Atoms in the same quantum state

John K Clark (
Sat, 18 Jul 1998 22:29:48 -0700 (PDT)


Eugene Leitl <> wrote:

> Two systems in the same quantum state are indistinguishable.

That's true but I certainly don't think you'd have to go as far as putting a copy of you in the same quantum state for it to be you. That's vast overkill.

>Of course this is pretty useless, for no macroscopic objects occupy
>the same quantum state.

Still not quite macroscopic but they are getting bigger and the progress is remarkable, the current record was set just this week by Daniel Kleppner and Tom Greytak of MIT. They put 100 million hydrogen atoms in the same quantum state by making a Bose Einstein condensate, what makes it even more impressive is that it's much harder to do it with Hydrogen than with more massive alkali atoms. That's 10 times as many atoms as the previous record that was made just a few months ago.

                                            John K Clark

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