trivedi

Non-Supersymmetric Attractors : Non-Supersymmetric Attractors Sandip Trivedi Tata Institute of Fundamental Research, Mumbai, India Irvine, June’06


Slide2 : Outline Motivation & Introduction What is an attractor? When does an attractor exist? a) Spherically symmetric attractors b) Rotating attractors Microscopic & Macroscopic Entropy Conclusions


Slide3 : Collaborators: K. Goldstein, N. Iizuka, R. Jena, S.P.T., hep-th/0507093 II) P. Tripathy, S.P.T., hep-th/0511117 III) K. Goldstein, G. Mandal, R. Jena, S.P.T., hep-th/0512138 IV) A. Dabholkar, A Sen, S.P.T., in prep. V) D. Astefanesei, K. Golstein, R. Jena, A. Sen, S. P. T.


Slide4 : Some Related References: Ferrara, Gibbons, Kallosh, hep-th/9702103 Denef, hep-th/0005049, … A. Sen, hep-th/0506177 … 4) Kallosh, … 5) Ferrara et. al., 6) Kraus and Larsen, 0506173, 0508218.


Slide5 : Some Related References Cont’d 7) Ooguri, Vafa, Verlinde, hepth/0502211 8) Gukov, Saraikin, Vafa, hepth/0509109, hep-th/0505204


Slide6 : Non-Supersymmetric Attractors Motivations: Black Hole Physics: Entropy, etc 2. Landscape. Vacuum Selection? Interesting Parallels with Flux Compactifications.


Slide7 : II. What is an Attractor? 4 Dim. Gravity, Gauge fields , Scalars, Family of Extremal Black Hole Solutions . The near horizon region of these black holes is universal, determined only by the charges. (Extremal Black Holes have minimum mass for given charge)


Slide8 : Attractor: Scalars take fixed values at horizon. Independent of Asymp. Values (but dependent on charges). Resulting near-horizon geometry of form, , also independent of asymptotic values of moduli. The near-horizon region has enhanced symmetry


Slide10 : So far Mainly explored in Supersymmetric Cases. Kallosh, Ferrara, Strominger . Denef ,Gibbons, …, Ooguri, Strominger, Vafa, … N=2 Supersymmetry. Black Holes BPS, preserve N=1 Susy.


Slide11 : In this talk we shall ask whether there are non-supersymmetric attractors. And what we can learn from them. The Black Holes we shall be interested in are Extremal and break supersymmetry. Aim of the Talk


Slide12 : Conditions for an Attractor (Not Necessarily Supersymmetric ): Spherically symmetric, Non-Rotating Black Holes:


Slide13 : Conditions for an Attractor : are electric and magnetic charges of black hole. : depend on the moduli fields


Slide14 : There is an attractor provided has a minimum : 1) 2) The attractor values are Entropy: Result:


Slide16 : The essential complication is that the equations of motion are non-linear second order equations. Difficult to solve exactly. Analysis:


Slide17 : Attractor Solution: Scalars take attractor value at infinty and are kept constant. Resulting solution: Extremal Reissner Nordstrom Black Hole


Slide18 : Small Parameter: Equations are second order but Linear in perturbation theory.


Slide19 : Generalisations: Attractor Mechanism works, with similar conditions on the effective potential in: Higher Dimensions Anti-DeSitter Space 3. De-Sitter Space


Slide22 : Related work: Entropy Function A. Sen Basic idea : By extremising the Entropy function one obtains the attractor values for the moduli and geometry. Entropy is the extremum value of the function. Focus on the near-horizon region and use it’s enhanced symmetries.


Slide23 : Advantage: Higher derivative corrections can be included. Limitation: Does not tell which extrema can be obtained starting from infinity. Nor does it distinguish between stable and unstable attractors. For two-derivative actions, in calculating the attractor values, it agrees with the results from Entropy Function Cont’d:


Slide24 : Rotating Attractors Motivation: How general is this phenomenon? Consider cases where supersymmetry is slightly broken.


Slide25 : II) Rotating Attractors We find similar results for rotating extremal black holes as well. Near horizon geometry :


Slide26 : Results: Generically all moduli and metric components have fixed functional form at horizon. Entropy is determined by charges alone. Analysis should generalise to higher dimensions and also for horizons with any compact topology.


Slide27 : Example: Type II on Calabi Yau Three-fold :Superpotential determined by the charges : Kahler potential


Slide28 : This is analogous to the potential in flux compactifications. W : Determined by the fluxes.


Slide29 : N=2 Susy Case Cont’d: Susy Attractor: Entropy ~


Slide30 : Non-Susy Attractor Condition 1: (But ) Condition 2: (with suitable generalisations)


Slide31 : Result Depending on charges one gets either a susy attractor or an non-susy extremum of the effective potential. Sometimes the non-susy extremum is an attractor. Entropy in the non-susy case is obtained by appropriately continuing the susy formula.


Slide32 : Type IIA at Large Volume I) No D6 Branes: D4 brane charge D0 brane charge


Slide33 : Susy solution exists when Non-susy attractor exists when


Slide34 : Susy entropy: Non-susy entropy:


Slide35 : With D6 brane charge: P0 D6 branes with units of D4 brane charge along the cycle and q0 units of D0 brane charge. Supersymmetric attractor exists if Non-supersymmetric Attractors


Slide36 : It has entropy, A Non-susy solution exists when


Slide37 : However, there are zero modes. The leading corrections along these directions are cubic: Thus non-positive. As a result extremum is not an attractor.


Slide38 : Microstate counting and Attractors The microstate counting for many non-susy extremal black holes agrees with their Beckenstein Hawking entropy. e.g. MSW string has the same left and right moving central charge (for large Q). Why?


Slide39 : Microscopic calculation and supergravity calculations are controlled in different regions of moduli space: Microscopic: Macroscopic:


Slide40 : Suppose the region and the region both lie in the same basin of attraction. That is they both flow to the same attractor. Then the entropy in the two cases must also agree. In effect the attractor mechansim provides an argument for the non-renormalisation of the entropy. Perhaps the Attractor phenomenon can provide an explanation:


Slide42 : Typically when , at asymptotic infinity, there will be some region where the supergravity description breaks down. Still, as long as the attractor geometry is unchanged the entropy will remain unchanged. Higher derivative corrections can be included, if need be, using the entropy function of Sen.


Slide43 : Some Assumptions: No phase transitions: i.e., the same basin of attraction Assume that extremal black holes correspond to states with minimum mass for given charge. Comments: Argument applies to susy black holes too. For total no. of states not an index.


Slide44 : A dynamical system is drawn to an attractor at late times regardless of initial conditions. For black holes the attractor behaviour is non-generic. Some comments related to Cosmology


Slide45 : Cosmology in an expanding universe: Friction term means system will settle to bottom of potential. This is the attractor.


Slide46 : Aside on the scalar perturbation equation for attractors: Anti-friction term Upside down sqaure well


Slide47 : Anti-friction aids the motion. Potential pushes it down. Note here


Slide48 : Analogue of the black hole attractor is early time behaviour in deSitter space of a negative mass scalar.


Slide49 : Requiring to be singularity free, means only one of the two solutions is allowed. For this solution vanishes leading to attractor behavior. Can we make something of this attractor?


Slide50 : Conclusions 1) Non-suspersymmetric extremal black holes show attractor behaviour. The phenomenon is quite general. 2) Includes examples in String Theory. 3) Interesting implications for microstate counting of black hole entropy . And maybe in future for cosmology.


Slide51 : From Strings to LHC January 2007 4th-11th Dabholim Beach Goa See you there! sridhar@tifr.res.in, sandip@tifr.res.in