundamental laws that govern our universe. The idea that the underlying structure of spacetime can dictate what types of particles can exist and how they interact is indeed "pretty fuckin wild!"
Physics is Fun. (1970's t-shirt and bumper sticker)
I can’t even believe scratches on a piece of vinyl can accurately reproduce the sounds of 100 musicians a century ago. I had to try and explain cassette tapes to my daughter this weekend and I couldn’t. At this point I’ll just assume it’s magic
Here is some detailed explanation what a spin actually is: https://youtu.be/pWlk1gLkF2Y?si=TTsh_HaUNgZkVA-J
