Recently the spectrum of KK modes in the framework of one flat extra-dimensional scenario was revisited in the paper Phys. Rev. D74 (2006) 124013, (hep-th/0607246) on the basis of self-adjoint extension of the quantum mechanical operator determining the KK masses. In this Letter we note that the range of allowed boundary conditions on the KK modes is overestimated in above mentioned paper and give all allowed possibilities.
Categories: hep-th gr-qc