I currently have determined a super Hamiltonian for a non-relativistic electron in an external electromagnetic field using an appropriate Lagrangian and use of the Euler-Lagrange equations:
H=12m(→p−qc→A)2+qϕ
I then considered an electron in a purely magnetic field finding that there is an additional interaction such that
H=12m(→p+qc→A)2+g2eℏ2mC→B⋅→σ.
By setting g=2 I can analyse the Hamiltonian in N=1 supersymmetry by considering the anti-commutation relations between supercharges and the Hamiltonian:
H=2Q2i={Qi,Qi}
where [H,Qi]=0. My struggle is that this closely follows the Fred Cooper book on Supersymmetric Quantum mechanics and he achieves a supercharge as shown below
Qi=1√4m(→p+ec→A)⋅→σ.
I am lost as to how this is found by simple factorisation. I am unsure, how is this done?
Answer
If you are unsure of how to verify it, start with Q2=(p+A)iσi(p+A)jσj,
If you are wondering how they figured out Q in the first place, I imagine they were aware of the identity →V⋅→σ→V⋅→σ=V2, for an ordinary (non-operator) →V, so they just looked at the kinetic term and tried out an operator Q=(→p+→A)⋅→σ. The maybe unexpected thing is this also gives you the magnetic field term with g=2.
No comments:
Post a Comment