Theoretical Particle Physics

TPP Journal Club History
Date	Room	Speaker	Title
Mar 21 2025 16:00	Room 132	Pierluigi Niro (SISSA)	Particle/Vortex Duality in 3d
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Feb 21 2025 16:00	Room 137	Giulio Barni (IFT, Madrid)	Inverse bubble from broken SUSY
ABSTRACT: We present inverse phase transitions in a supersymmetry-breaking sector, establishing a criterion based on the generalized pseudo-trace for distinguish the nature of the PT.
Feb 14 2025 16:00	Room 137	Johann Quenta (SISSA)	Cobordism classification of invertible phases of matter
ABSTRACT: Classifying the possible phases of quantum systems is of interest in both condensed matter and high energy physics. Although it's a difficult problem in general, such a classification has been worked out for "invertible" phases of matter — invertible in a sense that I'll describe in this talk. Starting from some basic assumptions like locality and unitarity, I'll argue why such phases are classified by mathematical objects called "cobordism invariants". Depending on time, I'll try to discuss some basic examples of invertible theories and how they fit into this classification.
Feb 07 2025 16:00	Room 137	Beniamino Valsesisa (SISSA)	A Celestial Dual for MHV Amplitudes [2403.18896]
ABSTRACT: Celestial amplitudes may be decomposed as weighted integrals of AdS3-Witten diagrams associated to each leaf of a hyperbolic foliation of spacetime. It is shown that the leaf amplitude related to MHV gluon bulk correlation function can be holographically generated by a “Dressed Liouville” 2d cft.
Dec 12 2024 16:00	Room 132	Pietro Moroni (SISSA)	The Duality Cascade [0505153]
ABSTRACT: I will review part of Strassler's paper on the Duality Cascade, focusing on the field theory aspects and leaving the supergravity part for the future. I will start by explaining when Seiberg duality can be understood as a full RG flow duality instead of an infrared one and how it can become an S-duality when a conformal manifold is present. I will then introduce the Klebanov-Witten model and its deformation given by the Klebanov-Strassler model, and explain the duality cascade phenomenon the latter exhibits.
Dec 06 2024 16:00	Room 137	Stefano Lanza (SISSA)	Aspects of generalized symmetries in 3d CS [2204.02407]
ABSTRACT: After reviewing some aspects of 3d Chern Simons theory I will introduce the notion of higher gauging following 2204.02407 to give a definition of charge conjugation that naturally explains its properties.
Nov 26 2024 14:00	7th floor meeting room	the new postdocs (SISSA)	Postdoc day
ABSTRACT: 14:00 - Pierluigirn14:20 - Philiprn14:40 - Neilrn15:00 - Simonrnrn15:20 - Coffee, cookies and socializingrnrn15:50 - Manuelrn16:10 - Nicklasrn16:30 - Motoo
Nov 15 2024 16:00	Room 137	Gabriel Pedde (SISSA)	Abelian planar duals of N=2 SQCD_3 [2411.05620]
ABSTRACT: I’ll talk about IR dualities in 3d susy gauge theories. I’ll start by reviewing mirror symmetry in 3d and its string theory interpretation. Then I’ll describe how we are able to propose new N=2 dualities starting from known N=4 ones and then gauging the R-symmetry in order to lower the amount of super symmetry. If time remains, I’ll describe how we’re able to check the proposed dualities employing RG-flow invariants.
Oct 25 2024 16:00	Room 137	Paul Veltman (SISSA)	Generalized gravitational entropy [1304.4926]
ABSTRACT: In this seminar, I want to discuss a generalisation of the usual black hole entropy formula following the work of Lewkowycz and Maldacena (arXiv:1304.4926). Originally, Gibbons and Hawking argued in the 70s that Euclidean gravity solutions allow for a thermodynamical interpretation. Based on the existence of a U(1) symmetry, they found that the entropy is related to the area of the codimension-two surface which is fixed under the U(1) symmetry. Interestingly, the notion of gravitational entropy can be extended to situations without a U(1) symmetry. An essential tool for the proof is the replica trick and the analytic continuation of ‘replicated gravity solutions’ to non-integer values. Understanding these steps will lead us to the result of L&M that the entropy of a classical Euclidean gravity solution is related to the area of a minimal codimension-two surface.
Oct 11 2024 16:00	Room 137	Alessandro Piazza (SISSA)	The random free field scalar theory [2409.10608]
ABSTRACT: Quantum field theories with quenched disorder are complicated enough that even exactly solvable free theories present puzzling aspects. A basic but non trivial issue is the choice of a good set of local observables. I will discuss the case of a free scalar theory coupled linearly to a random field. Despite the presence of an "apparent" mass scale, the theory is actually conformally invariant but the CFT nature is manifest only in suitable linear combinations of averages of products of correlators. I will present two complementary CFT descriptions and discuss their symmetries.
Apr 19 2024 16:00	Room 137	Marina Moleti (SISSA)	Geometric eng. of susy QFT’s with D-branes at isolated singularities [9811230, 0108120, 0201093]
ABSTRACT: In particular, I will focus on the connection between the moduli space of D-brane vacua and non commutative geometry.
Apr 12 2024 16:00	Room 137	Giovanni Rizi (SISSA)	Boundary conditions in 2d CFT's and their relation to topological defect lines
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Mar 22 2024 16:00	Room 137	Giulio Barni (SISSA)	Relativistic Hydrodynamics
ABSTRACT: I will give a brief introduction to what relativistic perfect fluids are, and what are the discontinuities that can be physical in a wave moving in such a fluid. I'll apply all this machinery to cosmological phase transition and show how bubbles can expand in a plasma considered as a perfect fluid. Then I will compare this solution with droplet collapse and inverse phase transitions (aka symmetry-restoring PT).
Mar 15 2024 16:00	Room 137	Alessandro Piazza (SISSA)	Introduction to (Numerical) Conformal Bootstrap
ABSTRACT: I will explain how this technique is used to rule out inconsistent CFTs and how it has been used to corner precisely the 3d critical Ising and O(N) vector models in theory space. If time permits, I will discuss a project I am involved in regarding the bootstrap of the 2d coupled Potts model.
Mar 01 2024 16:00	Room 137	Amartya Singh (SISSA)	Aspects of Entanglement Entropy and its Holography
ABSTRACT: The aim will be to quickly review some classic results, like the Ryu Takayanagi conjecture, and then discuss in particular the dual of relative entropy and \"emergent gravity\"
Feb 15 2024 16:00	Room 137	Anant Shri (SISSA)	3d Mirror Symmetry
ABSTRACT: I will provide a pedagogical introduction to some key concepts (like generalized bifundamentals and dualities across dimensions) before talking about mirror duals in theories with 4 supercharges.
Feb 09 2024 16:00	Room 137	Beniamino Valsesia (SISSA)	c=0 in Celestial Holography
ABSTRACT: The discussion begins with a concise introduction outlining two fundamental aspects of CCFTs, emphasizing the null central charge. The discussion proceeds to explore the implications of the c=0 catastrophe and its resolution through logarithmic conformal field theories (log CFT).
Feb 02 2024 16:00	Room 137	Giulio Neri (SISSA)	Thermodynamics of black holes in Lanczos-Lovelock theories
ABSTRACT: I will talk about my current work on the thermodynamics of black holes in Lanczos-Lovelock theories, which are the most natural generalization of General Relativity in dimensions higher than 4. I will take the opportunity to present the covariant phase space formalism and the way it allows for a nice formulation of the first law. I will also discuss the difficulties in implementing a generalization of the Smarr formula and in the interpretation of the temperature that appears in the first law.
Jan 26 2024 16:00	Room 137	Shreyansh Agrawal (SISSA)	Stress-energy tensor in Celestial CFT and related topics
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Jan 11 2024 14:00	Room 137	Giovanni Galati (SISSA)	Impurities in QFT
ABSTRACT: In the context of statistical mechanics and condensed matter physics, there is a common scenario where a system near criticality can be effectively described through a continuum framework, typically expressed in the language of conformal field theory. This description may include perturbations introduced by various deformations. In the real world, however, these systems are often exposed to impurities beyond our control, leading to disorder in the system. He will discuss how to describe this situation within the formalism of QFT.
Dec 14 2023 16:00	Room 137	Andrea Antinucci (SISSA)	(Gapped) Lattice Models
ABSTRACT: I will introduce the framework of (gapped) lattice models and explain, mostly though examples, some basic concepts (like topological order, symmetry protected topological phases, entanglement) and try to encourage you to compare with their friends on the continuum. Then I\'d like to discuss how symmetries and their generalization can be implemented in lattice models, and how the properties of the symmetries imply physical consequences on the Hilbert space. Maybe I can tell you something about a beautiful general construction (anyon chain) of lattice model with a given symmetry.
Dec 07 2023 14:00	Room 005	Giulio Barni (SISSA)	QFTs and First Order Phase Transitions
ABSTRACT: I will try to introduce QFTs (EFTs) in a translational spontaneously broken background and their quantisation, in the context of First Order Phase Transitions (FOPTs) in the Early Universe. I will introduce some problems related to that, among which thermal corrections to the masses in the very low energy theory and which is the right formalism to describe the interaction with branons (NGBs from the SSB of the Lorentz group).
Nov 10 2023 16:00	Room 137 - SISSA building	Giulio Barni (SISSA)	Emergent particles of de Sitter universe [2310.15216]
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Oct 27 2023 16:00	Room 137 - SISSA building	Beniamino Valsesia (SISSA)	Flat/Celestial CFT correspondence [2309.04307]
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Mar 31 2023 16:00	Room 137 - SISSA building	Francesco Garosi (SISSA)	An Equivalent Gauge and the Equivalence Theorem [1309.6055], Goldstone Equivalence and High Energy Electroweak Physics [1911.12366]
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Feb 03 2023 14:00	Room 137 - SISSA building	Fabiana De Cesare (SISSA)	Ginzburg-Landau Description and Emergent Supersymmetry of the (3,8) Minimal Model [ 2211.07029]
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Dec 15 2022 14:30	Room 137 - SISSA building	Flavio Riccardi (SISSA)	Probing de Sitter from the horizon [ 2211.11672]
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Nov 25 2022 14:00	Room 137 - SISSA building	Andrea Antinucci (SISSA)	Generalized symmetries and Holography - part II [ 2111.01139, 2210.09146 ]
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Nov 18 2022 15:00	Room 137 - SISSA building	Andrea Antinucci (SISSA)	Generalized symmetries and Holography - part I [ 1412.5148, 2204.02407 ]
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Nov 10 2022 14:00	Room 137 - SISSA building	Giulio Barni (SISSA)	Physical Tuning and Naturalness [ 2208.05431 ]
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Oct 21 2022 14:00	Room 137 - SISSA building	()	WIP - kick off meeting
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May 20 2016 14:00	Room 137	Gabriele Spada (SISSA)	DIVERGENT PERTURBATION SERIES AND COMPLEX SADDLES
ABSTRACT: As was first shown by Dyson, perturbation series in physics are often divergent. One possible way to make sense of them is to use Borel resummation but it has been pointed out that sometimes this procedure does not reproduce the full answer (when this is known) and additional contributions have to be taken into account. After a short introduction on the topic I will review Witten's idea to use Morse theory as a tool to classify these additional contributions and possibly provide a non-perturbative definition of the Feynman path integral.
May 06 2016 14:00	Room 137	Vladimir Bashmakov (SISSA)	Deformations of Superconformal Theories
ABSTRACT: Deformations of superconformal theories, preserving supersymmetries of the theory, admit a classification. I will review recently suggested systematic approach to the problem as well as some general consequences of the resulting classification.
Apr 15 2016 14:00	Room 137	Joao Penedo (SISSA)	Dirac Gauginos
ABSTRACT: In recent years, the idea that gauginos can be given Dirac-type masses in phenomenologically viable supersymmetric models has gained increasing support. I will present a broad overview of this subject.
Feb 19 2016 14:00	Room 137	Ok Song An (SISSA)	Black Hole Thermodynamics from a Variational Principle
ABSTRACT: After introduction of holographic renormalization from the view point of a well-posed variational problem, I will review black hole thermodynamics, presenting a simple example.
Feb 05 2016 2:00	Room 137	Leonardo Modesto (Fudan University)	Finite quantum gravity, conformal Invariance, and spacetime singularities
ABSTRACT: After a short introduction to quantum Einstein gravity and quantum higher-derivative gravity, we review a class of quasi-polynomial gravitational theories finite at quantum level. Afterwords, we show that these theories are actually in the spontaneously broken phase of the conformal symmetry. Therefore, we infer that these gravities are a range of anomaly-free conformal invariant theories. The situation is considered in odd as well as in even spacetime dimension. At classical level we remark that weak non-locality is not enough to get rid out of the spacetime singularities and we need to enlarge the underlying diffeomorphism invariance of general relativity to include the Weyl conformal symmetry. Indeed, local conformal invariance is likely able to tame the singularities, that plague not only Einstein gravity, but also local and weakly non-local higher derivative theories. Following the seminal paper by Narlikar and Kembhavi, we propose an explicit construction of singularity-free black hole exact solutions conformally equivalent to the Schwarzschild metric. We also show that the FRW cosmological solutions, the Belinski, Khalatnikov, Lifshitz (BKL) spacetimes, and the gravitational Oppenheimer-Volkov collapse are exact solutions of the weakly nonlocal theory and are all singularity free.
Dec 11 2015 14:00	Room 137	Lasma Alberte (ICTP)	Solid Holography and Massive Gravity
ABSTRACT: Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, it can be realized with massive gravity in the bulk. I shall initiate here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and store interesting condensed matter applications. I will show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. I will also show that the types of electric response that can be consistently described within this framework is much wider than what is captured by the class of models mostly considered so far.
Dec 04 2015 14:00	Room 137	Antonio Duarte Pereira Junior (SISSA)	Gribov copies and BRST symmetry
ABSTRACT: In this talk, I will review the Refined Gribov-Zwanziger framework designed to deal with the so-called Gribov copies in Yang-Mills theories. In particular, I will discuss its standard BRST soft breaking show that, within this scenario, the BRST transformations are modified in the non-perturbative regime in order to be a symmetry of the model. This fact has been supported by recent lattice simulations and opens a new avenue for the investigation of non-perturbative effects in Yang-Mills theories.
Jun 26 2015 11:00	Room 137	Alberto Parolini (IBS, Daejeon, Korea)	Anarchic Yukawas and top partial compositeness: the flavor of a successful marriage
ABSTRACT: The top quark can be singled out from other fermions in the SM due to its large mass, of the order of the electroweak scale. We follow this reasoning in models of pseudo Nambu Goldstone Boson composite Higgs. We consider a new class of flavour models, where the top quark obtains its mass via partial compositeness, while the lighter fermions acquire their masses by a deformation of the dynamics generated at a high flavour scale. One interesting feature of such scenario is that it can avoid all the flavour constraints without the need of flavour symmetries, since the flavour scale can be pushed high enough. We show that both flavour conserving and violating constraints can be satisfied with top partial compositeness without invoking any flavour symmetry for the up-type sector, in the case of the minimal SO(5)/SO(4) coset in a specific simple example. In the down-type sector, some degree of alignment is required if all down-type quarks are elementary.
May 22 2015 14:00	Room 137	Pietro Baratella (SISSA)	Broken Spacetime Symmetries
ABSTRACT: The first part of the talk will be a review of classic results on theories with broken internal symmetries. Then there will be a discussion on broken spacetime symmetries and field theories that realize this breaking. In the last part I will give an outline of our recent research on the topic.
May 08 2015 14:00	Room 137	Junya Yagi (SISSA)	Quiver gauge theories and integrable lattice models
ABSTRACT: I will review my recent work [1] on connections among supersymmetric quiver gauge theories, topological quantum field theories (TQFTs), and integrable lattice models in statistical mechanics. This work combines ideas from (1) the correspondence between 4d N=2 theories of class S and TQFTs, found by Gadde et al. [2]; (2) the "gauge/YBE correspondence" proposed by Yamazaki [3] which relates 4d N=1 supersymmetric indices and solutions of the Yang-Baxter equation; and (3) Costello's construction [4] of integrable lattice models from TQFTs equipped with line operators. [1] http://arxiv.org/abs/1504.04055 [2] http://arxiv.org/abs/0910.2225 [3] http://arxiv.org/abs/1203.5784 [4] http://arxiv.org/abs/1308.0370
Apr 24 2015 14:00	Room 137	Ivan Girardi (SISSA)	The possible hidden symmetries in the lepton sector
ABSTRACT: In this JC I will review some strategies in flavour model building based on discrete symmetries. I will explain the hidden connection between the form of the PMNS mixing matrix and possible symmetries in the lepton sector. This is essentially a simple pedagogical introduction to the subject.
Apr 10 2015 14:00	Room 137	Himanshu Raj (SISSA)	Localized anti-branes in flux backgrounds
ABSTRACT: Review of arXiv:1501.06568. Recently there has been some vexing issues in the literature regarding the use of anti-branes for constructing non-BPS solutions of supergravity theories. It has been observed that when we add branes that are non-BPS w.r.t to flux backgrounds, the backreacted geometry develops (potentially unphysical) naked singularities. There is a well motivated criterion (due to Gubser) which says that a naked singularity can be resolved in string theory if it is possible to cloak it under a horizon. The singularities associated to anti-branes were studied extensively and it was found that it is not possible to resolve them by any of the known mechanisms. However most of these results were obtained in an approximation where the added branes were "smeared". Very recently a no-go theorem was formulated which said that these singularities persisted even in the case of localized branes. In this journal club I will discuss a recent paper: arXiv:1501.06568 which points out a loop-hole in this theorem by constructing a perfectly smooth solution by using localized anti- (black) branes. Gubser's citerion then guarantees that such a singularity is in-fact physical and can be resolved in string theory thereby safeguarding the fate of the KVP vacua of Klebanov-Strassler theory and the KKLT construction of dS vacua in string theory.
Mar 20 2015 14:00	Room 137	Swapnamay Mondal (HARISH CHANDRA RESEARCH INSTITUTE, Allahabad)	A unified formulation of entanglement for entanglement of distinguishable and indistinguishable particles
ABSTRACT: Entanglement is well understood concept for distinguishable particles.However fundamental particles are inherently indistinguishable and when they occupy orthogonal modes, i.e. have orthogonal wave functions, they are effectively distinguishable. Thus there should exist a formulation for entanglement which works in the generic case, i.e. even when wave functions overlap. To achieve this, we consider R`enyi entropies which are measurable quantities. Outcomes of such measurements for a generic case are conjectured in terms of R`enyi entropies of spatial regions in a field theory. To leading order naive quantum mechanical answers are reproduced. Corrections depend on overlap of wave functions and exhibit novel features. In a generic case the Von Neumann entropy computed from these R`enyi entropies is argued to be a measure of entanglement of pure states and a formula for this is conjectured in terms of Von Neumann entropies of spatial regions in field theory.
Mar 13 2015 14:00	Room 137	Denis Karateev (SISSA)	4D CFT: Four-point Functions, Conformal Blocks and the Bootstrap
ABSTRACT: I will briefly summarize Twistor Techniques and Embeding Space approach (presented by Emtinan in the talk "4D CFT: Three-point Functions, Embedding Formalism and Twistors" last week ). Then I will outline how to construct three- and four- point functions using these methods, and discuss what consistency constraints one can impose on CFTs knowing precise expressions of four-point functions.
Mar 06 2015 14:00	Room 137	Emtinan Elkhidir (SISSA)	4D CFT: Three-point Functions, Embedding Formalism and Twistors
ABSTRACT: It's known that conformal symmetry fully constrains three-point function of primary operators (up to a constant). However ,specifying to 4d CFT, it's not easy to work out these constrains for fields in a general representation of Lorentz group (for example fermions). In this JC I will discuss how to solve this problem using embedding formalism in twistor space.
Feb 20 2015 14:00	Room 137	Bruno Lima de Souza (SISSA)	Conformal Anomalies in Hydrodynamics
ABSTRACT: In this journal club I will review the paper 1301.3170.
Feb 06 2015 14:00	Room 137	Piermarco Fonda (SISSA)	Energy conditions from entanglement dynamics
ABSTRACT: In this JC I will review the recent papers http://arxiv.org/pdf/1412.3514.pdf and http://arxiv.org/pdf/1412.5472.pdf where the Ryu-Takayanagi prescription is used to link inequalities that hold for the entanglement entropy on the CFT side and an integrated version of null energy conditions for the gravitational theory. Furthermore, I will try to explain and discuss the recent developments in the explorations of the connection between entanglement and gravity.
Dec 12 2014 14:00	Room 005	Postdoc Day (SISSA)	Ioannis Papadimitriou and Alexander Stuart
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Nov 21 2014 14:00	Room 137	Alba Grassi (University of Geneva)	Topological Strings from Quantum mechanics
ABSTRACT: In this talk I will propose a general correspondence which associates a non-perturbative quantum mechanical operator to a toric Calabi-Yau manifold, and I will propose a conjectural expression for its spectral determinant. As a consequence of these results, I will derive an exact quantization condition for the operator spectrum. I will give a concrete illustration of this conjecture by focusing on the example of local P2. This approach also provides a non-perturbative Fermi gas picture of topological strings on toric background and suggests the existence of an underlying theory of M2 branes behind this formulation.
Nov 14 2014 14:00	Room 137	Natalia Pinzani Fokeeva (Amsterdam University)	Effective actions for fluids from holography and the membrane paradigm
ABSTRACT: Motivated by recent reformulations of hydrodynamics as an effective field theory in this talk I will show how to derive the low energy dissipationless effective action for conformal fluids from holography. I will give a precise geometrical interpretation of the emerging Goldstone bosons in terms of a family of spatial geodesics extending between the conformal boundary of the AdS black brane background and a finite cutoff in the interior of spacetime. I will argue how such effective action might be unconsistent on its own unless dissipative effects are included. This can be done by coupling the UV effective action to the near horizon IR part of the spacetime which we replace for simplicity with a membrane paradigm type boundary condition. I will also discuss the limits of validity of such approximation.
Nov 07 2014 14:00	Room 137	Daniele Galloni (Durham University)	Anatomy of the amplituhedron
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Oct 10 2014 15:00	SISSA - Room 137	Alex Spencer-Smith (University of Sydney)	Higgs Vacuum Stability in a Mass-Dependent Renormalisation Scheme and Implications for Inflation and New Physics
ABSTRACT: The question of stability of the electroweak vacuum is important for both beyond the Standard Model physics and cosmological inflation. A large inflationary rate, as suggested by the recent BICEP measurements, implies that, if unstable, the electroweak vacuum should have decayed quickly during inflation, making the statistical likelihood of a universe like ours extremely low. I present new bounds on the critical values of the top and Higgs pole masses required for absolute stability of the Standard Model electroweak vacuum, derived using mass-dependent beta functions and discuss the implications for inflation. I also compare decay via the Hawking-Moss and Coleman-de Luccia instantons and the stochastic approach to vacuum decay employable for large Higgs quantum fluctuations during inflation and discuss the scenarios in which each dominates. Motivated by the need for a stable Higgs potential, I examine the effect of new physics models (particularly those related to neutrino mass generation) upon vacuum stability and use this as a guide as to which of these models may be realised in nature.
May 23 2014 14:00	SISSA - Room 137	Ivan Girardi (SISSA)	Generalised Geometrical CP Violation in a T' Lepton Flavour Model
ABSTRACT: Review of 1312.1966. We analyse the interplay of generalised CP transformations and the non-Abelian discrete group T' and use the semi-direct product Gf=T' x HCP, as family symmetry acting in the lepton sector. The family symmetry is shown to be spontaneously broken in a geometrical manner. In the resulting flavour model, naturally small Majorana neutrino masses for the light active neutrinos are obtained through the type I see-saw mechanism. The known masses of the charged leptons, lepton mixing angles and the two neutrino mass squared differences are reproduced by the model with a good accuracy. The model allows for two neutrino mass spectra with normal ordering (NO) and one with inverted ordering (IO). For each of the three spectra the absolute scale of neutrino masses is predicted with relatively small uncertainty. The value of the Dirac CP violation (CPV) phase delta in the lepton mixing matrix is predicted to be delta≅pi/2 or 3pi/2. Thus, the CP violating effects in neutrino oscillations are predicted to be maximal (given the values of the neutrino mixing angles) and experimentally observable. We present also predictions for the sum of the neutrino masses, for the Majorana CPV phases and for the effective Majorana mass in neutrinoless double beta decay. The predictions of the model can be tested in a variety of ongoing and future planned neutrino experiments.
Mar 28 2014 14:00	Room 137	Luca di Luzio (Karlsruhe U.)	Gauge dependence and the Standard Model vacuum stability
ABSTRACT: After reviewing the calculation of the one-loop effective potential in a linear R_xi gauge, I discuss which are the physical (gauge independent) observables entering the vacuum stability analysis. In particular, the field value at which the effective potential turns negative (the so-called instability scale, often identified with the scale of �new physics") is essentially gauge dependent. Such a gauge ambiguity is explicitly shown in the case of the Standard Model.
Mar 21 2014 14:00	SISSA - Room 137	Giovanni Grilli di Cortona (SISSA)	New Observables for Direct Detection of Axion Dark Matter
ABSTRACT: Review of 1306.6088. We propose new signals for the direct detection of ultralight dark matter such as the axion. Axion or axion like particle (ALP) dark matter may be thought of as a background, classical field. We consider couplings for this field which give rise to observable effects including a nuclear electric dipole moment, and axial nucleon and electron moments. These moments oscillate rapidly with frequencies accessible in the laboratory, ~ kHz to GHz, given by the dark matter mass. Thus, in contrast to WIMP detection, instead of searching for the hard scattering of a single dark matter particle, we are searching for the coherent effects of the entire classical dark matter field. We calculate current bounds on such time varying moments and consider a technique utilizing NMR methods to search for the induced spin precession. The parameter space probed by these techniques is well beyond current astrophysical limits and significantly extends laboratory probes. Spin precession is one way to search for these ultralight particles, but there may well be many new types of experiments that can search for dark matter using such time-varying moments.
Mar 14 2014 14:00	SISSA - Room 137	Juan Carlos Vasquez Carmona (SISSA)	Tetraquark Mesons in Large-N Quantum Chromodynamics
ABSTRACT: Review of 1303.0342. It is argued that exotic mesons consisting of two quarks and two antiquarks are not ruled out in quantum chromodynamics with a large number N of colors, as generally thought. Tetraquarks of one class are typically long-lived, with decay rates proportional to 1/N.
Mar 07 2014 14:00	SISSA - Room 137	Javier Pardo Vega (SISSA)	A Natural Higgs Mass in Supersymmetry from Non-Decoupling Effects
ABSTRACT: Review of 1308.0792. The Higgs mass implies fine-tuning for minimal theories of weak scale supersymmetry (SUSY). Non-decoupling effects can boost the Higgs mass when new states interact with the Higgs, but new sources of SUSY breaking that accompany such extensions threaten naturalness. We show that a singlet with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. We explore the modified Higgs phenomenology of this scenario, which we call the "Dirac NMSSM."
Feb 14 2014 14:00	SISSA - Room 137	Muteeb Nouman (SISSA)	The holographic dual of an EPR pair has a wormhole
ABSTRACT: I will review the following paper, arXiv:1307.1132, which constructs the holographic dual of two colored quasiparticles in maximally supersymmetric Yang-Mills theory entangled in a color singlet EPR pair. In the holographic dual the entanglement is encoded in a geometry of a non-traversable wormhole on the worldsheet of the flux tube connecting the pair. This gives a simple example supporting the recent claim by Maldacena and Susskind that EPR pairs and non-traversable wormholes are equivalent descriptions of the same physics.
Feb 07 2014 14:00	SISSA - Room 137	Bruno Lima de Souza (SISSA)	CP-Violating CFT and Trace Anomaly
ABSTRACT: Review of 1201.3428. It is logically possible that the trace anomaly in four dimensions includes the Hirzebruch-Pontryagin density in CP violating theories. Although the term vanishes at free conformal fixed points, the author realizes such a possibility in the holographic renormalization group and show that it is indeed possible. The Hirzebruch-Pontryagin term in the trace anomaly may serve as a barometer to understand how much CP is violated in conformal field theories.
Jan 31 2014 14:00	SISSA - Room 137	Piermarco Fonda (SISSA)	Time Evolution of Entanglement Entropy from Black Hole Interiors
ABSTRACT: Review of 1303.1080. Hartman and Maldacena compute the time-dependent entanglement entropy (EE) of a CFT which starts in relatively simple initial states. The initial states are the thermofield double for thermal states, dual to eternal black holes, and a particular pure state, dual to a black hole formed by gravitational collapse. The EE grows linearly in time. This linear growth is directly related to the growth of the black hole interior measured along "nice" spatial slices. These nice slices probe the spacelike direction in the interior, at a fixed special value of the interior time. In the case of a two-dimensional CFT, the authors match the bulk and boundary computations of the EE. They briefly discuss the long time behavior of various correlators, computed via classical geodesics or surfaces, and point out that their exponential decay comes about for similar reasons. The time evolution of the wavefunction in the tensor network description is also presented.
Jan 24 2014 11:00	SISSA - Room 137	Cristiano De Nobili (SISSA)	General Properties of Holographic Entanglement Entropy
ABSTRACT: Review of arXiv:1312.6717. The Ryu-Takayanagi formula implies many general properties of entanglement entropies in holographic theories. The autor reviews the known properties, such as continuity, strong subadditivity, and monogamy of mutual information, and fills in gaps in some of the previously-published proofs. He also adds a few new properties, including: properties of the map from boundary regions to bulk regions implied by the RT formula, such as monotonicity; conditions under which subadditivity-type inequalities are saturated; and an inequality concerning reflection-symmetric states. He attempts to draw lessons from these properties about the structure of the reduced density matrix in holographic theories.
Jan 17 2014 14:00	SISSA - Room 137	Flavio Porri (SISSA)	Holography for N=2* on S^4
ABSTRACT: Review of arXiv:1311.1508. The authors find the gravity dual of N=2* super-Yang-Mills theory on S^4 and use holography to calculate the universal contribution to the corresponding S^4 free energy at large N and large 't Hooft coupling. Their result matches the expression previously computed using supersymmetric localization in the field theory. This match represents a non-trivial precision test of holography in a non-conformal, Euclidean signature setting.
Nov 15 2013 14:00	SISSA - Room 137	Gautier Solard (LPTHE, Paris 6)	AdS vacua in IIB vacua, scale separation and SU(2) torsion
ABSTRACT: In this talk we study AdS_4 with N=1 supersymmetry in type IIB supergravity. Using Generalised Geometry it is easy to see that the internal manifold has to have SU(2) structure. We will then focus on coset and group manifolds and we will look for examples allowing for scale separation. We will also show that, for constant warp factor, it is not possible to have sourceless solutions.
Sep 20 2013 14:00	SISSA - Room 137	Alessandro Sfondrini (Utrecht University)	Integrability for the AdS3/CFT2 correspondence
ABSTRACT: Some physical systems enjoy a number of symmetries large enough to completely constrain their dynamics, and are therefore called �integrable�. It is a remarkable fact that some string theories on Anti-de Sitter (AdS) backgrounds seem to have this property. This feature, first explored for type IIB strings on AdS_5xS^5, allowed in that case to find the full energy spectrum of the strings, which by the AdS/CFT duality gives the two-point functions of primary operators in the dual D=4, N=4 superconformal theory.\r\nI will review these integrability techniques and discuss how they can be used to explore string theories on AdS3 x S^3 x T^4 and AdS_3 x S^3 x S^3 x S^1 and to find (part of) their world-sheet S-matrices, which in turn yield the spectrum through the Bethe-Yang equations. This presents new challenges with respect to the AdS5 case, and offers interesting insights in the yet-to-be-understood dual conformal field theories, through a spin-chain picture.
Sep 06 2013 14:00	SISSA - Room 137	Hiroaki Sugiyama (Maskawa Institute for Science and Culture, Kyoto Sangyo University)	Lepton number violation at the LHC with leptoquark and diquark
ABSTRACT: If neutrinos are Majorana particle, lepton number violating processes are possible. Such processes are usually searched for in low energy experiments, namely, neutrinoless double beta decay searches. We investigate a different possibility that lepton number violation is discovered at LHC. We show such a possibility in a model where leptoquark scalar and diquark scalar are introduced. Neutrino masses are generated at the two-loop level and suppressed appropriately.
May 31 2013 14:00	SISSA - Room 137	Giorgio Busoni (SISSA)	On the Minimum Dark Matter Mass Testable by Neutrinos from the Sun
ABSTRACT: We discuss a limitation on extracting bounds on the scattering cross section of dark matter with nucleons, using neutrinos from the Sun. If the dark matter particle is sufficiently light (less than about 4 GeV), the effect of evaporation is not negligible and the capture process goes in equilibrium with the evaporation. In this regime, the flux of solar neutrinos of dark matter origin becomes independent of the scattering cross section and therefore no constraint can be placed on it. We find the minimum values of dark matter masses for which the scattering cross section on nucleons can be probed using neutrinos from the Sun. We also provide simple and accurate fitting functions for all the relevant processes of GeV-scale dark matter in the Sun.
May 10 2013 11:00	SISSA - Room 137	Petr Vasko (SISSA)	Application of the two sphere partition function: the quintic threefold
ABSTRACT: In the first part of the talk I will briefly review the arguments of arXiv:1210.6022 why the two-sphere partition function of a N=(2,2) supersymmetric gauge theory corresponding to a nonsingular compact Calabi-Yau manifold (as target space of the nonlinear sigma model in the IR) is supposed to compute the quantum Kahler potential of that CY. In the second part I will show in detail how this formalism works on the example of a quintic threefold. This computation is motivated by arXiv:1208.6244, however rather than computing the Kahler potential directly, I will compute the so called I-function (which plays a major role in the Givental's approach to mirror symmetry in mathematics). If time allows I will also extract some interesting information from it, like the mirror map and Gromov-Witten invariants.
May 03 2013 14:00	SISSA - Room 137	Antonio Sciarappa (SISSA)	N = (2,2) gauge theories on the two-sphere
ABSTRACT: I will review the papers 1206.2356, 1206.2606, which explain how to construct N = (2,2) supersymmetric gauge theories on the two-sphere with vector and chiral multiplets. Via supersymmetric localization, it is also possible to compute exactly their partition function. This admits two representations, depending on the choice of localization term: one as an integral over the Coulomb branch, and the other as a sum over vortex and antivortex excitations on the Higgs branches. Possible applications will be discussed.
Apr 19 2013 11:00	SISSA - Room 137	Muhammad Nouman Muteeb (SISSA)	Localization and Supersymmetric Gauge Theories
ABSTRACT: We will describe the general idea of supersymmetric localization and then following arXiv:0909.4559 we will apply the localization technique to calculate exact results for some quantities in supersymmetric theories on a curved manifold.
Apr 12 2013 14:00	SISSA - Room 137	Victor Ivan Giraldo Rivera (SISSA)	Rigid Supersymmetry on curved 4d manifolds
ABSTRACT: We will describe the general arguments of arXiv:1105.0689 and arXiv:1109.5421 in which rigid N=1 supersymmetric sigma models are constructed.The result is obtained through the use of the N=1 minimal supergravity multiplet as a background superfield. Specifically the auxiliary fields in the gravity multiplet are not integrated out and the constraints on them determine the background one ends up with.
Mar 08 2013 11:00	SISSA - Room 137	Dan Xie (IAS, Princeton)	Higher laminations, webs, and N=2 line operators
ABSTRACT: A classification of half-BPS line operators of four dimensional N=2 theory engineered from six dimensional A_{N-1} (2,0) theory on a punctured Riemann surface is given by the lamination space of the corresponding local system. These line operators are represented by M2 brane wrapped on bipartite webs formed by three junctions on the Riemann surface. We also calculate the expectation value of these line operators.
Feb 22 2013 11:00	SISSA - Room 137	Lorenzo Di Pietro (SISSA)	A refinement of entanglement entropy and the number of degrees of freedom
ABSTRACT: The topic is (part of) arXiv:1202.2070. In the paper, it is shown how to extract the universal, divergence-free contribution to the entanglement entropy of a QFT across a spatial region of size R. The properties of this R-dependent coefficient are derived, and general results are established on its small and large R limits. In the case of a spherical entangling region, those properties make it a valid candidate for a C-function in any dimension. This conjecture is explored in gravity duals of 3d and 4d theories, using the holographic prescription to calculate entanglement entropy.
Feb 15 2013 11:00	SISSA - Room 137	Piermarco Fonda (SISSA)	Holographic Entanglement Entropy and c-theorems in higher dimensions
ABSTRACT: Based on results of arxiv:1202.2068. The use of holographic techniques in order to study the RG flows of QFTs is well established. Motivated by the idea of arXiv:0610.375 (reviewed in Alejandro Cabo Bizet's talk) of using entanglement entropy (EE) to define an alternative for the c-function in 2D QFTs and given the recent results - which will as well be discussed - in holographic computations of EE for arbitrary dimensions, it is possible to define a candidate for a generalized c-function from the EE evaluated for a strip of infinite length. The (numerical) results obtained will be discussed in both cases when the gravity side is assumed to be governed by Einstein-Hilbert action or by Gauss-Bonnet gravity.
Feb 08 2013 11:00	SISSA - Room 137	Alejandro Cabo Bizet (SISSA)	C-Theorem: Two "physical" proofs
ABSTRACT: Mainly I will review the key points behind two significant proposals of proof of the C-theorem in 2D RG flows. The first one by Komargodski (arXiv:1112.4538 [hep-th]) mainly based on conformal invariance and QFT unitarity arguments, and the second one by Casini and Huerta (arXiv:cond-mat/0610375 [cond-mat.stat-mech]) based on Lorentz Invariance and a universal property of Entanglement Entropy that allows to use it in the construction of a faithful candidate for c-function in 2D RG flows.
Feb 01 2013 11:00	SISSA - Room 137	Francesco Caracciolo (SISSA)	UV completions of composite Higgs models with partial compositeness
ABSTRACT: Models in which the Higgs boson is the pseudo Nambu-Goldstone boson of a strongly interacting theory represent a possible solution to the hierarchy problem; after reviewing some of the main features of such models and the usefulness of the concept of partial compositeness, it will be shown an approximately supersymmetric strongly interacting theory whose low-energy behaviour can be deduced and analyzed through the methods of Seiberg duality and whose spectrum contains both a pseudo Nambu-Goldstone boson, which can be identified with the Higgs, and partially composite Standard Model fermions.
Nov 09 2012 11:00	SISSA Santorio Building. Big Meeting Room, 7th floor.	Gianluca Blankenburg (Universit� degli Studi Roma 3)	U(2)^5 flavour symmetry, the lepton sector and RGE behaviour in supersymmetry
ABSTRACT: Motivated by the SUSY flavour and CP problems, the hierarchies in the Yukawa couplings and the absence so far of any direct evidence for SUSY, U(2)^3 is very promising flavour symmetry in the quark sector. We extend this framework in the lepton sector. In particular we analyze neutrino masses and Lepton Flavor Violation (LFV) in the context of supersymmetry. Neutrinos are expected to be almost degenerate, with masses close to present bounds from cosmology and neutrinoless double beta decay;. For slepton masses below 1 TeV we expect LFV within the reach of future experimental searches. We also study the behaviour of the theory under the SUSY Renormalizaton Group Equations (RGEs). In fact, even if usually the U(2)^5 symmetry is directly applied at the electroweak scale, the typical expectation is for this symmetry to be broken at a very high scale. We show if the properties of the symmetry are preserved at all scale and which are the initial conditions required to achieve the split scenario. We also study possible deviations from the minimal breaking of U(2)^5 compatible with the lepton sector.
Oct 12 2012 11:00	SISSA Santorio Building. Lecture Room 137	Diego Redigolo (Universit� Libre de Bruxelles & International Solvay Institute, Brussels)	Tame D-tadpoles in gauge mediation
ABSTRACT: We (arXiv:1206.7037) revisit models of gauge mediated supersymmetry breaking where messenger parity is violated. Such a symmetry is usually invoked in order to set to zero potentially dangerous hypercharge D-term tadpoles. A milder hypothesis is that the D-tadpole vanishes only at the ﬁrst order in the gauge coupling constant. Then the next order leads to a contribution to the sfermion masses which is of the same magnitude as the usual radiative one. This enlarges the parameter space of gauge mediated models. We ﬁrst give a completely general characterization of this contribution, in terms of particular three-point functions of hidden sector current multiplet operators. We then explore the parameter space by means of two simple weakly coupled models, where the D-tadpole arising at two-loops has actually a mild logarithmic divergence.
Jul 20 2012 11:00	Room 137	Alberto Parolini (SISSA)	(De)constructing a natural and flavorful supersymmetric Standard Model
ABSTRACT: I will discuss a work by Craig N., Green D. and Katz A., arXiv:1103.3708. Using the framework of deconstruction, they construct simple, weakly-coupled supersymmetric models that explain the Standard Model flavor hierarchy and produce a flavorful soft spectrum compatible with precision limits. Electroweak symmetry breaking is fully natural; the μ-term is dynamically generated with no Bμ-problem and the Higgs mass is easily raised above LEP limits without reliance on large radiative corrections. These models possess the distinctive spectrum of superpartners characteristic of �effective supersymmetry�: the third generation superpartners tend to be light, while the rest of the scalars are heavy.
Jul 13 2012 11:00	Room 137	Lorenzo Di Pietro (SISSA)	RG flow of soft masses in R-symmetric theories
ABSTRACT: The subject of the JC is 1206.3033. We will discuss the perturbation by soft supersymmetry-breaking masses of R-symmetric theories. The corresponding operator is a conserved current of the theory and its flow can be followed non-perturbatively by means of the techniques in 1109.3279 (Flavio Porri�s JC). If this operator flows to zero, the theory enjoys emergent supersymmetry in the IR, and we discuss constraints that can be put on such scenario.
Jun 29 2012 11:00	Lecture Room 137	Flavio Porri (SISSA)	A conjecture on RG flows in R-symmetric theories
ABSTRACT: In the paper 1109.3279 the author conjectured the existence of a new monotonic quantity in supersymmetric RG-flows which preserve an R-symmetry. This conjecture would provide a way to put bounds on the amount of accidental symmetries which may arise in the IR description of this kind of theories. I will introduce the definition of this quantity, show how it can be computed in some concrete examples and finally discuss its implication in the specific case of Intriligator, Seibeg and Shenker theory.
Jun 22 2012 11:00	Room 137	Vladimir Belavin (Lebedev Physical Institute, Moscow)	N = 2 superconformal blocks and instantons
ABSTRACT: We consider the problem of computing (irregular) conformal blocks in 2d CFTs whose chiral symmetry algebra is the N=2 superconformal algebra. Our construction uses two ingredients: (i) the relation between the representation theories of the N=2 rnsuperconformal algebra and the affine sl(2) algebra, extended to the level of the conformal blocks, and (ii) the relation between affine sl(2) conformal blocks and instanton partition functions in the 4d N=2 SU(2) gauge theory with a surface defect. By combining these two facts we derive combinatorial expressions for the N=2 superconformal blocks in the Gaiotto limit.
May 30 2012 16:00	Lecture Hall 128/129	Christian Hoelbling (Wuppertal)	Light quark masses and flavor physics from the lattice
ABSTRACT: I will present recent progress of lattice QCD calculations towards precision determination of light quark masses. I will describe the conceptual and technical advances that allowed recent precision determinations of the light quark masses within QCD to reach percent level accuracy with controlled systematic errors. Future challenges towards reaching sub-percent level precision are outlined. I will also briefly present some further results on light flavor physics that are relevant for checking the consistency of the standard model.
May 18 2012 11:00	Room 137	Alfredo Urbano ()	The dark side of the electroweak symmetry breaking
ABSTRACT: We show that dark matter could be a light composite scalar emerging from a TeV-scale strongly-coupled sector as a pseudo Nambu-Goldstone boson (pNGB). Such state arises naturally in scenarios where the Higgs is also a composite pNGB which are particularly predictive, since the low-energy interactions are determined by symmetry considerations. We discuss cosmological, direct and collider constraints.
Oct 07 2011 11:00	SISSA, Room 137	David Marzocca (SISSA)	The role of resonances in WW scattering in composite Higgs models
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Jun 10 2011 11:00	SISSA, room 137	Dinh Dinh (SISSA)	TBD
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May 20 2011 11:00	SISSA, room 137	Michele Del Zotto (SISSA)	D-brane physics and wall-crossing (part 2)
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May 06 2011 11:00	SISSA, room 137	Michele Del Zotto (SISSA)	D-brane physics and wall-crossing (part 1)
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Apr 19 2011 11:00	SISSA, room 137	Pietro Fr� (University of Torino)	Supergravity Black Holes, Nilpotent Orbits an tensor classifiers.
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Apr 08 2011 11:00	SISSA, Room 137	Futoshi Yagi (Institut des Hautes Etudes Scientifiques)	M5-branes from ABJM model
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Mar 27 2011 11:00	SISSA, room 137	Martin Spinrath (SISSA)	Right Unitarity Triangles from Discrete Symmetries
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Mar 25 2011 11:00	SISSA, room 137	Satoshi Nawata (Tata Institute of Fundamental Research)	Localization of N=4 SCFT and Index
ABSTRACT: We provide geometric meaning of N=4 superconformal index. This allows us to interpret the N=4 index as a partition function on a twisted background. By adding $Q$-exact term, one can apply the method of localization. The partition function localizes to flat connection. The 1-loop evaluation shows that the partition function becomes a certain matrix integral as desired.
Mar 16 2011 11:00	SISSA, room 137	Leslaw Rachwal (SISSA)	Recent developments in the theory of charged particles
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Mar 14 2011 14:00	SISSA, room 137	Francesco Caracciolo (SISSA)	Stimulated Supersymmetry Breaking
ABSTRACT: It is proposed an alternative framework of SUSY breaking mediation, based on a little amount of ingredients: there exist two sectors, S and P; on one side, sector S, in isolation, would not break SUSY and would possess tree-level pseudoflat directions, radiatively lifted; on the other side, the interactions between sector S and sector P generate soft terms in S which can create a SUSY breaking vacuum at one point along a pseudoflat direction; in this situation, the strength of SUSY breaking can be many orders of magnitude greater than that of the soft terms.
Feb 25 2011 11:00	SISSA, room 137	Aurora Meroni (SISSA)	CP-Nonconserving Mechanisms of Neutrinoless Double Beta Decay
ABSTRACT: I will consider the possibility of different mechanisms contributing to the neutrinoless double beta decay amplitude in the general case of CP nonconservation: light Majorana neutrino exchange, heavy left-handed (LH) and heavy right-handed (RH) Majorana neutrino exchanges and lepton charge non-conserving couplings in SUSY theories with R-parity breaking.
Feb 18 2011 11:00	SISSA, room 137	Ryu Sasaki (Yukawa Institute, Kyoto University)	Exceptional orthogonal polynomials in Quantum Mechanics
ABSTRACT: Global solutions of Fuchsian differential equations with more than 3 (hypergeometric) or four (Heun) regular singularities had been virtually unkown. Here I present a complete set of eigenfunctions of a Schroedinger equation with $3 +�ell$ ($�ell=1,2,�ldots$) regular singularities. They are obtained as the eigenfunctions of exactly solvable quantum mechanical systems.
Feb 11 2011 11:00	SISSA, room 137	Monica Guica (LPTHE Jussieu Paris)	Microscopic realization of the Kerr/CFT correspondence
ABSTRACT: Supersymmetric M/string compactifications to five dimensions contain BPS black string solutions with magnetic graviphoton charge P and near-horizon geometries which are quotients of AdS_3 x S^2. The holographic duals are typically known 2D CFTs with central charges c_L=c_R=6P^3 for large P. These same 5D compactifications also contain non-BPS but extreme Kerr-Newman black hole solutions with SU(2)_L spin J_L and electric graviphoton charge Q obeying Q^3 \leq J_L^2. It is shown that in the maximally charged limit Q^3 -> J_L^2, the near-horizon geometry coincides precisely with the right-moving temperature T_R=0 limit of the black string with magnetic charge P=J_L^{1/3}. The known dual of the latter is identified as the c_L=c_R=6J_L CFT predicted by the Kerr/CFT correspondence. Moreover, at linear order away from maximality, one finds a T_R \neq 0 quotient of the AdS_3 factor of the black string solution and the associated thermal CFT entropy reproduces the linearly sub-maximal Kerr-Newman entropy. Beyond linear order, for general Q^3
Jan 21 2011 11:00	SISSA, Room 137	Ilya Shapiro (Universidade Federal de Juiz de Fora)	One-loop form factors, multiplicative anomaly and galaxy rotation curves.
ABSTRACT: We report on some recent results on the evaluation of quantum corrections to the classical actions of gravity and electromagnetic fields. In the last case we consider the one-loop QED in curved space time and find that the effective action in the electromagnetic sector possess an ambiguity, which can be characterized as the nonlocal multiplicative anomaly. Moreover, by analyzing different space-time dimensions we come to the understanding of the real origin of this theoretical phenomenon which should probably take place also in other theories. The mentionded ambiguity may concern the exact form of the Appelquist and Carazzone theorem, but the general form of the decopuling rule remains the same. In gravity, Appelquist and Carazzone theorem can be also derived explicitly, but only for the higher derivative terms in the action. It is remarkable that the assumption of a standard quadratic decoupling for the Newton constant leads to the very good prediction for the rotation curve for a sample of nine different spiral galaxies.
Jan 14 2011 11:00		Takuya Okuda (Tokyo University)	TBD
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Dec 17 2010 11:00	SISSA, Room 137	Luca Mazzucato (Simons Center for Geometry and Physics)	Holographic dual of free field theories
ABSTRACT: We derive a holographic dual description of free quantum field theory in arbitrary dimensions, by reinterpreting the exact renormalization group, to obtain a higher spin gravity theory of the general type which had been proposed and studied as a dual theory. We show that the dual theory reproduces all correlation functions.
May 28 2010 11:30	SISSA, Room 137	Lisa Everett (University of Wisconsin, Madison)	Icosahedral Symmetry and the Standard Model Flavor Puzzle
ABSTRACT: In this talk, the possibility of using icosahedral symmetry as a family symmetry group is explored. The rotational icosahedral group, which is isomorphic to A5, the alternating group of five elements, provides a natural context in which to study (among other possibilities) the intriguing hypothesis that the solar neutrino mixing angle is governed by the golden ratio. The basic tools for flavor model-building within this framework will be described, and models of the fermion masses and mixings will be presented for both the lepton and quark sectors. The approach provides a rich setting in which to investigate the flavor puzzle of the Standard Model.
May 14 2010 11:30	SISSA, Room 137	Shahin Sheikh-Jabbari (IPM Tehran, Iran)	O-BTZ: Orientifolded BTZ Black Holes
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Apr 30 2010 11:30	SISSA, Santorio Building	Vladimir Tello (SISSA)	Left-Right Symmetry and its Phenomenological Implications
ABSTRACT: Left-right symmetric theories offer a natural connection between the smallness of neutrino mass and the scale of parity violation in weak interactions. I give here an introduction to these theories and discuss the connection between lepton number violation at colliders, neutrino-less double beta decay and lepton flavor violation. What emerges is a clear picture of the potential discovery of this theory at LHC.
Apr 23 2010 11:30	SISSA, Room 137	Luca Vecchi (LANL, Los Alamos)	The Conformal Window of deformed CFT's in the planar limit
ABSTRACT: We discuss in the planar approximation the effect of double-trace deformations on CFT?s. We show that this large class of models possesses a conformal window describing a non-trivial flow between two fixed points of the renormalization group, and reveal the presence of a resonance which we associate to the remnant of a dilaton pole. As the conformal window shrinks to zero measure the theory undergoes a conformal phase transition separating a symmetric from a nonsymmetric phase. The recently conjectured strongly coupled branch of non-supersymmetric, non-abelian gauge theories with a large number of flavors is analyzed in light of these results, and a model for the strong branch is proposed. Some phenomenological implications in the context of unparticle physics are also emphasized.
Feb 26 2010 11:30	SISSA, Room D	Jian Zhao (SISSA)	A simple introduction to localization and equivariant integration
ABSTRACT: Localization is a general principle in supersymmetric and topological field theory which has been used to treat counting problems such as counting intantons and counting curves. In this talk I will give a pedantic review on how does localization happens and how to get the equivariant integration on hyperKahler quotient space. Without much detail about ADHM construction, I want to show how to use equivariant integration to get Nekrasov's partition function.
Feb 12 2010 11:30	SISSA, Room D	Andrzej Hryczuk (SISSA)	Mirror Dark Matter
ABSTRACT: Mirror Matter is a hypothetical counterpart to ordinary matter, connected by the "mirror parity" transformation. Its existence would mean that there is a complicated dark sector with many possible phenomenological implications. In particular it provides a viable, although generally considered to be quite contrived, candidate for the dark matter. In my talk I will present the model of Mirror DM and discuss how does it fit to what we know about dark matter so far. I will also briefly discuss its direct detection and possible interpretation of DAMA results.
Jan 29 2010 11:30	SISSA, Room D	Alberto Tonero (SISSA)	Asymptotic freedom of two dimensional nonlinear sigma model
ABSTRACT: A scalar field theory in dimension d=2 is renormalizable by power counting. An example of such a theory is the so called nonlinear sigma model. It was first proposed as an alternative description of spontaneous symmetry breaking. There are some similarities between non-Abelian gauge theories in 4+e dimensions and the nonlinear sigma model in 2+e dimensions. They are both asymptotically free at e=0. In my talk I want to present the original derivation of the asymptotic freedom of the nonlinear sigma model in d=2 given by Polyakov (A.M.Polyakov, Phys. Lett. 59B, 79(1975)) and briefly discuss some alternative ways to derive the RG beta function for this model.
Jan 15 2010 11:30	SISSA, Room D	Maurizio Monaco (SISSA)	A brief introduction to little Higgs
ABSTRACT: One of the main open problems of the Standard Model is the presence of quadratically divergent quantum corrections in the Higgs mass. An interesting possibility to solve such a problem is to consider the Higgs particle as a pseudo-Nambu-Goldstone boson. In particular little Higgs theories are based on the fact that if a certain global symmetry is broken by the interplay of at least two coupling costants the Higgs mass happens to be free from quadratic divergencies at one loop. This particular kind of breaking, that is called "collective", is the essential ingredient for such a class of theories. In my talk I will give a pedagogical introduction to one of these little Higgs models, based on SU(3) symmetry group, focusing the attention on the crucial steps of the construction.
Jan 11 2010 11:30	SISSA, Room 137	Tomas Prochazka (SISSA)	Massive spin 2 field and its interaction
ABSTRACT: In this journal club I want to review some of the difficulties encountered when one tries to write down action of massive spin 2 field interacting with background metric or electromagnetic field. This is done in hep-th/0006144 and hep-th/0112182. Requirement of correct number of propagating degrees of freedom in the gravitational case leads to nontrivial restrictions on background metric and free parameters of Lagrangian. In the electromagnetic case it uniquely fixes the value of nonminimal magnetic moment coupling.
Jun 19 2009 11:00	SISSA, Room D	John Wang (Niagara University and SUNY, Buffalo (US))	Cosmology from Sbranes
ABSTRACT: We review S-brane actions derived in the context of tachyon condensation and construct a class of their cosmological solutions
Jun 05 2009 11:00	SISSA, Room D	Michael Schmidt (University of Durham)	The Hierarchy Problem in a LR Symmetric Model with Conformal Invariance
ABSTRACT: In classically conformally invariant models, a hierarchy between the Planck and the electroweak scale is naturally introduced and stabilized. However, within the Standard Model, conformal symmetry contradicts experimental data. Therefore, the Standard Model will have to be extended, if conformal symmetry ought to solve the hierarchy problem. One appealing extension is the minimal left-right symmetric model since parity is broken spontaneously and massive neutrinos are predicted. I discuss symmetry breaking in the minimal conformally invariant left-right symmetric model and demonstrate that parity is broken in a large fraction of parameter space and a > viable low energy phenomenology can be achieved.
Apr 24 2009 11:00	SISSA, Room D	Luca Di Luzio (SISSA)	The kinetic mixing in theories with several U(1) factors
ABSTRACT: After a brief description of the possible origins of U(1) factors. I will work out explicitly the renormalization of a U(1)_a \times U(1)_b unbroken theory, in order to identify those physical parameters which are needed to renormalize the theory. Among these, the kinetic mixing parameter is not generated radiatively only if some conditions on the charges are fulfilled. In the second part of the talk I will focus on low energy constraints for the kinetic mixing parameter both in the broken and unbroken case.
Mar 27 2009 13:15	SISSA, Room D	Alexander Blum (MPI, Heidelberg, Germany)	Ingredients for a flavor symmetry
ABSTRACT: Flavor symmetries are a popular method for explaining the observed regularities in the masses and the mixing of the fundamental fermions. This talk deals with the basics of such flavor symmetry models, discussing the necessary group theory and presenting simple examples.
Mar 20 2009 11:00	SISSA, Room D	Shahin Sheikh Jabbari (IPM, Tehran)	A review of the Kerr/CFT correspondence
ABSTRACT: In arXiv:0809.4266[hep-th] Strominger et.al., extending the usual AdS/CFT ideology, propose a CFT dual for an extremal 4d Kerr black hole. The proposed CFT dual in this case is a chiral half of a 2d CFT in the temperature 1/(2\pi). Using the Asymptotic Symmetry Group arguments, the central charge of this chiral CFT is also computed. Based on these considerations it is conjectured that (quantum gravity) on the (near horizon of the) extremal Kerr black hole is a chiral 2d CFT, which is, however, not specified. This correspondence has since been extended to any extremal black hole, static or stationary, in various dimensions. In this talk we review this paper and the followup papers.
Mar 06 2009 11:00	Room D	Lorenzo Seri (SISSA)	DLCQ and Plane Wave Matrix Big Bang Models
ABSTRACT: In first part I will discuss basic properties of singular homogeneous plane waves and I will explain how they arise universally as Penrose limits of space-time singularities. Then I will review the main points of the DLCQ (Dicrete Light Cone Quantization) procedure in the lightlike linear dilaton background, known as Craps-Sethe-Verlinde matrix Big Bang. My final goal is to describe how such a procedure can be generalised to singular homogeneous plane waves, and to study a few properties of the model obtained in this way.
Feb 20 2009 11:00	SISSA, Room D	Marco Nardecchia (SISSA)	The Supersymmetric Flavor Problem
ABSTRACT: I will start with a review of the flavor problem in the MSSM. I will discuss the generic mechanisms to suppress supersymmetric contributions to FCNC processes. Then I will focus on the specific case of hierarchical soft terms in which the first two generations of squarks and sleptons are heavier than the rest of the supersymmetric spectrum (arXiv:0812.3610).