Irrotational perfect fluids with a purely electric Weyl tensor

1989 ◽  
Vol 6 (7) ◽  
pp. 949-960 ◽  
Author(s):  
A Barnes ◽  
R R Rowlingson
Keyword(s):  
1975 ◽  
Vol 16 (12) ◽  
pp. 2361-2363 ◽  
Author(s):  
E. N. Glass
Keyword(s):  

2008 ◽  
Vol 30 ◽  
pp. 241-244
Author(s):  
N. Van den Bergh ◽  
H. Reza Karimian

Author(s):  
YU NAKAYAMA

I will discuss how an unexpected form of trace anomaly can be obtained from holographic models with no simple string interpretation. In addition to the usual trace anomaly, Euler density and Weyl tensor squared, we pursue the possibility that it is given by Ricci scalar and Hirzebruch-Pontryagin density. It has a deep connection with scale but non-conformal field theories and their holographic dual. I would like to urge you to judge whether such holographic theories are consistent or pathological.


2016 ◽  
Vol 13 (02) ◽  
pp. 1650015 ◽  
Author(s):  
Carlo Alberto Mantica ◽  
Young Jin Suh

In this paper we present some new results about [Formula: see text]-dimensional pseudo-Z symmetric space-times. First we show that if the tensor Z satisfies the Codazzi condition then its rank is one, the space-time is a quasi-Einstein manifold, and the associated 1-form results to be null and recurrent. In the case in which such covector can be rescaled to a covariantly constant we obtain a Brinkmann-wave. Anyway the metric results to be a subclass of the Kundt metric. Next we investigate pseudo-Z symmetric space-times with harmonic conformal curvature tensor: a complete classification of such spaces is obtained. They are necessarily quasi-Einstein and represent a perfect fluid space-time in the case of time-like associated covector; in the case of null associated covector they represent a pure radiation field. Further if the associated covector is locally a gradient we get a Brinkmann-wave space-time for [Formula: see text] and a pp-wave space-time in [Formula: see text]. In all cases an algebraic classification for the Weyl tensor is provided for [Formula: see text] and higher dimensions. Then conformally flat pseudo-Z symmetric space-times are investigated. In the case of null associated covector the space-time reduces to a plane wave and results to be generalized quasi-Einstein. In the case of time-like associated covector we show that under the condition of divergence-free Weyl tensor the space-time admits a proper concircular vector that can be rescaled to a time like vector of concurrent form and is a conformal Killing vector. A recent result then shows that the metric is necessarily a generalized Robertson–Walker space-time. In particular we show that a conformally flat [Formula: see text], [Formula: see text], space-time is conformal to the Robertson–Walker space-time.


1980 ◽  
Vol 12 (11) ◽  
pp. 871-880 ◽  
Author(s):  
M. Novello ◽  
J. Duarte De Oliveira
Keyword(s):  

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