I'm not able to find any sources. Can you point me to some?
I found this interesting article that talks about creating a Fredkin quantum gate (controlled SWAP) : https://advances.sciencemag.org/content/2/3/e1501531
I hope this can help you in your search.
This playlist by QuTech Academy on the 'building blocks' of a quantum computer might offer some nice insights.
Video $10$ & $11$ introduce spin qubits, with the second video specifically on the operations on spin qubits.
Video $12$ & $13$ introduce NV centre qubits, with again the second video specifically on the operations on spin qubits.
Video $20$ through $25$ introduce the concepts behind a majorana-based topological quantum computer, but so far there's little 'physical' about that (unfortunately)
Notable omissions include (as QuTech doesn't work on these technologies):
- Trapped ion systems. Check for instance this video by MIT Opencourseware for the basics.
- Photon-based systems, most notably the linear KLM model. Check the (wiki)link for the introduction on how the gates are implemented (hint: beam splitters and mirrors).
Of course there's also adiabatic-style quantum computers, but there you don't perform 'gates', you just tune the coupling between qubit neighbour pairs.
You can find some information about gates implementation here in this article:
Although the proposed setup is rather experimental, it may give you some ideas how to implement gates on computers with superconducting qubits.