Does quantum entanglement, in and of itself, make the constituent particles more sensitive to external fields and forces?

Question

I just watched PBS Space time episode called, 'Navigating with quantum entanglement'.

At about 10:25, host Matthew O'Dowd says that Peter Hore of Oxford University reviewed the evidence for quantum biology, especially birds' magneto-navigation, and concluded that only truly entangled particles, not just ones interacting via 'ordinary' 'spin-spin' interaction, could feel the weak influence of Earth's magnetic field.

Why? How could a particular (small) number of entangled particles be noticeably more affected by a field than the same number of interacting, albeit non-entangled, particles?

P.S.: Where exactly does the line lay between strongly 'interacting' or 'coupled' particles and truly 'entangled' ones? How close do they have to get, or what have you?

Answer 1

Only to the extent that an entangled pair of molecules (specifically, in this case, a radical pair) will have correlated states. If these states were positively correlated then an entangled pair would react more strongly on average to a magnetic field than a non-entangled pair, because the reactions of the entangled pair would reinforce one another. On the other hand, if the states of the entangled molecules were negatively correlated then this would have the opposite effect - their reactions would cancel out, so the entangled pair would be less sensitive on average than an unentangled pair.

According to this Wikipedia article, radical pair production has been proposed as one possible explanation for magnetoreception in animals, but the connection is not proven and the exact details of the mechanism remain unknown.