Some considerations on the Mac Dowell-Mansouri action

Anabalón, Andrés

doi:10.1088/1126-6708/2008/06/069

Cited by 10 publications

(12 citation statements)

References 36 publications

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“…In order to write this field equation manner analogous to Einstein's equations, one chooses to leave the term proportional to the Einstein tensor on the left side of (9) and using (14) we obtain (17). This result allows us to interpret δL M /δh a as the energymomentum tensor for a second type of matter, not ordinary.…”

Section: Einstein-chern-simons Field Equationsmentioning

confidence: 99%

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Accelerated FRW solutions in Chern–Simons gravity

et al. 2014

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We consider a five-dimensional Einstein-ChernSimons action which is composed of a gravitational sector and a sector of matter where the gravitational sector is given by a Chern-Simons gravity action instead of the EinsteinHilbert action and where the matter sector is given by the socalled perfect fluid. It is shown that (i) the Einstein-ChernSimons (EChS) field equations subject to suitable conditions can be written in a similar way to the Einstein-Maxwell field equations; (ii) these equations have solutions that describe an accelerated expansion for the three possible cosmological models of the universe, namely, spherical expansion, flat expansion, and hyperbolic expansion when α, a parameter of the theory, is greater than zero. This result allows us to conjecture that these solutions are compatible with the era of dark energy and that the energy-momentum tensor for the field h a , a bosonic gauge field from the Chern-Simons gravity action, corresponds to a form of positive cosmological constant. It is also shown that the EChS field equations have solutions compatible with the era of matter: (i) In the case of an open universe, the solutions correspond to an accelerated expansion (α > 0) with a minimum scale factor at initial time that, when time goes to infinity, the scale factor behaves as a hyperbolic sine function. (ii) In the case of a flat universe, the solutions describe an accelerated expansion whose scale factor behaves as an exponential function of time. (iii) In the case of a closed universe there is found only one solution for a universe in expansion, which behaves as a hyperbolic cosine function of time.

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Section: Einstein-chern-simons Field Equationsmentioning

confidence: 99%

“…[14], subsequently Ref. [15][16][17], and most recently Ref. [18] it was pointed out that Chern-Simons theories are connected with some even-dimensional structures known as gauged Wess-Zumino-Witten (gW Z W ) terms.…”

Section: Deceleratedmentioning

confidence: 99%

Accelerated FRW solutions in Chern–Simons gravity

et al. 2014

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“…In order to obtain the dilaton black hole solutions, the potential V (Φ) has to be chosen appropriately. It reads [5]:…”

Section: Gravity Solutionmentioning

confidence: 99%

“…Since the boundary theory is in general not scale invariant below some dynamical scale, it is more important to study non-relativistic holography with scale invariance broken in the bulk. In this paper, we introduce a dilaton field to effectively break the scale invariance of the bulk geometry [5][6][7][8]. We then move on to discuss p-wave superconductors using SU(2) non-Abelian gauge field [4].…”

Section: Introductionmentioning

confidence: 99%

p‐wave superconductors in dilaton gravity

Fan¹

2014

Fortschritte der Physik

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In this paper, we study peculiar properties of p-wave superconductors in dilaton gravity. The scale invariance of the bulk geometry is effectively broken due to the existence of dilaton. By coupling the dilaton to the non-Abelian gauge field, i.e., − 1 4 e −βΦ F a µν F aµν , we find that the dissipative conductivity of the normal phase decreases and approaches zero at the zero frequency as β increases. Intuitively, the system behaves more and more like an insulator. When the hairy solution is turned on, the system crosses a critical point to the superconducting phase. We find that the critical chemical potential decreases with the increasing of β and the maximum height of the conductivity is suppressed gradually which are consistent with our intuition for insulator/supercondutor transition.

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“…[16], subsequently in Ref. [17][18][19] and most recently in Ref. [20], it was pointed out that Chern-Simons theories are connected with even-dimensional gravity theories trough gauged Wess-Zumino-Witten (gWZW) terms and topological defects.…”

Section: Introductionmentioning

confidence: 99%