340 research outputs found
Aspects of Integrability in N =4 SYM
Various recently developed connections between supersymmetric Yang-Mills
theories in four dimensions and two dimensional integrable systems serve as
crucial ingredients in improving our understanding of the AdS/CFT
correspondence. In this review, we highlight some connections between
superconformal four dimensional Yang-Mills theory and various integrable
systems. In particular, we focus on the role of Yangian symmetries in studying
the gauge theory dual of closed string excitations. We also briefly review how
the gauge theory connects to Calogero models and open quantum spin chains
through the study of the gauge theory duals of D3 branes and open strings
ending on them. This invited review, written for Modern Physics Letters-A, is
based on a seminar given at the Institute of Advanced Study, Princeton.Comment: Invited brief review for Mod. Phys. Lett. A based on a talk at I.A.S,
Princeto
Yangian Symmetry at Two Loops for the su(2|1) Sector of N=4 SYM
We present the perturbative Yangian symmetry at next-to-leading order in the
su(2|1) sector of planar N=4 SYM. Just like the ordinary symmetry generators,
the bi-local Yangian charges receive corrections acting on several neighboring
sites. We confirm that the bi-local Yangian charges satisfy the necessary
conditions: they transform in the adjoint of su(2|1), they commute with the
dilatation generator, and they satisfy the Serre relations. This proves that
the sector is integrable at two loops.Comment: 13 pages, v2: minor correction
How to foster Sustainable Continuous Improvement: A cause-effect relations map of Lean soft practices
A Classical Sequential Growth Dynamics for Causal Sets
Starting from certain causality conditions and a discrete form of general
covariance, we derive a very general family of classically stochastic,
sequential growth dynamics for causal sets. The resulting theories provide a
relatively accessible ``half way house'' to full quantum gravity that possibly
contains the latter's classical limit (general relativity). Because they can be
expressed in terms of state models for an assembly of Ising spins living on the
relations of the causal set, these theories also illustrate how
non-gravitational matter can arise dynamically from the causal set without
having to be built in at the fundamental level. Additionally, our results bring
into focus some interpretive issues of importance for causal set dynamics, and
for quantum gravity more generally.Comment: 28 pages, 9 figures, LaTeX, added references and a footnote, minor
correction
Higher Charges in Dynamical Spin Chains for SYM Theory
We construct, to the first two non-trivial orders, the next conserved charge
in the su(2|3) sector of N=4 Super Yang-Mills theory. This represents a test of
integrability in a sector where the interactions change the number of sites of
the chain. The expression for the charge is completely determined by the
algebra and can be written in a diagrammatic form in terms of the interactions
already present in the Hamiltonian. It appears likely that this diagrammatic
expression remains valid in the full theory and can be generalized to higher
loops and higher charges thus helping in establishing complete integrability
for these dynamical chains.Comment: 14 pages; V2: Appendix added with diagrammatic expression for H_{3,2
A Generalized Scaling Function for AdS/CFT
We study a refined large spin limit for twist operators in the sl(2) sector
of AdS/CFT. We derive a novel non-perturbative equation for the generalized
two-parameter scaling function associated to this limit, and analyze it at weak
coupling. It is expected to smoothly interpolate between weakly coupled gauge
theory and string theory at strong coupling.Comment: 27 pages, no figures; v2: references added and typos fixe
The low FODMAP diet in the management of irritable bowel syndrome:an evidence-based review of FODMAP restriction, reintroduction and personalisation in clinical practice
Dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) is effective in the management of functional gastrointestinal symptoms that occur in irritable bowel syndrome (IBS). Numerous reviews have been published regarding the evidence for their restriction in the low FODMAP diet; however, few reviews discuss the implementation of the low FODMAP diet in practice. The aim of this review is to provide practical guidance on patient assessment and the implementation and monitoring of the low FODMAP diet. Broadly speaking, the low FODMAP diet consists of three stages: FODMAP restriction; FODMAP reintroduction; and FODMAP personalisation. These stages can be covered in at least two dietetic appointments. The first appointment focuses on confirmation of diagnosis, comprehensive symptom and dietary assessment, detailed description of FODMAPs and their association with symptom induction, followed by counselling regarding FODMAP restriction. Dietary counselling should be tailored to individual needs and appropriate resources provided. At the second appointment, symptoms and diet are re-assessed and, if restriction has successfully reduced IBS symptoms, education is provided on FODMAP reintroduction to identify foods triggering symptoms. Following this, the patient can follow FODMAP personalisation for which a less restrictive diet is consumed that excludes their personal FODMAP triggers and enables a more diverse dietary intake. This review provides evidence and practice guidance to assist in delivering high-quality clinical service in relation to the low FODMAP diet
Bethe Ansatz in Stringy Sigma Models
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).Comment: 37 pages, 11 figure
Integrability and Transcendentality
We derive the two-loop Bethe ansatz for the sl(2) twist operator sector of
N=4 gauge theory directly from the field theory. We then analyze a recently
proposed perturbative asymptotic all-loop Bethe ansatz in the limit of large
spacetime spin at large but finite twist, and find a novel all-loop scaling
function. This function obeys the Kotikov-Lipatov transcendentality principle
and does not depend on the twist. Under the assumption that one may extrapolate
back to leading twist, our result yields an all-loop prediction for the
large-spin anomalous dimensions of twist-two operators. The latter also appears
as an undetermined function in a recent conjecture of Bern, Dixon and Smirnov
for the all-loop structure of the maximally helicity violating (MHV) n-point
gluon amplitudes of N=4 gauge theory. This potentially establishes a direct
link between the worldsheet and the spacetime S-matrix approach. A further
assumption for the validity of our prediction is that perturbative BMN
(Berenstein-Maldacena-Nastase) scaling does not break down at four loops, or
beyond. We also discuss how the result gets modified if BMN scaling does break
down. Finally, we show that our result qualitatively agrees at strong coupling
with a prediction of string theory.Comment: 45 pages LaTeX, 3 postscript figures. v2: Chapter on BMN scaling and
transcendentality added. v3: version accepted for publication in JSTA
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