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An ensemble of interacting particles will, over time, develop entanglement between widely separated parts*, so this is similar to asking whether an interacting system can still be a BEC. The short answer is yes, but a subtlety is that various authors define BEC in slightly different ways. One way of defining BEC, as I mention in a recent answer, is the ...


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It is not possible to get a Bose-Einstein condensate of photons in three-dimensional equilibrium. Since the photons have no mass gap and no chemical potential, they can just be absorbed by the walls. In this example, however, the experimenters used a gas that was out of equilibrium, with different effective temperatures for the motion in different ...


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The Landau criterion is not in itself a criterion for superfluidity, but a criterion for the breakdown of superfluidity. Indeed, if applied to insulators or ordinary fluids, it would tell you that all of these are also superfluid... What the Landau criterion tells you is the velocity of the superfluid flow at which excitations are created from the ...


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One can avoid the concept of symmetry breaking in this context, to avoid "non-conservation of the particle number". People have devised way to do that, see for example http://arxiv.org/pdf/cond-mat/0105058v1.pdf. However, all these approaches gives the same results than standard Bogoliubov-like methods in the thermodynamic limit. This is not too ...


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Well, the trite answer is "no" because every bit of matter we see around us is in an entangled state. It's the normal classical world.



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