An analysis is made of the results of a recent polarization correlation experiment by Bovino (unpublished) where about 60,000 data have been obtained. I assume that the state of the photon pairs produced in the source (a non-linear crystal) are in a (sligh
a)theinitialtwo-photonstate(3)withweightµaµb,
b)asingle-photonstatehorizontallypolarizedforAlicewithweightµa(1 µb)/(2+2γ+γ2),
c)asingle-photonstateverticallypolarizedforAlicewithweightµa(1 µb)(1+γ)2/(2+2γ+γ2)),
d)asingle-photonstatehorizontallypolarizedforBobwithweightµb(1 µa)(1+γ)2/(2+2γ+γ2)),
e)asingle-photonstateverticallypolarizedforBobwithweightµb(1 µa)/(2+2γ+γ2),
f)thevacuumstatewithweight1 µa µb+µaµb.
3.ThetransmittancesofthepolarizationanalyzersofAliceforhorizontalorverticalpolarizationaresuchthat,whenabeamoflinearlypolarizedlightwithintensityIinarrivesatthepolarizer,thetransmittedandre ectedintensitiesare,respectively,
1Ia+(θ)=Iin(Ta+ ta+)cos2θ+ta+=
2Iin[(Ta +ta )+(Ta ta )cos2θ],
andsimilarforBobwiththechangesa→b.ThesumT+tisclosetounitywhilst0<t<<1.
4.Thequantume cienciesofthe4detectorsaredi erent,sayζa+andζa forAliceandζb+andζb forBob.
Intheidealsituationthequantumpredictionforthe4coincidenceprob-abilitiesofstate(3)wouldbe[3]
P++=1
[(1+γ)sinαsinβ+cosαcosβ]2,
P +=1+(1+γ)12
1+(1+γ)2[(1+γ)cosαsinβ sinαcosβ]2,(5)
whereα(β)istheangleofAlice´s(Bob´s)polarizationanalyzer.NowIintroducethemostrelevantnon-idealitiesasfollows.Duetolossesand
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