Constructing the off-diagonal part of active-neutrino mass matrix from   annihilation and creation matrices in neutrino-generation space
  The off-diagonal part of the active-neutrino mass matrix is constructed from two $3\times 3$ matrices playing the role of annihilation and creation matrices acting in the neutrino-generation space of $\nu_e, \nu_\mu, \nu_\tau$. The construction leads to a new relation, $M_{\mu \tau} = 4\sqrt{3} M_{e \mu} $, which predicts in the case of tribimaximal neutrino mixing that $m_3 - m_1 = \eta (m_2 - m_1)$ with $\eta = 5.28547$. Then, the maximal possible value of ${\Delta m^2_{32}}/{\Delta m^2_{21}}$ is equal to $\eta^2 -1 = 26.9362$ and gives $m_1 = 0$. With the experimental estimate ${\Delta m^2_{21}}\sim 8.0\times 10^{-5} {\rm eV}^2$, this maximal value, if realized, predicts $\Delta m^2_{32} \sim 2.2\times 10^{-3} {\rm eV}^2$, near to the popular experimental estimation $\Delta m^2_{32} \sim 2.4\times 10^{-3} {\rm eV}^2$. 
Wojciech Krolikowski