Calabi Yau manifolds are kahlerKähler manifolds with vanishing first chernChern class. According to the conjecture of E. Calabi , for a kahlerKähler manifold M , if $c_1 (M) = 0 $ , then M would admit a Ricci-flat kahlerKähler metric . Explicitly, $Ric(g) = \sqrt(-1)\partial\bar{\partial}log(det(g))=0 $$Ric(g) = -i\partial\bar{\partial}log(det(g))=0 $
Or , $\partial\bar{\partial}log(det(g))=0$. This means that this is a combination of holomorphic and anti-holomorohic fucntions since both holomorphic and anti-holomorphic are present multiplicatively . Then we conclude that $log(det(g))=\bar{f(x)}+f(x)$$log(det(g))=\bar{f}(x)+f(x)$
$det(g) = \bar{\omega}(x)\omega(x)$ where the kahlerKähler metric is given by $g=i\partial\bar{\partial}K$ , $K = Kahler -potential$$K$ is the Kähler potential.
Now a Schwarz type topological quantum field theory satisfies the condition that the correlation function of the observables of the theory must be independent of the metric which encodes the geometry of background manifold of the theory i.e. $\frac{\delta}{\delta g^{\mu\nu}}\langle O_{1}....O_{\alpha}\rangle = \frac{\int_{}^{}[D\phi]O_1....O_\alpha e^{-iS[\phi]}}{\int_{}^{}[D\phi]e^{-iS}} = 0 $
If the metric is Hermitian , then its called a Hermitian quantum field theory . Now if we a consider that the metric is KahlerKähler , what additional conditions should we impose on the theory so that the backgoundambient manifold of the theory is Calabi Yau -Yau?
The explicit form of the metric ofmetric of Calabi Yau-Yau space is still unknown , is that a big restriction against defining such a theory ?