arXiv subjects

Yutaka Yoshida

Publications and source records attributed to Yutaka Yoshida.

41 records · Page 3Linked to original sources

arXiv2012

Numerical studies of the ABJM theory for arbitrary N at arbitrary coupling constant

We show that the ABJM theory, which is an N=6 superconformal U(N)*U(N) Chern-Simons gauge theory, can be studied for arbitrary N at arbitrary coupling constant by applying a simple Monte Carlo method to the matrix model that can be derived from the theory by using the localization technique. This opens up the possibility of probing the quantum aspects of M-theory and testing the AdS_4/CFT_3 duality at the quantum level. Here we calculate the free energy, and confirm the N^{3/2} scaling in the M-theory limit predicted from the gravity side. We also find that our results nicely interpolate the analytical formulae proposed previously in the M-theory and type IIA regimes. Furthermore, we show that some results obtained by the Fermi gas approach can be clearly understood from the constant map contribution obtained by the genus expansion. The method can be easily generalized to the calculations of BPS operators and to other theories that reduce to matrix models.

hep-th↗

arXiv2011

Squark Contributions to Photon Structure Functions and Positivity Constraints

Photon structure functions in supersymmetric QCD are investigated in terms of the parton model where squark contributions are evaluated. We calculate the eight virtual photon structure functions by taking the discontinuity of the squark massive one-loop diagrams of the photon-photon forward amplitude. The model-independent positivity constraints derived from the Cauchy-Schwarz inequalities are satisfied by the squark parton model calculation and actually the two equality relations hold for the squark contribution. We also show that our polarized photon structure function $g_1^γ$ for the real photon leads to the vanishing 1st moment sum rule, and the constraint $|g_1^γ|\leq F_1^γ$ is satisfied by the real photon. We also discuss a squark signature in the structure function $W_{TT}^τ$.

hep-ph↗

arXiv2011

A note on statistical model for BPS D4-D2-D0 states

We construct a statistical model that reproduces the BPS partition function of D4-D2-D0 bound states on a class of toric Calabi-Yau three-folds. The Calabi-Yau three-folds we consider are obtained by adding a compact two-cycle to $A_{N-1}$-ALE $\times \mathbb{C}$. We show that in the small radii limit of the Calabi-Yau the D4-D2-D0 partition function is correctly reproduced by counting the number of triangles and parallelograms.

hep-th↗

arXiv2011

Localization of Vortex Partition Functions in $\mathcal{N}=(2,2) $ Super Yang-Mills theory

In this article, we study the localizaiton of the partition function of BPS vortices in $\mathcal{N}=(2,2)$ $U(N)$ super Yang-Mills theory with $N$-flavor on $\R^2$. The vortex partition function for $\mathcal{N}=(2,2)$ super Yang-Mills theory is obtained from the one in $\mathcal{N}=(4,4)$ super Yang-Mills theory by mass deformation. We show that the partition function can be written as $Q$-exact form and integration in the partition functions is localized to the fixed points which are related to $N$-tuple one dimensional partitions of positive integers.

hep-th↗

arXiv2009

The Virtual Photon Structure Functions and AdS/QCD Correspondence

We study the virtual photon structure functions from gauge/string duality. If the Bjorken variable x is not small, supergravity approximation becomes good in dual string theory. We calculate the virtual photon structure functions at large 't Hooft coupling in a moderate x-region and determine x-behavior of the structure functions. We also show that the Callan-Gross relation F_L=0 is satisfied to a good approximation in gravity calculation.

hep-th↗