| 1. |
- Beisert, N., et al.
(författare)
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Long-range gl(n) integrable spin chains and plane-wave matrix theory
- 2006
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Ingår i: Journal of Statistical Mechanics: Theory and Experiment. - 1742-5468. ; :7, s. P07006-
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Tidskriftsartikel (refereegranskat)abstract
- Quantum spin chains arise naturally from perturbative large-N field theories and matrix models. The Hamiltonian of such a model is a long-range deformation of nearest-neighbor type interactions. Here, we study the most general long-range integrable spin chain with spins transforming in the fundamental representation of gl(n). We derive the Hamiltonian and the corresponding asymptotic Bethe ansatz at the leading four perturbative orders with several free parameters. Furthermore, we propose Bethe equations for all orders and identify the moduli of the integrable system. We finally apply our results to plane-wave matrix theory and show that the Hamiltonian in a closed sector is not of this form and therefore not integrable beyond the first perturbative order. This also implies that the complete model is not integrable.
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| 2. |
- Beisert, Niklas, et al.
(författare)
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Review of AdS/CFT Integrability : An Overview
- 2012
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Ingår i: Letters in Mathematical Physics. - : Springer Science and Business Media LLC. - 0377-9017 .- 1573-0530. ; 99:1-3, s. 3-32
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Forskningsöversikt (refereegranskat)abstract
- This is the introductory chapter of a review collection on integrability in the context of the AdS/CFT correspondence. In the collection we present an overview of the achievements and the status of this subject as of the year 2010.
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| 3. |
- Benna, Marcus, et al.
(författare)
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Superconformal Chern-Simons theories and AdS(4)/CFT3 correspondence
- 2008
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 072-
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the N = 2 superspace formulation of the N = 8 superconformal Bagger-Lambert-Gustavsson theory, and of the N = 6 superconformal Aharony-Bergman-Jafferis-Maldacena U(N) x U(N) Chern-Simons theory. In particular, we prove the full SU(4)R-symmetry of the ABJM theory. We then consider orbifold projections of this theory that give non-chiral and chiral (U( N) x U(N))(n) superconformal quiver gauge theories. We argue that these theories are dual to certain AdS(4) x S-7/(Z(n) x Z (k$) over tilde) backgrounds of M-theory. We also study a SU(3) invariant mass term in the superpotential that makes the N = 8 theory flow to a N = 2 superconformal gauge theory with a sextic superpotential. We conjecture that this gauge theory is dual to the U(1)(R) x SU(3) invariant extremum of the N = 8 gauged supergravity, which was discovered by N. Warner 25 years ago and whose uplifting to 11 dimensions was found more recently.
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| 4. |
- Dekel, Amit, et al.
(författare)
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Correlation function of circular Wilson loops at strong coupling
- 2013
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :11, s. 117-
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Tidskriftsartikel (refereegranskat)abstract
- We study the correlation function of two circular Wilson loops at strong coupling in N = 4 super Yang-Mills theory. Using the AdS/CFT correspondence, the problem maps to finding the minimal surface between two circles defined on the boundary of AdS, and the fluctuations around the classical solution in AdS(5) x S-5. At the classical level, we derive the string solution in H-3 X S-1 explicitly, and focus on properties such as stability and phase transition. Furthermore, a computation of the associated algebraic curve is given. At the quantum level, the one-loop partition function is constructed by introducing quadratic bosonic and fermionic fluctuations around the classical solution, embedded in AdS(5) x S-5. We find an analytic, formal expression for the partition function in terms of an infinite product by employing the Gel'fand-Yaglom method and supersymmetric regularization. We regulate the expression and evaluate the partition function numerically.
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| 5. |
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| 6. |
- Giangreco Marotta Puletti, Valentina, et al.
(författare)
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Factorized world-sheet scattering in near-flat AdS5×S5
- 2008
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 792:3, s. 228-256
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Tidskriftsartikel (refereegranskat)abstract
- We show the factorization of the three-particle world-sheet S-matrix of AdS5×S5 superstring theory in the near-flat-space limit at one loop order. This is done by computing various scattering amplitudes from Feynman diagrams in the world-sheet theory. The knowledge of certain highest weight amplitudes allows us to fix all the freedom in the three-particle S-matrix, which we argue to be constrained up to four scalar functions due to the symmetries of the model. We demonstrate that these amplitudes are given by corresponding products of the known two-particle S-matrix elements, from which it follows that the scattering of any three world-sheet excitations factorizes. This provides an explicit and direct check of the quantum integrability of string theory in near-flat AdS5×S5 as it renders evidence for the existence of higher conserved charges. By computing further amplitudes we also obtain an indirect confirmation of the supersymmetries of the near-flat-space model.
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| 7. |
- Harder, Thomas, et al.
(författare)
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Evidence-based decision-making in infectious diseases epidemiology, prevention and control: matching research questions to study designs and quality appraisal tools
- 2014
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Ingår i: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 14:69
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:The Project on a Framework for Rating Evidence in Public Health (PRECEPT) was initiated and is being funded by the European Centre for Disease Prevention and Control (ECDC) to define a methodology for evaluating and grading evidence and strength of recommendations in the field of public health, with emphasis on infectious disease epidemiology, prevention and control. One of the first steps was to review existing quality appraisal tools (QATs) for individual research studies of various designs relevant to this area, using a question-based approach.METHODS:Through team discussions and expert consultations, we identified 20 relevant types of public health questions, which were grouped into six domains, i.e. characteristics of the pathogen, burden of disease, diagnosis, risk factors, intervention, and implementation of intervention. Previously published systematic reviews were used and supplemented by expert consultation to identify suitable QATs. Finally, a matrix was constructed for matching questions to study designs suitable to address them and respective QATs. Key features of each of the included QATs were then analyzed, in particular in respect to its intended use, types of questions and answers, presence/absence of a quality score, and if a validation was performed.RESULTS:In total we identified 21 QATs and 26 study designs, and matched them. Four QATs were suitable for experimental quantitative study designs, eleven for observational quantitative studies, two for qualitative studies, three for economic studies, one for diagnostic test accuracy studies, and one for animal studies. Included QATs consisted of six to 28 items. Six of the QATs had a summary quality score. Fourteen QATs had undergone at least one validation procedure.CONCLUSIONS:The results of this methodological study can be used as an inventory of potentially relevant questions, appropriate study designs and QATs for researchers and authorities engaged with evidence-based decision-making in infectious disease epidemiology, prevention and control.
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| 8. |
- Klose, Johannes, et al.
(författare)
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Semi-synthetic salinomycin analogs exert cytotoxic activity against human colorectal cancer stem cells
- 2018
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 495:1, s. 53-59
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Tidskriftsartikel (refereegranskat)abstract
- Salinomycin, a polyether antibiotic, is a well-known inhibitor of human cancer stem cells. Chemical modification of the allylic C20 hydroxyl of salinomycin has enabled access to synthetic analogs that display increased cytotoxic activity compared to the native structure. The aim of this study was to investigate the activity of a cohort of C20-O-acyl analogs of salinomycin on human colorectal cancer cell lines in vitro. Two human colorectal cancer cell lines (SW480 and SW620) were exposed to three C20-O-acylated analogs and salinomycin. The impact of salinomycin and its analogs on tumor cell number, migration, cell death, and cancer stem cell specifity was analyzed. Exposure of human colorectal cancer cells to the C20-O-acylated analogs of salinomycin resulted in reduced tumor cell number and impaired tumor cell migration at lower concentrations than salinomycin. When used at higher (micromolar) concentrations, these effects were accompanied by induction of apoptotic cell death. Salinomycin analogs further expose improved activity against cancer stem cells compared to salinomycin.
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| 9. |
- Klose, Thomas, et al.
(författare)
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A light-cone approach to three-point functions in AdS(5) x S-5
- 2012
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; :4, s. 80-
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Tidskriftsartikel (refereegranskat)abstract
- We consider worldsheet correlation functions for strings in AdS(5) x S-5 using a light-cone gauge for the worldsheet theory. We compute the saddle-point approximation to three-point functions of BMN vertex operators, all with large charges, by explicitly finding the intersection of three euclidean BMN strings. We repeat this calculation for non-BPS circular winding strings extended along a great circle of the S5, though in this case the appropriate form of the vertex operator is uncertain. Furthermore, we compute the spectrum of fluctuations about euclidean BMN strings for generic boundary conditions, and show that the spectrum depends only on the total charge and not the details of the string configuration. We extend our considerations to include near-BMN vertex operators and through the evaluation of the string path integral make contact with the light-cone string field theory calculations of gauge theory three-point structure constants.
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| 10. |
- Klose, Thomas, et al.
(författare)
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Bethe ansatz in stringy sigma models
- 2006
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Ingår i: J. Stat. Mech.. ; 0605, s. P006-
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Tidskriftsartikel (refereegranskat)abstract
- We compute the exact S-matrix and give the Bethe ansatz solution for three sigma-models which arise as subsectors of string theory in AdS(5)xS(5): Landau-Lifshitz model (non-relativistic sigma-model on S(2)), Alday-Arutyunov-Frolov model (fermionic sigma-model with su(1|1) symmetry), and Faddeev-Reshetikhin model (string sigma-model on S(3)xR).
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| 11. |
- Klose, Thomas, et al.
(författare)
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Comments on world-sheet form factors in AdS/CFT
- 2014
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Ingår i: Journal of Physics A. - : IOP Publishing. - 1751-8113 .- 1751-8121. ; 47:5, s. 055401-
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Tidskriftsartikel (refereegranskat)abstract
- We study form factors in the light-cone gauge world-sheet theory for strings in AdS(5) x S-5. We perturbatively calculate the two-particle form factor in a closed su(2) sector to one-loop in the near-plane-wave limit and to two-loops in the Maldacena-Swanson limit. We also perturbatively solve the functional equation which follows from the form factor axioms for the world-sheet theory and show that the 'minimal' solution correctly reproduces the discontinuities of the perturbative calculations. Finally we propose a prescription, valid for polynomial orders of the inverse world-sheet length, for extracting the finite-volume world-sheet matrix element from the form factors and show that the two-excitation matrix element matches with the thermodynamic limit of the spin-chain description of certain tree-level N = 4 SYM structure constants.
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| 12. |
- Klose, Thomas, et al.
(författare)
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Reduced sigma-model on AdS(5) x S-5 : one-loop scattering amplitudes
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :2, s. 071-
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Tidskriftsartikel (refereegranskat)abstract
- We compute the one-loop S-matrix in the reduced sigma-model which describes AdS5 × S5 string theory in the near-flat-space limit. The result agrees with the corresponding limit of the S-matrix in the full sigma-model, which demonstrates the consistency of the reduction at the quantum level.
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| 13. |
- Klose, Thomas
(författare)
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Review of AdS/CFT Integrability, Chapter IV.3 : N=6 Chern-Simons and Strings on AdS(4) x CP3
- 2012
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Ingår i: Letters in Mathematical Physics. - : Springer Science and Business Media LLC. - 0377-9017 .- 1573-0530. ; 99:1-3, s. 401-423
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Forskningsöversikt (refereegranskat)abstract
- We review the duality and integrability of N = 6 superconformal Chern-Simons theory in three dimensions and IIA superstring theory on the background AdS(4)xCP(3). We introduce both of these models and describe how their degrees of freedom are mapped to excitations of a long-range integrable spin-chain. Finally, we discuss the properties of the Bethe equations, the S-matrix and the algebraic curve that are special to this correspondence and differ from the case of N = 4 SYM theory and strings on AdS(5)xS(5).
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| 14. |
- Klose, Thomas, et al.
(författare)
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World-sheet scattering in AdS5 × S5 at two loops
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :8, s. 051-
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Tidskriftsartikel (refereegranskat)abstract
- We study the AdS5 × S5 sigma-model truncated to the near-flat-space limit to two-loops in perturbation theory. In addition to extending previously known one-loop results to the full SU(2|2)2 S-matrix we calculate the two-loop correction to the dispersion relation and then compute the complete two-loop S-matrix. The result of the perturbative calculation can be compared with the appropriate limit of the conjectured S-matrix for the full theory and complete agreement is found.
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| 15. |
- Klose, Thomas, et al.
(författare)
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Worldsheet form factors in AdS/CFT
- 2013
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:2, s. 026004-
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Tidskriftsartikel (refereegranskat)abstract
- We formulate a set of consistency conditions appropriate to worldsheet form factors in the massive, integrable but nonrelativistic, light-cone gauge fixed AdS(5) x S-5 string theory. We then perturbatively verify that these conditions hold, at tree level in the near-plane-wave limit and to one loop in the near-flat (Maldacena-Swanson) limit, for a number of specific cases. We further study the form factors in the weakly coupled dual description, verifying that the relevant conditions naturally hold for the one-loop Heisenberg spin chain. Finally, we note that the near-plane-wave expressions for the form factors, when further expanded in small momentum or, equivalently, large charge density, reproduce the thermodynamic limit of the spin-chain results at leading order.
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| 16. |
- Klose, Thomas, et al.
(författare)
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Worldsheet scattering in AdS(5) x S-5
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 094-
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Tidskriftsartikel (refereegranskat)abstract
- We calculate the S-matrix in the gauge-fixed sigma-model on AdS(5) x S-5 to the leading order in perturbation theory, and analyze how supersymmetry is realized on the scattering states. A mild nonlocality of the supercharges implies that their action on multi-particle states does not follow the Leibniz rule, which is replaced by a nontrivial coproduct. The plane wave symmetry algebra is thus naturally enhanced to a Hopf algebra. This structure mirrors that of the large't Hooft coupling expansion of the S-matrix for the spin chain in the dual super-Yang-Mills theory.
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| 17. |
- Pufu, Silviu S., et al.
(författare)
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Green's functions and non-singlet glueballs on deformed conifolds
- 2011
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Ingår i: Journal of physics. A, Mathematical and theoretical. - : IOP Publishing. - 1751-8113 .- 1751-8121. ; 44:5, s. 055404-
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Tidskriftsartikel (refereegranskat)abstract
- We study the Laplacian on Stenzel spaces (generalized deformed conifolds), which are tangent bundles of spheres endowed with Ricci flat metrics. The (2d-2)-dimensional Stenzel space has SO(d) symmetry and can be embedded in C-d through the equation Sigma(d)(i=1) z(i)(2) = epsilon(2). We discuss Green's function with a source at a point on the Sd-1 zero section of T Sd-1. Its calculation is complicated by mixing between different harmonics with the same SO(d) quantum numbers due to the explicit breaking by the epsilon-deformation of the U(1) symmetry that rotates z(i) by a phase. A similar mixing affects the spectrum of normal modes of warped deformed conifolds that appear in gauge/gravity duality. We solve the mixing problem numerically to determine certain bound state spectra in various representations of SO(d) for the d = 4 and d = 5 examples.
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| 18. |
- Wunderling, Nico, 1992-, et al.
(författare)
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Climate tipping point interactions and cascades : a review
- 2024
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Ingår i: Earth System Dynamics. - 2190-4979 .- 2190-4987. ; 15:1, s. 41-74
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Forskningsöversikt (refereegranskat)abstract
- Climate tipping elements are large-scale subsystems of the Earth that may transgress critical thresholds (tipping points) under ongoing global warming, with substantial impacts on the biosphere and human societies. Frequently studied examples of such tipping elements include the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), permafrost, monsoon systems, and the Amazon rainforest. While recent scientific efforts have improved our knowledge about individual tipping elements, the interactions between them are less well understood. Also, the potential of individual tipping events to induce additional tipping elsewhere or stabilize other tipping elements is largely unknown. Here, we map out the current state of the literature on the interactions between climate tipping elements and review the influences between them. To do so, we gathered evidence from model simulations, observations, and conceptual understanding, as well as examples of paleoclimate reconstructions where multi-component or spatially propagating transitions were potentially at play. While uncertainties are large, we find indications that many of the interactions between tipping elements are destabilizing. Therefore, we conclude that tipping elements should not only be studied in isolation, but also more emphasis has to be put on potential interactions. This means that tipping cascades cannot be ruled out on centennial to millennial timescales at global warming levels between 1.5 and 2.0 ∘C or on shorter timescales if global warming surpassed 2.0 ∘C. At these higher levels of global warming, tipping cascades may then include fast tipping elements such as the AMOC or the Amazon rainforest. To address crucial knowledge gaps in tipping element interactions, we propose four strategies combining observation-based approaches, Earth system modeling expertise, computational advances, and expert knowledge.
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