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**Kastening, Boris** (2004):

*Nonuniversal critical quantities from variational perturbation theory and their application to the Bose-Einstein condensation temperature shift.*

In: Physical Review A, American Physical Society, pp. 043621-1-043621-20, 70, (4), ISSN 1050-2947, [Online-Edition: http://dx.doi.org/10.1103/PhysRevA.70.043621],

[Article]

## Abstract

For an OsNd-symmetric scalar field theory with Euclidean action ed3 xf 12 u ¹fu2+ 12 rf2+ 14!uf4g, where f=sf1 , . . . ,fNd is a vector of N real-field components, variational perturbation theory through seven loops is employed for N=0,1,2,3,4 to compute the renormalized value of r / sN+2du2 at the phase transition. Its exact large-N limit is determined as well. We also extend an earlier computation of the interaction-induced shift Dkf2l /Nu from N=1,2,4 to N=0,3. For N=2, the results for the two quantities are used to compute the second-order shift of the condensation temperature of a dilute Bose gas, both in the homogenous case and for the wide limit of a harmonic trap. Our results are in agreement with earlier Monte Carlo simulations for N =1,2,4. The Appendix contains previously unpublished numerical seven-loop data.

Item Type: | Article |
---|---|

Erschienen: | 2004 |

Creators: | Kastening, Boris |

Title: | Nonuniversal critical quantities from variational perturbation theory and their application to the Bose-Einstein condensation temperature shift |

Language: | English |

Abstract: | For an OsNd-symmetric scalar field theory with Euclidean action ed3 xf 12 u ¹fu2+ 12 rf2+ 14!uf4g, where f=sf1 , . . . ,fNd is a vector of N real-field components, variational perturbation theory through seven loops is employed for N=0,1,2,3,4 to compute the renormalized value of r / sN+2du2 at the phase transition. Its exact large-N limit is determined as well. We also extend an earlier computation of the interaction-induced shift Dkf2l /Nu from N=1,2,4 to N=0,3. For N=2, the results for the two quantities are used to compute the second-order shift of the condensation temperature of a dilute Bose gas, both in the homogenous case and for the wide limit of a harmonic trap. Our results are in agreement with earlier Monte Carlo simulations for N =1,2,4. The Appendix contains previously unpublished numerical seven-loop data. |

Journal or Publication Title: | Physical Review A |

Volume: | 70 |

Number: | 4 |

Publisher: | American Physical Society |

Divisions: | 11 Department of Materials and Earth Sciences > Material Science > Advanced Thin Film Technology 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences |

Date Deposited: | 09 Jan 2013 08:52 |

Official URL: | http://dx.doi.org/10.1103/PhysRevA.70.043621 |

Identification Number: | doi:10.1103/PhysRevA.70.043621 |

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