arXiv subjects

Satoshi Yamada

Publications and source records attributed to Satoshi Yamada.

61 records · Page 4Linked to original sources

arXiv2004

Wrapped membranes, matrix string theory and an infinite dimensional Lie algebra

We examine the algebraic structure of the matrix regularization for the wrapped membrane on $R^{10}\times S^1$ in the light-cone gauge. We give a concrete representation for the algebra and obtain the matrix string theory having the boundary conditions for the matrix variables corresponding to the wrapped membrane, which is referred to neither Seiberg and Sen's arguments nor string dualities. We also embed the configuration of the multi-wrapped membrane in matrix string theory.

hep-th↗

arXiv2003

Recovering Lorentz Invariance of DLCQ

We propose a way to recover Lorentz invariance of the perturbative S matrix in the Discrete Light-Cone Quantization (DLCQ) in the continuum limit without spoiling the trivial vacuum.

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arXiv2002

Comments on the global constraints in light-cone string and membrane theories

In the light-cone closed string and toroidal membrane theories, we associate the global constraints with gauge symmetries. In the closed string case, we show that the physical states defined by the BRS charge satisfy the level-matching condition. In the toroidal membrane case, we show that the Faddeev-Popov ghost and anti-ghost corresponding to the global constraints are essentially free even if we adopt any gauge fixing condition for the local constraint. We discuss the quantum double-dimensional reduction of the wrapped supermembrane with the global constraints.

hep-th↗

arXiv2002

On the quantum matrix string

We study the behavior of matrix string theory in the strong coupling region, where it is expected to reduce to discrete light-cone type IIA superstring. In the large $N$ limit, the reduction corresponds to the double-dimensional reduction from wrapped supermembranes on $R^{10}\times S^1$ to type IIA superstrings on $R^{10}$ in the light-cone gauge, which is shown classically, however it is not obvious quantum mechanically. We analyze the problem in matrix string theory by using the strong coupling ($1/g$) expansion. We find that the quantum corrections do not cancel out at $\mathcal{O}(1/g^2)$. Detailed calculations can be seen in Ref.\cite{UY}.

hep-th↗

arXiv2002

On the strong coupling region in quantum matrix string theory

We study the behavior of matrix string theory in the strong coupling region, where matrix strings reduce to discrete light-cone type IIA superstrings except at the usual string-interaction points. In the large N limit, this reduction corresponds to the double-dimensional reduction from wrapped supermembranes on R^{10} x S^1 to type IIA superstrings on R^{10} in the light-cone gauge. Such reductions were shown classically, while they are not obvious quantum mechanically. Recently, Sekino and Yoneya analyzed the double-dimensional reduction of the wrapped supermembrane quantum mechanically to one-loop order in the strong coupling expansion. We analyze the problem in matrix string theory by using the same expansion. At the one-loop level, the quantum corrections cancel out as was presented by them. However, at the two-loop level we find that the quantum corrections cancel out only for the leading terms in the large N.

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arXiv2001

Does DLCQ S-matrix have a covariant continuum limit?

We develop a systematic DLCQ perturbation theory and show that DLCQ S-matrix does not have a covariant continuum limit for processes with $p^+=0$ exchange. This implies that the role of the zero mode is more subtle than ever considered in DLCQ and hence must be treated with great care also in non-perturbative approach. We also make a brief comment on DLCQ in string theory.

hep-th↗

arXiv2000

On the DLCQ as a light-like limit in string theory

We study the issue of defining the discrete light-cone quantization (DLCQ) in perturbative string theory as a light-like limit. While this limit is unproblematic at the classical level, it is non-trivial at the quantum level due to the divergences by the zero-mode loops. We reconsider this problem in bosonic string theory. We construct the multi-loop scattering amplitudes in both open and closed string theories by using the method of Kikkawa, Sakita and Virasoro (KSV), and then we show that these scattering amplitudes are perfectly well-defined in this limit. We also discuss the vacuum amplitudes of the string theory. They are, however, ill-defined in the light-like limit due to the zero-mode loop divergences, and hence we want supersymmetry to cure those pathological divergences even in string theory.

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