"Exercise 7.8 (Dr. W.Lindner)" u = (1,0) d = (0,1) uu = (1,0,0,0) ud = (0,1,0,0) du = (0,0,1,0) dd = (0,0,0,1) -- waves: -- uu ud du dd -- 1 2 3 4 psi1 = (1/2, 1/2, 1/2, 1/2) psi2 = (1/sqrt(2),0,0, 1/sqrt(2)) psi3 = (3/5, 4/5, 0, 0) -- per example: psi = psi3 "1. calculate ALICE's density matrix" "using rho_a'a = Sum( psi*(a,b).psi(a',b) b=uu,ud,du,dd" rhouu = psi[1]*psi[1]+psi[2]*psi[2] rhouu rhoud = psi[3]*psi[1]+psi[4]*psi[2] rhoud rhodu = psi[1]*psi[3]+psi[2]*psi[4] rhodu rhodd = psi[3]*psi[3]+psi[4]*psi[4] rhodd "ALICE density matrix:" rhoAlice = ((rhouu,rhoud),(rhodu,rhodd)) rhoAlice "2. calculate BOB's density matrix" "using rho_b'b = Sum( psi*(a,b).psi(a,b') a=uu,ud,du,dd" -- uu ud du dd -- 1 2 3 4 rhouu = psi[1]*psi[1]+psi[3]*psi[3] rhouu rhoud = psi[2]*psi[1]+psi[4]*psi[3] rhoud rhodu = psi[1]*psi[2]+psi[3]*psi[4] rhodu rhodd = psi[2]*psi[2]+psi[4]*psi[4] rhodd "BOB density matrix:" rhoBob = ((rhouu,rhoud),(rhodu,rhodd)) rhoBob Run