# Bose-Einstein Condensate Properties

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• FallenApple
In summary, a Bose Einstein condensate is a state of matter that occurs at extremely low temperatures where the quantum wave states of atoms overlap and become one single object. It is not more rigid than solids and is not a stable state of matter, as the stable state at such low temperatures would be solid. The identities of individual atoms are not erased, but they behave coherently and are fundamentally indistinguishable. BECs are classified as a separate state of matter due to their unique properties and behavior. They require a reduction in temperature and collisions with other atoms to form. They are not more dense than solids, but rather very dilute.
bob012345 said:
Thanks. That brings up the concept of what do we mean by 'measurement'. I believe every interaction between everything in nature constitutes a 'measurement' and thus obeys the HUP at all times and situation. Thus every Rb atom in the BEC obeys the HUP at continuously. I assume you disagree? I never thought the HUP was principle about humans taking data.
This is getting off-topic.

But no, all interaction is not a measurement, especially not a particular type of measurement. Take the example of spin. If a prepare system in the spin-up state according to the z axis, it is in an undetermined spin state along x and y. If something interacts with that spin in a way that can't change the spin, by your account its spin would become indeterminate with respect to all axes. I expect it to stay in the spin-up state along z.

Anyway, you will find a few recent threads on the question of the HUP and its meaning. Please have a look at them.

DrClaude said:
This is getting off-topic.

But no, all interaction is not a measurement, especially not a particular type of measurement. Take the example of spin. If a prepare system in the spin-up state according to the z axis, it is in an undetermined spin state along x and y. If something interacts with that spin in a way that can't change the spin, by your account its spin would become indeterminate with respect to all axes. I expect it to stay in the spin-up state along z.

Anyway, you will find a few recent threads on the question of the HUP and its meaning. Please have a look at them.
Thanks, I will.

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