arXiv subjects

Stepan Sidorov

Publications and source records attributed to Stepan Sidorov.

14 recordsLinked to original sources

arXiv2026

${\cal N}{=}\,4$ supersymmetric multiparticle systems based on indecomposable multiplets

We construct new multiparticle models of $\mathcal{N}=4$ supersymmetric mechanics with spin degrees of freedom by employing nonlinear indecomposable supermultiplets ${\bf (1,4,3){\supset\hspace{-1.1em}+}(4,4,0)}$. These systems are proper deformations of those associated with the standard irreducible $d=1$, $\mathcal{N}=4$ multiplets. In this way we find a deformation of $\mathcal{N}=4$ supersymmetric U$(2)$-spin rational Calogero system invariant under $d=1$ superconformal group OSp$(4|2)$. One more deformed model reproduces $\mathcal{N}=4$ supersymmetric U$(2)$-spin hyperbolic Calogero system, up to a shift of the Hamiltonian by some U$(1)$ generators.

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arXiv2025

${\cal N}=8$ supersymmetric mechanics with spin variables from indecomposable multiplets

We define two new indecomposable (not fully reducible) ${\cal N}=8$, $d=1$ off-shell multiplets and consider the corresponding models of ${\cal N}=8$ supersymmetric mechanics with spin variables. Each multiplet is described off shell by a scalar superfield which is a nonlinear deformation of the standard scalar superfield $X$ carrying the $d=1$ multiplet ${\bf (1,8,7)}$. Deformed systems involve, as invariant subsets, two different off-shell versions of the irreducible multiplet ${\bf (8,8,0)}$. For both systems we present the manifestly ${\cal N}=8$ supersymmetric superfield constraints, as well as the component off- and on-shell invariant actions, which for one version exactly match those given in arXiv:2402.00539 [hep-th]. The two models differ off shell, but prove to be equivalent to each other on shell, with the spin variables sitting in the adjoint representation of the maximal $R$-symmetry group ${\rm SO}(8)$.

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arXiv2024

Dual superfield approach to supersymmetric mechanics with spin variables

We consider a reducible ${\cal N}=4$, $d=1$ multiplet described by a real superfield as a coupling of the mirror ${\bf (1, 4, 3)}$ and ordinary ${\bf (3, 4, 1)}$ multiplets. Employing this so-called "long multiplet", we construct a coupled system of dynamical and semi-dynamical multiplets. We show that the corresponding {\it on-shell} model reproduces the model of Fedoruk, Ivanov and Lechtenfeld presented in 2012. Furthermore, there is a hidden supersymmetry acting on the long multiplet that extends the full world-line supersymmetry to SU(2$|$2). In other words, the ${\cal N}=4$ long multiplet can be derived from an irreducible SU(2$|$2) multiplet.

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arXiv2023

Non-linear (3, 4, 1) multiplet of ${\cal N} = 4$, $d = 1$ supersymmetry as a semi-dynamical spin multiplet

We consider a new type of ${\cal N}=4$, $d=1$ semi-dynamical multiplet based on the non-linear version of the mirror multiplet ${\bf (3, 4, 1)}$, with the triplet of bosonic physical fields parametrizing a three-dimensional sphere $S^3$ of the radius $R$. The limit $R\to\infty$ amounts to the contraction $S^3\to\mathbb{R}^3$ and leads to the linear mirror multiplet ${\bf (3, 4, 1)}$. Spin degrees of freedom described by a Wess-Zumino action specify a two-dimensional surface embedded in the sphere $S^3$. A pair of the examples considered correspond to the round and squashed ``fuzzy'' 2-spheres. We couple the squashed 2-sphere model to the dynamical mirror multiplet ${\bf (2, 4, 2)}$. A notable feature of this coupling is the dependence of the squashing parameter on the bosonic fields $z, \bar z$ of the chiral multiplet.

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arXiv2022

Couplings of ${\cal N}=4$, $d=1$ mirror supermultiplets

We construct models of coupled semi-dynamical (spin) and dynamical mirror multiplets of ${\cal N}=4$ supersymmetric mechanics in $d=1$ harmonic superspace. Specifically, we consider a semi-dynamical mirror multiplet ${\bf (3,4,1)}$ coupled to dynamical mirror multiplets ${\bf (1, 4, 3)}$ and ${\bf (2, 4, 2)}$. Coupling of the multiplets ${\bf (3, 4, 1)}$ and ${\bf (1, 4, 3)}$ yields a mirror counterpart of the earlier constructed model implying the Nahm equations for the spin variables with the bosonic component of the multiplet ${\bf (1, 4, 3)}$ as an evolution parameter. We also couple the mirror multiplet ${\bf (2,4,2)}$ to the mirror semi-dynamical multiplet ${\bf (3, 4, 1)}$ using chiral ${\cal N}=4$ superspace. The models constructed admit a generalization to the SU$(2|1)$ deformation of ${\cal N}=4$, $d=1$ Poincaré supersymmetry.

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arXiv2020

Quantum SU$(2|1)$ supersymmetric $\mathbb{C}^N$ Smorodinsky--Winternitz system

We study quantum properties of SU$(2|1)$ supersymmetric (deformed ${\cal N}=4$, $d=1$ supersymmetric) extension of the superintegrable Smorodinsky--Winternitz system on a complex Euclidian space $\mathbb{C}^N$. The full set of wave functions is constructed and the energy spectrum is calculated. It is shown that SU$(2|1)$ supersymmetry implies the bosonic and fermionic states to belong to separate energy levels, thus exhibiting the "even-odd" splitting of the spectra. The superextended hidden symmetry operators are also defined and their action on SU$(2|1)$ multiplets of the wave functions is given. An equivalent description of the same system in terms of superconformal SU$(2|1,1)$ quantum mechanics is considered and a new representation of the hidden symmetry generators in terms of the SU$(2|1,1)$ ones is found.

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arXiv2020

SU$(2|1)$ supersymmetric spinning models of chiral superfields

We construct SU$(2|1)$, $d=1$ supersymmetric models based on the coupling of dynamical and semi-dynamical (spin) multiplets, where the interaction term of both multiplets is defined on the generalized chiral superspace. The dynamical multiplet is defined as a chiral multiplet ${\bf (2,4,2)}$, while the semi-dynamical multiplet is associated with a multiplet ${\bf (4,4,0)}$ of the mirror type.

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arXiv2019

Symmetries of deformed supersymmetric mechanics on Kähler manifolds

Based on the systematic Hamiltonian and superfield approaches we construct the deformed $\mathcal{N}=4,8$ supersymmetric mechanics on Kähler manifolds interacting with constant magnetic field, and study their symmetries. At first we construct the deformed $\mathcal{N}=4,8$ supersymmetric Landau problem via minimal coupling of standard (undeformed) $\mathcal{N}=4,8$ supersymmetric free particle systems on Kähler manifold with constant magnetic field. We show that the initial "flat" supersymmetries are necessarily deformed to $SU(2|1)$ and $SU(4|1)$ supersymmetries, with the magnetic field playing the role of deformation parameter, and that the resulting systems inherit all the kinematical symmetries of the initial ones. Then we construct $SU(2|1)$ supersymmetric Kähler oscillators and find that they include, as particular cases, the harmonic oscillator models on complex Euclidian and complex projective spaces, as well as superintegrable deformations thereof, viz. $\mathbb{C}^N$-Smorodinsky-Winternitz and $\mathbb{CP}^N$-Rosochatius systems. We show that the supersymmetric extensions proposed inherit all the kinematical symmetries of the initial bosonic models. They also inherit, at least in the case of $\mathbb{C}^N$ systems, hidden (non-kinematical) symmetries. The superfield formulation of these supersymmetric systems is presented, based on the worldline $SU(2|1)$ and $SU(4|1)$ superspace formalisms.

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arXiv2019

Hidden Supersymmetries of Deformed Supersymmetric Mechanics

We consider quantum models corresponding to superymmetrizations of the two-dimensional harmonic oscillator based on worldline $d=1$ realizations of the supergroup SU$(\,{\cal N}/2\,|1)$, where the number of supersymmetries ${\cal N}$ is arbitrary even number. Constructed models possess the hidden supersymmetry SU$(\,{\cal N}/2\,|2)$. Degeneracies of energy levels are spanned by representations of the hidden supersymmetry group.

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arXiv2018

Deformed ${\cal N}{=}\,8$ mechanics of ${\bf(8,8,0)}$ multiplets

We construct new models of `curved' SU$(4|1)$ supersymmetric mechanics based on two versions of the off-shell multiplet ${\bf(8,8,0)}$ which are `mirror' to each other. The worldline realizations of the supergroup SU$(4|1)$ are treated as a deformation of flat ${\cal N}{=}\,8$, $d\,{=}\,1$ supersymmetry. Using SU$(4|1)$ chiral superfields, we derive invariant actions for the first-type ${\bf(8,8,0)}$ multiplet, which parametrizes special Kähler manifolds. Since we are not aware of a manifestly SU$(4|1)$ covariant superfield formalism for the second-type ${\bf(8,8,0)}$ multiplet, we perform a general construction of SU$(4|1)$ invariant actions for both multiplet types in terms of SU$(2|1)$ superfields. An important class of such actions enjoys superconformal OSp$(8|2)$ invariance. We also build off-shell actions for the SU$(4|1)$ multiplets ${\bf(6,8,2)}$ and ${\bf(7,8,1)}$ through appropriate substitutions for the component fields in the ${\bf(8,8,0)}$ actions. The ${\bf(6,8,2)}$ actions are shown to respect superconformal SU$(4|1,1)$ invariance.

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arXiv2018

Quantum SU(2$|$1) supersymmetric Calogero-Moser spinning systems

${\rm SU}(2|1)$ supersymmetric multi-particle quantum mechanics with additional semi-dynamical spin degrees of freedom is considered. In particular, we provide an $\mathcal{N}{=}\,4$ supersymmetrization of the quantum ${\rm U}(2)$ spin Calogero-Moser model, with an intrinsic mass parameter coming from the centrally-extended superalgebra $\widehat{su}(2|1)$. The full system admits an ${\rm SU}(2|1)$ covariant separation into the center-of-mass sector and the quotient. We derive explicit expressions for the classical and quantum ${\rm SU}(2|1)$ generators in both sectors as well as for the total system, and we determine the relevant energy spectra, degeneracies, and the sets of physical states.

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arXiv2018

Deformed supersymmetric quantum mechanics with spin variables

We quantize the one-particle model of the ${\rm SU}(2|1)$ supersymmetric multi-particle mechanics with the additional semi-dynamical spin degrees of freedom. We find the relevant energy spectrum and the full set of physical states as functions of the mass-dimension deformation parameter $m$ and ${\rm SU}(2)$ spin $q \in \big( \mathbb{Z}_{>0}\,$, $1/2 + \mathbb{Z}_{\geqslant 0}\big)\,$. It is found that the states at the fixed energy level form irreducible multiplets of the supergroup ${\rm SU}(2|1)\,$. Also, the hidden superconformal symmetry ${\rm OSp}(4|2)$ of the model is revealed in the classical and quantum cases. We calculate the ${\rm OSp}(4|2)$ Casimir operators and demonstrate that the full set of the physical states belonging to different energy levels at fixed $q$ are unified into an irreducible ${\rm OSp}(4|2)$ multiplet.

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arXiv2016

SU(2|2) supersymmetric mechanics

We introduce a new kind of non-relativistic ${\cal N}{=}\,8$ supersymmetric mechanics, associated with worldline realizations of the supergroup $SU(2|2)$ treated as a deformation of flat ${\cal N}{=}\,8$, $d{=}1$ supersymmetry. Various worldline $SU(2|2)$ superspaces are constructed as coset manifolds of this supergroup, and the corresponding superfield techniques are developed. For the off-shell $SU(2|2)$ multiplets $({\bf 3,8,5})$, $({\bf 4,8,4})$ and $({\bf 5,8,3})$, we construct and analyze the most general superfield and component actions. Common features are mass oscillator-type terms proportional to the deformation parameter and a trigonometric realization of the superconformal group $OSp(4^*|4)$ in the conformal cases. For the simplest $({\bf 5, 8, 3})$ model the quantization is performed.

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arXiv2016

Long N=2, 4 multiplets in supersymmetric mechanics

We define SU(2|1) supermultiplets described by chiral superfields having non-zero external spins with respect to SU(2) \subset SU(2|1) and show that their splitting into N=2, d=1 multiplets contains the so called "long" indecomposable N=2, d=1 multiplets (2, 4, 2)_l. We give superfield formulation for this type of N=2 long multiplets and construct their most general superfield action. A simple example of long N=4, d=1 multiplet is also considered, both in the superfield and the component formulations.

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