- #1
BillKet
- 312
- 29
Hello! This is quite technical, but any advice would be greatly appreciated (@Twigg ?). It is about this paper: https://arxiv.org/pdf/1909.02650.pdf. In principle, beside the EDM, we also have spin dependent parity violating (time-reversal conserving) effects. This is always true, as we need a nuclear spin for this method to work. The formula for these effects is usually ##H_P = W_P \ n\cdot (I\times S)##. Following the same notation as in the paper the effective hamiltonian becomes: ##H_P = W_P \xi\cdot (I\times S)_z##, assuming again that the electric field is in the z direction. By doing the math, and working in the 2 level system spanned by ##|g>## and ##|e>##, this is equivalent to ##H_P = i W_P \xi S_z##. So it is basically the same as the PT-violating effect, except for the complex factor i. Now equation (3) will have in addition: ##\frac{\Omega_P}{2}(\sin\beta\sigma_x+\cos\beta\sigma_y)##, and in (4) the term inside the sine squared becomes: ##\Omega_B+\Omega_{PT}\cos\beta+\Omega_P\sin\beta##, where ##\Omega_P \equiv \frac{1}{2}W_P\xi##. But for most (all?) systems, ##\Omega_P >>> \Omega_{PT}##, so unless ##\beta<<<1##, ##\Omega_P\sin\beta## will dominate and any EDM signal will be hidden by the P-odd, T-even signal. This seems like a non-reducible background. Am I doing something wrong in my calculations? Thank you!