1. S

    Spin and Magnet

    Suppose in a magnetic field which is in the z-direction we send a magnet with its N-pole directed in the x-direction. We know the magnet would rotate and become in line with the magnetic field. However, if we send a pure spin state |S_x,+> it can depart in the two opposite directions +z and -z...
  2. K

    Does a photon spin?

    Does a photon have zero spin? around any axis? If it has zero spin are we 100% sure or is that uncertainty governed by Heisenbergs's uncertainty principle?
  3. M

    Can some body explain how the spin on the ball is accelarated

    Hi , I am not very good at physics , But it would be appriciated if some body explain how and why the spin (revs) on the ball is getting faster (accelarated) between the ball leaves the hand and pitched to the ground in the video from 1:18 to 1:30 https://www.youtube.com/watch?v=sFwhAsoax7w...
  4. C

    Entanglement, Measurement and spin

    Hello, Im new to the concept of quantum mechanics and after watching this video https://www.youtube.com/watch?v=ZuvK-od647c it explained to me entanglement, measurement and spins in simple ways so Can someone explain to me(or provide a source to explain in the same simple way) what is the...
  5. J

    Spin Foam Model

    I find it "spooky" that speed relativity and gravity relativity works for SR and GR. QFT is awesome in its own right but completely incapable of defining gravity even with the Higgs as it was initially described as the particle responsible for particles having mass, not as a "carrier" of the...
  6. K

    What made electrons spin?

    Spin implies angular momentum which implies torque existed at some point. However the electron appears to be a perfect sphere. http://phys.org/news/2011-05-electron-surprisingly-scientists-year.html How can torque be applied to a sphere? Your thoughts?
  7. E

    Parity, Spin and Decays

    Hi, I'm getting really confused by addition of spin and angular momenta, particularly when it applies to decays. I'm working on this problem at the moment - I think if I get this I could do the rest. "A particle X is observed to undergo the decays X -> (rho+) + (pi-) and X -> K + K, where...
  8. J

    Temperature depence of the spin flip scattering length?

    Hey Im working with Spin valves at the moment. And im wondering if magnetoresistiance can be measured at room temperature? It should be possible, if the spin flip scattering length is´nt too small. Does anyone know the temperature depence of the spin flip scattering length
  9. S

    can a hydrogen atom have an electron spin number in the 2p energy level?

    can someone please also give me more information on the fourth quantum number? I'm failing to understand wikipedia's description
  10. W

    Spin of the Earth

    My roommate and I have been arguing about this and I need help from someone who can explain it. If it were possible, and you could drive the whole way around the the world. Would the spin of the earth effect your drive time. Basically depending on which way you drove no matter how small...
  11. S

    Normalization of particle with spin 1/2

    Basically, I need to show this: \int d^3\vec{r} |{\psi_+(\vec{r})}|^2+\int d^3\vec{r} |{\psi_-(\vec{r})}|^2=1 I was given the following hints: <\vec{r}|\vec{r'}>=\delta(\vec{r}-\vec{r'}) <m_s|m_s'>=\delta_{m_sm_s'} \Rightarrow...