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5-(4-BromoÂanilinomethylÂene)-2,2-dimethyl-1,3-dioxane-4,6-dione
In the title compound, C13H12BrNO4, the dihedral angles between the aminoÂmethylÂene group and the dioxane ring and between the benzyl ring and the aminoÂmethylÂene unit are 7.96 (4) and 12.15 (4)°, respectively. The dioxane ring shows a half-boat conformation, in which the C atom between the dioxane ring O atoms is 0.460 (8) Å out of the plane through the remaining ring atoms. An intraÂmolecular N—H⋯O hydrogen bond may stabilize the planar conformation of the molÂecule. An interÂmolecular C—H⋯O interÂaction is also present
BCS-BEC crossover in a relativistic boson-fermion model beyond mean field approximation
We investigate the fluctuation effect of the di-fermion field in the
crossover from Bardeen-Cooper-Schrieffer (BCS) pairing to a Bose-Einstein
condensate (BEC) in a relativistic superfluid. We work within the boson-fermion
model obeying a global U(1) symmetry. To go beyond the mean field approximation
we use Cornwall-Jackiw-Tomboulis (CJT) formalism to include higher order
contributions. The quantum fluctuations of the pairing condensate is provided
by bosons in non-zero modes, whose interaction with fermions gives the
two-particle-irreducible (2PI) effective potential. It changes the crossover
property in the BEC regime. With the fluctuations the superfluid phase
transition becomes the first order in grand canonical ensemble. We calculate
the condensate, the critical temperature and particle abundances as
functions of crossover parameter the boson mass.Comment: The model Lagrangian is re-formulated by decomposing the complex
scalar field into its real and imaginary parts. The anomalous propagators of
the complex scalar are then included at tree level. All numerical results are
updated. ReVTex 4, 13 pages, 10 figures, PRD accepted versio
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