In geometric quantization which assigns a (quantum) Hilbert space to a symplectic manifold ( for example the phase space of a system) the metaplectic correction is needed to obtain a nonzero Hilbert space when using a real polarization.

In the case of a complex polarization when geometrically quantizing the harmonic oscillator, it allows to reproduce the well-known formula

$$E_n = (1/2 + n)\hbar\omega$$

for the energy levels, with the $1/2$ coming from the metaplectic correction.

Is this just a coincidence or is it generally the case that the vacuum energy of a (geometrically quantizable) system can be obtained by applying an (appropriate) metaplectic correction?