71 research outputs found
Reciprocity and integrability in the sl(2) sector of N=4 SYM
No full textWe analyze the higher conserved charges of type IIB superstring on from the perspective of a recently discovered generalized Gribov-Lipatov reciprocity. We provide several evidences that reciprocity holds for all the higher charges and not only for the energy. This is discussed in the simple case of twist , and operators in the sl subsector at (a) multi-loop level in weak coupling, (b) classical level at strong coupling for the dual folded string
New Physics signals from measurable polarization asymmetries at LHC
No full textWe propose a new type of Z polarization asymmetry in bottom-Z production at LHC that should be realistically measurable and would provide the determination of the so-called Ab parameter, whose available measured value still appears to be in disagreement with the Standard Model prediction; we discuss the overall expected precision of this measurement and its implications. If Supersymmetry is found, a second polarization, i.e. the top longitudinal polarization in top-charged Higgs production, would neatly identify the tan β parameter. In this case, the value of Ab should be in agreement with the Standard Model. If Supersymmetry does not exist, a residual disagreement of AbAb from the Standard Model prediction would be a clean signal of New Physics of “non-Supersymmetric” origin
A macro-model with nonlinear springs for seismic analysis of URM buildings
No full textSeismic assessment of existing unreinforced masonry buildings represents a current challenge in structural engineering. Many historical masonry buildings in earthquake regions were not designed to withstand seismic loading, thus these structures often do not meet the basic safety requirements recommended by current seismic codes and need to be strengthened considering the results from realistic structural analysis. This paper presents an efficient modelling strategy for representing the nonlinear response of unreinforced masonry components under in-plane cyclic loading which can be used for practical and accurate seismic assessment of masonry buildings. According to the proposed strategy, a generic masonry perforated walls is modelled using an equivalent frame approach, where each masonry component is described utilising multi-spring nonlinear elements connected by rigid links. When modelling piers and spandrels, nonlinear springs are placed at the two ends of the masonry element for describing the flexural behaviour, and in the middle for representing the response in shear. Specific hysteretic rules allowing for degradation of stiffness and strength are then used for modelling the member response under cyclic loading. The accuracy and the significant potential of the proposed modelling approach are shown in several numerical examples, including comparisons against experimental results and the nonlinear dynamic analysis of a building structure
Chiral trace relations in Ω-deformed = 2 theories
No full textWe study chiral trace relations in N = 2 supersymmetric theories. Applying localization formulae for chiral observables, we derive closed chiral trace relations relating the vacuum expectation values of chiral ring elements. In this setting, we discuss how the Omega-background breaks the polynomial nature of such relations. These results are interpreted in the light of AGT duality, thus making contact with the integrable structure of conformal field theories on Riemann surfaces
Chiral Trace Relations in Supersymmetric Gauge Theories
No full textWe analyze the chiral ring in Ω-deformed N =2∗ supersymmetric gauge theories. Applying localization
techniques, we derive closed identities for the vacuum expectation values of chiral trace operators. In
the SU(2) case, we provide an AGT framework to identify chiral trace operators and the system of local
integrals of motion in the related two-dimensional conformal field theory. In this setup, we predict some
universal terms appearing in chiral trace identities
Quantum corrections to short folded superstring in AdS_3 x S^3 x M^4
No full textWe consider integrable superstring theory on AdS × S × M where M = T or M = S × S with generic ratio of the radii of the two 3-spheres. We compute the one-loop energy of a short folded string spinning in AdS and rotating in S. The computation is performed by world-sheet small spin perturbation theory as well as by quantizing the classical algebraic curve characterizing the finite-gap equations. The two methods give equal results up to regularization contributions that are under control. One important byproduct of the calculation is the part of the energy which is due to the dressing phase in the Bethe Ansatz. Remarkably, this contribution E turns out to be independent on the radii ratio. In the M = T limit, we discuss how E relates to a recent proposal for the dressing phase tested in the su(2) sector. We point out some difficulties suggesting that quantization of the AdS classical finite-gap equations could be subtler than the easier AdS × S case
Probing Complexity with Epidemics: A New Reactive Immunization Strategy
No full textEpidemic evolution on complex networks strongly depends on their topology and the infection dynamical
properties, as highly connected nodes and individuals exposed to the contagion have competing roles in the
disease spreading. In this spirit, we propose a new immunization strategy exploiting the knowledge of network
geometry and dynamical information about the spreading infection. The flexibility and effectiveness of the
proposed scheme are successfully tested with numerical simulations on a wide set of complex network
An evolutionary game model for behavioral gambit of loyalists: Global awareness and risk-aversion
No full textWe study the phase diagram of a minority game where three classes of agents are present. Two types of agents play a risk-loving game that we model by the standard Snowdrift Game. The behaviour of the third type of agents is coded by indifference with respect to the game at all: their dynamics is designed to account for risk-aversion as an innovative behavioral gambit. From this point of view, the choice of this solitary strategy is enhanced when innovation starts, while is depressed when it becomes the majority option. This implies that the payoff matrix of the game becomes dependent on the global awareness of the agents measured by the relevance of the population of the indifferent players. The resulting dynamics is nontrivial with different kinds of phase transition depending on a few model parameters. The phase diagram is studied on regular as well as complex networks
Generalized Gribov-Lipatov Reciprocity and AdS/CFT
No full textPlanar
=4
SYM theory and QCD share the gluon sector, suggesting the investigation
of Gribov-Lipatov reciprocity in the supersymmetric theory. Since the
AdS/CFT correspondence links
=4
SYM and superstring dynamics on
Ad
S
5
×
S
5
, reciprocity is also expected to show up in the quantum corrected energies of certain
classical string configurations dual to gauge theory twist-operators. We review recent
results confirming this picture and revisiting the old idea of Gribov-Lipatov reciprocity
as a modern theoretical tool useful for the study of open problems in AdS/CFT
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