Bachas: Massive Ads Gravity from String Theory

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Bachas: Massive Ads Gravity from String Theory Massive AdS Gravity from String Theory Costas BACHAS (ENS, Paris) Conference on "Geometry and Strings’’ Schloss Ringberg, July 23 - 27, 2018 Based on two papers with Ioannis Lavdas arXiv: 1807.00591 arXiv: 1711.11372 Earlier work with John Estes arXiv: 1103.2800 If I have time, I may also comment briefly on arXiv: 1711.06722 with Bianchi & Hanany Plan of Talk 1. Foreword 2. g-Mass from holography 3. Representation merging 4. Review of N=4 AdS4/CFT3 5. g-Mass operator 6. `Scottish Bagpipes’ 7. 3 rewritings & bigravity 8. Final remarks 1 Foreword An old question: Can gravity be `higgsed’ (become massive) ? Extensive (recent & less recent) literature: Pauli, Fierz, Proc.Roy.Soc. 1939 . Nice reviews: Hinterblicher 1105.3735; de Rham 1401.4173 Schmidt-May & von Strauss 1512.00021 The question is obviously interesting, since any sound IR modification of General Relativity could have consequences for cosmology [degravitating dark energy? `mimicking dark matter’ ? . ] The main messages of this talk : — Massive AdS Gravity is part of the string-theory landscape — A quasi-universal, quantized formula for the mass Setting is 10d IIB sugra, and holographic dual CFTs If <latexit sha1_base64="RY3Mceo40A2JogR2P79cFMHL7hM=">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</latexit> time, I will comment on gauged 4d supergravity 9 Have little to say about the effective 4d theory around these string-theory vacua But note that in certain sense massive AdS gravity is an `easier’ case: m 0 the limit <latexit sha1_base64="mybtUkQUT/MZwyOi8nPg/PbM4YA=">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</latexit> g is smooth ! van Dam-Veltman-Zakharov discontinuity 69<latexit sha1_base64="hYm/eqY6JDpRDHLCrWE9GUmdBr0=">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</latexit> No need for strong non-linearities of Vainshtein screening Kogan, Mouslopoulos, Papazoglou ’00 Porrati ‘00 2 G-mass from Holography Consider AdS<latexit sha1_base64="FvYRYTpFuM5bjTRrOhZKbu/jeSQ=">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</latexit> CFT 4 $ 3 For a primary spin-2 operator: m2L 2 = ∆(∆ 3) <latexit sha1_base64="QBIvtDuvC/9YeYC3BGWANbup3Fo=">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</latexit> 4 (like stress tensor T<latexit sha1_base64="pnG9moH4tU5IlCXsYdAmACl6Zvk=">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</latexit> ab ) − ab If conserved, @<latexit sha1_base64="heXjNnBPawjreDCkeUu9iUz/65c=">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</latexit> aT =0, the representation is short & an algebraic manipulation gives ∆ =3 = m =0 <latexit sha1_base64="pYgDBq3Mim3r9nFfGuE2MXLome4=">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</latexit> ) g canonical So to get G-mass we must allow 3d energy-momentum to leak out Two options consistent with 3d conformal invariance: — Couple to another 3d CFT: one massless & one massive graviton (bigravity models) — Leaking out to a 4d (or higher ?) defect CFT to get a `single’ massive-graviton theory ∆<latexit sha1_base64="42Xm8I3AQa5qmXxkP+h7ZtTvcDg=">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</latexit> .<latexit sha1_base64="B08Rmmmr9ksp+8jWtHaiW8nsBT0=">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</latexit> .<latexit sha1_base64="B08Rmmmr9ksp+8jWtHaiW8nsBT0=">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</latexit> .<latexit sha1_base64="B08Rmmmr9ksp+8jWtHaiW8nsBT0=">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</latexit> Need weak leakage 4<latexit sha1_base64="z0DfbDolk8vyxYWaG2DQmkvsdkQ=">AAACxHicjVHLSsNAFD2Nr1pfVZdugkVwVRIp6LIoiMsWbC3UIkk6rUPTJMxMhFL0B9zqt4l/oH/hnXEKahGdkOTMufecmXtvmMVcKs97LTgLi0vLK8XV0tr6xuZWeXunLdNcRKwVpXEqOmEgWcwT1lJcxayTCRaMw5hdhaMzHb+6Y0LyNLlUk4z1xsEw4QMeBYqoZu2mXPGqnlnuPPAtqMCuRlp+wTX6SBEhxxgMCRThGAEkPV348JAR18OUOEGImzjDPUqkzSmLUUZA7Ii+Q9p1LZvQXntKo47olJheQUoXB6RJKU8Q1qe5Jp4bZ83+5j01nvpuE/qH1
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  • The Romance Between Maths and Physics
    The Romance Between Maths and Physics Miranda C. N. Cheng University of Amsterdam Very happy to be back in NTU indeed! Question 1: Why is Nature predictable at all (to some extent)? Question 2: Why are the predictions in the form of mathematics? the unreasonable effectiveness of mathematics in natural sciences. Eugene Wigner (1960) First we resorted to gods and spirits to explain the world , and then there were ….. mathematicians?! Physicists or Mathematicians? Until the 19th century, the relation between physical sciences and mathematics is so close that there was hardly any distinction made between “physicists” and “mathematicians”. Even after the specialisation starts to be made, the two maintain an extremely close relation and cannot live without one another. Some of the love declarations … Dirac (1938) If you want to be a physicist, you must do three things— first, study mathematics, second, study more mathematics, and third, do the same. Sommerfeld (1934) Our experience up to date justifies us in feeling sure that in Nature is actualized the ideal of mathematical simplicity. It is my conviction that pure mathematical construction enables us to discover the concepts and the laws connecting them, which gives us the key to understanding nature… In a certain sense, therefore, I hold it true that pure thought can grasp reality, as the ancients dreamed. Einstein (1934) Indeed, the most irresistible reductionistic charm of physics, could not have been possible without mathematics … Love or Hate? It’s Complicated… In the era when Physics seemed invincible (think about the standard model), they thought they didn’t need each other anymore.
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  • Life at the Interface of Particle Physics and String Theory∗
    NIKHEF/2013-010 Life at the Interface of Particle Physics and String Theory∗ A N Schellekens Nikhef, 1098XG Amsterdam (The Netherlands) IMAPP, 6500 GL Nijmegen (The Netherlands) IFF-CSIC, 28006 Madrid (Spain) If the results of the first LHC run are not betraying us, many decades of particle physics are culminating in a complete and consistent theory for all non-gravitational physics: the Standard Model. But despite this monumental achievement there is a clear sense of disappointment: many questions remain unanswered. Remarkably, most unanswered questions could just be environmental, and disturbingly (to some) the existence of life may depend on that environment. Meanwhile there has been increasing evidence that the seemingly ideal candidate for answering these questions, String Theory, gives an answer few people initially expected: a huge \landscape" of possibilities, that can be realized in a multiverse and populated by eternal inflation. At the interface of \bottom- up" and \top-down" physics, a discussion of anthropic arguments becomes unavoidable. We review developments in this area, focusing especially on the last decade. CONTENTS 6. Free Field Theory Constructions 35 7. Early attempts at vacuum counting. 36 I. Introduction2 8. Meromorphic CFTs. 36 9. Gepner Models. 37 II. The Standard Model5 10. New Directions in Heterotic strings 38 11. Orientifolds and Intersecting Branes 39 III. Anthropic Landscapes 10 12. Decoupling Limits 41 A. What Can Be Varied? 11 G. Non-supersymmetric strings 42 B. The Anthropocentric Trap 12 H. The String Theory Landscape 42 1. Humans are irrelevant 12 1. Existence of de Sitter Vacua 43 2. Overdesign and Exaggerated Claims 12 2.
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  • Tensor Modes on the String Theory Landscape Arxiv:1206.4034V1 [Hep
    Tensor modes on the string theory landscape Alexander Westphal Deutsches Elektronen-Synchrotron DESY, Theory Group, D-22603 Hamburg, Germany We attempt an estimate for the distribution of the tensor mode fraction r over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards large-field or small-field inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for small-field vs large-field inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped Calabi-Yau flux compactifications of type IIB string theory. arXiv:1206.4034v1 [hep-th] 18 Jun 2012 June 19, 2012 Contents 1 Introduction and Motivation 2 2 Assumptions 5 2.1 Need for symmetry . 5 2.2 Properties of scalar fields in compactified string theory . 7 2.3 Populating vacua { tunneling and quantum diffusion . 8 3 An almost argument { field displacement is expensive 11 4 Counting ... 24 4.1 Eternity . 24 4.2 Democracy { tumbling down the rabbit hole . 26 4.3 Vacuum energy distribution . 31 4.4 Multitude . 32 4.5 An accessible sector of landscape . 36 5 Discussion 38 A Suppression of uphill tunneling 41 A.1 CdL tunneling in the thin-wall approximation . 41 A.2 CdL tunneling away from the thin-wall approximation . 42 A.3 Hawking-Moss tunneling - the 'no-wall' limit .
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  • The String Landscape, the Swampland and The
    The String Landscape The Swampland And Our Universe Cumrun Vafa Harvard University Feb. 28, 2020 KITP, Santa Barbara https://www.cumrunvafa.orG Quantum Field Theories—without gravity included— are well understood. They beautifully describe the interaction of all the elementary particles we know. To include gravity, `Couple the QFT to Gravity’ we need to consider fluctuating metric for spacetime instead of fixed Minkowski space. However, when one tries to add gravity into the mix (in the form of gravitons) the formalism breaks down. The computation of physical processes leads to incurable infinities! This naively suggests: Quantum Field Theories cannot be coupled to gravity! This cannot be true! After all we live in a universe with both gravity and with quantum fields! Resolution? String Theory: A consistent framework which unifies quantum theory and Einstein's theory of gravity—a highly non-trivial accomplishment! Leads to consistent coupling of QFT’s to gravity. Joining and splitting of strings leads to interaction between strings Resolves the inconsistency between quantum theory and gravity Extra Dimensions One of the novel features of string theory is the prediction that there are extra dimensions, beyond 3 spatial dimensions and 1 time. These must be tiny to avoid experimental detection to date. Extra dimensions of string theory can have a large number of distinct possibilities The physical properties observed in 3+1 dimensions depends on the choice of the compact tiny space: Number of forces, particles and their masses, etc. Since there are a vast number of allowed tiny spaces which are allowed we get a huge number of consistent possible effective 3+1 dimensional theories; The String Landscape Each choice of compactification space leads to a distinct observable physics in 4 dimensions.
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  • What If String Theory Has No De Sitter Vacua? Arxiv:1804.01120V2 [Hep-Th] 17 Apr 2018
    UUITP-09/18 What if string theory has no de Sitter vacua? Ulf H. Danielssona and Thomas Van Rietb b Institutionen f¨orfysik och astronomi, Uppsala Universitet, Uppsala, Sweden ulf.danielsson @ physics.uu.se cInstituut voor Theoretische Fysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium thomas.vanriet @ fys.kuleuven.be Abstract We present a brief overview of attempts to construct de Sitter vacua in string theory and explain how the results of this 20-year endeavor could point to the fact that string theory harbours no de Sitter vacua at all. Making such a statement is often considered controversial and \bad news for string theory". We discuss how perhaps the opposite can be true. arXiv:1804.01120v2 [hep-th] 17 Apr 2018 Contents 1 Introduction 3 2 dS constructions in string sofar 5 2.1 Conceptual framework . .5 2.2 Classification scheme . .7 2.3 Classical . .8 2.4 Non-geometric . 10 2.5 Quantum . 11 2.5.1 IIB string theory . 12 2.5.2 Other string theories . 16 3 They all have problems? 17 3.1 Classical . 17 3.2 Non-geometric . 19 3.3 Quantum . 20 3.3.1 Anti-brane backreaction inside extra dimensions . 21 3.3.2 Anti-brane backreaction on the moduli . 23 3.3.3 Issues with non-SUSY GKP solutions? . 25 4 What now? 26 4.1 What about dark energy? . 27 4.2 What about the AdS landscape? . 27 4.3 What about dS/CFT? . 29 5 Conclusion 30 2 1 Introduction Since the middle of the 1970s string theory has been argued to be the way in which quantum mechanics and general relativity are to be unified into a theory of quantum gravity.
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  • Plenary Talk at SUSY 2006
    The Landscape, Supersymmetry and Naturalness Michael Dine SUSY 2006 UC Irvine, June, 2006 The LHC: Will it Find Anything? It will almost surely find a Higgs particle. But we all hope for more. These hopes are based on the notion of naturalness. Puzzles: Cosmological constant • M /Mp • higgs θ • qcd Fermion mass hierarchy • ... • 1 Recently, in light of the landscape, naturalness has been declared (almost) dead by Douglas Susskind, Arkani- Hamed, Dimopoulos and others. Claims today: 1. The landscape actually makes the question of nat- uralness sharp. Low energy effective theories se- lected from distributions. Observed couplings, scales, may be much more common in some regions of the landscape than in others. 2. It is questions of naturalness which one has best hope to address in landscape context. Precisely questions of what is generic, of correlations, statis- tics, as opposed to hunting for particulars. 3. If you are an advocate of naturalness, the landscape [right or wrong, anthropic or not] is currently the best (theoretical) framework in which to test your ideas. (supersymmetry, warping, technicolor). 2 Aspects of Naturalness Usual notion: Quantity x naturally small if theory be- comes more symmetric in the limit that x 0. → 8π2 − Large ratios of scales from small couplings: e g2 small for g of order 1. Prior to string theory, with its original aura of unique- ness, this notion of naturalness had almost a mystical quality. As if one was worried a supreme being should not have to work to hard to make the universe more or less like it is (strongly anthropic).
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  • String Theory and Cosmology
    Strings 2008, August 18, Geneva! •! String cosmology: general status and new developments since Strings 07 •! On a possibility of a UV finite N= 8 supergravity Standard cosmological model remains in good shape after WMAP5 release in 2008 B-mode polarization experimentalists are more optimistic about their ability to detect gravity waves from inflation In inflationary model building: String theory models of chaotic inflation predicting gravity waves Stringy D3/D7 hybrid inflation with 10% of cosmic strings fitting the data Update on the KKLMMT Tension grows between the low scale SUSY (LHC) and the possibility of detection of gravity waves •! String Theory and Particle Physics in general have to adapt to these changes •! It is now 10 years after the discovery of the Universe acceleration and the first indications of the !CDM model So far 6 basic parameters are explaining all the data from the sky! 2008 2008 Stringy Landscape and Metastable dS vacua" •! It is possible to stabilize internal dimensions and describe an accelerating universe. Eventually, our part of the universe will decay, but it will take a very long time." •! Vacuum stabilization can be achieved in about 10500 different ways. The value of CC ~ 10-120 in Planck units is not impossible in the context of string theory landscape with anthropic reasoning" •! " = - 1, CC=const, is in agreement with the data so far. No good stringy models of quintessence different from the CC=const." •! If we use string theory to understand inflation which occurs now (acceleration due to dark energy), we should also try to explain inflation in the early universe.
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