Branes from a non-Abelian (2,0) tensor multiplet with 3-algebra

In this paper, we study the equations of motion for non-Abelian N=(2,0) tensor multiplets in six dimensions, which were recently proposed by Lambert and Papageorgakis. Some equations are regarded as constraint equations. We employ a loop extension of the Lorentzian three-algebra (3-algebra) and examine the equations of motion around various solutions of the constraint equations. The resultant equations take forms that allow Lagrangian descriptions. We find various (5+d)-dimensional Lagrangians and investigate the relation between them from the viewpoint of M-theory duality.Comment: 44+1 pages, reference added, typos corrected, and several discussions added; v3, reference added, many typos corrected, the language improved; v4, some typos and references corrected, final version to appear in J. Phys.

Charged particle-like branes in ABJM

We study the effect of adding lower dimensional brane charges to the 't Hooft monopole, di-baryon and baryon vertex configurations in $AdS_4 \times \mathbb{P}^3$. We show that these configurations capture the background fluxes in a way that depends on the induced charges, and therefore, require additional fundamental strings in order to cancel the worldvolume tadpoles. The study of the dynamics reveals that the charges must lie inside some interval in order to find well defined configurations, a situation familiar from the baryon vertex in $AdS_5 \times S^5$ with charges. For the baryon vertex and the di-baryon the number of fundamental strings must also lie inside an allowed interval. Our configurations are sensitive to the flat $B$-field recently suggested in the literature. We make some comments on its possible role. We also discuss how these configurations are modified in the presence of a non-zero Romans mass.Comment: 31 pages, 14 figures, discussion of charges improved, published versio

Wilson loops in Five-Dimensional Super-Yang-Mills

We consider circular non-BPS Maldacena-Wilson loops in five-dimensional supersymmetric Yang-Mills theory (d = 5 SYM) both as macroscopic strings in the D4-brane geometry and directly in gauge theory. We find that in the Dp-brane geometries for increasing p, p = 4 is the last value for which the radius of the string worldsheet describing the Wilson loop is independent of the UV cut-off. It is also the last value for which the area of the worldsheet can be (at least partially) regularized by the standard Legendre transformation. The asymptotics of the string worldsheet allow the remaining divergence in the regularized area to be determined, and it is found to be logarithmic in the UV cut-off. We also consider the M2-brane in AdS_7 x S^4 which is the M-theory lift of the Wilson loop, and dual to a "Wilson surface" in the (2,0), d = 6 CFT. We find that it has exactly the same logarithmic divergence in its regularized action. The origin of the divergence has been previously understood in terms of a conformal anomaly for surface observables in the CFT. Turning to the gauge theory, a similar picture is found in d = 5 SYM. The divergence and its coefficient can be recovered for general smooth loops by summing the leading divergences in the analytic continuation of dimensional regularization of planar rainbow/ladder diagrams. These diagrams are finite in 5 - epsilon dimensions. The interpretation is that the Wilson loop is renormalized by a factor containing this leading divergence of six-dimensional origin, and also subleading divergences, and that the remaining part of the Wilson loop expectation value is a finite, scheme-dependent quantity. We substantiate this claim by showing that the interacting diagrams at one loop are finite in our regularization scheme in d = 5 dimensions, but not for d greater than or equal to 6.Comment: 1+18 pages, 3 figures. v2 added a reference and made minor cosmetic changes, JHEP version. v3 added generalization to arbitrary smooth, closed contours, added references. v4 added references and clarified discussion beneath eq. (23

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

Static Charges in the Low-Energy Theory of the S-Duality Twist

We continue the study of the low-energy limit of N=4 super Yang-Mills theory compactified on a circle with S-duality and R-symmetry twists that preserve N=6 supersymmetry in 2+1D. We introduce external static supersymmetric quark and anti-quark sources into the theory and calculate the Witten Index of the resulting Hilbert space of ground states on a torus. Using these results we compute the action of simple Wilson loops on the Hilbert space of ground states without sources. In some cases we find disagreement between our results for the Wilson loop eigenvalues and previous conjectures about a connection with Chern-Simons theory.Comment: 73 pages, two paragraphs added, one to the introduction and one to the discussio

Entanglement entropy of Wilson surfaces from bubbling geometries in M-theory

We consider solutions of eleven-dimensional supergravity constructed in [1,2] that are half-BPS, locally asymptotic to $AdS_7\times S^4$ and are the holographic dual of heavy Wilson surfaces in the six-dimensional $(2,0)$ theory. Using these bubbling solutions we calculate the holographic entanglement entropy for a spherical entangling surface in the presence of a planar Wilson surface. In addition, we calculate the holographic stress tensor and, by evaluating the on-shell supergravity action, the expectation value of the Wilson surface operator.Comment: 42 pages, 4 figures, v2: minor modification

Deformation of half-BPS solution in ABJM model and instability of supermembrane

It is well-known that a supermembrane in the light-cone gauge has a continuous spectrum and is unstable. Physical interpretation of this instability is that a supermembrane can have a long thin tube without cost of energy and consequently it becomes a spiky configuration in which multiple membranes are connected by thin tubes. On the other hand, the ABJM model was proposed as a low-energy description of multiple M2-branes in the static gauge. It is natural that an M2-brane is also unstable in this gauge if we believe the physical picture in the light-cone gauge. In order to examine this, we construct a BPS solution explicitly both in the Nambu-Goto action of a supermembrane in the static gauge and in the U(1){\times}U(1) ABJM model, which represents intersecting M2-branes. Since this configuration is regarded as a single M2-brane emitting another one, we study the instability of an M2-brane by analyzing fluctuations around it. We show that a zero mode exists which can deform the configuration. For comparison, we also examine a similar configuration on the D2-brane and check that it does not have such zero modes under a fixed string charge. Furthermore we confirm that the novel Higgs mechanism translates our BPS solution in the ABJM model into that in the D2-brane world volume theory, where the winding number of the former around the fixed point of the orbifold becomes the number of strings ending on the D2-brane in the latter.Comment: 27 page

Interaction between a bisphosphonate, tiludronate, and biomimetic nanocrystalline apatites.

Bisphosphonates (BPs) are well established as successful antiresorptive agents for the prevention and treatment of bone diseases such as osteoporosis and Paget's disease. The aim of this work was to clarify the reaction mechanisms between a BP molecule, tiludronate, and the nanocrystalline apatite surface. The adsorption of tiludronate on well characterized synthetic biomimetic nanocrystalline apatites with homogeneous but different compositions and surface characteristics was investigated to determine the effect of the nanocrystalline apatite substrate on the adsorption behavior. The results show that the adsorption of tiludronate on nanocrystalline biomimetic apatite surfaces varies over a large range. The most immature apatitic samples exhibited the highest affinity and the greatest amount adsorbed at saturation. Maturation of the nanocrystals induces a decrease of these values. The amount of phosphate ion released per adsorbed BP molecule varied, depending on the nanocrystalline substrate considered. The adsorption mechanism, although associated with a release of phosphate ions, cannot be considered as a simple ion exchange process involving one or two phosphate ions on the surface. A two-step process is proposed consisting of a surface binding of BP groups to calcium ions associated with a proton release inducing the protonation of surface orthophosphate ions and their eventual solubilization

Dressed Giant Magnons on CP^3

A new example of AdS/CFT duality relating IIA string theory on AdS_4 x CP^3 to N=6 superconformal Chern-Simons theory has recently been provided by ABJM. By now a number of papers have considered particular giant magnon classical string solutions in the CP^3 background, corresponding to excitations in the spin chain picture of the dual field theory. In this paper we apply the CP^3 = SU(4)/S(U(3) x U(1)) dressing method to the problem of constructing general classical string solutions describing various configurations of giant magnons. As a particular application we present a new giant magnon solution on CP^3. Interestingly the dressed solution carries only a single SO(6) charge, in contrast with the dyonic magnons found in previous applications of the dressing method.Comment: 13 pages, harvmac; v3: fixed misstatement of the dispersion relation(!), v3: typos fixed and a few clarifying remarks adde