Optical control of TMDCs valley pseudospin qubits

NMR has been the workhorse for the experimental implementation of quantum protocols, allowing exquisite control of systems up to seven qubits in size. However, there exists some experimental limitations in terms of the cross-talk, coupled evolution, instrumental errors and so on. Thanks to the current advanced pulse techniques, we can reduce these influences and extend this technique to a new stage that the experimental limits can be neglected. In this experiment, we try to use composite pulses to compensate RF field strength variations and frequency offsets.

Group members

• XU ZIZHOU
  • Matric Number: A0229645W
  • Email: zizhou_xu@u.nus.edu
• CHU WENHAO

Description

We aim to use the C-shaped electromagnet that we build, to send magnetic pulse to the solid sample, which is between the poles of the magnet. Then we will observe the reaction of the sample to see if we can control the electron spin direction within it.

Method

Fabrication of C-shaped electromagnet

C-shaped Electromagnet

1. The main components of the electromagnet we are building are non-grain oriented electrical steel, by using laser beam, we cut the C-shaped piece out of the steel plate. After that, we accumulate all the pieces that we cut, forming ... cm thick. (Note that the gap between two poles should be ... mm, as long as suitable enough to put sample in)
2. Then we use copper wiles to entwine each pole of the steel, ..., number of coils required for generating ... radio frequency pulse is according to the formula below:
   • $B=2{\mu }_{0}nI$
     • ${\mu }_0=4\pi \times 10^{-7}(\text{T}\cdot \text{m}/A)$
     • n is the number of loops per unit length of the solenoid ($n=\frac{N}{L}$, with N being the number of loops and L the length)
3. Next, connect the electromagnet we made to the power source

Experimental setup

1. Put our sample within the gap of the C-shaped electromagnet...
2. Change the input radio frequency pulse to control the spin of the electrons within sample
3. Use hall probe connected to sample to readout the result