Quantum Field Theory: Developments and Perspectives

Contribution List

13. A Novel Algebraic Approach to Quantum and Classical Dualities

Mr EMILIO COBANERA (INDIANA UNIVERSITY, BLOOMINGTON)

Few non-perturbative tools available to the theoretical physicist are as widely useful as Dualities. These "connections" among diverse models (or one and the same model in different regions of its coupling space) can provide a wealth of qualitative and quantitative information up to exact critical couplings in favorable cases; which explains why dualities have been researched constantly over...

25. Affine sl(N) conformal blocks from N=2 SU(N) gauge theories

Dr Filippo Passerini (Humboldt University)

Alday and Tachikawa have recently proposed a relation between conformal blocks in a two-dimensional theory with affine sl(2) symmetry and instanton partition functions in four-dimensional conformal N=2 SU(2) quiver gauge theories in the presence of a certain surface operator. I will describe how to extend this proposal to a relation between conformal blocks in theories with affine sl(N)...

9. Analytic Computation of t T production at Hadron Colliders

Ralf Sattler (HU Berlin)

We present new compact analytic one-loop helicity amplitudes for $t \bar{t}$ production at Hadron colliders. The results were obtained employing a combination of on-shell methods and advanced Feynman diagram techniques. In particular the tadpole, the rational and mass renormalization contributions were extracted from the latter approach. For the cut constructible pieces we used the method of...

35. Anomaly Mediation from String Theory

Dr Mark Goodsell (DESY, Hamburg)

I shall study anomaly mediated supersymmetry breaking in type IIB string theory and use the results to test the supergravity formula for anomaly mediated gaugino masses. This involves calculating the one-loop gaugino masses for models of D3-branes on orbifold singularities in a three-form flux background by calculating the annulus correlator of two gauginos with a three-form flux insertion.

16. Arithmetic Quantum Gravity

Mr Michael Koehn (Albert-Einstein-Institut, Potsdam)

It has been realized long ago that spacetime singularities generically appear in the classical theory of general relativity, and it is expected that such singularities will be resolved through quantum effects. The classical BKL analysis leads to a cosmological billiards description of space-time near the singularity, which is in general not integrable, but instead chaotic. The shape of the...

20. Asymptotic symmetries of 3D higher-spin gauge theories and W-algebras

Dr Andrea Campoleoni (Albert Eisntein Institute)

We discuss the relation between W-algebras and asymptotic symmetries of higher-spin gauge theories coupled to three-dimensional gravity with a negative cosmological constant. We first show how to describe interactions for higher-spin gauge fields D=2+1 via G x G Chern-Simons actions. Then we identify the asymptotically AdS solutions of the field equations and we show that their asymptotic...

42. B_s mixing and non-minimal flavour violating supersymmetry

Jae-hyeon Park (DESY)

Effects of gluino-squark loops on B_s mixing are discussed in the context of non-minimal flavour violating MSSM. Special attention is paid to the recent data of like-sign dimuon charge asymmetry from D0.

21. Chiral symmetry breaking in an expanding plasma

Dr Ingo Kirsch (DESY Hamburg)

I discuss the effect of an expanding plasma on probe matter by studying time-dependent D7 brane embeddings in the holographic dual of an expanding viscous plasma in the presence of an external magnetic field B. The main focus will be on the chiral phase transition and the behavior of the chiral condensate as a function of time and B.

28. Closed flux tubes and their string description: a lesson by lattice gauge theories

Dr Andreas Athenodorou (DESY, Zeuthen)

During the last decade, much effort has been invested in the investigation of the effective string description of the flux-tube in SU(N) gauge theories; this has been done both analytically and numerically (by means of extracting the flux-tube spectrum using the machinery of lattice gauge theories). Using lattice techniques, we calculate the energy spectrum of a confining flux tube that is...

4. Complex matrix model duality

Dr Thomas Brown (DESY)

The same complex matrix model calculates both tachyon scattering for the $c=1$ non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in $\cN=4$ super-Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is...

8. Dark Energy from Quantum Matter

Dr Thomas-Paul Hack (II. Institut fuer theoretische Physik, Universitaet Hamburg)

We study the backreaction of free quantum fields on a flat Robertson-Walker spacetime. Apart from renormalization freedom, the vacuum energy density receives contributions from both the trace anomaly and the thermal nature of the quantum state. The former represents a dynamical realisation of dark energy, while the latter mimics an effective dark matter component. The semiclassical dynamics...

31. Deterministic Quantum Field theory in Compact Space-Time

Dr Donatello Dolce (Institut für Physik (WA THEP) Johannes-Gutenberg-Universität)

We propose an unexplored quantization method in field theory. It is based on the assumption of dynamic space-time intrinsic periodicities for relativistic fields, which in turn can be regarded as dual to extra-dimensional fields. In a generalization of the AdS/CFT correspondence, we obtain a unified and consistent interpretation of Special Relativity and Quantum Mechanics in terms of...

17. Effective theory methods for heavy coloured (s)particles at hadron colliders

Dr Christian Schwinn (Freiburg University)

Perturbative corrections to pair production process of heavy coloured particles (such as top quarks or supersymmetric partners of quarks and gluons) are enhanced for small velocities of the heavy particles. This enhancement is due to emission of soft gluons and the exchange of Coulomb gluons. I will discuss the use of effective theory methods to disentangle the two effects and perform a...

22. Extremal Three-point Correlators in Kerr/CFT

Dr Waldemar Schulgin (Texas A&M University)

We compute three-point correlation functions in the near-extremal, near-horizon region of a Kerr black hole, and compare to the corresponding finite-temperature conformal field theory correlators. For simplicity, we focus on scalar fields dual to operators ${\cal O}_h$ whose conformal dimensions obey $h_3=h_1+h_2$, which we name \emph{extremal} in analogy with the classic $AdS_5 \times S^5$...

43. Four-dimensional conformal supergravity from N=4 gauged supergravity on asymptotically AdS$_5$

Christoph Uhlemann (Wuerzburg University)

We consider N=4 SU(2)$\otimes$U(1) gauged supergravity on asymptotically AdS$_5$ backgrounds. By a near-boundary analysis we determine the boundary-dominant components of the bulk fields from their partially gauge-fixed field equations. The residual bulk symmetries are found to act on the boundary fields as four-dimensional diffeomorphisms, N=2 supersymmetry and (super-)Weyl...

11. Gravitational shock wave collision and matter equilibration in heavy ion collisions

Dr Shu Lin (MPI for Physics, Munich)

Successful applications of hydrodynamical simulation implies an early thermalization time of quark gluon plasma produced in heavy ion collisions. This suggests the quark gluon plasma is strongly coupled. Theoretical understanding of the equilibration of the strongly coupled matter remains an open problem. In this talk, we will study the matter equilibration in heavy ion collisions with...

34. Hidden $b\bar{b}$ tetraquark spectroscopy and evidence in Belle data near the $\Upsilon(5S)$ resonance

Mr Christian Hambrock (DESY)

In the past several years, experiments at the two B-factories, BaBar and Belle, and at the Tevatron collider, CDF and D0, have discovered an impressive number of new hadronic states in the mass region of the charmonia labeled as $X$, $Y$ and $Z$, which, however, defy a conventional $c\bar{c}$ charmonium interpretation. Different frameworks have been suggested to describe the observed states,...

15. Holographic p-wave Superfluids

Patrick Kerner (Max-Planck-Institut für Physik)

We discuss holographic duals of strongly interacting gauge theories which show properties of superfluids. In this talk we consider p-wave superfluid condensates which in addition to an Abelian symmetry also break the spatial rotational symmetry. First we examine a phenomenological gravity setup, a non-Abelian Einstein-Yang-Mills theory, and therein construct black hole solutions with a vector...

18. J/Psi production with NRQCD: HERA, Tevatron, RHIC and LHC

Dr Mathias Butenschön (Universität Hamburg)

The factorization theorem of nonrelativistic QCD (NRQCD) is a framework for the production and decay of heavy quarkonia. In order to establish NRQCD it is necessary to show the significance of the color-octet (CO) contributions and the universality of the "long distance matrix elements" (LDME) in different high energy processes. We have now succeeded in calculating the cross section of both...

37. Ladder Topologies for Massive 3-Loop Operator Matrix Elements

Mr Alexander Hasselhuhn (DESY Zeuthen)

We calculate massive 3-loop graphs for operator matrix elements which belong to ladder topologies. These diagrams contribute to the $O(\alpha_s^3)$ heavy flavor corrections to the deep-inelastic structure function $F_2(x,Q^2)$. The diagrams are represented in terms of generalized hypergeometric and Appell-functions, which lead to nested sums of hypergeometric terms equipped with harmonic sums....

23. Mathieu moonshine and the elliptic genus of K3

Dr Roberto Volpato (ETH Zurich)

It has recently been conjectured by Eguchi, Ooguri and Tachikawa that the elliptic genus of K3 can be written in terms of dimensions of Mathieu group M24 representations. We provide explicit formulae for the corresponding twining characters and verifying that they satisfy the expected modular properties. This allows us to identify the decomposition of all expansion coefficients in terms of...

24. Matter and Dark Matter from False Vacuum Decay

Mr Kai Schmitz (DESY)

I discuss tachyonic preheating associated with the spontaneous breaking of B-L, the difference of baryon and lepton number: Reheating occurs through the decays of heavy Majorana neutrinos which are produced during preheating and in decays of the Higgs particles of B-L breaking. Baryogenesis is an interplay of nonthermal and thermal leptogenesis, accompanied by thermally produced gravitino dark...

30. N-soliton solutions in field and string theory

Dr Chrysostomos Kalousios (Humboldt University)

Solitonic solutions play an important role in both field and string theory. Due to Pohlmeyer there is a certain map between solitons in those two theories. Motivated by recent advances in the context of AdS/CFT I will present a method (dressing method) to generate N-soliton solutions and I will further present exact results. The talk will be mainly based on the recent paper arXiv:1005.1066.

44. N=2 flavored SYM Theory on S^3 in an external magnetic field.

I focus on a recenly studied quantum phase transition in flavored N=2 SYM on S^3. I describe the general set up of our holographic study. I briefly review the nature of the phase transition and discuss the meson spectrum of the theory with emphasis on structure of the spectrum at vanishing bare mass. I discuss the cases of both 1+3 and 1+2 dimensional fundamental fields. I discuss the effect...

14. Non-supersymmetric Extremal RN-AdS Black Holes in N=2 Gauged Supergravity

Dr Tetsuji Kimura (KEK)

We investigate extremal Reissner-Nordstrom-AdS black holes in four-dimensional N=2 abelian gauged supergravity. We find a new attractor equation which is not reduced to the one in the asymptotically flat spacetime. We also argue a formula which is available even in the presence of the scalar potential. We apply them to the T^3-model and the STU-model in generic black hole charge distributions....

12. On BCFW shifts of integrands and integrals

Dr Rutger Boels (II. institut für theoretische physik)

n this talk a first step is made towards the extension of Britto-Cachazo-Feng-Witten (BCFW) tree level on-shell recursion relations to integrands and integrals of scattering amplitudes to arbitrary loop order. Surprisingly, it is shown that the large BCFW shift limit of the integrands has the same structure as the corresponding tree level amplitude in any minimally coupled Yang-Mills theory in...

41. Properties of the QCD vacuum induced by strong magnetic field (a lattice study).

Mr Tigran Kalaydzhyan (DESY)

We study some properties of the non-Abelian vacuum in the presence of external magnetic field. Orders of magnitude of the field have been chosen to be relevant for the recent experiments with heavy ion collisions. As a framework we used the quenched SU(3) lattice gauge theory with tadpole-improved Luescher-Weisz action and chirally invariant lattice Dirac operator. Within this approach the...

7. Quantum Field Theory on Noncommutative Curved Spacetimes

Mr Alexander Schenkel (Wuerzburg University)

In this talk I show how to construct the quantum field theory of a free real scalar field on a class of noncommutative manifolds, obtained via deformation quantization using abelian Drinfel'd twists. I define action functionals in the framework of twist-deformed differential geometry, derive the associated equations of motion and solve them in terms of formal power series. In analogy to the...

45. R-Parity violating decays of NLSPs at the LHC

Supersymmetric extensions of the Standard Modell with small R-parity and lepton number breaking naturally yield a consistent cosmology incorporating primordial nucleosynthesis, leptogenesis, and gravitino dark matter. Since the gravitino is no longer stable, its highly supressed decays should lead to characteristic signatures in high-energy cosmic rays. This talk examines the implications of...

6. Semiclassical strings exactly

Dr Valentina Forini (Max Planck Institute for Gravitational Physics, Albert Einstein Institute)

We present a systematic analytic treatment of semiclassical fluctuations  around non-trivial solutions for the Green Schwarz string action in AdS5xS5 space. The 1-loop partition function for the cases of the minimal surface corresponding to a Wilson loop with parallel lines and for the folded string are considered, leading in the first case to a prediction  for the subleading correction to the...

32. Smearing versus localising sources in flux compactifications

Mr Daniel Junghans (Leibniz Universität Hannover)

We investigate whether vacuum solutions in flux compactifications that are obtained with smeared sources still survive when the sources are localised. This seems to rely on whether the solutions are BPS or not. First we consider a set of BPS solutions that all relate to the GKP solution through T-duality: (p+1)-dimensional solutions from spacetime-filling Op planes with a conformally flat internal...

29. Space-like string surfaces in AdS_3 x S^3 of vacuum type

Mr Sebastian Wuttke (HU Berlin)

Minimal surfaces in AdS with closed light-like polygonal boundaries play an important role for gluon scattering amplitudes in N=4 SYM theory. However, explicit formulae are available for the tetragon case only. As the string dual to N=4 SYM lives in AdS_5 x S^5 a more complete treatment should also involve the spherical factor with similar boundary conditions. We construct and classify all...

36. Status of sub-GeV Hidden Particle Searches

Sarah Andreas (Deutsches Elektronen-Synchrotron DESY, Notketrasse 85, D-22607 Hamburg, Germany)

Hidden sectors are frequently proposed as part of the physics beyond the standard model. Since their interactions with the visible sectors are very weak, so are the current experimental bounds. In fact, those sectors might even contain particles with masses in the sub-GeV range that have so far escaped detection. Among those weakly interacting slim particles (WISPs) are hidden U(1) gauge...

33. Strong CP problem reconciles Thermal Leptogenesis with Gravitino Dark Matter

Mr Jasper Hasenkamp (Hamburg U.)

Many extensions of the Standard Model predict super-weakly interacting particles, which typically have to decay before Big Bang Nucleosynthesis (BBN). The entropy produced in the decays may help to reconcile thermal leptogenesis and BBN in scenarios with gravitino dark matter, which is usually difficult due to late decays of the next-to-lightest supersymmetric particle (NLSP) spoiling the...

39. Structure of the broken phase of the sine-Gordon model

Dr Vincent Pangon (GSI/FIAS)

We present the IR behavior of the flow of the sine-Gordon model in d=2 using functional renormalization at the local potential approximation. We demonstrate that the broken phase exhibits a continuum of non-perturbative IR fixed points that can not be seen using the usual Fourier expansion. We also show that that the phase boundary remains valid when starting with a strongly coupled bare...

38. The $O(\alpha_s^3)$ Massive Operator Matrix Elements of $O(n_f)$ for the Structure Function $F_2(x,Q^2)$

Mr Fabian Wißbrock (DESY Zeuthen)

The contributions $\propto n_f$ to the $O(\alpha_s^3)$ massive operator matrix elements describing the heavy flavor Wilson coefficients in the limit $Q^2 \gg m^2$ were computed for the structure function $F_2(x,Q^2)$ and transversity for general values of the Mellin variable $N$. Here, for two matrix elements, $A_{qq,Q}^{\sf PS}(N)$ and $A_{qg,Q}(N)$, the complete result has been obtained. A...

40. Thrust distribution at N^3LL with power corrections and precision determination of alpha_s

Dr Vicent Mateu (Max-Plank-Institute for Physics)

A traditional method for determining the strong coupling constant (QCD) with high precision is the analysis of jet cross sections at e+ e- colliders. Event-shape distributions play a special role as they have been extensively measured with small experimental uncertainties and are theoretically clean and accessible to high-order perturbative computations. The strong coupling constant alpha_s...

27. Universal properties of screening in strongly coupled plasmas

Mr Konrad Schade (Institut für Theoretische Physik, Universität Heidelberg)

The talk deals with the analysis of universal properties of two physical observables in strongly coupled plasmas in heavy-ion collisions (for example at RHIC). By using the AdS/CFT correspondence expectation the free energy and the screening length of a heavy quark-antiquark pair and a baryon configuration will be computed. In order to study general properties of these quantities, which can...

10. Vanishing Chiral Algebras

Dr Junya Yagi (Center for Frontier Science, Chiba University)

The chiral algebras of two-dimensional theories with (0,2) supersymmetry are vertex-algebra generalizations of the chiral rings of (2,2) supersymmetric theories, the most famous of which is the quantum cohomology ring. We show that the chiral algebra of a (0,2) supersymmetric sigma model vanishes if the target space is a Kähler manifold with positive first Chern class. This implies that...

26. Wrapped branes, consistent truncations and AdS/CMT

Dr Oscar Varela (Albert Einstein Institute)

Branes wrapping calibrated cycles of special holonomy manifolds provide supersymmetric AdS solutions in String and M-theory. We show that, associated to those backgrounds, consistent truncations retaining massive modes, down to a lower dimensional matter-coupled supergravity theory with that AdS as its vacuum, can be performed. We discuss a particular AdS4 example in M-theory and comment on...