Jeudi 28 février 2013
About thirty years have passed since the standard model of particle theory is
established. It is considered to describe three of the fundamental interactions
correctly, that is, the electromagnetic, weak and strong interactions, and
at present we have no experimental result that contradicts with it. On the
other hand, the gravitational interaction has a difficulty because the ordinary
quantum field theory does not work for it. In fact the quantum fluctuations of the
gravitational field become too large at short distances to construct a consistent
quantum theory. However, string theory miraculously avoids this problem. Not
only its quantum fluctuations are finite and controllable, it provides a unified
description of all the interactions and matter fields. Although string theory is
a very good candidate of the ultimate theory in this sense, there is a serious
problem. So far string theory is defined based on the perturbation theory, and
because of the lack of the complete definition we cannot find the real ground
state, that is, the vacuum. In fact we have infinitely many fake vacua in the
perturbation theory, and in order to make realistic predictions, we need a
complete formulation of string theory. Some theories are proposed as such a
formulation based on the matrix models, on which several analyses are being
made.
RECRUTEMENT ACCES DIRECT
Le département de physique
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