Hi Georgina,
You ask: "What is parameter lambda? Not just wavelength? Is it a Part of standard entanglement theory? How does sharing this parameter value give the correlated outcomes?"
lambda is a hidden variable and insofar a physical property of a particle. More is not needed for the purpose of the model but can be subject for further research.
How sharing this parameter value gives the correlated outcomes is described in the paper.
This is valid for the singlet state. For single photons the measurement value also depends on the polarization which in case of entangled photons is given by the polarizer setting .
What exists before measurement is the value of lambda. Together with a particular setting of the polarizers or the Stern Gerlach apparatus the measurement values are determined.
Robert:
First of all: After Bell's theorem no local model can reproduce spin measurement results with entangled photons or electrons.
The paper shows there is a local model which can do so thus refuting Bell's theorem.
It is not necessary that the model replaces quantum mechanics.
Secondly indistinguishability is not the sole reason why the model works. Model assumption MA4 is also necessary.
