Study of hole pair condensation based on the SU(2) slave-boson approach to the t–J Hamiltonian

We present a phase diagram of high Tc cuprates involving the holon pair condensation based on the SU(2) slave-boson approach to the t–J Hamiltonian. Owing to the proper account of low-energy phase fluctuations by the SU(2) theory, we find that the predicted holon pairing temperature (the superconducting transition temperature) is in better agreement with experiments, compared to the U(1) mean field theory.