{ "cell_id": 4331041475102962477, "cells": [ { "cell_id": 9724265789201400066, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 9710205063486850115, "cell_origin": "client", "cell_type": "latex_view", "source": "\\algorithm{join_gamma}{Work out the product of two generalised Dirac gamma matrices.}\n\nJoin two fully anti-symmetrised gamma matrix products according to the\nexpression\n\\begin{equation}\n \\Gamma^{b_{1}\\dots b_{n}}\\Gamma_{a_{1}\\dots a_{m}} =\n \\sum_{p=0}^{\\text{min}(n,m)}\\ \\frac{n! m!}{(n-p)! (m-p)! p!}\n \\Gamma^{[b_{1}\\ldots b_{n-p}}{}_{[a_{p+1}\\ldots a_{m}}\n \\eta^{b_{n-p+1}\\ldots b_{n}]}{}_{a_{1}\\ldots a_{m-p}]} \\, .\n\\end{equation}\nThis is the opposite of \\algo{split_gamma}.\n\nWithout further arguments, the anti-symmetrisations will be worked out\nexplicitly (changed from v1). The setting the flag ``{\\tt expand}'' to\nfalse instead keeps them implicit. Compare" } ], "hidden": true, "source": "\\algorithm{join_gamma}{Work out the product of two generalised Dirac gamma matrices.}\n\nJoin two fully anti-symmetrised gamma matrix products according to the\nexpression\n\\begin{equation}\n \\Gamma^{b_{1}\\dots b_{n}}\\Gamma_{a_{1}\\dots a_{m}} =\n \\sum_{p=0}^{\\text{min}(n,m)}\\ \\frac{n! m!}{(n-p)! (m-p)! p!}\n \\Gamma^{[b_{1}\\ldots b_{n-p}}{}_{[a_{p+1}\\ldots a_{m}}\n \\eta^{b_{n-p+1}\\ldots b_{n}]}{}_{a_{1}\\ldots a_{m-p}]} \\, .\n\\end{equation}\nThis is the opposite of \\algo{split_gamma}.\n\nWithout further arguments, the anti-symmetrisations will be worked out\nexplicitly (changed from v1). The setting the flag ``{\\tt expand}'' to\nfalse instead keeps them implicit. Compare" }, { "cell_id": 2947240613828784017, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 17300951477357957419, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 4472257405767180424, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n} \\Gamma_{p}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n} \\Gamma_{p}\\end{dmath*}" }, { "cell_id": 5629509010473670416, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 5284856236849942701, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n p} + 2\\Gamma_{m} g_{n p}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n p}+2\\Gamma_{m} g_{n p}\\end{dmath*}" } ], "source": "\\Gamma{#}::GammaMatrix(metric=g).\nex:= \\Gamma_{m n} \\Gamma_{p};\njoin_gamma(ex, expand=False);" }, { "cell_id": 12124424772252241647, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 10410932945721111027, "cell_origin": "client", "cell_type": "latex_view", "source": "with" } ], "hidden": true, "source": "with" }, { "cell_id": 15611766653738663169, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 3478877256762712012, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 8525122839191917179, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n} \\Gamma_{p}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n} \\Gamma_{p}\\end{dmath*}" }, { "cell_id": 10982516367231400775, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 4718554144418310653, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n p} + \\Gamma_{m} g_{n p}-\\Gamma_{n} g_{m p}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n p}+\\Gamma_{m} g_{n p}-\\Gamma_{n} g_{m p}\\end{dmath*}" } ], "source": "\\Gamma{#}::GammaMatrix(metric=g).\nex:= \\Gamma_{m n} \\Gamma_{p};\njoin_gamma(ex, expand=True);" }, { "cell_id": 9430663871766692927, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 17614251815043467495, "cell_origin": "client", "cell_type": "latex_view", "source": "Note that the gamma matrices need to have a metric associated to them\nin order for this algorithm to work." } ], "hidden": true, "source": "Note that the gamma matrices need to have a metric associated to them\nin order for this algorithm to work." }, { "cell_id": 16437583614585627386, "cell_origin": "client", "cell_type": "latex", "cells": [ { "cell_id": 5501818122039199499, "cell_origin": "client", "cell_type": "latex_view", "source": "In order to reduce the number of terms somewhat, one can instruct the algorithm\nto make use of generalised Kronecker delta symbols in the result;\nthese symbols are defined as\n\\begin{equation}\n\\delta^{r_1}{}_{s_1}{}^{r_2}{}_{s_2}\\cdots{}^{r_n}{}_{s_n}\n= \\delta^{[r_1}{}_{s_1}\\delta^{r_2}{}_{s_2}\\cdots {}^{r_n]}{}_{s_n}\\, .\n\\end{equation}\nAnti-symmetrisation is implied in the set of even-numbered\nindices. The use of these symbols is triggered by the \\verb|use_gendelta| option," } ], "hidden": true, "source": "In order to reduce the number of terms somewhat, one can instruct the algorithm\nto make use of generalised Kronecker delta symbols in the result;\nthese symbols are defined as\n\\begin{equation}\n\\delta^{r_1}{}_{s_1}{}^{r_2}{}_{s_2}\\cdots{}^{r_n}{}_{s_n}\n= \\delta^{[r_1}{}_{s_1}\\delta^{r_2}{}_{s_2}\\cdots {}^{r_n]}{}_{s_n}\\, .\n\\end{equation}\nAnti-symmetrisation is implied in the set of even-numbered\nindices. The use of these symbols is triggered by the \\verb|use_gendelta| option," }, { "cell_id": 7789778040065469689, "cell_origin": "client", "cell_type": "input", "cells": [ { "cell_id": 7408405214600871734, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 2331280886798738445, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n} \\Gamma^{p q}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n} \\Gamma^{p q}\\end{dmath*}" }, { "cell_id": 14412138631638015690, "cell_origin": "server", "cell_type": "latex_view", "cells": [ { "cell_id": 12818109545470385155, "cell_origin": "server", "cell_type": "input_form", "source": "\\Gamma_{m n}^{p q} + \\Gamma_{m}^{q} \\delta_{n}^{p}-\\Gamma_{m}^{p} \\delta_{n}^{q}-\\Gamma_{n}^{q} \\delta_{m}^{p} + \\Gamma_{n}^{p} \\delta_{m}^{q} + 2\\delta_{n}^{p}_{m}^{q}" } ], "source": "\\begin{dmath*}{}\\Gamma_{m n}\\,^{p q}+\\Gamma_{m}\\,^{q} \\delta_{n}\\,^{p}-\\Gamma_{m}\\,^{p} \\delta_{n}\\,^{q}-\\Gamma_{n}\\,^{q} \\delta_{m}\\,^{p}+\\Gamma_{n}\\,^{p} \\delta_{m}\\,^{q}+2\\delta_{n}\\,^{p}\\,_{m}\\,^{q}\\end{dmath*}" } ], "source": "{m,n,p,q}::Indices(position=fixed).\n\\Gamma{#}::GammaMatrix(metric=\\delta).\nex:=\\Gamma_{m n} \\Gamma^{p q};\njoin_gamma(_, use_gendelta=True);" }, { "cell_id": 17814295563262518594, "cell_origin": "client", "cell_type": "input", "source": "" } ], "description": "Cadabra JSON notebook format", "version": 1.0 }