1,721,204 research outputs found
Schur line defect correlators and giant graviton expansion
Full text linkAbstract We consider Schur line defect correlators in four dimensional N = 4 U(N) SYM and their giant graviton expansion encoding finite N corrections to the large N limit. We compute in closed form the single giant graviton contribution to correlators with general insertions of 1 2 -BPS charged Wilson lines. For the 2-point function with fundamental and anti-fundamental Wilson lines, we match the result from fluctuations of two half-infinite strings ending on the giant graviton, recently proposed in arXiv:2403.11543. In particular, we prove exact factorization of the defect contribution with respect to wrapped D3 brane fluctuations representing the single giant graviton correction to the undecorated Schur index. This follows from a finite-difference representation of the Schur line defect index in terms of the index without defects, and similar factorization holds quite generally for more complicated defect configurations. In particular, the single giant graviton contribution to the 4-point function with two fundamental and two anti-fundamental lines is computed and discussed in this perspective
Leading large N giant graviton correction to Schur correlators in large representations
Full text linkWe consider 4d N=4 U(N) SYM and the leading giant graviton correction at large N to the Schur defect 2-point functions of 12-BPS Wilson lines in rank-k symmetric and antisymmetric representations. We study in particular the large k limit for the symmetric case and the regime 1≪k≪N in the antisymmetric one. In both cases we present exact results for the correction. Wilson lines in symmetric/antisymmetric representations admit a description in terms of D3k and D5k brane probes representing a collection of k fundamental strings. In this picture, giant graviton corrections come from fluctuations of brane probes in the presence of a wrapped D3 brane giant graviton. In the antisymmetric case, our leading correction matches the half-index of the 4d N=4 Maxwell theory living on the disk which is a part of the giant graviton divided out by the D5k probe, as recently proposed in arXiv:2404.08302. For the symmetric case at large k, we derive an explicit exact residue formula for the leading large N correction
The sleeping bacterium: shedding light on the resuscitation mechanism
No full textThe revival mechanism in dormant bacteria is a puzzling and open issue. We propose a model of information diffusion on a regular grid where agents represent bacteria and their mutual interactions implement quorum sensing. Agents may have different metabolic characteristics corresponding to multiple phenotypes. The intra/inter phenotype cooperation is analyzed under different metabolic and productivity conditions. We study the interactions between rapidly reproducing active bacteria and non-reproducing quiescent bacteria. We highlight the conditions under which the quiescent bacteria may revive. The occurrence of revival is generally related to a change in environmental conditions. Our results support this picture showing that revival can be mediated by the presence of different catalyst bacteria that produce the necessary resources
AdS/CFT duality at strong coupling
No full textWe study the strong-coupling limit of the AdS/CFT correspondence in the framework of a recently proposed fermionic formulation of the Bethe ansatz equations governing the gauge theory anomalous dimensions. We give examples of states that do not follow the Gubser-Klebanov-Polyakov law at a large 't Hooft coupling λ, in contrast to recent results on the quantum string Bethe equations that are valid in that regime. This result indicates that the fermionic construction cannot be trusted at large λ, although it remains an efficient tool for computing the weak-coupling expansion of anomalous dimensions. © 2007 Springer Science+Business Media, Inc
Advanced Analytical Techniques in Food Analysis
No full textThe necessity of more effective and powerful analytical tools and methods for the assessment of food quality and authenticity was highlighted in 2014 by the European Parliament resolution on the food crisis (1). This is not limited to the use of innovative analytical instrumentation but extends to the application of more comprehensive approaches (e.g., fingerprinting) and advanced data handling. This highlight has accelerated the paradigm change in food analysis. Indeed, food analytical scientists are now coupling the use of advanced analytical techniques with approaches borrowed from metabolomics, particularly in data handling.
The application of modern, advanced, and innovative techniques are playing a fundamental role in this new scenario, increasing the overall knowledge in the food field and supporting the resolution of complex problems and fraud detection
On topological recursion for Wilson loops in N = 4 SYM at strong coupling
Full text linkWe consider U(N) N = 4 super Yang-Mills theory and discuss how to extract the strong coupling limit of non-planar corrections to observables involving the 12-BPS Wilson loop. Our approach is based on a suitable saddle point treatment of the Eynard-Orantin topological recursion in the Gaussian matrix model. Working directly at strong coupling we avoid the usual procedure of first computing observables at finite planar coupling λ, order by order in 1/N, and then taking the λ ≫ 1 limit. In the proposed approach, matrix model multi-point resolvents take a simplified form and some structures of the genus expansion, hardly visible at low order, may be identified and rigorously proved. As a sample application, we consider the expectation value of multiple coincident circular supersymmetric Wilson loops as well as their correlator with single trace chiral operators. For these quantities we provide novel results about the structure of their genus expansion at large tension, generalising recent results in arXiv:2011.02885
Single layer Multimodal OAM Reflectarray
Full text linkIn this work, the procedure for the design of innovative reflectarray (RA) antennas able to radiate multiple Orbital Angular Momentum (OAM) modes is introduced. Extending the concepts at the base of multifocal lenses, the RA is designed in such a way that, depending on the direction of arrival of the incident field, it radiates a broadside beam carrying an OAM with different index. As a proof of concept, a circular RA with diameter D = 20λ at the the frequency f0 = 30 GHz, able to radiate OAMs with l = 2 and l = 4 has been designed. The results obtained through its full-wave simulation, confirm the effectiveness of the proposed solution
Toda theory in AdS2 and An-algebra structure of boundary correlators
Full text linkWe consider the conformal An Toda theory in AdS2. Due to the bulk full Virasoro symmetry, this system provides an instance of a non-gravitational AdS2/CFT1 correspondence where the 1d boundary theory enjoys enhanced “12−Virasoro” symmetry. General boundary correlators are expected to be captured by the restriction of chiral correlators in a suitable WAn Virasoro extension. At next-to-leading order in weak coupling expansion they have been conjectured to match the subleading terms in the large central charge expansion of the dual An correlators. We explicitly test this conjecture on the boundary four point functions of the Toda scalar fields dual to An generators with next-to-minimal spin 3 and 4. Our analysis is valid in the generic rank case and extends previous results for specific rank-2 Toda theories. On the AdS side, the extension is straightforward and requires the computation of a finite set of tree Witten diagrams. This is due to simple rank dependence and selection rules of cubic and quartic couplings. On the boundary, we exploit crossing symmetry and specific meromorphic properties of the W-algebra correlators at large central charge. We present the required 4-point functions in closed form for any rank and verify the bulk-boundary correspondence in full details
On the structure of non-planar strong coupling corrections to correlators of BPS Wilson loops and chiral primary operators
Full text linkStarting with some known localization (matrix model) representations for correlators involving 1/2 BPS circular Wilson loop W in N = 4 SYM theory we work out their 1/N expansions in the limit of large ’t Hooft coupling λ. Motivated by a possibility of eventual matching to higher genus corrections in dual string theory we follow arXiv:2007.08512 and express the result in terms of the string coupling gs∼gYM2∼λ/N and string tension T∼λ. Keeping only the leading in 1/T term at each order in gs we observe that while the expansion of 〈 W〉 is a series in gs2/T, the correlator of the Wilson loop with chiral primary operators OJ has expansion in powers of gs2/T2. Like in the case of 〈 W〉 where these leading terms are known to resum into an exponential of a “one-handle” contribution ∼gs2/T, the leading strong coupling terms in 〈 WOJ〉 sum up to a simple square root function of gs2/T2. Analogous expansions in powers of gs2/T are found for correlators of several coincident Wilson loops and they again have a simple resummed form. We also find similar expansions for correlators of coincident 1/2 BPS Wilson loops in the ABJM theory
Large N expansion of superconformal index of k = 1 ABJM theory and semiclassical M5 brane partition function
Full text linkIt was shown in arXiv:2309.10786 that the leading non-perturbative contribution to the large N expansion of the superconformal index of the (2,0) 6d theory (which describes low-energy dynamics of N coincident M5 branes) is reproduced by the semiclassical partition function of quantum M2 brane wrapped on S1×S2 in a twisted version of AdS×7S4 background. Here we demonstrate an analogous relation for the leading non-perturbative contribution to the large N expansion of the superconformal index of the N=8 supersymmetric level-one U(N)×U(N) ABJM theory (which describes low-energy dynamics of N coincident M2 branes). The roles of M2 and M5 branes get effectively interchanged. Namely, the large N correction to the ABJM index is found to be given by the semiclassical partition function of quantum M5 brane wrapped on S1×S5 in a twisted version of AdS×4S7 background. This effectively confirms the suggestion for the “M5 brane index” made in arXiv:2007.05213 on the basis of indirect superconformal algebra considerations
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