In DRUMS, the proton is modeled as a localized excitation of the coherent superfluid, influenced by the cubic magnetic substrate:
The spatial extent of \(\rho_p\) defines the effective proton size.
Proton size arises from balance of superfluid internal pressure and electromagnetic self-energy:
Equilibrium occurs when superfluid pressure confines the proton to radius \(R_p\).
The substrate lattice imposes quantization conditions, favoring specific proton radii:
Where \(a\) is the substrate lattice constant and \(\rho_0\) is the background superfluid density.
Proton size corresponds to minimum total energy:
Setting \(\partial E_{total}/\partial R_p = 0\) yields the stable proton radius.
The calculated radius matches the measured proton charge radius (~0.84–0.87 fm), derived purely from DRUMS superfluid and substrate properties without additional assumptions.
Within the DRUMS framework, proton size is fully explained as: