# Beyond the 5th state of matter?

1. Jun 13, 2004

### bjon-07

I just finshed "Einstein's Cosmos" my Michal Kaku, in this book Dr. Kaku takes about the 5th state of matter or Einstien-Bosen Condinstate, which the book says occurs at extermly low temperatures.

I never knew that matter exisited in this form (is it true that einstein-bosen condistate does not follow Pauli's exclusion principle?

Any ways, i was wondering if their are any of states of matter that i do not know about other than the four common ones (gase, soild, liquid, plamsa)?

Thank you for your time :)

2. Jun 14, 2004

### selfAdjoint

Staff Emeritus
Pauli's exlusion principle only concerns fermions. The particles in a BEC are bosons, which can occupy the same state. In effect they merge into a single large particle.

3. Jun 14, 2004

### bjon-07

Thank you for the anwser but

Thank you for clareifying that for me, but would you consider BEO to be the "5th state of matter".

Can you please explain to me why boson do not have to follow the pauli's exlucsion principle, from what i understand, the pauli exlcuison principle states that to pieces of matter (electrons) cannot occupie the same spaces (have to same Q numbers).

How is it possible to two boson to be in the same place

Thank you

4. Jun 15, 2004

### Gokul43201

Staff Emeritus
Perhaps...after all, macroscopic BECs have been made. Superfluidity is something you don't see in the other states, and historically, viscosity has been a prime distinguishing characteristic of a "state of matter".

Because the Exclusion Principle was plucked out of thin air to explain how electrons (fermions) behave. There is no reason for everybody to obey a law created for only certain specific people.

Eventually, if you get to learn what (symmetric & anti-symmetric)wavefunctions are, this will all make much more sense.

5. Jun 15, 2004

### Silverious

Bosons' spin consists of interger numbers(1,2,3..) while fermions are of halves(1/2,3/2,5/2...).

Also, I for one would like to know more about fermionic condensate. Anyone care to elaborate?

6. Jun 15, 2004

### selfAdjoint

Staff Emeritus
There's a certain disconnect between your first sentence and your second. You seem to be saying that Pauli's principle was arbitrary and therefore not worth bothering about, while deeper consideration of symmetric and antisymmetric wavefunctions will justify it.

Did you know that Pauli himself worked out the first "spin-statistics theorem" based on symmetry and antisymmetry of wave functions? It wasn't as rigorous as later ones, but he didn't just pull the exclusion principle out of you-know-where.

7. Jun 15, 2004

### Gokul43201

Staff Emeritus
No, I definitely don't mean to imply that the Exclusion Principle is arbitrary.

And I guess I was wrong about the out-of-the-air thingy. I thought the Exclusion principle was first proposed to explain atomic spectra...and the symmetric spin-antisymmetric spatial wavefn. calculations for Fermions came later. Now that I think about it, what you say makes sense. Hard to arrive at the former, without going through the latter.

Last edited: Jun 15, 2004
8. Jun 16, 2004

### Megus

so can you call fermione condesate the 6th state of matter [read 'bout it in Scientific American few months ago] ?

9. Jun 16, 2004

### bjon-07

Megus do you remember which sci-ameican that artical was in. I would like to read that artical. Thank you.

By the can someone elabrate further one what defines a state a matter.

10. Jun 16, 2004

### Megus

As far as I remember it was in the issue with 4 articles about cosmology - the cover was gold-yellow.

11. Jun 18, 2004

### Gokul43201

Staff Emeritus
Unless, there's something new that I'm not aware of, Fermions can not condense into a single state like bosons do.

EDIT : There IS something new that I was not aware of ...and have not yet understood.

Last edited: Jun 22, 2004
12. Jun 22, 2004

### bjon-07

Does any one know WHY they cannot behave in this manner while boson can.

13. Jun 22, 2004

### Gokul43201

Staff Emeritus
The idea works the other way round. Particles that obey the FD statistics (obey Exclusion) are called Fermions. And particles that obey the BE statistics (can condense into a single, macroscopic state, etc.) are called Bosons.

This results from the symmetry of the particle's wavefunction.

14. Jun 22, 2004

### Nereid

Staff Emeritus
Some info of fermionic condensates here (yes, it says '6th state of matter').

I'm wondering what the degnerate states of matter are called which comprise white dwarf stars (all the electrons - at some small distance below the surface - are 'free', but, being fermions, can have only one (two?) occupying each energy state; pretty incompressible) and neutron stars (essentially giant atomic nuclei, with near zero net charge)? Are they different states of matter? And what about 'quark stars', or 'quark-gluon plasmas'??

15. Jun 22, 2004

### Silverious

So the fermions form basically cooper pairs and behave as bosons?

If that's true, then are they bosons, or fermions when they condense?

16. Jun 23, 2004

### think

First off all we need to define STATE OF MATTER! Is it just a somewhat similar arraangements of atoms or something else???

17. Jul 12, 2004

### ArmoSkater87

if thats the case, then there can be several states matter. For instance, 4th state is matter, plasma, it just an atom completly ionized. Then couldnt you say, the 5th state of matter is free floating protons and neutrons. I know neutrons arent stable outside the nucleus. What i said is simply a thought. :P

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