  We use the effective potential method to study the $\mathcal{PT}$-symmetry
breaking of the non-Hermitian $i\phi^{3}$ field theory in $6-\epsilon$
space-time dimensions. The critical exponents so obtained coincide with the
exact values listed in the literature. We showed that at the point of
$\mathcal{PT}$-symmetry breaking, the vacuum-vacuum amplitude is certainly zero
and the fugacity is one which mimics a Yang-Lee edge singularity in magnetic
systems. What makes this work interesting is that it takes into account
problems which are always overlooked in the literature for the Yang-Lee model
like stability, unitarity and generation of Stokes wedges at space-time
dimensions for which divergences occur in the theory . Besides, here we make
direct calculation of critical exponents from the dependance of the order
parameter on external magnetic field not from the density of zeros of the
partition function.
