Read more at: http://phys.org/news/2014-04-micro-macro-entangled-cat-states-day.html#jCp
In Schrödinger's famous thought experiment, a cat's quantum state becomes entangled with the quantum state of a decaying nucleus, resulting in the odd situation that the cat is both alive and dead at the same time. The thought experiment was originally intended to convey the absurdity of applying quantum mechanics to macroscopic objects, but recently physicists have been questioning whether "quantum" effects such as entanglement and superposition may apply on all scales.
In order to extend quantum effects to the macroscopic level, physicists are working on creating entanglement between a macroscopic and microscopic system. This situation is very similar to that of the entanglement between the quantum state of the macroscopic cat and that of the microscopic decaying nucleus. So far, micro-macro entanglement has been experimentally demonstrated in optical systems, and is currently being pursued in other areas, such as electro-mechanical and opto-mechanical systems.
In a new study published in Physical Review Letters, physicists Roohollah Ghobadi, et al., have proposed a method for generating optomechanical micro-macro entanglement.