Recent observations of diminishing superfluid phase stiffness in overdoped
cuprate high-temperature superconductors challenges the conventional picture of
superconductivity. Here, through analytic estimation and verified via
variational Monte Carlo calculation of an emergent Bose liquid, we point out
that Mottness of the underlying doped holes dictates a strong phase fluctuation
of the superfluid at moderate carrier density. This effect turns the expected
doping-increased phase stiffness into a dome shape, in good agreement with the
recent observation. Specifically, the effective mass divergence due to
"jamming" of the low-energy bosons reproduces the observed nonlinear relation
between phase stiffness and transition temperature. Our results suggest a new
paradigm, in which the high-temperature superconductivity in the cuprates is
dominated by physics of Bose-Einstein condensation, as opposed to
pairing-strength limited Cooper pairing.Comment: 6+3 pages, 4+1 figure