From high temperature supercondutivity to quantum spin liquid: progress in strong correlation physics

Understand

This review gives a rather general discussion of high temperature superconductors as an example of a strongly correlated material.

• The argument is made that in view of the many examples of unconventional superconductors discovered in the past twenty years, we should no longer be surprised that superconductivity emerges as a highly competitive ground state in systems where Coulomb repulsion plays a dominant role.
• The physics of the cuprates is discussed, emphasizing the unusual pseudogap phase in the underdoped region.
• It is argued that the resonating valence bond (RVB) picture, as formulated using gauge theory with fermionic and bosonic matter fields, gives an adequate physical understanding, even though many details are beyond the powers of current calculational tools.