In cyclic cosmology based on phantom dark energy the requirement that our universe satisfy a CBE-condition ( Comes Back Empty ) imposes a lower bound on the number N _ { cp } of causal patches which separate just prior to turnaround .
This bound depends on the dark energy equation of state w = p / \rho = -1 - \phi with \phi > 0 .
More accurate measurement of \phi will constrain N _ { cp } .
The critical density \rho _ { c } in the model has a lower bound \rho _ { c } \geq ( 10 ^ { 9 } { GeV } ) ^ { 4 } or \rho _ { c } \geq ( 10 ^ { 18 } { GeV } ) ^ { 4 } when the smallest bound state has size 10 ^ { -15 } m , or 10 ^ { -35 } m , respectively .