ncg

bachelorthesis in physics
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commit 5d3c6f911cae56d27532921f25ef57c3d73228c6
parent 258e29d485faf66c87ca5d12b75124d7621b86b0
Author: miksa234 <milutin@popovic.xyz>
Date:   Wed, 21 Jul 2021 19:55:03 +0200

checkpoint done fermionic action

Diffstat:
Msrc/thesis/chapters/electroncg.tex | 567++++++++++++++++++++++++++++++++++++-------------------------------------------
Msrc/thesis/main.pdf | 0
Msrc/thesis/main.tex | 1-
Asrc/thesis/questions.md | 8++++++++
4 files changed, 263 insertions(+), 313 deletions(-)

diff --git a/src/thesis/chapters/electroncg.tex b/src/thesis/chapters/electroncg.tex @@ -397,7 +397,7 @@ from equation \ref{eq:feddirac}. \subsubsection{The almost-commutative Manifold} The almost commutative manifold $M\times F_{ED}$ has KO-dimension 2, and is represented by the following spectral triple -\begin{align} +\begin{align}\label{eq:almost commutative manifold} M\times F_{ED} := \big(C^\infty(M,\mathbb{C}^2),\ L^2(S)\otimes \mathbb{C}^4,\ D_M\otimes 1 +\gamma _M \otimes D_F;\; J_M\otimes J_F,\ \gamma_M\otimes @@ -434,7 +434,7 @@ gauge group \text{$\mathfrak{B}$}(M\times F_{ED}) \simeq C^\infty(M, U(1)) \end{align} -Our space $N = M\times X \simeq M\sqcup M$ consists of two copies of $M$. +The space $N = M\times X$ consists of two copies of $M$. If $D_F = 0$ we have infinite distance between the two copies. Now have hacked the spectral triple to have nonzero Dirac operator $D_F$. The new Dirac operator still has a commuting relation with the algebra $[D_F, a] = 0$ @@ -442,313 +442,256 @@ $\forall a \in A$, and we should note that the distance between the two copies of $M$ is still infinite. This is purely an mathematically abstract observation and doesn't affect physical results. -%\subsubsection{The Spectral Action} -%Here we calculate the Lagrangian of the almost commutative Manifold $M\times -%F_{ED}$, which corresponds to the Lagrangian of Electrodynamics on a curved -%background Manifold (+ gravitational Lagrangian). It consists of the spectral -%action $S_b$ (bosonic) and of the fermionic action $S_f$. -% -%The simples spectral action of a spectral triple $(A, H, D)$ is given by the -%trace of some function of $D$, we also allow inner fluctuations of the Dirac -%operator $D_\omega = D + \omega + \varepsilon' J\omega J^{-1}$ where $\omega = -%\omega ^* \in \Omega_D^1(A)$. -%\begin{definition} -% Let $f:\mathbb{R} \rightarrow \mathbb{R}$ be a suitable function -% \textbf{positive and even}. The spectral action is then -% \begin{align} -% S_b [\omega] := \text{Tr}f(\frac{D_\omega}{\Lambda}) -% \end{align} -% where $\Lambda$ is a real cutoff parameter. The minimal condition on $f$ -% is that $f(\frac{D_\omega}{\Lambda})$ is a traclass operator, which mean -% that it should be compact operator with well defined finite trace -% independent of the basis. The subscript $b$ of $S_b$ refers to bosonic, -% because in physical applications $\omega$ will describe bosonic fields. -% -% Furthermore there is a topological spectral action, defined with the -% grading $\gamma$ -% \begin{align} -% S_{\text{top}}[\omega] := \text{Tr}(\gamma\ -% f(\frac{D_\omega}{\Lambda})). -% \end{align} -%\end{definition} -%\begin{definition} -% The fermionic action is defined by -% \begin{align} -% S_f[\omega, \psi] = (J\tilde{\psi}, D_\omega \tilde{\psi}) -% \end{align} -% with $\tilde{\psi} \in H_{cl}^+ := \{\tilde{\psi}: \psi \in H^+\}$. -% $H_{cl}^+$ is the set of Grassmann variables in $H$ in the +1-eigenspace -% of the grading $\gamma$. -%\end{definition} -%The grasmann variables are a set of Basis vectors of a vector space, they -%form a unital algebra over a vector field say $V$ where the generators are anti commuting, that is for -%$\theta _i, \theta _j$ some Grassmann variables we have -%\begin{align} -% &\theta _i \theta _j = -\theta _j \theta _i \\ -% &\theta _i x = x\theta _j \;\;\;\; x\in V \\ -% &(\theta_i)^2 = 0 \;\;\; (\theta _i \theta _i = -\theta _i \theta _i) -%\end{align} -%\begin{proposition} -% The spectral action of the almost commutative manifold $M$ with $\dim(M) -% =4$ with a fluctuated Dirac operator is. -% \begin{align} -% \text{Tr}(f\frac{D_\omega}{\Lambda}) \sim \int_M \mathcal{L}(g_{\mu\nu}, -% B_\mu, \Phi) \sqrt{g}\ d^4x + O(\Lambda^{-1}) -% \end{align} -% with -% \begin{align} -% \mathcal{L}(g_{\mu\nu}, B_\mu, \Phi) = -% N\mathcal{L}_M(g_{\mu\nu}) -% \mathcal{L}_B(B_\mu)+ -% \mathcal{L}_\phi(g_{\mu\nu}, B_\mu, \Phi) -% \end{align} -% where $N=4$ and $\mathcal{L}_M$ is the Lagrangian of the spectral triple -% $(C^\infty(M) , L^2(S), D_M)$ -% \begin{align}\label{lagr} -% \mathcal{L}_M(g_{\mu\nu}) := \frac{f_4 \Lambda ^4}{2\pi^2} - -% \frac{f_2 \Lambda^2}{24\pi ^2}s - \frac{f(0)}{320\pi^2} C_{\mu\nu -% \varrho \sigma}C^{\mu\nu \varrho \sigma}. -% \end{align} -% Here $C^{\mu\nu \varrho \sigma}$ is defined in terms of the Riemannian -% curvature tensor $R_{\mu\nu \varrho \sigma}$ and the Ricci tensor -% $R_{\nu\sigma} = g^{\mu\varrho} R_{\mu\nu \varrho\sigma}$. -% -% -% Furthermore $\mathcal{L}_B$ describes the kinetic term of the gauge field -% \begin{align} -% \mathcal{L}_B(B_\mu) := \frac{f(0)}{24\pi^2} -% \text{Tr}(F_{\mu\nu}F^{\mu\nu}). -% \end{align} -% Last $\mathcal{L}_\phi$ is the scalar-field Lagrangian with a boundary -% term. -% \begin{align} -% \mathcal{L}_\phi(g_{\mu\nu}, B_\mu, \Phi) := -% &-\frac{2f_2\Lambda^2}{4\pi^2}\text{Tr}(\Phi^2) + \frac{f(0)}{8\pi^2} -% \text{Tr}(\Phi^4) + \frac{f(0)}{24\pi^2} \Delta(\text{Tr}(\Phi^2))\\ -% &+ \frac{f(0)}{48\pi^2}s\text{Tr}(\Phi^2) -% \frac{f(0)}{8\pi^2}\text{Tr}((D_\mu \Phi)(D^\mu \Phi)). -% \end{align} -%\end{proposition} -%\begin{proof} -% the dimension of our manifold $m$ is $\dim(m) = \text{tr}(id) =4 $. let us -% take a $x \in m$, we have an asymtotic expansion of -% $\text{tr}(f(\frac{d_\omega}{\lambda}))$ as $\lambda \rightarrow \infty$ -% \begin{align} -% \text{tr}(f(\frac{d_\omega}{\lambda})) \simeq& \ 2f_4 \lambda ^4 -% a_0(d_\omega ^2)+ 2f_2\lambda^2 a_2(d_\omega^2) \\&+ f(0) a_4(d_\omega^4) -% +o(\lambda^{-1}). -% \end{align} -% note that the heat kernel coefficients are zero for uneven $k$, -% furthermore they are dependent on the fluctuated dirac operator -% $d_\omega$. we can rewrite the heat kernel coefficients in terms of $d_m$, -% for the first two we note that $n:= \text{tr}\mathbbm{1_{h_f}})$ -% \begin{align} -% a_0(d_\omega^2) &= na_0(d_m^2)\\ -% a_2(d_\omega^2 &= na_2(d_m^2) - \frac{1}{4\pi^2}\int_m -% \text{tr}(\phi^2)\sqrt{g}d^4x -% \end{align} -% for $a_4$ we need to extend in terms of coefficients of $f$, look week9.pdf -% for the standard version, -% \begin{align} -% &\frac{1}{360}\text{tr}(60sf)= -\frac{1}{6}s(ns + 4 -% \text{tr}(\phi^2))\\ -% \nonumber\\ -% &f^2 = \frac{1}{16}s^2\otimes 1 + 1\otimes \phi^4 - \frac{1}{4} -% \gamma^\mu\gamma^\nu \gamma^\varrho\gamma^\sigma f_{\mu\nu}f^{\mu\nu}+\\ -% &\;\;\;\;\;\;\;+\gamma^\mu\gamma^\nu\otimes(d_\mu\phi)(d_\nu -% \phi)+\frac{1}{2}s\otimes \phi^2 + \ \text{traceless terms}\\ -% \nonumber\\ -% &\frac{1}{360}\text{tr}(180f^2) = \frac{1}{8}s^2n + 2\text{tr}(\phi^4) -% + \text{tr}(f_{\mu\nu}f^{\mu\nu}) +\\ -% &\;\;\;\;\;\;\;+2\text{tr}((d_\mu\phi)(d^\mu\phi)) -% + s\text{tr}(\phi^2)\\ -% \nonumber\\ -% &\frac{1}{360}\text{tr}(-60\delta f)= -% \frac{1}{6}\delta(ns+4\text{tr}(\phi^2)). -% \end{align} -% now for the cross terms of $\omega_{\mu\nu}^e\omega^{e\mu\nu}$ the trace -% vanishes because of the anti-symmetric properties of the Riemannian -% curvature tensor -% \begin{align} -% \omega_{\mu\nu}^e\omega^{e\mu\nu} = \omega_{\mu\nu}^s\omega^{s\mu\nu} -% \otimes 1 - 1\otimes f_{\mu\nu}f^{\mu\nu} + 2i\omega_{\mu\nu}^s -% \otimes f^{\mu\nu} -% \end{align} -% the trace of the cross term vanishes because -% \begin{align} -% \text{tr}(\omega^{s}_{\mu\nu} = \frac{1}{4} -% r_{\mu\nu\varrho\sigma}\text{tr}(\gamma^\mu\gamma^\nu) = \frac{1}{4} -% r_{\mu\nu\varrho\sigma}g^{\mu\nu} =0 -% \end{align} -% and the trace of the whole term is -% \begin{align} -% \frac{1}{360}\text{tr}(30\omega^e_{\mu\nu}\omega^{e\mu\nu}) = -% \frac{n}{24}r_{\mu\nu\varrho\sigma}r^{\mu\nu\varrho\sigma} -% -\frac{1}{3}\text{tr}(f_{\mu\nu}f^{\mu\nu}). -% \end{align} -% plugging the results into $a_4$ and simplifying we can write -% \begin{align} -% a_4(x, d_\omega^4) &= na_4(x, d_m^2) + \frac{1}{4\pi^2}\bigg(\frac{1}{12} s -% \text{tr}(\phi^2) + \frac{1}{2}\text{tr}(\phi^4) \\ -% &+ \frac{1}{4} -% \text{tr}((d_\mu\phi)(d^\mu \phi)) + \frac{1}{6} -% \delta\text{tr}(\phi^2) + \frac{1}{6} -% \text{tr}(f_{\mu\nu}f^{\mu\nu})\bigg) -% \end{align} -% the only thing left is to plug in the heat kernel coefficients into the -% heat kernel expansion above. -%\end{proof} -% -%Here on we go and calculate the spectral action of $M\times F_{ED}$ -%\begin{proposition} -% The Spectral action of $M\times F_{ED}$ is -% \begin{align} -% \text{Tr}(f\frac{D_\omega}{\Lambda}) \sim \int_M \mathcal{L}(g_{\mu\nu}, -% Y_\mu) \sqrt{g}\ d^4x + O(\Lambda^{-1}) -% \end{align} -% where the Lagrangian is -% \begin{align} -% \mathcal{L}(g_{\mu\nu}, Y_\mu) = -% 4\mathcal{L}_M(g_{\mu\nu})+ -% \mathcal{L}_Y(Y_\mu)+ -% \mathcal{L}_\phi(g_{\mu\nu}, d) -% \end{align} -% here the $d$ in $\mathcal{L}_\phi$ is from $D_F$ in equation -% \ref{dirac}. The Lagrangian $\mathcal{L}_M$ is like in equation -% \ref{lagr}. The Lagrangian $\mathcal{L}_Y$ is the kinetic term of the -% $U(1)$ gauge field $Y_\mu$ -% \begin{align} -% \mathcal{L}_Y(Y_\mu):= \frac{f(0)}{6\pi^2} -% Y_{\mu\nu}Y^{\mu\nu}\;\;\;\;\;\;\;\;\text{with}\;\;\; Y_{\mu\nu} = -% \partial_\mu Y_\nu - -% \partial_\nu Y_\mu. -% \end{align} -% Then there is $\mathcal{L}_\phi$, which has two constant terms -% (disregarding the boundary term) that add up to the Cosmological Constant -% and a term that for the Einstein-Hilbert action -% \begin{align} -% \mathcal{L}_\phi(g_{\mu\nu}, d) := \frac{2f_2 \Lambda ^2}{\pi^2} -% |d|^2 + \frac{f(0)}{2\pi^2} |d|^4 + \frac{f(0)}{12\pi ^2} s |d|^2. -% \end{align} -%\end{proposition} -%\begin{proof} -% The Trace of $\mathbb{C}^4$ (the Hilbertspace) gives $N=4$. With $B_\mu$ -% like in equation \ref{field} we have $\text{Tr}(F_{\mu\nu} -% F^{\mu\nu})=4Y_{\mu\nu}Y^{\mu\nu}$. This provides $\mathcal{L}_Y$. -% Furthermore we have $\Phi^2 = D_F^2 = |d|^2$ and $\mathcal{L}_\phi$ only -% give numerical contributions to the cosmological constant and the -% Einstein-Hilbert action. -% -% The proof is relying itself on just plugging the terms into the previous -% proposition, for which I didn't write the proof for. -%\end{proof} -% -% -%\subsection{fermionic action} -%a quick reminder with what we are dealing with, the fermionic action is defined -%in the following way. -%\begin{definition} -% the fermionic action is defined by -% \begin{align} -% s_f[\omega, \psi] = (j\tilde{\psi}, d_\omega \tilde{\psi}) -% \end{align} -% with $\tilde{\psi} \in h_{cl}^+ := \{\tilde{\psi}: \psi \in h^+\}$. -% $h_{cl}^+$ is the set of grassmann variables in $h$ in the +1-eigenspace -% of the grading $\gamma$. -%\end{definition} -% -%the almostcommutative manifold we are dealing with is the following -%\begin{align} -% &m\times f_{ed} := \left(c^\infty(m,\mathbb{c}^2),\ l^2(s)\otimes -% \mathbb{c}^4,\ -% d_m\otimes 1 +\gamma _m \otimes d_f;\; j_m\otimes j_f,\ \gamma_m\otimes -% \gamma _f\right).\\ -% \nonumber\\ -% &\text{where:} \nonumber \\ -% &c^\infty(m,\mathbb{c}^2) = c^\infty(m) \otimes c^\infty(m) -% &\mathcal{h} = \mathcal{h}^+ \otimes \mathcal{h}^-\\ -% &\mathcal{h} = l^2(s)^+ \otimes h_f^+ \oplus l^2(s)^- \otimes h_f^-. -%\end{align} -%where $h_f$ is separated into the particle-anitparticle states with onb $\{e_r, -%e_l, \bar{e}_r, \bar{e}_l\}$. the onb of $h_f^+$ is $\{e_l, \bar{e}_r\}$ and -%for $h_f^-$ we have $\{e_r, \bar{e}_l\}$. furthermore we can decompose a spinor -%$\psi \in l^2(s)$ for each of the eigenspaces $h_f^\pm$, $\psi = \psi_r -%\psi_l$. thus we can write for an arbitrary $\psi \in \mathcal{h}^+$ -%\begin{align} -% \psi = \chi_r \otimes e_r + \chi_l \otimes e_l + \psi_l \otimes \bar{e}_r -% \psi_r \otimes \bar{e}_l -%\end{align} -%for $\chi_l, \psi_l \in l^2(s)^+$ and $\chi_r, \psi_r \in l^2(s)^-$. -%\begin{proposition} -% we can define the action of the fermionic art of $m\times f_{ed}$ in the -% following way -% \begin{align} -% s_f = -i\big(j_m\tilde{\chi}, \gamma(\nabla^s_\mu - i\gamma_\mu) -% \tilde{\psi}\big) + \big(s_m\tilde{\chi}_l, \bar{d}\tilde{\psi}_l\big) - -% \big(j_m\tilde{\chi}_r, d \tilde{\psi}_r\big) -% \end{align} -%\end{proposition} -%\begin{proof} -% we take the fluctuated Dirac operator -% \begin{align} -% d_\omega = d_m \otimes i + \gamma^\mu \otimes b_\mu + \gamma_m \otimes -% d_f -% \end{align} -%\end{proof} -%the fermionic action is $s_f = (j\tilde{\xi}, d_\omega\tilde{\xi})$ for a $\xi -%\in \mathcal{h}^+$, we can begin to calculate (note that we add the constant -%$\frac{1}{2}$ to the action) -%\begin{align} -% \frac{1}{2}(j\tilde{\xi}, d_\omega\tilde{\xi}) =&\\ -% &+\frac{1}{2}(j\tilde{\xi}, (d_m \otimes i)\tilde{\xi})\label{eq:1}\\ -% &+\frac{1}{2}(j\tilde{\xi}, (\gamma^\mu \otimes b_\mu) -% \tilde{\xi})\label{eq:2}\\ -% &+\frac{1}{2}(j\tilde{\xi}, (\gamma_m\otimes -% d_f)\tilde{\xi})\label{eq:3}. -%\end{align} -%for equation \ref{eq:1} we calculate -%\begin{align} -% \frac{1}{2}(j\tilde{\xi}, (d_m\otimes 1)\tilde{\xi}) &= -% \frac{1}{2}(j_m\tilde{\chi}_r,d_m\tilde{\psi}_l)+ -% \frac{1}{2}(j_m\tilde{\chi}_l,d_m\tilde{\psi}_r)+ -% \\&+\frac{1}{2}(j_m\tilde{\psi}_l,d_m\tilde{\psi}_r)+ -% \frac{1}{2}(j_m\tilde{\chi}_r,d_m\tilde{\chi}_l)\\ -% &= (j_m\tilde{\chi},d_m\tilde{\chi}). -%\end{align} -%for equation \ref{eq:2} we have -%\begin{align} -% \frac{1}{2}(j\tilde{\xi}, (\gamma^\mu \otimes b_\mu)\tilde{\xi})&= -% -\frac{1}{2}(j_m\tilde{\chi}_r, \gamma^\mu y_\mu\tilde{\psi}_r) -% -\frac{1}{2}(j_m\tilde{\chi}_l, \gamma^\mu y_\mu\tilde{\psi}_r)+\\ -% &+\frac{1}{2}(j_m\tilde{\psi}_l, \gamma^\mu y_\mu\tilde{\chi}_r)+ -% \frac{1}{2}(j_m\tilde{\psi}_r, \gamma^\mu y_\mu\tilde{\chi}_l)=\\ -% &= -(j_m\tilde{\chi}, \gamma^\mu y_\mu\tilde{\psi}). -%\end{align} -%for equation \ref{eq:3} we have -%\begin{align} -% \frac{1}{2}(j\tilde{\xi}, (\gamma_m\otimes d_f)\tilde{\xi})&= -% +\frac{1}{2}(j_m\tilde{\chi}_r, d\gamma_m\tilde{\chi}_r) -% +\frac{1}{2}(j_m\tilde{\chi}_l, \bar{d}\gamma_m\tilde{\chi}_l)+\\ -% &+\frac{1}{2}(j_m\tilde{\chi}_l, \bar{d}\gamma_m\tilde{\chi}_l) -% +\frac{1}{2}(j_m\tilde{\chi}_r, d\gamma_m\tilde{\chi}_r)=\\ -% &= i(j_m\tilde{\chi}, m\tilde{\psi}) -%\end{align} -%note that we obtain a complex mass parameter $d$, so we write $d:=im$ for $m\in \mathbb{r}$, -%which stands for the real mass and we obtain a nice result -% -%\begin{theorem} -% the full lagrangian of $m\times f_{ed}$ is the sum of purely gravitational -% lagrangian -% \begin{align} -% \mathcal{l}_{grav}(g_{\mu\nu})=4\mathcal{l}_m(g_{\mu\nu}) -% \mathcal{l}_\phi (g_{\mu\nu}) -% \end{align} -% and the lagrangian of electrodynamics -% \begin{align} -% \mathcal{l}_{ed} = -i\bigg\langle -% j_m\tilde{\chi},\big(\gamma^\mu(\nabla^s_\mu - iy_\mu) -m\big)\tilde{\psi}) -% \bigg\rangle -% +\frac{f(0)}{6\pi^2} y_{\mu\nu}y^{\mu\nu}. -% \end{align} -% -%\end{theorem} +\subsubsection{The Spectral Action} +In this chapter we bring all our results together to establish an +Action functional to describe a physical system. It turns out that +the Lagrangian of the almost commutative manifold $M\times F_{ED}$ +corresponds to the Lagrangian of Electrodynamics on a curved +background manifold (+ gravitational Lagrangian), consisting of the spectral +action $S_b$ (bosonic) and of the fermionic action $S_f$. + +The simplest spectral action of a spectral triple $(A, H, D)$ is given by the +trace of a function of $D$. We also consider inner fluctuations of the Dirac +operator $D_\omega = D + \omega + \varepsilon' J\omega J^{-1}$ where $\omega = +\omega ^* \in \Omega_D^1(A)$. +\begin{definition} + Let $f:\mathbb{R} \rightarrow \mathbb{R}$ be a suitable function + \textbf{positive and even}. The spectral action is then + \begin{align} + S_b [\omega] := \text{Tr}\big(f(\frac{D_\omega}{\Lambda})\big) + \end{align} + where $\Lambda$ is a real cutoff parameter. The minimal condition on $f$ + is that $f(\frac{D_\omega}{\Lambda})$ is a trace class operator. A trace + class operator is a compact operator with a well defined finite trace + independent of the basis. The subscript $b$ in $S_b$ stands for bosonic, + because in physical applications $\omega$ will describe bosonic fields. + + In addition to the bosonic action $S_b$ we can define a topological spectral + action $S_{top}$. Leaning on the grading $\gamma$ the topological spectral action is + \begin{align} + S_{\text{top}}[\omega] := \text{Tr}(\gamma\ + f(\frac{D_\omega}{\Lambda})). + \end{align} +\end{definition} +\begin{definition}\label{def:fermionic action} + The fermionic action is defined by + \begin{align} + S_f[\omega, \psi] = (J\tilde{\psi}, D_\omega \tilde{\psi}) + \end{align} + with $\tilde{\psi} \in H_{cl}^+ := \{\tilde{\psi}: \psi \in H^+\}$, where + $H_{cl}^+$ is a set of Grassmann variables in $H$ in the +1-eigenspace + of the grading $\gamma$. +\end{definition} + +%---------------------- APPENDIX ?????????????-------------------- +\textbf{APPENDIX??} +Grassmann variables are a set of Basis vectors of a vector space, they +form a unital algebra over a vector field $V$, where the generators are +anti commuting, that is for Grassmann variables $\theta _i, \theta _j$ we have +\begin{align} + &\theta _i \theta _j = -\theta _j \theta _i \\ + &\theta _i x = x\theta _j \;\;\;\; x\in V \\ + &(\theta_i)^2 = 0 \;\;\; (\theta _i \theta _i = -\theta _i \theta _i) +\end{align} +%---------------------- APPENDIX ?????????????-------------------- +\begin{proposition} + The spectral action of the almost commutative manifold $M$ with $\dim(M) + =4$ with a fluctuated Dirac operator is + \begin{align} + \text{Tr}(f\frac{D_\omega}{\Lambda}) \sim \int_M \mathcal{L}(g_{\mu\nu}, + B_\mu, \Phi) \sqrt{g}\ d^4x + O(\Lambda^{-1}), + \end{align} + where + \begin{align} + \mathcal{L}(g_{\mu\nu}, B_\mu, \Phi) = + N\mathcal{L}_M(g_{\mu\nu}) + \mathcal{L}_B(B_\mu)+ + \mathcal{L}_\phi(g_{\mu\nu}, B_\mu, \Phi). + \end{align} + The Lagrangian $\mathcal{L}_M$ is of the spectral triple, represented by + the following term + $(C^\infty(M) , L^2(S), D_M)$ + \begin{align}\label{lagr} + \mathcal{L}_M(g_{\mu\nu}) := \frac{f_4 \Lambda ^4}{2\pi^2} - + \frac{f_2 \Lambda^2}{24\pi ^2}s - \frac{f(0)}{320\pi^2} C_{\mu\nu + \varrho \sigma}C^{\mu\nu \varrho \sigma}, + \end{align} + here $C^{\mu\nu \varrho \sigma}$ is defined in terms of the Riemannian + curvature tensor $R_{\mu\nu \varrho \sigma}$ and the Ricci tensor + $R_{\nu\sigma} = g^{\mu\varrho} R_{\mu\nu \varrho\sigma}$. + The kinetic term of the gauge field is described by the Lagrangian + $\mathcal{L}_B$, which takes the following shape + \begin{align} + \mathcal{L}_B(B_\mu) := \frac{f(0)}{24\pi^2} + \text{Tr}(F_{\mu\nu}F^{\mu\nu}). + \end{align} + Lastly $\mathcal{L}_\phi$ is the scalar-field Lagrangian with a boundary + term, given by + \begin{align} + \mathcal{L}_\phi(g_{\mu\nu}, B_\mu, \Phi) := + &-\frac{2f_2\Lambda^2}{4\pi^2}\text{Tr}(\Phi^2) + \frac{f(0)}{8\pi^2} + \text{Tr}(\Phi^4) + \frac{f(0)}{24\pi^2} \Delta(\text{Tr}(\Phi^2))\\ + &+ \frac{f(0)}{48\pi^2}s\text{Tr}(\Phi^2) + \frac{f(0)}{8\pi^2}\text{Tr}((D_\mu \Phi)(D^\mu \Phi)). + \end{align} +\end{proposition} +\begin{proof} + The dimension of the manifold $M$ is $\dim(M) = \text{Tr}(id) =4$. For + an $x \in M$, we have an asymptotic expansion of the term + $\text{Tr}(f(\frac{D_\omega}{\Lambda}))$ as $\Lambda$ goes to infinity, + which can be written as + \begin{align}\label{eq:trheatkernel} + \text{Tr}(f(\frac{D_\omega}{\Lambda})) \simeq& \ 2f_4 \Lambda ^4 + a_0(D_\omega ^2)+ 2f_2\Lambda^2 a_2(D_\omega^2) \\&+ f(0) a_4(D_\omega^4) + +O(\Lambda^{-1}). + \end{align} + We have to note here that the heat kernel coefficients are zero for uneven $k$, + and they are dependent on the fluctuated Dirac operator + $D_\omega$. We can rewrite the heat kernel coefficients in terms of $D_M$, + for the first two terms $a_0$ and $a_2$ we use $N:= + \text{Tr}\mathbbm{1_{H_F}})$ and write + \begin{align} + a_0(D_\omega^2) &= Na_0(D_M^2),\\ + a_2(D_\omega^2 &= Na_2(D_M^2) - \frac{1}{4\pi^2}\int_M. + \text{Tr}(\Phi^2)\sqrt{g}d^4x + \end{align} + For $a_4$ we extend in terms of coefficients of $F$, \textbf{REWRITE: look week9.pdf + for the standard version} + \begin{align} + &\frac{1}{360}\text{Tr}(60sF)= -\frac{1}{6}S(Ns + 4 + \text{Tr}(\Phi^2))\\ + \nonumber\\ + &F^2 = \frac{1}{16}s^2\otimes 1 + 1\otimes \Phi^4 - \frac{1}{4} + \gamma^\mu\gamma^\nu \gamma^\varrho\gamma^\sigma F_{\mu\nu}F^{\mu\nu}+\\ + &\;\;\;\;\;\;\;+\gamma^\mu\gamma^\nu\otimes(D_\mu\Phi)(D_\nu + \Phi)+\frac{1}{2}s\otimes \Phi^2 + \ \text{traceless terms}\\ + \nonumber\\ + &\frac{1}{360}\text{Tr}(180F^2) = \frac{1}{8}s^2N + 2\text{Tr}(\Phi^4) + + \text{Tr}(F_{\mu\nu}F^{\mu\nu}) +\\ + &\;\;\;\;\;\;\;+2\text{Tr}((D_\mu\Phi)(D^\mu\Phi)) + + s\text{Tr}(\Phi^2)\\ + \nonumber\\ + &\frac{1}{360}\text{Tr}(-60\Delta F)= + \frac{1}{6}\Delta(Ns+4\text{Tr}(\Phi^2)). + \end{align} + The cross terms of the trace in $\Omega_{\mu\nu}^E\Omega^{E\mu\nu}$ + vanishes because of the antisymmetric property of the Riemannian + curvature tensor, thus we can write + \begin{align} + \Omega_{\mu\nu}^E\Omega^{E\mu\nu} = \Omega_{\mu\nu}^S\Omega^{S\mu\nu} + \otimes 1 - 1\otimes F_{\mu\nu}F^{\mu\nu} + 2i\Omega_{\mu\nu}^S + \otimes F^{\mu\nu}. + \end{align} + The trace of the cross term $\Omega^{S}_{\mu\nu}$ vanishes because + \begin{align} + \text{Tr}(\Omega^{S}_{\mu\nu}) = \frac{1}{4} + R_{\mu\nu\varrho\sigma}\text{Tr}(\gamma^\mu\gamma^\nu) = \frac{1}{4} + R_{\mu\nu\varrho\sigma}g^{\mu\nu} =0, + \end{align} + then the trace of the whole term is given by + \begin{align} + \frac{1}{360}\text{Tr}(30\Omega^E_{\mu\nu}\Omega^{E\mu\nu}) = + \frac{N}{24}R_{\mu\nu\varrho\sigma}R^{\mu\nu\varrho\sigma} + -\frac{1}{3}\text{Tr}(F_{\mu\nu}F^{\mu\nu}). + \end{align} + Finally plugging the results into the coefficient $a_4$ and simplifying we get + \begin{align} + a_4(x, D_\omega^4) &= Na_4(x, D_M^2) + \frac{1}{4\pi^2}\bigg(\frac{1}{12} s + \text{Tr}(\Phi^2) + \frac{1}{2}\text{Tr}(\Phi^4) \\ + &+ \frac{1}{4} + \text{Tr}((D_\mu\Phi)(D^\mu \Phi)) + \frac{1}{6} + \Delta\text{Tr}(\Phi^2) + \frac{1}{6} + \text{Tr}(F_{\mu\nu}F^{\mu\nu})\bigg). + \end{align} + The only thing left is to substitute the heat kernel coefficients into the + heat kernel expansion in equation \ref{eq:trheatkernel}. +\end{proof} + +\subsubsection{Fermionic Action} +We remind ourselves the definition of the fermionic action in +\ref{def:fermionic action} and the manifold we are dealing with in equation +\ref{eq:almost commutative manifold}. The Hilbertspace $H_F$ is separated +into the particle-antiparticle states with ONB $\{e_R, e_L, \bar{e}_R, +\bar{e}_L\}$. The orthonormal basis of $H_F^+$ is $\{e_L, \bar{e}_R\}$ and +consequently for $H_F^-$, $\{e_R, \bar{e}_L\}$. We can decompose a spinor +$\psi \in L^2(S)$ in each of the eigenspaces $H_F^\pm$, $\psi = \psi_R+ +\psi_L$. That means for an arbitrary $\psi \in H^+$ we can write +\begin{align} + \psi = \chi_R \otimes e_R + \chi_L \otimes e_L + \psi_L \otimes + \bar{e}_R+ + \psi_R \otimes \bar{e}_L, +\end{align} +where $\chi_L, \psi_L \in L^2(S)^+$ and $\chi_R, \psi_R \in L^2(S)^-$. + +Since the fermionic action yields too much restriction on $F_{ED}$ (modified +Two-Point space $F_X$) we redefine it by taking account the fluctuated Dirac +operator +\begin{align} + D_\omega = D_M \otimes i + \gamma^\mu \otimes B_\mu + \gamma_M \otimes + D_F. +\end{align} +The Fermionic Action is +\begin{align} +S_F = (J\tilde{\xi}, D_\omega\tilde{\xi}) +\end{align} +for a $\xi \in H^+$. Then the straight forward calculation gives \begin{align} + \frac{1}{2}(J\tilde{\xi}, D_\omega\tilde{\xi}) + &=\frac{1}{2}(J\tilde{\xi}, (D_M \otimes + i)\tilde{\xi})\label{eq:fermionic1}\\ + &+\frac{1}{2}(J\tilde{\xi}, (\gamma^\mu \otimes B_\mu) + \tilde{\xi})\label{eq:fermionic2}\\ + &+\frac{1}{2}(J\tilde{\xi}, (\gamma_M\otimes + D_F)\tilde{\xi})\label{eq:fermionic3}, +\end{align} +(note that we add the constant $\frac{1}{2}$ to the action). +For the term in \ref{fermionic:1} we calculate +\begin{align} + \frac{1}{2}(J\tilde{\xi}, (D_M\otimes 1)\tilde{\xi}) &= + \frac{1}{2}(J_M\tilde{\chi}_R,D_M\tilde{\psi}_L)+ + \frac{1}{2}(J_M\tilde{\chi}_L,D_M\tilde{\psi}_R)+ + \\&+\frac{1}{2}(J_M\tilde{\psi}_L,D_M\tilde{\psi}_R)+ + \frac{1}{2}(J_M\tilde{\chi}_R,D_M\tilde{\chi}_L)\\ + &= (J_M\tilde{\chi},D_M\tilde{\chi}). +\end{align} +For the term in \ref{eq:fermionic2} we have +\begin{align} + \frac{1}{2}(J\tilde{\xi}, (\gamma^\mu \otimes B_\mu)\tilde{\xi})&= + -\frac{1}{2}(J_M\tilde{\chi}_R, \gamma^\mu Y_\mu\tilde{\psi}_R) + -\frac{1}{2}(J_M\tilde{\chi}_L, \gamma^\mu Y_\mu\tilde{\psi}_R)+\\ + &+\frac{1}{2}(J_M\tilde{\psi}_L, \gamma^\mu Y_\mu\tilde{\chi}_R)+ + \frac{1}{2}(J_M\tilde{\psi}_R, \gamma^\mu Y_\mu\tilde{\chi}_L)=\\ + &= -(J_M\tilde{\chi}, \gamma^\mu Y_\mu\tilde{\psi}). +\end{align} +And for \ref{eq:fermionic3} we can write +\begin{align} + \frac{1}{2}(J\tilde{\xi}, (\gamma_M\otimes D_F)\tilde{\xi})&= + +\frac{1}{2}(J_M\tilde{\chi}_R, d\gamma_M\tilde{\chi}_R) + +\frac{1}{2}(J_M\tilde{\chi}_L, \bar{d}\gamma_M\tilde{\chi}_L)+\\ + &+\frac{1}{2}(J_M\tilde{\chi}_L, \bar{d}\gamma_M\tilde{\chi}_L) + +\frac{1}{2}(J_M\tilde{\chi}_R, d\gamma_M\tilde{\chi}_R)=\\ + &= i(J_M\tilde{\chi}, m\tilde{\psi}). +\end{align} +A small problem arises, we obtain a complex mass parameter $d$, but we can +write $d:=im$ for $m\in \mathbb{R}$, which stands for the real mass. + +Finally the fermionic action of $M\times F_{ED}$ takes the form + \begin{align} + S_f = -i\big(J_M\tilde{\chi}, \gamma(\nabla^S_\mu - i\Gamma_\mu) + \tilde{\Psi}\big) + \big(S_M\tilde{\chi}_L, \bar{d}\tilde{\psi}_L\big) - + \big(J_M\tilde{\chi}_R, d \tilde{\psi}_R\big). + \end{align} +Ultimately we arrive at the full Lagrangian of $M\times F_{ED}$, which is the +sum of purely gravitational Lagrangian + \begin{align} + \mathcal{L}_{grav}(g_{\mu\nu})=4\mathcal{L}_M(g_{\mu\nu})+ + \mathcal{L}_\phi (g_{\mu\nu}), + \end{align} +and the Lagrangian of electrodynamics + \begin{align} + \mathcal{L}_{ED} = -i\bigg\langle + J_M\tilde{\chi},\big(\gamma^\mu(\nabla^S_\mu - iY_\mu) -m\big)\tilde{\psi}) + \bigg\rangle + +\frac{f(0)}{6\pi^2} Y_{\mu\nu}Y^{\mu\nu}. + \end{align} + + diff --git a/src/thesis/main.pdf b/src/thesis/main.pdf Binary files differ. diff --git a/src/thesis/main.tex b/src/thesis/main.tex @@ -24,7 +24,6 @@ \input{chapters/electroncg} - %------------------- BACKHAND --------------------- \input{chapters/conclusion} diff --git a/src/thesis/questions.md b/src/thesis/questions.md @@ -0,0 +1,8 @@ +# List of Questions + + * Boxed environment for def., theorem, proposition, etc., like tprak + stoffer? Minimum lining, nothing fancy only emphasize the beginning and + the end. (Lisa if you are reading this I will show you the pictures) + * Apendix section for small additions like Grassmann variables, + Riemannian Geometry, etc.? + * Table of contents ?