1,144 research outputs found
Correlators of Wilson loops and local operators from multi-matrix models and strings in AdS
We study correlation functions of Wilson loops and local operators in a
subsector of N=4 SYM which preserves two supercharges. Localization arguments
allow to map the problem to a calculation in bosonic two-dimensional Yang-Mills
theory. In turn, this can be reduced to computing correlators in certain
Gaussian multi-matrix models. We focus on the correlation function of a Wilson
loop and two local operators, and solve the corresponding three-matrix model
exactly in the planar limit. We compare the strong coupling behavior to string
theory in AdS_5xS^5, finding precise agreement. We pay particular attention to
the case in which the local operators have large R-charge J \sim sqrt{lambda}
at strong coupling.Comment: 50 pages, 9 figures. v2: minor changes, references adde
On the reflection of magnon bound states
We investigate the reflection of two-particle bound states of a free open
string in the light-cone AdS_5 x S^5 string sigma model, for large angular
momentum J=J_56 and ending on a D7 brane which wraps the entire AdS_5 and a
maximal S^3 of S^5. We use the superspace formalism to analyse fundamental and
two-particle bound states in the cases of supersymmetry-preserving and
broken-supersymmetry boundaries. We find the boundary S-matrices corresponding
to bound states both in the bulk and on the boundary.Comment: 35 pages, v2: few typos and ref corrected, accepted for publication
in JHE
The generalized cusp in ABJ(M) N = 6 Super Chern-Simons theories
We construct a generalized cusped Wilson loop operator in N = 6 super
Chern-Simons-matter theories which is locally invariant under half of the
supercharges. It depends on two parameters and interpolates smoothly between
the 1/2 BPS line or circle and a pair of antiparallel lines, representing a
natural generalization of the quark-antiquark potential in ABJ(M) theories. For
particular choices of the parameters we obtain 1/6 BPS configurations that,
mapped on S^2 by a conformal transformation, realize a three-dimensional
analogue of the wedge DGRT Wilson loop of N = 4. The cusp couples, in addition
to the gauge and scalar fields of the theory, also to the fermions in the
bifundamental representation of the U(N)xU(M) gauge group and its expectation
value is expressed as the holonomy of a suitable superconnection. We discuss
the definition of these observables in terms of traces and the role of the
boundary conditions of fermions along the loop. We perform a complete two-loop
analysis, obtaining an explicit result for the generalized cusp at the second
non-trivial order, from which we read off the interaction potential between
heavy 1/2 BPS particles in the ABJ(M) model. Our results open the possibility
to explore in the three-dimensional case the connection between localization
properties and integrability, recently advocated in D = 4.Comment: 53 pages, 10 figures, added references, this is the version appeared
on JHE
The secret symmetries of the AdS/CFT reflection matrices
We find new twisted Yangian symmetries of the AdS/CFT reflection matrices for
the Y=0 maximal giant graviton and D5-brane. These new symmetries originate
from the known secret symmetries of the Yangian symmetry of the AdS/CFT
S-matrix.Comment: 9 pages, v2: published versio
The Role of Dimensionality on the Optoelectronic Properties of Oxide and Halide Perovskites, and their Halide Derivatives
Funder: Kim and Juliana Silverman Research FellowshipFunder: Graduate Assistance in Areas of National NeedAbstract: Halide perovskite semiconductors have risen to prominence in photovoltaics and light‐emitting diodes (LEDs), but traditional oxide perovskites, which overcome the stability limitations of their halide counterparts, have also recently witnessed a rise in potential as solar absorbers. One of the many important factors underpinning these developments is an understanding of the role of dimensionality on the optoelectronic properties and, consequently, on the performance of the materials in photovoltaics and LEDs. This review article examines the role of structural and electronic dimensionality, as well as form factor, in oxide and halide perovskites, and in lead‐free alternatives to halide perovskites. Insights into how dimensionality influences the band gap, stability, charge‐carrier transport, recombination processes and defect tolerance of the materials, and the impact these parameters have on device performance are brought forward. Particular emphasis is placed on carrier/exciton‐phonon coupling, which plays a significant role in the materials considered, owing to their soft lattices and composition of heavy elements, and becomes more prominent as dimensionality is reduced. It is finished with a discussion of the implications on the classes of materials future efforts should focus on, as well as the key questions that need to be addressed
Paternal obesity is associated with IGF2 hypomethylation in newborns: results from a Newborn Epigenetics Study (NEST) cohort
Data from epidemiological and animal model studies suggest that nutrition during pregnancy may affect the health status of subsequent generations. These transgenerational effects are now being explained by disruptions at the level of the epigenetic machinery. Besides in vitro environmental exposures, the possible impact on the reprogramming of methylation profiles at imprinted genes at a much earlier time point, such as during spermatogenesis or oogenesis, has not previously been considered. In this study, our aim was to determine associations between preconceptional obesity and DNA methylation profiles in the offspring, particularly at the differentially methylated regions (DMRs) of the imprinted Insulin-like Growth Factor 2 (IGF2) gene
Orally active antischistosomal early leads identified from the open access malaria box.
BACKGROUND: Worldwide hundreds of millions of schistosomiasis patients rely on treatment with a single drug, praziquantel. Therapeutic limitations and the threat of praziquantel resistance underline the need to discover and develop next generation drugs. METHODOLOGY: We studied the antischistosomal properties of the Medicines for Malaria Venture (MMV) malaria box containing 200 diverse drug-like and 200 probe-like compounds with confirmed in vitro activity against Plasmodium falciparum. Compounds were tested against schistosomula and adult Schistosoma mansoni in vitro. Based on in vitro performance, available pharmacokinetic profiles and toxicity data, selected compounds were investigated in vivo. PRINCIPAL FINDINGS: Promising antischistosomal activity (IC50: 1.4-9.5 µM) was observed for 34 compounds against schistosomula. Three compounds presented IC50 values between 0.8 and 1.3 µM against adult S. mansoni. Two promising early leads were identified, namely a N,N'-diarylurea and a 2,3-dianilinoquinoxaline. Treatment of S. mansoni infected mice with a single oral 400 mg/kg dose of these drugs resulted in significant worm burden reductions of 52.5% and 40.8%, respectively. CONCLUSIONS/SIGNIFICANCE: The two candidates identified by investigating the MMV malaria box are characterized by good pharmacokinetic profiles, low cytotoxic potential and easy chemistry and therefore offer an excellent starting point for antischistosomal drug discovery and development
Integrable Wilson loops
The generalized quark-antiquark potential of N=4 supersymmetric Yang-Mills
theory on S^3 x R calculates the potential between a pair of heavy charged
particles separated by an arbitrary angle on S^3 and also an angle in flavor
space. It can be calculated by a Wilson loop following a prescribed path and
couplings, or after a conformal transformation, by a cusped Wilson loop in flat
space, hence also generalizing the usual concept of the cusp anomalous
dimension. In AdS_5 x S^5 this is calculated by an infinite open string. I
present here an open spin-chain model which calculates the spectrum of
excitations of such open strings. In the dual gauge theory these are cusped
Wilson loops with extra operator insertions at the cusp. The boundaries of the
spin-chain introduce a non-trivial reflection phase and break the bulk symmetry
down to a single copy of psu(2|2). The dependence on the two angles is captured
by the two embeddings of this algebra into \psu(2|2)^2, i.e., by a global
rotation. The exact answer to this problem is conjectured to be given by
solutions to a set of twisted boundary thermodynamic Bethe ansatz integral
equations. In particular the generalized quark-antiquark potential or cusp
anomalous dimension is recovered by calculating the ground state energy of the
minimal length spin-chain, with no sites. It gets contributions only from
virtual particles reflecting off the boundaries. I reproduce from this
calculation some known weak coupling perturtbative results.Comment: 40 pages, 11 figures; v2-some formulas corrected, results unchange
Quantum Spectral Curve at Work: From Small Spin to Strong Coupling in N=4 SYM
We apply the recently proposed quantum spectral curve technique to the study
of twist operators in planar N=4 SYM theory. We focus on the small spin
expansion of anomalous dimensions in the sl(2) sector and compute its first two
orders exactly for any value of the 't Hooft coupling. At leading order in the
spin S we reproduced Basso's slope function. The next term of order S^2
structurally resembles the Beisert-Eden-Staudacher dressing phase and takes
into account wrapping contributions. This expansion contains rich information
about the spectrum of local operators at strong coupling. In particular, we
found a new coefficient in the strong coupling expansion of the Konishi
operator dimension and confirmed several previously known terms. We also
obtained several new orders of the strong coupling expansion of the BFKL
pomeron intercept. As a by-product we formulated a prescription for the correct
analytical continuation in S which opens a way for deriving the BFKL regime of
twist two anomalous dimensions from AdS/CFT integrability.Comment: 53 pages, references added; v3: due to a typo in the coefficients C_2
and D_2 on page 29 we corrected the rational part of the strong coupling
predictions in equations (1.5-6), (6.22-24), (6.27-30) and in Table
Reflection algebra, Yangian symmetry and bound-states in AdS/CFT
We present the `Heisenberg picture' of the reflection algebra by explicitly
constructing the boundary Yangian symmetry of an AdS/CFT superstring which ends
on a boundary with non-trivial degrees of freedom and which preserves the full
bulk Lie symmetry algebra. We also consider the spectrum of bulk and boundary
states and some automorphisms of the underlying algebras.Comment: 31 page, 8 figures. Updated versio
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