Bose-Einstein condensate
From Freepedia
A Bose-Einstein condensate is a gaseous superfluid phase formed by atoms cooled to temperatures very near to absolute zero. The first such condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder, using a gas of rubidium atoms cooled to 170 nanokelvins (nK). Under such conditions, a large fraction of the atoms collapse into the lowest quantum state, producing a superfluid.
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Theory
The collapse of the atoms into a single quantum state is known as Bose condensation or Bose-Einstein condensation. This phenomenon was predicted in the 1920s by Satyendra Nath Bose and Albert Einstein, based on Bose's work on the statistical mechanics of photons, which was then formalized and generalized by Einstein. The result of the efforts of Bose and Einstein is the concept of a Bose gas, governed by the Bose-Einstein statistics, which describes the statistical distribution of certain types of identical particles now known as bosons. Bosonic particles, which include the photon as well as atoms such as helium-4, are allowed to share quantum states with each other. Einstein speculated that cooling bosonic atoms to a very low temperature would cause them to fall (or "condense") into the lowest accessible quantum state, resulting in a new form of matter.
The critical temperature (in a uniform three-dimensional gas with no or uniform external potential) at which this happens can be derived to be:
- <math>T_c=\left(\frac{n}{\zeta(3/2)}\right)^{2/3}\frac{2\pi h^2}{m k_B}</math>
where:
-
<math>T_c</math> is the critical temperature, <math>n</math> the particle density, <math>m</math> the mass per boson, <math>h</math> Planck's constant, <math>k_B</math> the Boltzmann constant, and <math>\zeta</math> the Riemann zeta function; <math>\zeta(3/2)</math> ≈ 2.6124.
See also
- Electromagnetically induced transparency
- Slow glass
- Gravastar
- Superfluid
- Supersolid
- Super-heavy atom
- Tonks-Girardeau gas
- Gas in a box
- Bose gas
- Fermionic condensate
External links
- Bose-Einstein Condensates at JILA
- Atom Optics at UQ
- Europhysics News Report on Slowed Light
- Einstein's manuscript on the Bose-Einstein condensate discovered at Leiden University
- Bose-Einstein Condensation of Helium and Hydrogen inside Bundles of Carbon Nanotubes
References
- S. N. Bose, Z. Phys. 26, 178 (1924)
- A. Einstein, Sitz. Ber. Preuss. Akad. Wiss. (Berlin) 22, 261 (1924)
- L.D. Landau, J. Phys. USSR 5, 71 (1941)
- L.D. Landau, Phys. Rev. 60, 356 (1941)
- M.H. Anderson, J.R. Ensher, M.R. Matthews, C.E. Wieman, and E.A. Cornell, Science 269, 198 (1995).
- D.S. Jin, J.R. Ensher, M.R. Matthews, C.E. Wieman, and E.A. Cornell, Phys. Rev. Lett. 77, 420 (1996).
- M.R. Matthews, B.P. Anderson,P.C. Haljan, D.S. Hall, C.E.Wieman, E.A. Cornell, Phys. Rev. Lett. 83, pp. 2498 (1999)
- S. Jochim, M. Bartenstein, A. Altmeyer, G. Hendl, S. Riedl, C. Chin, J. Hecker Denschlag, and R. Grimm, Science 302, 2101 (2003)
- M. Greiner, C.A. Regal, and D.S. Jin, Nature 426, 537 (2003)
- M.W. Zwierlein, C.A. Stan, C.H. Schunck, S.M.F. Raupach, S. Gupta, Z. Hadzibabic, and W. Ketterle, Phys. Rev. Lett. 91, 250401 (2003).
- C. J. Pethick and H. Smith, "Bose-Einstein Condensation in Dilute Gases", Cambridge University Press, Cambridge, 2004.
| Phases of matter |
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| Solid | Amorphous solid | Liquid | Gas | Gel | Plasma | Superfluid | Supersolid | Degenerate matter | Neutronium | Quark-gluon plasma | Fermionic condensate | Bose-Einstein condensate | Strange matter |
