de Sitter space and Holography

de Sitter space and Holography de Sitter space and Holography

hep.physics.uoc.gr
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13.07.2015 Views

3. dS/CFT correspondenceFrom what we have learned in AdS/CFT correspondence onemay hope that some kind of holography can also be appliedhere and could help us to understand the quantum gravity ondS.There is a naive observation:Consider a AdS space with radius l, under l → il one getsΛ −→ −ΛAdS −→ dSSO(2,d) −→ SO(1, d + 1)Gravity on dS is dual to a Euclidean CFT.One can make this statement more precise which is in factwhat is known as dS/CFT correspondence.30

How to define conserved charges?The deviation of the metric and other fields near spatialinfinity from the vacuum provides a way to define conservedcharges like mass, angular momentum....Equivalently the conserved charges can be computed fromthe asymptotic symmetries of a space time.For example the eigenvalue of an asymptotic timelike Killingvector will give the mass.There are two basic problems to apply this definition for dSspace (spacetime which is asymptotically dS):1. There is no spatial infinity.2. There is no globally defined asymptotic timelike Killingvector.Fortunately there is a way to proceed generalizing the Brown-York construction to define stress tensor on the Euclideanboundary and by using this quantity to define mass or othercharges for spaces which are asymptotically dS.31

3. dS/CFT correspon<strong>de</strong>nceFrom what we have learned in AdS/CFT correspon<strong>de</strong>nce onemay hope that some kind of holography can also be appliedhere <strong>and</strong> could help us to un<strong>de</strong>rst<strong>and</strong> the quantum gravity ondS.There is a naive observation:Consi<strong>de</strong>r a AdS <strong>space</strong> with radius l, un<strong>de</strong>r l → il one getsΛ −→ −ΛAdS −→ dSSO(2,d) −→ SO(1, d + 1)Gravity on dS is dual to a Eucli<strong>de</strong>an CFT.One can make this statement more precise which is in factwhat is known as dS/CFT correspon<strong>de</strong>nce.30

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