Speaker
Prof.
Hiroshi Suzuki
Description
An interesting possibility that the ambiguity in perturbation theory caused by the IR renormalon is cancelled by the instability associated with a semi-classical object called bion has been suggested in the context of the resurgence program of asymptotically-free quantum field theories. To reinforce this picture on the IR renormalon, the understanding of the IR renormalon in a compactified space such as $R^{D−1}\times S^1$ seems to be a basic premise. In this talk, I report our recent analysis on the IR renormalon in the gluon condensate in the $SU(N)$ QCD(adj.) on $R^3\times S^1$ with the $Z_N$ twisted boundary conditions. In the large $N$ limit within the so-called large $\beta_0$ approximation, we find that the vacuum polarization of the W-boson, which acquires the twisted momentum from the boundary conditions, gives rise to the renormalon ambiguity that is identical to that in the system in the un-compactified space, $R^4$. This situation is completely different from that in the 2D $CP^{N-1}$ model on $R^1\times S^1$ (the analyses on the latter will be presented by Dr. Takaura and Mr. Morikawa).
