After studying the BCS theory of superconductivity, I do not understand this quote from my notes:

"The phase of the BCS wavefunction is well defined."

I do not see this "phase" from the coherent state form of the BCS ground state. What is it?


It just means that in the BCS ground state, all the electrons form bosonic pair states that condense in a single wavefunction, which hase a phase $\Phi_0$. In this case you can say that all the electrons "share" the same phase $\Phi_0$.

This is not the case in a general metallic state where electrons are much less correlated : their relative phases are random. In this case you say that the "global phase" is not well-defined.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.