Hadrons, Superconducting Vortices, and Cosmological Constant

We explore the roles of the trace anomaly in several hadron properties. We point out that the energy-equilibrium correspondence derived from the gravitational form factors (GFF) of hadrons infers an equation of state where the trace anomaly matrix element, emerging from the glue condensate in  the vacuum, gives a negative constant pressure that leads to confinement, much like the confinement mechanism for the vortices in type II superconductors where the negative pressure is due to the cost of depleting the superconducting condensate.  We also note that both the trace anomaly in the QCD energy-momentum tensor and the cosmological constant in Einstein's equation are associated with the metric term and they play similar roles.   Their difference in terms of the role the pressure plays is also discussed. Finally, we note that a lattice calculation of the trace anomaly distribution in the pion has addressed a question about the trace anomaly contribution to the pion mass and suggests that the conformal symmetry breaking and chiral symmetry breaking in QCD are intertwined in this case.