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This page features interactive sage calculations concerned with aspects of loop Quantum Gravity = Sage Interactions - Loop Quantum Gravity =
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<<TableOfContents>>



== Quantum tetrahedron volume eigenvalues ==
by David Horgan.
Given the values of J1, J2, J3 and J4 this interact calculates the volume eigenvalues of a quantum tetrahedron.

{{{#!sagecell

html('<h3>Quantum tetrahedron Volume Eigenvalue</h3>')
html('Enter the four J values into the input boxes')
html('k values k ranges from kmin to kmax in integer steps')
html('The dimension d of the Hilbert space H4, d = kmax - kmin + 1')
html('kmin = max(|j1-j2|,|j3 -j4|) kmax = min(j1+j2,j3 +j4)')
html('The the dimension of the hilbert space is given by d = kmax -kmin + 1')
html('V^2 =M = 2/9(real antisymmetrix matrix))')
html('Spins must satisfy (j1+j2)<= (j3+j4)')
html('Reference: Bohr-Sommerfeld Quantization of Space by Eugenio Bianchi and Hal M. Haggard ')






import numpy



@interact




def _(j1 = input_box(6.0, 'J1'),
      j2= input_box(6.0, 'J2'),
      j3= input_box(6.0, 'J3'),
      j4= input_box(7.0, 'J1'), auto_update=False):
    if (j1+j2)<= (j3+j4):
        html('<h3>Values of Volume Eigenvalue</h3>')
        kmin = int(max(abs(j1-j2),abs(j3 -j4)))
        kmax = int(min((j1+j2),(j3 +j4)))
        d = kmax -kmin + 1
        y=numpy.arange(kmin,kmax+1,1)
        kmatrix = matrix(CDF,int(d), int(d))
        r=list()
        for j in range(d):
            k=int(y[j])
            c1 = -i*k
            c2 = sqrt(4*k*k - 1)
            c3 = sqrt(j1*(j1+1))
            c4 = sqrt((2*j1+1))
            c5 = sqrt(j3*(j3+1))
            c6 = sqrt((2*j3+1))
            c7 = wigner_6j(j1,1,j1,k,j2,k-1)
            c8 = wigner_6j(j3,1,j3,k,j4,k-1)
            a = c1*c2*c3*c4*c5*c6*c7*c8
            r.append(a)
            q=numerical_approx(a, digits=10)
            #print r
        for j in range(d-1):
            kmatrix[[j],[j+1]]=r[j+1]
            kmatrix[[j+1],[j]]=-r[j+1]
            #print kmatrix
    
        M = (2/9)*kmatrix
        #print M
        s=M.eigenvalues()
        #print s
    
        for j in range(d):
            e= sqrt(s[j])
            if e.imag() ==0:
                print (e)

}}}

Sage Interactions - Loop Quantum Gravity

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Quantum tetrahedron volume eigenvalues

by David Horgan. Given the values of J1, J2, J3 and J4 this interact calculates the volume eigenvalues of a quantum tetrahedron.

interact/Loop Quantum Gravity (last edited 2019-04-06 16:42:59 by chapoton)