If macroscopic objects become entangled, how can we tell? The usual way to measure entanglement on the microscopic level is to carry out a
These kinds of quantum measurements are not possible with macroscopic bodies but recent work suggests there may be other ways to spot entanglement. Vlatko Vedral at the
Their idea is based on the third law of thermodynamics which states that the entropy at absolute zero is dependent only on the degeneracy of the ground state. This in turn implies that the specific heat capacity of a material must asymptotically approach zero as the temperature gets closer to absolute zero. But if particles within the material were entangled, Vedral and pals say this would not be the case.
Best of all, measuring heat capacity is standard technique so there’s no reason this can’t be done pronto.