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I feel like the answer should be "no" since all superfluids are not strictly BEC since they can undergo a Kosterlitz–Thouless transition in 2D, for example. I believe the ideal gas isn't superfluid, but is there any experimental evidence of a BEC without superfluid properties? I've been searching with no luck.

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up vote 4 down vote accepted

You can have superfluids that are not BECs and BECs that are not superfluid. Let me quote a text, "Bose-Einstein Condensation in Dilute Gases", Pethick & Smith, 2nd edition (2008), chapter 10:

Historically, the connection between superfluidity and the existence of a condensate, a macroscopically occupied quantum state, dates back to Fritz London's suggestion in 1938, as we have described in Chapter 1. However, the connection between Bose-Einstein condensation and superfluidity is a subtle one. A Bose-Einstein condensed system does not necessarily exhibit superfluidity, an example being the ideal Bose gas for which the critical velocity vanishes, as demonstrated in Sec. 10.1 below. Also lower-dimensional systems may exhibit superfluid behavior in the absence of a true condensate, as we shall see in Chapter 15.

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I really feel that my answer is a lose. I couldn't find any evidence either. I suspect it has to be done because it's such an important part of the "accepted wisdom" that goes into the leading textbook. The professor who I took the class from just left WSU for U Texas, Dallas, so he's not around to ask. :( – Carl Brannen Jul 3 '12 at 23:46
A BEC without any interactions is not a superfluid, which is the example described in the above passage. However, I do not think that condensation without superfluidity has been observed. Exotic condensates, like photon condensates, exist for which the concept of superfluidity might not makes sense. – emarti Dec 21 '12 at 23:06

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