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F. Delduc

Publications and source records attributed to F. Delduc.

At least 19 recordsLinked to original sources
arXiv2019

${\cal N}{=}4$ Supersymmetric $d=1$ Sigma Models on Group Manifolds

We construct manifestly ${\cal N}=4$ supersymmetric off-shell superfield actions for the HKT $d=1$ sigma models on the group manifolds U(2) and SU(3), using the harmonic $d=1$ approach. The underlying $({\bf 4, 4, 0})$ and $({\bf 4, 4, 0})\oplus({\bf 4, 4, 0})$ multiplets are described, respectively, by one and two harmonic analytic superfields $q^+$ satisfying the appropriate nonlinear harmonic constraints. The invariant actions in both cases are bilinear in the superfields. We present the corresponding superfield realizations of the U(2) and SU(3) isometries and show that in fact they are enlarged to the products U(2)$\times$SU(2) and SU(3)$\times$U(2). We prove the corresponding invariances at both the superfield and component levels and present the bosonic $d=1$ sigma model actions, as integral over $t$ in the U(2) case and over $t$ and ${\rm SU}(2)$ harmonics in the SU(3) case. In the U(2) case we also give a detailed comparison with the general harmonic approach to HKT models and establish a correspondence with a particular action of the off-shell nonlinear multiplet $({\bf 3, 4, 1})$. A possible way of generalizing U(2) model to the matrix U($2n$) case is suggested.

hep-th↗
arXiv2012

Geometry and Harmonic Superspace: some recent progress

This contribution follows the talk, given by F. Delduc at the conference SQS'2011 in Dubna, Russia (July 18-23, 2011). To a considerable extent it is a summary of known facts about the links between geometry and extended supersymmetry in d=1 mechanics, with emphasis on the harmonic superspace method created in Dubna in the 80's. Some recent developments based on ref. [1] are also presented.

hep-th↗
arXiv2011

N = 4 mechanics of general (4, 4, 0) multiplets

We construct the manifestly N=4 supersymmetric off-shell superfield "master" action for any number n of the N=4 supermultiplets (4, 4, 0) described by harmonic analytic superfields q^{+a}(ζ, u), a= 1, ... 2n, subjected to the most general harmonic constraints. The action consists of the sigma-model and Wess-Zumino parts. We present the general expressions for the target space metric, torsion and background gauge fields. The generic target space geometry is shown to be weak HKT (hyper-Kähler with torsion), with the strong HKT and HK ones as particular cases. The background gauge fields obey the self-duality condition. Our formulation suggests that the weak HKT geometry is fully specified by the two primary potentials: an unconstrained scalar potential {\cal L}(q^+, q^-, u)|_{θ= 0} which is the θ= 0 projection of the superfield sigma-model Lagrangian, and a charge 3 harmonic analytic potential {\cal L}^{+ 3a}(q^+, u)|_{θ= 0} coming from the harmonic constraint on q^{+ a}. The reductions to the strong HKT and HK geometries amount to simple restrictions on the underlying potentials. We also show, using the N=2 superfield approach, that the most general bosonic target geometry of the N=4, d=1 sigma models, of which the weak HKT geometry is a particular case, naturally comes out after adding the mirror (4, 4, 0) multiplets with different transformation laws under N=4 supersymmetry and SO(4) R symmetry. Thus the minimal dimension of the target spaces exhibiting such a "weakest" geometry is 8, which corresponds to a pair of the mutually mirror (4, 4, 0) multiplets.

hep-th↗
arXiv2008

Gauging isometries in N=4 supersymmetric mechanics

This talk summarizes the study of superfield gaugings of isometries of extended supersymmetric mechanics in hep-th/0605211, hep-th/0611247 and arXiv:0706.0706. The gauging procedure provides a manifestly supersymmetric realization of d=1 automorphic dualities which interrelate various irreducible off-shell multiplets of d=1 extended supersymmetry featuring the same number of physical fermions but different divisions of bosonic fields into the physical and auxiliary subsets. We concentrate on the most interesting N=4 case and demonstrate that, with a suitable choice of the symmetry to be gauged, all such multiplets of N=4 supersymmetric mechanics and their generic superfield actions can be obtained from the "root" multiplet (4,4,0) and the appropriate gauged subclasses of the generic superfield action of the latter by a simple universal recipe.

hep-th↗
arXiv2007

The Common Origin of Linear and Nonlinear Chiral Multiplets in N=4 Mechanics

Elaborating on previous work (hep-th/0605211, hep-th/0611247), we show how the linear and nonlinear chiral multiplets of N=4 supersymmetric mechanics with the off-shell content (2,4,2) can be obtained by gauging three distinct two-parameter isometries of the ``root'' (4,4,0) multiplet actions. In particular, two different gauge groups, one abelian and one non-abelian, lead, albeit in a disguised form in the second case, to the same (unique) nonlinear chiral multiplet. This provides an evidence that no other nonlinear chiral N=4 multiplets exist. General sigma model type actions are discussed, together with the restricted potential terms coming from the Fayet-Iliopoulos terms associated with abelian gauge superfields. As in our previous work, we use the manifestly supersymmetric language of N=4, d=1 harmonic superspace. A novel point is the necessity to use in parallel the λand τgauge frames, with the ``bridges'' between these two frames playing a crucial role. It is the N=4 harmonic analyticity which, though being non-manifest in the τframe, gives rise to both linear and nonlinear chirality constraints.

hep-th↗
arXiv2007

N=2 supersymmetric unconstrained matrix GNLS hierarchies are consistent

We develop a pseudo-differential approach to the N=2 supersymmetric unconstrained matrix (k|n,m)-Generalized Nonlinear Schroedinger hierarchies and prove consistency of the corresponding Lax-pair representation (nlin.SI/0201026). Furthermore, we establish their equivalence to the integrable hierarchies derived in the super-algebraic approach of the homogeneously-graded loop superalgebra sl(2k+n|2k+m)\otimes C[{lambda},{lambda}^{-1}] (nlin.SI/0206037). We introduce an unconventional definition of N=2 supersymmetric strictly pseudo-differential operators so as to close their algebra among themselves.

nlin.SI↗
arXiv2007

New Model of N=8 Superconformal Mechanics

Using an N=4, d=1 superfield approach, we construct an N=8 supersymmetric action of the self-interacting off-shell N=8 multiplet {\bf (1, 8, 7)}. This action is found to be invariant under the exceptional N=8, d=1 superconformal group F(4) with the R-symmetry subgroup SO(7). The general N=8 supersymmetric {\bf (1, 8, 7)} action is a sum of the superconformal action and the previously known free bilinear action. We show that the general action is also superconformal, but with respect to redefined superfield transformation laws. The scalar potential can be generated by two Fayet-Iliopoulos N=4 superfield terms which preserve N=8 supersymmetry but break the superconformal and SO(7) symmetries.

hep-th↗
arXiv2006

Gauging N=4 supersymmetric mechanics II: (1,4,3) models from the (4,4,0) ones

Exploiting the gauging procedure developed by us in hep-th/0605211, we study the relationships between the models of N=4 mechanics based on the off-shell multiplets (4,4,0) and (1,4,3). We make use of the off-shell N=4, d=1 harmonic superspace approach as most adequate for treating this circle of problems. We show that the most general sigma-model type superfield action of the multiplet (1,4,3) can be obtained in a few non-equivalent ways from the (4,4,0) actions invariant under certain three-parameter symmetries, through gauging the latter by the appropriate non-propagating gauge multiplets. We discuss in detail the gauging of both the Pauli-Gursey SU(2) symmetry and the abelian three-generator shift symmetry. We reveal the (4,4,0) origin of the known mechanisms of generating potential terms for the multiplet (1,4,3), as well as of its superconformal properties. A new description of this multiplet in terms of unconstrained harmonic analytic gauge superfield is proposed. It suggests, in particular, a novel mechanism of generating the (1,4,3) potential terms via coupling to the fermionic off-shell N=4 multiplet (0,4,4).

hep-th↗
arXiv2006

Gauging N=4 Supersymmetric Mechanics

We argue that off-shell dualities between d=1 supermultiplets with different sets of physical bosonic components and the same number of fermionic ones are related to gauging some symmetries in the actions of the supermultiplets with maximal sets of physical bosons. Our gauging procedure uses off-shell superfields and so is manifestly supersymmetric. We focus on N=4 supersymmetric mechanics and show that various actions of the multiplet (3,4,1) amount to some gauge choices in the gauged superfield actions of the linear or nonlinear (4,4,0) multiplets. In particular, the conformally invariant (3,4,1) superpotential is generated by the Fayet-Iliopoulos term of the gauge superfield. We find a new nonlinear variant of the multiplet (4,4,0), such that its simplest superfield action produces the most general 4-dim hyper-Kähler metric with one triholomorphic isometry as the bosonic target metric. We also elaborate on some other instructive examples of N=4 superfield gaugings, including a non-abelian gauging which relates the free linear (4,4,0) multiplet to a self-interacting (1,4,3) multiplet.

hep-th↗
arXiv2002

Lax pair formulation of the N=4 Toda chain (KdV) hierarchy in N=4 superspace

Lax pair and Hamiltonian formulations of the N=4 supersymmetric Toda chain (KdV) hierarchy in N=4 superspace are proposed. The general formulae for the infinite tower of its bosonic flows in terms of the Lax operator in N=4 superspace are derived. A new N=4 superfield basis in which the flows are local is constructed and its embedding in the N=4 O(4) superconformal supercurrent is established. A proof that the flows possess five complex conjugations and aninfinite-dimensional group of discrete symmetries in N=4 superspace is presented. A relation between the two descriptions of the hierarchy in N=4 superspace used in the literature is established. All known N=2 superfield representations of the N=4 KdV hierarchy are shown to derive from our N=4 superspace Lax representation.

nlin.SI↗
arXiv2001

Partial Supersymmetry Breaking and AdS4 Supermembrane

We consider partial spontaneous breaking of N=1 AdS4 supersymmetry OSp(1|4) down to N=1, d=3 Poincare supersymmetry in the nonlinear realizations framework. We construct the corresponding worldvolume Goldstone superfield action and show that it describes the N=1 AdS4 supermembrane. It enjoys OSp(1|4) supersymmetry realized as a field-dependent modification of N=1, d=3 superconformal symmetry and goes into the superfield action of ordinary N=1, D=4 supermembrane in the flat limit. Its bosonic core is the Maldacena-type conformally invariant action of the AdS4 membrane. We show how to reproduce the latter action within a nonlinear realization of the AdS4 group SO(2,3). The same universal nonlinear realizations techniques can be used to construct conformally-invariant worldvolume actions for (d-2)-branes in generic AdSd spaces.

hep-th↗
arXiv1999

1/4 PBGS and Superparticle Actions

We construct the worldline superfield massive superparticle actions which preserve 1/4 portion of the underlying higher-dimensional supersymmetry. We consider the cases of N=4/N=1 and N=8/N=2 partial breaking. In the first case we present the corresponding Green-Schwarz type target superspace action with one kappa supersymmetry. In the second case we find out two possibilities, one of which is a direct generalization of the N=4/N=1 case, while another is essentially different.

hep-th↗
arXiv1999

1/4 Partial Breaking of Global Supersymmetry and New Superparticle Actions

We construct the worldline superfield massive superparticle actions which preserve 1/4 portion of the underlying higher-dimensional supersymmetry. The rest of supersymmetry is spontaneously broken and realized by nonlinear transformations. We consider the cases of N=4 to N=1 and N=8 to N=2 partial breaking. In the first case we present the corresponding Green-Schwarz type target superspace action with one $κ$-supersymmetry. It is related to the superfield action via a field redefinition. In the second case we find out two possible models, one of which is a direct generalization of the N=4 to N=1 case, while another is essentially different. For the first model we formulate Green-Schwarz type action with two kappa supersymmetries. We elaborate on the bosonic part of the superfield action for the second model and find that only in two special limits it takes the standard Nambu-Goto form. In the general case it is determined by a fourth-order algebraic equation. The characteristic common feature of these new superparticle models is that the algebras of their spontaneously broken supersymmetries are non-trivial truncations of the general extensions of N=1 and N=2 Poincare D=4 superalgebras by tensorial central charges.

hep-th↗
arXiv1999

A note on real forms of the complex N=4 supersymmetric Toda chain hierarchy in real N=2 and N=4 superspaces

Three inequivalent real forms of the complex N=4 supersymmetric Toda chain hierarchy (Nucl. Phys. B558 (1999) 545, solv-int/9907004) in the real N=2 superspace with one even and two odd real coordinates are presented. It is demonstrated that the first of them possesses a global N=4 supersymmetry, while the other two admit a twisted N=4 supersymmetry. A new superfield basis in which supersymmetry transformations are local is discussed and a manifest N=4 supersymmetric representation of the N=4 Toda chain in terms of a chiral and an anti-chiral N=4 superfield is constructed. Its relation to the complex N=4 supersymmetric KdV hierarchy is established. Darboux-Backlund symmetries and a new real form of this last hierarchy possessing a twisted N=4 supersymmetry are derived.

solv-int↗
arXiv1999

N=2 local and N=4 nonlocal reductions of supersymmetric KP hierarchy in N=2 superspace

A N=4 supersymmetric matrix KP hierarchy is proposed and a wide class of its reductions which are characterized by a finite number of fields are described. This class includes the one-dimensional reduction of the two-dimensional N=(2|2) superconformal Toda lattice hierarchy possessing the N=4 supersymmetry -- the N=4 Toda chain hierarchy -- which may be relevant in the construction of supersymmetric matrix models. The Lax pair representations of the bosonic and fermionic flows, corresponding local and nonlocal Hamiltonians, finite and infinite discrete symmetries, the first two Hamiltonian structures and the recursion operator connecting all evolution equations and the Hamiltonian structures of the N=4 Toda chain hierarchy are constructed in explicit form. Its secondary reduction to the N=2 supersymmetric alpha=-2 KdV hierarchy is discussed.

solv-int↗
arXiv1999

Non-standard matrix formats of Lie superalgebras

The standard format of matrices belonging to Lie superalgebras consists of partitioning the matrices into even and odd blocks. In this paper, we study other possible matrix formats and in particular the so-called diagonal format which naturally occurs in various applications, e.g. in superconformal field theory, superintegrable models, for super W-algebras and quantum supergroups.

math-ph↗
arXiv1997

Nonstandard Drinfeld-Sokolov reduction

Subject to some conditions, the input data for the Drinfeld-Sokolov construction of KdV type hierarchies is a quadruplet $(\A,Λ, d_1, d_0)$, where the $d_i$ are $\Z$-gradations of a loop algebra $\A$ and $Λ\in \A$ is a semisimple element of nonzero $d_1$-grade. A new sufficient condition on the quadruplet under which the construction works is proposed and examples are presented. The proposal relies on splitting the $d_1$-grade zero part of $\A$ into a vector space direct sum of two subalgebras. This permits one to interpret certain Gelfand-Dickey type systems associated with a nonstandard splitting of the algebra of pseudo-differential operators in the Drinfeld-Sokolov framework.

solv-int↗