Here's the breakdown:
* Individual atoms in a BEC do have quantum fluctuations: They don't have a fixed position like a marble on a table. Instead, they exist in a superposition of states, meaning their position is described by a probability wave. So, in that sense, they are constantly "moving" or fluctuating.
* The BEC as a whole can exhibit collective motion: The atoms in a BEC are all in the same quantum state, which means they behave like a single entity. This entity can be moved and manipulated as a whole, like a giant atom.
* The BEC doesn't exhibit thermal motion: Unlike a regular gas, the atoms in a BEC don't have random thermal motion. This is because they are all in the lowest energy state possible.
So, to answer your question:
* Individual atoms in a BEC do have quantum fluctuations, which can be interpreted as a form of "motion".
* The BEC as a whole can be moved and manipulated, exhibiting collective motion.
* The BEC doesn't exhibit random thermal motion.
It's important to remember that the concept of "motion" in quantum mechanics is different from our everyday understanding.
