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Sergei M. Kuzenko

Publications and source records attributed to Sergei M. Kuzenko.

At least 145 records · Page 8Linked to original sources
arXiv2012

Lectures on nonlinear sigma-models in projective superspace

N = 2 supersymmetry in four space-time dimensions is intimately related to hyperkahler and quaternionic Kahler geometries. On one hand, the target spaces for rigid supersymmetric sigma-models are necessarily hyperkahler manifolds. On the other hand, when coupled to N = 2 supergravity, the sigma-model target spaces must be quaternionic Kahler. It is known that such manifolds of restricted holonomy are difficult to generate explicitly. Projective superspace is a field-theoretic approach to constructing general N = 2 supersymmetric nonlinear sigma-models, and hence to generate new hyperkahler and quaternionic Kahler metrics. Intended for a mixed audience consisting of both physicists and mathematicians, these lectures provide a pedagogical introduction to the projective-superspace approach.

hep-th↗
arXiv2012

Nonlinear self-duality in N = 2 supergravity

For nonlinear models of an Abelian vector supermultiplet coupled to N = 2 supergravity in four dimensions, we formulate the self-duality equation which expresses invariance under U(1) duality rotations. In the flat space limit, this equation reduces to the N = 2 self-duality equation proposed in hep-th/0001068. We also give an example of a self-dual locally supersymmetric model containing a higher-derivative extension of the Born-Infeld action at the component level.

hep-th↗
arXiv2012

New higher-derivative couplings in 4D N = 2 supergravity

Using the off-shell formulation for general N = 2 supergravity-matter systems developed in arXiv:0905.0063, we propose a construction to generate a restricted chiral superfield from any real weight-zero projective multiplet L. One can choose L to be composed of tensor multiplets, O(2n) multiplets, with n=2,3,..., and polar hypermultiplets. In conjunction with the standard procedure to induce a N = 2 linear multiplet from any chiral weight-one scalar, we obtain a powerful mechanism to generate higher-derivative couplings in supergravity. In the case that L is a homogeneous function of n tensor multiplets of degree zero, we show that our construction is equivalent to that developed by de Wit and Saueressig in arXiv:hep-th/0606148 using the component superconformal tensor calculus. We also work out nontrivial examples with L composed of O(2n)and tensor multiplets.

hep-th↗
arXiv2012

Vector-tensor supermultiplets in AdS and supergravity

In N = 2 Poincare supersymmetry in four space-time dimensions, there exist off-shell supermultiplets with intrinsic central charge, including the important examples of the Fayet-Sohnius hypermultiplet, the linear and the nonlinear vector-tensor (VT) multiplets. One can also define similar supermultiplets in the context of N = 2 anti-de Sitter (AdS) supersymmetry, although the origin of the central charge becomes somewhat obscure. In this paper we develop a general setting for N = 2 AdS supersymmetric theories with central charge. We formulate a supersymmetric action principle in N = 2 AdS superspace and then reformulate it in terms of N = 1 superfields. We prove that N = 2 AdS supersymmetry does not allow existence of a linear VT multiplet. For the nonlinear VT multiplet, we derive consistent superfield constraints in the presence of any number of N = 2 Yang-Mills vector multiplets, give the supersymmetric action and elaborate on the N = 1 superfield and component descriptions of the theory. Our description of the nonlinear VT multiplet in AdS is then lifted to N = 2 supergravity. Moreover, we derive consistent superfield constraints and Lagrangian that describe the linear VT multiplet in N = 2 supergravity in the presence of two vector multiplets, one of which gauges the central charge. These supergravity constructions thus provide the first superspace formulation for the component results derived in arXiv:hep-th/9710212. We also construct higher-derivative couplings of the VT multiplet to any number of N = 2 tensor multiplets.

hep-th↗
arXiv2012

Generating higher-derivative couplings in N=2 supergravity

Using a recently developed off-shell formulation for general 4D N=2 supergravity-matter systems, we propose a construction to generate higher derivative couplings. We address here mainly the interactions of tensor and vector multiplets, but the construction is quite general. For a certain subclass of terms, the action is naturally written as an integral over 3/4 of the Grassmann coordinates of superspace.

hep-th↗
arXiv2011

The structure of N=2 supersymmetric nonlinear sigma models in AdS_4

We present a detailed study of the most general N=2 supersymmetric sigma models in four-dimensional anti-de Sitter space AdS_4 formulated in terms of N=1 chiral superfields. The target space is demonstrated to be a non-compact hyperkahler manifold restricted to possess a special Killing vector field which generates an SO(2) group of rotations on the two-sphere of complex structures and necessarily leaves one of them invariant. All hyperkahler cones, that is the target spaces of N=2 superconformal sigma models, prove to possess such a vector field that belongs to the Lie algebra of an isometry group SU(2) acting by rotations on the complex structures. A unique property of the N=2 sigma models constructed is that the algebra of OSp(2|4) transformations closes off the mass shell. We uncover the underlying N=2 superfield formulation for the N=2 sigma models constructed and compute the associated N=2 supercurrent. We give a special analysis of the most general systems of self-interacting N=2 tensor multiplets in AdS_4 and their dual sigma models realized in terms of N=1 chiral multiplets. We also briefly discuss the relationship between our results on N=2 supersymmetric sigma models formulated in the N=1 AdS superspace and the off-shell sigma models constructed in the N=2 AdS superspace in arXiv:0807.3368.

hep-th↗
arXiv2011

N=2 supersymmetric sigma-models in AdS

We construct the most general N=2 supersymmetric nonlinear sigma-model in four-dimensional anti-de Sitter (AdS) space in terms of N=1 chiral superfields. The target space is shown to be a non-compact hyperkahler manifold restricted to possess a special Killing vector field. A remarkable property of the sigma-model constructed is that the algebra of OSp(2|4) transformations is closed off the mass shell.

hep-th↗
arXiv2011

Comments on N = 2 supersymmetric sigma models in projective superspace

For the most general off-shell N = 2 supersymmetric sigma model in projective superspace, we elaborate on its formulation in terms of N = 1 chiral superfields. A universal (model-independent) expression is obtained for the holomorphic symplectic two-form, which determines the second supersymmetry transformation. This two-form is associated with the two complex structures of the hyperkahler target space, which are complimentary to the one used to realize the target space as a Kahler manifold.

hep-th↗
arXiv2011

A dual formulation of supergravity-matter theories

Generating supersymmetric AdS solutions in non-minimal supergravity in four dimensions is notoriously difficult. Indeed, it is a longstanding lore that such solutions exist only for old minimal supergravity. In this paper, we construct a dual formulation for general N=1 supergravity-matter systems that avoids the problem. In the case of pure supergravity without a cosmological constant, it coincides with the usual non-minimal (n=-1) supergravity, but in the presence of matter (or a cosmological constant) our formulation differs considerably. We also elaborate upon the framework of conformal superspace and the compensator method as applied to our theory. In particular, we show that one can encode the details of the Kahler potential and superpotential entirely within the geometry of superspace so that the general sigma-model action is encoded in a single compact term: the supervolume. Finally, we discuss the issue of supercurrents and propose a general form for the supercurrent in AdS.

hep-th↗
arXiv2011

N=2 AdS supergravity and supercurrents

We consider the minimal off-shell formulation for four-dimensional N=2 supergravity with a cosmological term, in which the second compensator is an improved tensor multiplet. We use it to derive a linearized supergravity action (and its dual versions) around the anti-de Sitter (AdS) background in terms of three N=2 off-shell multiplets: an unconstrained scalar superfield, vector and tensor multiplets. This allows us to deduce the structure of the supercurrent multiplet associated with those supersymmetric theories which naturally couple to the supergravity formulation chosen, with or without a cosmological term. Finally, our linearized N=2 AdS supergravity action is reduced to N=1 superspace. The result is a sum of two N=1 linearized actions describing (i) old minimal supergravity; and (ii) an off-shell massless gravitino multiplet. We also derive dual formulations for the massless N=1 gravitino multiplet in AdS. As a by-product of our consideration, we derive the consistent supergravity extension of the N=1 supercurrent multiplet advocated recently by Komargodski and Seiberg.

hep-th↗
arXiv2011

Comments on the gauge models for massless higher spin off-shell supermultiplets

In recent papers arXiv:1103.3564 and arXiv:1103.3565, Gates and Koutrolikos announced the construction of new off-shell formulations for massless higher spin supermultiplets. Here we demonstrate that all of their models are obtained from (some of) those constructed in 1993 by Kuzenko, Postnikov and Sibiryakov by applying special field redefinitions.

hep-th↗
arXiv2011

On the Goldstino actions and their symmetries

Starting from the Akulov-Volkov (AV) action, we compute a finite-dimensional Lie group G of all field transformations of the form λ-> λ' = λ+ O(λ^3) which preserve the functional structure of low-energy Goldstino-like actions. Associated with G is its twelve-parameter subgroup H of trivial symmetries of the AV action. The coset space G/H is naturally identified with the space of all Goldstino models. We then apply our construction to study the properties of five different Goldstino actions available in the literature. Making use of the most general field redefinition derived, we find explicit maps between all five cases. In each case there is a twelve- parameter freedom in these maps due to trivial symmetries inherent in the Goldstino actions. Finally, by using the pushforward of the AV supersymmetry, we find the off-shell nonlinear supersymmetry transformations of the other five actions and compare to those normally associated with these actions.

hep-th↗
arXiv2011

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.

hep-th↗
arXiv2010

N=2 supergravity and supercurrents

We address the problem of classifying all N=2 supercurrent multiplets in four space-time dimensions. For this purpose we consider the minimal formulation of N=2 Poincare supergravity with a tensor compensator, and derive its linearized action in terms of three N=2 off-shell multiplets: an unconstrained scalar superfield, a vector multiplet, and a tensor multiplet. Such an action was ruled out to exist in the past. Using the action constructed, one can derive other models for linearized N=2 supergravity by applying N=2 superfield duality transformations. The action depends parametrically on a constant non-vanishing real isotriplet g^{ij}=g^{ji} which originates as an expectation value of the tensor compensator. Upon reduction to N=1 superfields, we show that the model describes two dually equivalent formulations for the massless multiplet (1,3/2)+(3/2,2) depending on a choice of g^{ij}. In the case g^{11}=g^{22}=0, the action describes (i) new minimal N=1 supergravity; and (ii) the Fradkin-Vasiliev-de Wit-van Holten gravitino multiplet. In the case g^{12}=0, on the other hand, the action describes (i) old minimal N=1 supergravity; and (ii) the Ogievetsky-Sokatchev gravitino multiplet.

hep-th↗
arXiv2010

Anomalous Magnetic Properties of Sr2YRuO6

Anomalous magnetic properties of the double perovskite ruthenates compound Sr2YRuO6 are reported here. Magnetization measurements as a function of temperature in low magnetic fields show clear evidence for two components of magnetic order (TM1 ~ 32K and TM2 ~ 27K) aligned opposite to each other with respect to the magnetic field direction even though only Ru5+moments can order magnetically in this compound. The second component of the magnetic order at TM2 ~ 27K results only in a magnetization reversal, and not in the negative magnetization when the magnetization is measured in the field cooled (FC) mode. Isothermal magnetization (M-H) measurements show hysteresis with maximum coercivity (Hc) and remnant magnetization (Mr) at T ~ 27 K, corroborating the presence of the two oppositely aligned magnetic moments, each with a ferromagnetic component. The two components of magnetic ordering are further confirmed by the double peak structure in the heat capacity measurements. These anomalous properties have significance to some of the earlier results obtained for the Cu-substituted superconducting Sr2YRu1-xCuxO6 compounds.

cond-mat.str-el↗
arXiv2010

Variant supercurrents and Noether procedure

Consistent supercurrent multiplets are naturally associated with linearized off-shell supergravity models. In arXiv:1002.4932 we presented the hierarchy of such supercurrents which correspond to all the models for linearized 4D N = 1 supergravity classified a few years ago. Here we analyze the correspondence between the most general supercurrent given in arXiv:1002.4932 and the one obtained eight years ago in hep-th/0110131 using the superfield Noether procedure. We apply the Noether procedure to the general N = 1 supersymmetric nonlinear sigma-model and show that it naturally leads to the so-called S-multiplet, revitalized in arXiv:1002.2228.

hep-th↗
arXiv2010

Variant supercurrent multiplets

In N = 1 rigid supersymmetric theories, there exist three standard realizations of the supercurrent multiplet corresponding to the (i) old minimal, (ii) new minimal and (iii) non-minimal off-shell formulations for N = 1 supergravity. Recently, Komargodski and Seiberg in arXiv:1002.2228 put forward a new supercurrent and proved its consistency, although in the past it was believed not to exist. In this paper, three new variant supercurrent multiplets are proposed. Implications for supergravity-matter systems are discussed.

hep-th↗