نتایج جستجو برای: gas condensate

تعداد نتایج: 254403  

2008
Michael C. Birse

Soft-pion theorems are used to show how chiral symmetry constrains the contributions of low-momentum pions to the quark condensate, the pion decay constant and hadron masses, all of which have been proposed as signals of partial restoration of chiral symmetry in matter. These have contributions of order T 2 for a pion gas or of order mπ for cold nuclear matter, which have different coefficients...

2007

In an earlier paper (J. Phys. A: Math. Gen. 26 (1993) 4689) we introduced the notion of cycle percolation in the Bose gas and conjectured that it occurs if and only if there is Bose-Einstein condensation. Here we give a complete proof of this statement for the perfect and the imperfect (mean-field) Bose gas and also show that in the condensate there is an infinite number of macroscopic cycles.

2000
Jens O. Andersen

We consider the ground state of a trapped Bose-Einstein condensate in two dimensions. In the mean-field approximation, the ground state density profile satisfies the Gross-Pitaevskii equation. We compute the leading quantum corrections to the density profile to second order in an expansion around the Thomas-Fermi limit. By summing the ladder diagrams,we are generalizing Schick’s result for the ...

Ali Jodeyri Entezari Amir Nasiri Hassan Bahrami Reza Azin,

In this work, studies of underground gas storage (UGS) were performed on a partially depleted, naturally fractured gas reservoir through compositional simulation. Reservoir dynamic model was calibrated by history matching of about 20 years of researvoir production. Effects of fracture parameters, i.e. fracture shape factor, fracture permeability and porosity were studied. Results show...

Journal: :Science 1998
Miesner Stamper-Kurn Andrews Durfee Inouye Ketterle

The formation of a Bose-Einstein condensate of a dilute atomic gas has been studied in situ with a nondestructive, time-resolved imaging technique. Sodium atoms were evaporatively cooled close to the onset of Bose-Einstein condensation and then suddenly quenched to below the transition temperature. The subsequent equilibration and condensate formation showed a slow onset distinctly different fr...

2001
Y. Q. Zhang C. Y. Zhai Y. Q. Wang J. W. Zhang

The paper sets up the theory model that includes in the exchange of matter and energy between the heat background gas and the condensate on the base of Bose-Einstein Condensate(BEC) at the premise of induced gravity-like. We introduce the coefficient of loss ratio of three body recombination collision. The conclusion indicates that the model accords with the real situation of the Schwartzchild ...

2001
Immanuel Bloch Theodor W. Hänsch Tilman Esslinger

Using continuous radio-frequency waves a coherent beam of atoms can be extracted from a magnetically trapped gaseous Bose-Einstein condensate. These novel atomic beams have matter-wave properties that are very similar to those of laser light in classical optics and are therefore called atom lasers. Furthermore, coupling out atoms from a Bose gas allows one to probe the dramatic changes in the p...

2001
I. Cabrera D. Oliva

It is suggested a general mechanism through which a -type behavior is produced in the speci c heat of a Bose gas near the critical temperature Tc. It is essential that the quasiparticle spectra have a gap proportional to the condensate. It works for a general class of quasiparticle spectra, and in particular, for the weakly interacting Bose gas. The introduction of a chemical potential in the t...

2004
K. K. Rajagopal

We evaluate the thermodynamic critical angular velocity Ωc(T ) for creation of a vortex of lowest quantized angular momentum in a strictly two-dimensional Bose gas at temperature T , using a mean-field two-fluid model for the condensate and the thermal cloud. Our results show that (i) a Thomas-Fermi description of the condensate badly fails in predicting the particle density profiles and the en...

Journal: :Physical review letters 2005
Axel Griesmaier Jörg Werner Sven Hensler Jürgen Stuhler Tilman Pfau

We report on the generation of a Bose-Einstein condensate in a gas of chromium atoms, which have an exceptionally large magnetic dipole moment and therefore underlie anisotropic long-range interactions. The preparation of the chromium condensate requires novel cooling strategies that are adapted to its special electronic and magnetic properties. The final step to reach quantum degeneracy is for...

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