655 research outputs found
Wilson Loop Renormalization Group Flows
The locally BPS Wilson loop and the pure gauge Wilson loop map under AdS/CFT
duality to string world-sheet boundaries with standard and alternate
quantizations of the world-sheet fields. This implies an RG flow between the
two operators, which we verify at weak coupling. Many additional loop operators
exist at strong coupling, with a rich pattern of RG flows.Comment: 10 p, 2 figures. v3: Title change, expanded treatment of RG flow
Quantum AdS_5 x S^5 superstring in the AdS light-cone gauge
We consider the AdS_5 x S^5 superstring in the light-cone gauge adapted to a
massless geodesic in AdS5 in the Poincare patch. The resulting action has a
relatively simple structure which makes it a natural starting point for various
perturbative quantum computations. We illustrate the utility of this AdS
light-cone gauge action by computing the 1-loop and 2-loop corrections to the
null cusp anomalous dimension reproducing in a much simpler and efficient way
earlier results obtained in conformal gauge. This leads to a further insight
into the structure of the superstring partition function in non-trivial
background.Comment: 21pages, Late
Design and evaluation of the immunogenicity and efficacy of a biomimetic particulate formulation of viral antigens
Subunit viral vaccines are typically not as efficient as live attenuated or inactivated vaccines at inducing protective immune responses. This paper describes an alternative 'biomimetic' technology; whereby viral antigens were formulated around a polymeric shell in a rationally arranged fashion with a surface glycoprotein coated on to the surface and non-structural antigen and adjuvant encapsulated. We evaluated this model using BVDV E2 and NS3 proteins formulated in poly-(D, L-lactic-co-glycolic acid) (PLGA) nanoparticles adjuvanted with polyinosinic:polycytidylic acid (poly(I:C) as an adjuvant (Vaccine-NP). This Vaccine-NP was compared to ovalbumin and poly(I:C) formulated in a similar manner (Control-NP) and a commercial adjuvanted inactivated BVDV vaccine (IAV), all inoculated subcutaneously and boosted prior to BVDV-1 challenge. Significant virus-neutralizing activity, and E2 and NS3 specific antibodies were observed in both Vaccine-NP and IAV groups following the booster immunisation. IFN-γ responses were observed in ex vivo PBMC stimulated with E2 and NS3 proteins in both vaccinated groups. We observed that the protection afforded by the particulate vaccine was comparable to the licenced IAV formulation. In conclusion, the biomimetic particulates showed a promising immunogenicity and efficacy profile that may be improved by virtue of being a customisable mode of delivery
Semiclassical Analysis of M2-brane in AdS_4 x S^7 / Z_k
We start from the classical action describing a single M2-brane on AdS_4 x
S^7/ Z_k and consider semiclassical fluctuaitions around a static, 1/2 BPS
configuration whose shape is AdS_2 x S^1. The internal manifold S^7/ Z_k is
described as a U(1) fibration over CP^3 and the static configuration is wrapped
on the U(1) fiber. Then the configuration is reduced to an AdS_2 world-sheet of
type IIA string on AdS_4 x CP^3 through the Kaluza-Klein reduction on the S^1.
It is shown that the fluctuations form an infinite set of N=1 supermultiplets
on AdS_2, for k=1,2. The set is invariant under SO(8) which may be consistent
with N=8 supersymmetry on AdS_2. We discuss the behavior of the fluctuations
around the boundary of AdS_2 and its relation to deformations of Wilson loop
operator.Comment: 27 pages, v2: references added, v3: major revision including the
clarification of k=2 case, references added, version to appear in JHE
Quantum States and Phases in Driven Open Quantum Systems with Cold Atoms
An open quantum system, whose time evolution is governed by a master
equation, can be driven into a given pure quantum state by an appropriate
design of the system-reservoir coupling. This points out a route towards
preparing many body states and non-equilibrium quantum phases by quantum
reservoir engineering. Here we discuss in detail the example of a \emph{driven
dissipative Bose Einstein Condensate} of bosons and of paired fermions, where
atoms in an optical lattice are coupled to a bath of Bogoliubov excitations via
the atomic current representing \emph{local dissipation}. In the absence of
interactions the lattice gas is driven into a pure state with long range order.
Weak interactions lead to a weakly mixed state, which in 3D can be understood
as a depletion of the condensate, and in 1D and 2D exhibits properties
reminiscent of a Luttinger liquid or a Kosterlitz-Thouless critical phase at
finite temperature, with the role of the ``finite temperature'' played by the
interactions.Comment: 9 pages, 2 figure
Holographic three-point functions of semiclassical states
We calculate the holographic three-point functions in N = 4 super-Yang-Mills
theory in the case when two of the operators are semiclassical and one is dual
to a supergravity mode. We further discuss the transition to the regime when
all three operators are semiclassical.Comment: 17 pages, 3 figures; v2: refs. added, discussion in sec. 2.1
expanded; v3: misprint in (2.28) corrected, published versio
D-branes in Generalized Geometry and Dirac-Born-Infeld Action
The purpose of this paper is to formulate the Dirac-Born-Infeld (DBI) action
in a framework of generalized geometry and clarify its symmetry. A D-brane is
defined as a Dirac structure where scalar fields and gauge field are treated on
an equal footing in a static gauge. We derive generalized Lie derivatives
corresponding to the diffeomorphism and B-field gauge transformations and show
that the DBI action is invariant under non-linearly realized symmetries for all
types of diffeomorphisms and B-field gauge transformations. Consequently, we
can interpret not only the scalar field but also the gauge field on the D-brane
as the generalized Nambu-Goldstone boson.Comment: 32 pages, 4 figures, ver2:typos corrected, references adde
Generalized quark-antiquark potential at weak and strong coupling
We study a two-parameter family of Wilson loop operators in N=4
supersymmetric Yang-Mills theory which interpolates smoothly between the 1/2
BPS line or circle and a pair of antiparallel lines. These observables capture
a natural generalization of the quark-antiquark potential. We calculate these
loops on the gauge theory side to second order in perturbation theory and in a
semiclassical expansion in string theory to one-loop order. The resulting
determinants are given in integral form and can be evaluated numerically for
general values of the parameters or analytically in a systematic expansion
around the 1/2 BPS configuration. We comment about the feasibility of deriving
all-loop results for these Wilson loops.Comment: 43 pages: 15 comprising the main text and 25 for detailed appendice
Heavy quark density in N=4 SYM: from hedgehog to Lifshitz spacetimes
We study the effect of an order N^2 density of heavy quarks in strongly
coupled N=4 SUSY Yang-Mills theory in the large N limit. This is achieved in
the type IIB supergravity dual by introducing a uniformly smeared density of
macroscopic string sources stretching to the boundary of AdS_5 x S^5. The
backreacted system exhibits a flow from an AdS_5 "hedgehog" geometry to a
scaling Lifshitz-like solution Lif_5 x S^5 with dynamical critical exponent
z=7, wherein the scaling symmetry is broken by a logarithmic running dilaton.
We find an exact black brane solution within the scaling regime which describes
the low temperature thermodynamics of the system.Comment: 20 pages, 2 figures, references adde
Off-shell superconformal nonlinear sigma-models in three dimensions
We develop superspace techniques to construct general off-shell N=1,2,3,4
superconformal sigma-models in three space-time dimensions. The most general
N=3 and N=4 superconformal sigma-models are constructed in terms of N=2 chiral
superfields. Several superspace proofs of the folklore statement that N=3
supersymmetry implies N=4 are presented both in the on-shell and off-shell
settings. We also elaborate on (super)twistor realisations for (super)manifolds
on which the three-dimensional N-extended superconformal groups act
transitively and which include Minkowski space as a subspace.Comment: 67 pages; V2: typos corrected, one reference added, version to appear
on JHE
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