@@ -2039,7 +2039,7 @@ Using the algebra~\eqref{eq:ns-algebra} we compute the \ope of fermion fields as
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\qquad
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\abs{w} < \abs{z},
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\end{equation}
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where the operation $\no{\cdot}$ is the normal ordering with respect to the \SL{2}{R} vacuum defined in~\eqref{eq:NS_SL2_vacuum}.
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where the operation $\no{\cdot}$ is the normal ordering with respect to the \SL{2}{\R} vacuum defined in~\eqref{eq:NS_SL2_vacuum}.
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We then get the expression of the stress-energy tensor:
|
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\begin{equation}
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\begin{split}
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@@ -2189,7 +2189,7 @@ From the usual definition of the stress-energy tensor in terms of the Virasoro g
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\end{split}
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\end{equation}
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We already hinted to the fact that the vacua state involved are not in general \SL{2}{R} invariant.
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We already hinted to the fact that the vacua state involved are not in general \SL{2}{\R} invariant.
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In particular we can see that that the excited vacua \eexcvacket is a primary field
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\begin{equation}
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\begin{split}
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@@ -2394,7 +2394,7 @@ The last expression shows that the energy momentum tensor $\cT( z )$ is radial t
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First of all we notice that the vacuum $\Gexcvacket$ is actually $\GGexcvacket$, i.e.\ it depends only on $x_{(t)}$ and $\rE_{(t)}$.
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We can try to interpret the previous result in the light of the usual \cft approach.
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In particular we can refine the idea we discussed after~\eqref{eq:asymp_beha_Psi_on_exc_vac} that the singularity in the modes~\eqref{eq:generic-case-basis} and~\eqref{eq:generic-case-basis-conjugate} at the point $x_{(t)}$ is associated with a primary conformal operator which creates \eexcvacket with $\rE = \rE_{(t)}$.
|
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By comparison with the stress energy tensor of an excited vacuum~\eqref{eq:T_excited_vacuum}, from the second order singularity we learn that at the points $x_{(t)}$ there is an operator which creates the excited vacuum \GGexcvacket from the \SL{2}{R} vacuum \regvacuum.
|
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By comparison with the stress energy tensor of an excited vacuum~\eqref{eq:T_excited_vacuum}, from the second order singularity we learn that at the points $x_{(t)}$ there is an operator which creates the excited vacuum \GGexcvacket from the \SL{2}{\R} vacuum \regvacuum.
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Given the discussion in the previous section this is an excited spin field $\rS_{\rE_{(t)}}\qty( x_{(t)}) = e^{i \rE_{(t)} \phi( x_{(t)} )}$.
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The first order singularities in $x_{(u)} - x_{(t)}$ are then the result of the interaction between two of the previous excited spin fields.
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Using the \cft operator approach we postulate that the following identification holds
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@@ -2818,7 +2818,7 @@ Therefore we have
|
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\end{equation}
|
||||
which can be solved by
|
||||
\begin{equation}
|
||||
\ln \left\langle
|
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\left\langle
|
||||
\rR\qty[%
|
||||
\rS_{\rE_{(t)}}\qty(x_{(t)})
|
||||
\prod\limits_{\substack{u = 1 \\ u \neq t}}^N
|
||||
@@ -2828,7 +2828,7 @@ which can be solved by
|
||||
=
|
||||
\cN_0
|
||||
\qty( \qty{\rE_{(t)}} )
|
||||
\prod\limits_{\substack{t = 1}{t > u}}^N
|
||||
\prod\limits_{\substack{t = 1 \\ t > u}}^N
|
||||
\qty( x_{(u)} - x_{(t)} )^{\rE_{(u)} \rE_{(t)}}.
|
||||
\end{equation}
|
||||
The constant $\cN_0\qty( \qty{\rE_{(t)}} )$ which depends on the $\rE_{(t)}$ only can be fixed by using the \ope
|
||||
|
||||
@@ -12,7 +12,7 @@ In fact in~\cite{Liu:2002:StringsTimeDependentOrbifold} the four tachyons amplit
|
||||
\begin{equation}
|
||||
A_4 \sim \int\limits_{q \sim \infty} \frac{\dd{q}}{\abs{q}} \ccA( q )
|
||||
\end{equation}
|
||||
where $\ccA_{\text{closed}}( q ) \sim q^{4 - \ap \norm{\vec{p}_{\perp}}^2}$ and $\ccA_{\text{closed}}( q ) \sim q^{1 - \ap \norm{\vec{p}_{\perp}}^2} \tr\qty( \liebraket{T_1}{T_2}_+ \liebraket{T_3}{T_4}_+ )$ ($T_i$ for $i = 1,\, 2,\, 3,\, 4$ are Chan-Paton matrices).
|
||||
where $\ccA_{\text{closed}}( q ) \sim q^{4 - \ap \norm{\vec{p}_{\perp}}^2}$ and $\ccA_{\text{open}}( q ) \sim q^{1 - \ap \norm{\vec{p}_{\perp}}^2} \tr\qty( \liebraket{T_1}{T_2}_+ \liebraket{T_3}{T_4}_+ )$ ($T_i$ for $i = 1,\, 2,\, 3,\, 4$ are Chan-Paton matrices).
|
||||
Moreover divergences in string amplitudes are not limited to four points: interestingly we show that the open string three point amplitude with two tachyons and the first massive state may be divergent when some \emph{physical} polarisations are chosen.
|
||||
The true problem is therefore not related to a gravitational issue but to the non existence of the effective field theory.
|
||||
In fact when we express the theory using the eigenmodes of the kinetic terms some coefficients do not exist, not even as a distribution.
|
||||
|
||||
10
thesis.tex
10
thesis.tex
@@ -54,11 +54,11 @@
|
||||
\newcommand{\cint}[1]{\ensuremath{\oint\limits_{\ccC_{#1}}}}
|
||||
|
||||
%---- states
|
||||
\newcommand{\regvacuum}{\ensuremath{\ket{0}_{\SL{2}{R}}}\xspace}
|
||||
\newcommand{\regvacuumin}{\ensuremath{\ket{0_{(\text{in})}}_{\SL{2}{R}}}\xspace}
|
||||
\newcommand{\regvacuumout}{\ensuremath{\ket{0_{(\text{out})}}_{\SL{2}{R}}}\xspace}
|
||||
\newcommand{\regvacuuminconj}{\ensuremath{\tensor[_{\SL{2}{R}}]{\bra{0_{(\text{in})}}}{}}\xspace}
|
||||
\newcommand{\regvacuumoutconj}{\ensuremath{\tensor[_{\SL{2}{R}}]{\bra{0_{(\text{out})}}}{}}\xspace}
|
||||
\newcommand{\regvacuum}{\ensuremath{\ket{0}_{\SL{2}{\R}}}\xspace}
|
||||
\newcommand{\regvacuumin}{\ensuremath{\ket{0_{(\text{in})}}_{\SL{2}{\R}}}\xspace}
|
||||
\newcommand{\regvacuumout}{\ensuremath{\ket{0_{(\text{out})}}_{\SL{2}{\R}}}\xspace}
|
||||
\newcommand{\regvacuuminconj}{\ensuremath{\tensor[_{\SL{2}{\R}}]{\bra{0_{(\text{in})}}}{}}\xspace}
|
||||
\newcommand{\regvacuumoutconj}{\ensuremath{\tensor[_{\SL{2}{\R}}]{\bra{0_{(\text{out})}}}{}}\xspace}
|
||||
\newcommand{\twsvacket}{\ensuremath{\ket{\mathrm{T}}}\xspace}
|
||||
\newcommand{\twsvacbra}{\ensuremath{\bra{\mathrm{T}}}\xspace}
|
||||
\newcommand{\excvacket}{\ensuremath{\ket{T_{\rE,\, \brE}}}\xspace}
|
||||
|
||||
Reference in New Issue
Block a user