Lecture 7 | New Revolutions in Particle Physics: Basic Concepts

(November 13, 2009) Leonard Susskind discusses the theory and mathematics of angular momentum.

Leonard Susskind, Felix Bloch Professor of Physics, received a PhD from Cornell University and has taught at Stanford since 1979. He has won both the Pregel Award from the New York Academy of Science and the J.J. Sakurai Prize in theoretical particle physics. He is also a member of the National Academy of Sciences.

Stanford University:
http://www.stanford.edu/

Stanford Continuing Studies Program
http://csp.stanford.edu/

Category:

Education

Tags:

• classical quantum physics
• science
• biology
• engineering
• abstract math
• formula
• angular momentum
• elementary particles
• spin
• rotation
• kinetic energy
• propulsion
• atom
• vector
• velocity
• speed
• direction
• moment of inertia
• particle
• crossproduct
• simu

[piraders]

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[csmcmillion]

0:24:55 - The anus and bnus of a system???

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[alhobbel]

@technopagan724

Two electrons with opposite spin do not make a boson, but a superposition of two electrons,total spin 0. From a reasonable distance, this can be approximated by a single particle with spin 0, i.e. a boson: the unc. princ.: ΔxΔv = hbar/2m so if the mass is very large, then it's a good approximation (pi meson) if you don't localize the particle so that the speed of its parts takes it far of the localization. Electrons around the atom OTOH do see the separate parts.

[grunder20]

Contemplating the relativity of Physics and Chemistry, I would personally prefer

Physics.

[technopagan724]

If a system of two electrons makes a boson, then how come, even though two individual electrons of the same spin cannot inhabit the same orbital, why couldn't multiple coupled systems of two electrons (a singlet) inhabit the same orbital. Electron singlets would be spin 0 (+1/2 - 1/2). Therefore, should they not be able to behave as bosons and coexist in the same orbital?

[technopagan724]

...for a solid object, it would be the integral of the angular momentum of the individual differential mass elements over the object. Quantum particles, however, have a spin angular momentum due to the "intrinsic spin" of the particle. It's a quantity that has no equivalent conceptualization in classical physics. Whereas the spin angular momentum for a classical system can be described as Iw (moment of inertia times angular velocity), this equation breaks down when talking about point particles.