Flat Superspace Research Articles

Hierarchy of supersymmetric higher spin connections

We focus on the geometrical reformulation of free higher spin supermultiplets in $4\rm{D},~\mathcal{N}=1$ flat superspace. We find that there is a de Wit-Freedman like hierarchy of superconnections with simple gauge transformations. The requirement for sensible free equations of motion imposes constraints on the gauge parameter superfields. Unlike the nonsupersymmetric case, we find several different constraints that can decouple the higher superconnections. By lifting these constraints nongeometrically via compensators we recover all known descriptions of arbitrary integer and half-integer gauge supermultiplets. In the constrained formulation we find a new description of half-integer supermultiplets, generalizing the new-minimal and virial formulations of linearized supergravity to higher spins. However this description can be formulated using compensators. The various descriptions can be labeled as geometrical or nongeometrical if the equations of motion can be expressed purely in terms of superconnections or not.

Field theories with (2,0) AdS supersymmetry in N=1 AdS superspace

In three dimensions, it is known that field theories possessing extended $(p,q)$ anti-de Sitter (AdS) supersymmetry with ${\cal N}=p+q \geq 3$ can be realised in (2,0) AdS superspace. Here we present a formalism to reduce every field theory with (2,0) AdS supersymmetry to ${\cal N}=1$ AdS superspace. As nontrivial examples, we consider supersymmetric nonlinear sigma models formulated in terms of ${\cal N}=2$ chiral and linear supermultiplets. The $(2,0) \to (1,0)$ AdS reduction technique is then applied to the off-shell massless higher-spin supermultiplets in (2,0) AdS superspace constructed in [1]. As a result, for each superspin value $\hat s$, integer $(\hat s= s)$ or half-integer $(\hat s= s+1/2)$, with $s=1,2,\dots $, we obtain two off-shell formulations for a massless ${\cal N}=1$ superspin-$\hat s$ multiplet in AdS${}_3$. These models prove to be related to each other by a superfield Legendre transformation in the flat superspace limit, but the duality is not lifted to the AdS case. Two out of the four series of ${\cal N}=1$ supersymmetric higher-spin models thus derived are new. The constructed massless ${\cal N}=1$ supersymmetric higher-spin actions in AdS${}_3$ are used to formulate (i) higher-spin supercurrent multiplets in ${\cal N}=1$ AdS superspace; and (ii) new topologically massive higher-spin off-shell supermultiplets. Examples of ${\cal N}=1$ higher-spin supercurrents are given for models of a complex scalar supermultiplet. We also present two new off-shell formulations for a massive ${\cal N}=1$ gravitino supermultiplet in AdS${}_3$.

N=2 supersymmetric higher spin gauge theories and current multiplets in three dimensions

We describe several families of primary linear supermultiplets coupled to three-dimensional ${\cal N}=2$ conformal supergravity and use them to construct topological $BF$-type terms. We introduce conformal higher-spin gauge superfields and associate with them Chern-Simons-type actions that are constructed as an extension of the linearised action for ${\cal N}=2$ conformal supergravity. These actions possess gauge and super-Weyl invariance in any conformally flat superspace and involve a higher-spin generalisation of the linearised ${\cal N}=2$ super-Cotton tensor. For massless higher-spin supermultiplets in (1,1) anti-de Sitter (AdS) superspace, we propose two off-shell Lagrangian gauge formulations, which are related to each other by a dually transformation. Making use of these massless theories allows us to formulate consistent higher-spin supercurrent multiplets in (1,1) AdS superspace. Explicit examples of such supercurrent multiplets are provided for models of massive chiral supermultiplets. Off-shell formulations for massive higher-spin supermultiplets in (1,1) AdS superspace are proposed.

Supersymmetric action for multiple D0-brane system

We have constructed a complete action for the system of N D0-branes in flat 10D type IIA superspace. It is invariant under the rigid spacetime supersymmetry and local worldline supersymmetry (κ-symmetry). This latter can be considered as supersymmetry of maximal 1d SU(N) SYM model which is made local by coupling to supergravity induced by embedding of the center of energy worldline into the target superspace. The spinor moving frame technique is essentially used to achieve such a coupling. We discuss the differences with Panda-Sorokin multiple 0-brane action and with the dimensionally reduced 11D multiple M-wave action.

N =1 supergravitational heterotic galileons

Heterotic M -theory consists of a five-dimensional manifold of the form S1/Z2 × M4. It has been shown that one of the two orbifold planes, the “observable” sector, can have a low energy particle spectrum which is precisely the N = 1 super-symmetric standard model with three right-handed neutrino chiral supermultiplets. The other orbifold plane constitutes a “hidden” sector which, since its communication with the observable sector is suppressed, will be ignored in this paper. However, the finite fifth-dimension allows for the existence of three-brane solitons which, in order to render the vacuum anomaly free, must appear. That is, heterotic M -theory provides a natural framework for brane-world cosmological scenarios coupled to realistic particle physics. The complete worldvolume action of such three-branes is unknown. Here, treating these solitons as probe branes, we construct their scalar worldvolume Lagrangian as a derivative expansion of the heterotic DBI action. In analogy with similar calculations in the M5 and AdS5 context, this leads to the construction of “heterotic Galileons”. However, realistic vacua of heterotic M -theory are necessarily N = 1 supersymmetric in four dimensions. Hence, we proceed to supersymmetrize the three-brane worldvolume action, first in flat superspace and then extend the results to N = 1 supergravity. Such a worldvolume action may lead to interesting cosmology, such as “bouncing” universe models, by allowing for the violation of the Null Energy Condition (NEC).

Supergravitational conformal Galileons

The worldvolume actions of 3+1 dimensional bosonic branes embedded in a five-dimensional bulk space can lead to important effective field theories, such as the DBI conformal Galileons, and may, when the Null Energy Condition is violated, play an essential role in cosmological theories of the early universe. These include Galileon Genesis and “bouncing” cosmology, where a pre-Big Bang contracting phase bounces smoothly to the presently observed expanding universe. Perhaps the most natural arena for such branes to arise is within the context of superstring and M -theory vacua. Here, not only are branes required for the consistency of the theory, but, in many cases, the exact spectrum of particle physics occurs at low energy. However, such theories have the additional constraint that they must be N = 1 supersymmetric. This motivates us to compute the worldvolume actions of N = 1 supersymmetric three-branes, first in flat superspace and then to generalize them to N = 1 supergravitation. In this paper, for simplicity, we begin the process, not within the context of a superstring vacuum but, rather, for the conformal Galileons arising on a co-dimension one brane embedded in a maximally symmetric AdS5 bulk space. We proceed to N = 1 supersymmetrize the associated worldvolume theory and then generalize the results to N = 1 supergravity, opening the door to possible new cosmological scenarios

Super-Laplacians and their symmetries

A super-Laplacian is a set of differential operators in superspace whose highestdimensional component is given by the spacetime Laplacian. Symmetries of super-Laplacians are given by linear differential operators of arbitrary finite degree and are determined by superconformal Killing tensors. We investigate these in flat superspaces. The differential operators determining the symmetries give rise to algebras which can be identified in many cases with the tensor algebras of the relevant superconformal Lie algebras modulo certain ideals. They have applications to Higher Spin theories.

Minimal mathcal{N}=4 topologically massive supergravity

Using the superconformal framework, we construct a new off-shell model for mathcal{N}=4 topologically massive supergravity which is minimal in the sense that it makes use of a single compensating vector multiplet and involves no free parameter. As such, it provides a counterexample to the common lore that two compensating multiplets are required within the conformal approach to supergravity with eight supercharges in diverse dimensions. This theory is an off-shell mathcal{N}=4 supersymmetric extension of chiral gravity. All of its solutions correspond to non-conformally flat superspaces. Its maximally supersymmetric solutions include the so-called critical (4,0) anti-de Sitter superspace introduced in [25], and well as warped critical (4,0) anti-de Sitter superspaces. We also propose a dual formulation for the theory in which the vector multiplet is replaced with an off-shell hypermultiplet. Upon elimination of the auxiliary fields belonging to the hypermultiplet and imposing certain gauge conditions, the dual action reduces to the one introduced in [20].

Notes on super Killing tensors

The notion of a Killing tensor is generalised to a superspace setting. Conserved quantities associated with these are defined for superparticles and Poisson brackets are used to define a supersymmetric version of the Schouten-Nijenhuis bracket. Superconformal Killing tensors in flat superspaces are studied for spacetime dimensions 3,4,5,6 and 10. These tensors are also presented in analytic superspaces and super-twistor spaces for 3,4 and 6 dimensions. Algebraic structures associated with superconformal Killing tensors are also briefly discussed

SU (2|1) mechanics and harmonic superspace

We define the worldline harmonic superspace and its analytic subspace as a deformation of the flat harmonic superspace. The harmonic superfield description of the two mutually mirror off-shell supermultiplets is developed and the corresponding invariant actions are presented, as well as the relevant classical and quantum supercharges. Whereas the σ-model actions exist for both types of the multiplet, the invariant Wess–Zumino term can be defined only for one of them, thus demonstrating non-equivalence of these multiplets in the case as opposed to the flat supersymmetry. A superconformal subclass of general actions invariant under the trigonometric-type realizations of the supergroup is singled out. The superconformal Wess–Zumino actions are shown to possess an infinite-dimensional supersymmetry forming the centerless super Virasoro algebra. We solve a few simple instructive examples of the supersymmetric quantum mechanics of the multiplets and reveal the representation contents of the corresponding sets of the quantum states.

Noncommutative supergeometry and quantum supergroups

This is a review of concepts of noncommutative supergeometry - namely Hilbert superspace, C*-superalgebra, quantum supergroup - and corresponding results. In particular, we present applications of noncommutative supergeometry in harmonic analysis of Lie supergroups, non-formal deformation quantization of supermanifolds, quantum field theory on noncommutative spaces; and we give explicit examples as deformation of flat superspaces, noncommutative supertori, solvable topological quantum supergroups.

Integral invariants in flat superspace

We are solving for the case of flat superspace some homological problems that were formulated by Berkovits and Howe. (Our considerations can be applied also to the case of supertorus.) These problems arise in the attempt to construct integrals invariant with respect to supersymmetry. They appear also in other situations, in particular, in the pure spinor formalism in supergravity.

Supersymmetric non-abelian multiwaves in D = 3 AdS superspace

We present a covariant, supersymmetric and kappa-symmetric action for non-Abelian multiwave system (nAmW) in D=3 AdS superspace. Its flat superspace limit provides a simplest counterpart of the recently proposed action for 11 dimensional system of N nearly coincident M-waves (multiple M0-branes), which is presently known for the case of flat target superspace only.

Extended supersymmetric sigma models in AdS4 from projective superspace

There exist two superspace approaches to describe N=2 supersymmetric nonlinear sigma models in four-dimensional anti-de Sitter (AdS_4) space: (i) in terms of N=1 AdS chiral superfields, as developed in arXiv:1105.3111 and arXiv:1108.5290; and (ii) in terms of N=2 polar supermultiplets using the AdS projective-superspace techniques developed in arXiv:0807.3368. The virtue of the approach (i) is that it makes manifest the geometric properties of the N=2 supersymmetric sigma-models in AdS_4. The target space must be a non-compact hyperkahler manifold endowed with a Killing vector field which generates an SO(2) group of rotations on the two-sphere of complex structures. The power of the approach (ii) is that it allows us, in principle, to generate hyperkahler metrics as well as to address the problem of deformations of such metrics. Here we show how to relate the formulation (ii) to (i) by integrating out an infinite number of N=1 AdS auxiliary superfields and performing a superfield duality transformation. We also develop a novel description of the most general N=2 supersymmetric nonlinear sigma-model in AdS_4 in terms of chiral superfields on three-dimensional N=2 flat superspace without central charge. This superspace naturally originates from a conformally flat realization for the four-dimensional N=2 AdS superspace that makes use of Poincare coordinates for AdS_4. This novel formulation allows us to uncover several interesting geometric results.

(p + 1)-Algebra for a super p-brane: the Nambu bracket reformulation

We express the covariant actions of a super p-brane and the corresponding equations of motion, in the flat and curved superspaces, in terms of the Nambu (p+1)-brackets. These brackets make the (p+1)-algebra structure of super p-brane manifest. For the flat superspace, this reconstruction of the action also allows reformulating it in terms of two sets of differential forms.

Superembedding approach to M0-brane and multiple M0-brane system

We study the possibility to describe multiple M0-brane system in the frame of superembedding approach. The simplest framework is provided by the maximally supersymmetric non-Abelian SU(N) Yang–Mills supermultiplet on the d=1N=16 superspace the embedding of which to the target D=11 supergravity superspace is determined by the so-called superembedding equation, characteristic of the worldline superspace of a single M0-brane. We use it to obtain a covariant generalization of the Matrix model equations describing the multiple M0-system in flat target superspace.

Generalized Berezin-Toeplitz quantization of Kähler supermanifolds

We extend the construction of generalized Berezin and Berezin-Toeplitz quantization to the case of compact Hodge supermanifolds. Our approach is based on certain super-analogues of Rawnsley's coherent states. As applications, we discuss the quantization of affine and projective superspaces. Furthermore, we propose a definition of supersymmetric sigma-models on quantized Hodge supermanifolds. The corresponding quantum field theories are finite and thus yield supersymmetry-preserving regularizations for QFTs defined on flat superspace.

Field theory in 4D 𝒩 = 2 conformally flat superspace

Building on the superspace formulation for four-dimensional = 2 matter-coupled supergravity developed in [1], we elaborate upon a general setting for field theory in = 2 conformally flat superspaces, and concentrate specifically on the case of anti-de Sitter (AdS) superspace. We demonstrate, in particular, that associated with the = 2 AdS supergeometry is a unique vector multiplet such that the corresponding covariantly chiral field strength 0 is constant, 0 = 1. This multiplet proves to be intrinsic in the sense that it encodes all the information about the = 2 AdS supergeometry in a conformally flat frame. Moreover, it emerges as a building block in the construction of various supersymmetric actions. Such a vector multiplet, which can be identified with one of the two compensators of = 2 supergravity, also naturally occurs for arbitrary conformally flat superspaces. An explicit superspace reduction = 2 → = 1 is performed for the action principle in general conformally flat = 2 backgrounds, and examples of such reduction are given.

Conformally flat supergeometry in five dimensions

Using the superspace formulation for the 5D N = 1 Weyl supermultiplet developed in arXiv:0802.3953, we elaborate the concept of conformally flat superspace in five dimensions. For a large family of supersymmetric theories (including sigma-models and Yang-Mills theories) in the conformally flat superspace, we describe an explicit procedure to formulate their dynamics in terms of rigid 4D N = 1 superfields. The case of 5D N = 1 anti-de Sitter superspace is discussed as an example.

Formula omitted] mechanics in [formula omitted] harmonic superspace

The N = 8 , 1D analytic bi-harmonic superspace is shown to provide a natural setting for N = 8 supersymmetric mechanics associated with the off-shell multiplet ( 4 , 8 , 4 ) . The latter is described by an analytic superfield q 1 , 1 , and we construct the general superfield and component actions for any number of such multiplets. The set of transformations preserving the flat superspace constraints on q 1 , 1 constitutes N = 8 extension of the two-dimensional Heisenberg algebra h ( 2 ) , with an operator central charge. The corresponding invariant q 1 , 1 action is constructed. It is unique and breaks 1D scale invariance. We also find a one-parameter family of scale-invariant q 1 , 1 actions which, however, are not invariant under the full N = 8 Heisenberg supergroup. Based on preserving the bi-harmonic Grassmann analyticity, we formulate N = 8 , 1D supergravity in terms of the appropriate analytic supervielbeins. For its truncated version we construct, both at the superfield and component levels, the first example of off-shell q 1 , 1 action with local N = 8 , 1D supersymmetry. This construction can be generalized to any number of self-interacting q 1 , 1 .