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Edit detail for SandBoxLorentzTransformation revision 2 of 30

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Editor: Bill Page
Time: 2013/09/22 02:27:30 GMT+0
Note:

changed:
-L(P,Q) == diagonalMatrix([1,1,1,1]) + tensor(P+Q,P+Q)/g(P,Q) - 2*tensor(P,Q)
-L(P,R)
-L(P,R)*P 
L(P,Q) == diagonalMatrix([1,1,1,1]) + tensor(P+Q,P+Q)/(1-g(P,Q)) - 2*tensor(P,Q)
L(R,P)
L(R,P)*R 

Lorentz transformations.

Book by T. Matolcsi

Mathematical Preliminaries

A vector is represented as a nx1 matrix (column vector)

fricas
vect(x:List Expression Integer):Matrix Expression Integer == matrix map(y+->[y],x)
Function declaration vect : List(Expression(Integer)) -> Matrix( Expression(Integer)) has been added to workspace.
Type: Void
fricas
vect [a1,a2,a3]
fricas
Compiling function vect with type List(Expression(Integer)) -> 
      Matrix(Expression(Integer))

\label{eq1}\left[ 
\begin{array}{c}
a 1 
\
a 2 
\
a 3 
(1)
Type: Matrix(Expression(Integer))

Then a row vector is

fricas
transpose(vect [a1,a2,a3])

\label{eq2}\left[ 
\begin{array}{ccc}
a 1 & a 2 & a 3 
(2)
Type: Matrix(Expression(Integer))

Tensor product is

fricas
tensor(v,w) == v*transpose(w)
Type: Void
fricas
tensor(vect [a1,a2,a3], vect [b1,b2,b3])
fricas
Compiling function tensor with type (Matrix(Expression(Integer)),
      Matrix(Expression(Integer))) -> Matrix(Expression(Integer))

\label{eq3}\left[ 
\begin{array}{ccc}
{a 1 \  b 1}&{a 1 \  b 2}&{a 1 \  b 3}
\
{a 2 \  b 1}&{a 2 \  b 2}&{a 2 \  b 3}
\
{a 3 \  b 1}&{a 3 \  b 2}&{a 3 \  b 3}
(3)
Type: Matrix(Expression(Integer))

Applying the Lorentz form produces a row vector

fricas
g(x)==transpose(x)*diagonalMatrix [-1,1,1,1]
Type: Void

or a scalar

fricas
g(x,y)== (transpose(x)*diagonalMatrix([-1,1,1,1])*y)::EXPR INT
Type: Void

For difficult verifications it is sometimes convenient to replace symbols by random numerical values.

fricas
possible(x)==subst(x, map(y+->(y=(random(100) - random(100))),variables x) )
Type: Void
fricas
Is?(eq:Equation EXPR INT):Boolean == (lhs(eq)-rhs(eq)=0)::Boolean
Function declaration Is? : Equation(Expression(Integer)) -> Boolean has been added to workspace.
Type: Void
fricas
Is2?(eq:Equation(Matrix(EXPR(INT)))):Boolean == _
( (lhs(eq)-rhs(eq)) :: Matrix Expression AlgebraicNumber = _
zero(nrows(lhs(eq)),ncols(lhs(eq)))$Matrix Expression AlgebraicNumber )::Boolean
Function declaration Is2? : Equation(Matrix(Expression(Integer))) -> Boolean has been added to workspace.
Type: Void

The AlgebraicNumber? domain can test for numerical equality of complicated expressions involving \sqrt{n}.

fricas
IsPossible?(eq:Equation EXPR INT):Boolean == _
  (possible(lhs(eq)-rhs(eq)) :: Expression AlgebraicNumber=0)::Boolean
Function declaration IsPossible? : Equation(Expression(Integer)) -> Boolean has been added to workspace.
Type: Void
fricas
IsPossible2?(eq:Equation(Matrix(EXPR(INT)))):Boolean == _
  ( map(possible,(lhs(eq)-rhs(eq))) :: Matrix Expression AlgebraicNumber = _
zero(nrows(lhs(eq)),ncols(lhs(eq)))$Matrix Expression AlgebraicNumber )::Boolean
Function declaration IsPossible2? : Equation(Matrix(Expression( Integer))) -> Boolean has been added to workspace.
Type: Void

Massive Objects

An object (also referred to as an obserser) is represented by a time-like 4-vector

fricas
P:=vect [sqrt(p1^2+p2^2+p3^2+1),p1,p2,p3];
Type: Matrix(Expression(Integer))
fricas
g(P,P)
fricas
Compiling function g with type (Matrix(Expression(Integer)),Matrix(
      Expression(Integer))) -> Expression(Integer)

\label{eq4}- 1(4)
Type: Expression(Integer)
fricas
Q:=vect [sqrt(q1^2+q2^2+q3^2+1),q1,q2,q3];
Type: Matrix(Expression(Integer))
fricas
g(Q,Q)

\label{eq5}- 1(5)
Type: Expression(Integer)
fricas
R:=vect [1,0,0,0]

\label{eq6}\left[ 
\begin{array}{c}
1 
\
0 
\
0 
\
0 
(6)
Type: Matrix(Expression(Integer))
fricas
g(R,R)

\label{eq7}- 1(7)
Type: Expression(Integer)

Associated with each such vector is the orthogonal 3-d Euclidean subspace E_P =\{x | P \cdot x = 0\}

Relative Velocity

An object Q has a unique relative velocity w(P,Q) with respect to object P given by

fricas
w(P,Q)==-Q/g(P,Q)-P
Type: Void

Lorentz factor

fricas
gamma(v)==1/sqrt(1-g(v,v))
Type: Void

Binary Boost

fricas
b(P,v)==gamma(v)*(P+v)
Type: Void

Observer P measures velocity u. u is space-like and in E_P.

fricas
u:=w(P,Q);
fricas
Compiling function w with type (Matrix(Expression(Integer)),Matrix(
      Expression(Integer))) -> Matrix(Expression(Integer))
Type: Matrix(Expression(Integer))
fricas
g(P,u)

\label{eq8}0(8)
Type: Expression(Integer)
fricas
possible(g(u,u))::EXPR Float
fricas
Compiling function possible with type Expression(Integer) -> 
      Expression(Integer)

\label{eq9}0.9999857413_817665124(9)
Type: Expression(Float)

fricas
L(P,Q) == diagonalMatrix([1,1,1,1]) + tensor(P+Q,P+Q)/(1-g(P,Q)) - 2*tensor(P,Q)
Type: Void
fricas
L(R,P)
fricas
Compiling function L with type (Matrix(Expression(Integer)),Matrix(
      Expression(Integer))) -> Matrix(Expression(Integer))

\label{eq10}\left[ 
\begin{array}{cccc}
{{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}-{{p 3}^{2}}-{{p 2}^{2}}-{{p 1}^{2}}+ 1}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}& - p 1 & - p 2 & - p 3 
\
p 1 &{{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+{{p 1}^{2}}+ 1}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{p 1 \  p 2}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{p 1 \  p 3}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}
\
p 2 &{{p 1 \  p 2}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+{{p 2}^{2}}+ 1}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{p 2 \  p 3}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}
\
p 3 &{{p 1 \  p 3}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{p 2 \  p 3}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}&{{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+{{p 3}^{2}}+ 1}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}
(10)
Type: Matrix(Expression(Integer))
fricas
L(R,P)*R

\label{eq11}\left[ 
\begin{array}{c}
{{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}-{{p 3}^{2}}-{{p 2}^{2}}-{{p 1}^{2}}+ 1}\over{{\sqrt{{{p 3}^{2}}+{{p 2}^{2}}+{{p 1}^{2}}+ 1}}+ 1}}
\
p 1 
\
p 2 
\
p 3 
(11)
Type: Matrix(Expression(Integer))