Investigation of dualities in string/M-theory and in gauge field theories. Studies of D-brane scattering processes, evaluation of quantum corrections to the effective action of super Yang-Mills theories describing D-brane dynamics. Construction of a quantum scheme for description of quarks interaction within the framework of duality between string theories in anti-de Sitter spacetimes and gauge field theories in Minkowski spacetimes.
Application of the harmonic-superspace approach for a geometric description of self-dual gauge and gravity theories and for a classification of supersymmetric gauge theories and supergravities in low dimensions, in their intimate relationships with the superstrings, p-branes and M-theory.
The study of new symmetry structures in the models with the partial spontaneous breaking of extended supersymmetries and the analysis of their relation to superbranes in a fixed gauge; in particular, the description, within the nonlinear realizations approach, the spontaneous breaking of N=4, D=4 supersymmetry down to N=2, D=4 and N=(2,0), D=6 to N=(1,0), D=6, the revealing of a possible relation of this theory to M5-brane and supersymmetric Born-Infeld models.
The general geometric and group-theoretical structure of superhierarchies with the N=2,3,4 supersymmetry will be analyzed. The N=2,3,4 supersymmetric Liouville equation with spontaneously broken supersymmetries will be constructed and its relevance in the context of superembedding program will be analyzed. The KdV hierarchies associated with N=3 and ``large'' N=4 superconformal algebras and their integrability properties will be studied. The relationships of these integrable systems with supersymmetric WZW models and superstring and higher p-brane models will be investigated. The problem of construction of N=4 supersymmetric extension of W3 algebra will be attacked using the harmonic superspace approach and non-local Poisson brackets structures.
Development of new methods of covariant and canonical quantization of general gauge theories and their application to specific field models possessing global and local symmetries, investigation of supersymmetry aspects under quantization.
Klaus Jünemann and Bernd Spendig:
D-brane scattering of N=2 strings
hep-th/0108069 (Phys. Lett. B 520 (2001) 163-169)
Tatiana A. Ivanova and Alexander D. Popov:
Cech, Dolbeault and de Rham cohomologies in Chern-Simons and BF theories
hep-th/0101150
(Proceedings of the XXIII Intern. Colloquium on Group Theoretical Methods in Physics, August 2000, Dubna)
Olaf Lechtenfeld, Alexander D. Popov and Bernd Spendig:
Open N=2 strings in a B-field background and noncommutative self-dual Yang-Mills
hep-th/0012200 (Phys. Lett. B 507 (2001) 317-326)
Evgeny Ivanov, Sergey Krivonos, Olaf Lechtenfeld and Boris Zupnik:
Partial spontaneous breaking of two-dimensional supersymmetry
hep-th/0012199 (Nucl. Phys. B 600 (2001) 235-271)
Olaf Lechtenfeld and Alexander D. Popov:
On the integrability of covariant field theory for the open N=2 string
hep-th/0009144 (Phys. Lett. B 494 (2000) 148-154)
Olaf Lechtenfeld and Alexander Sorin:
Hidden N=(2|2) supersymmetry of the N=(1|1) supersymmetric Toda lattice hierarchy
nlin.SI/0007009 (J. Nonlinear Math. Phys. 8 (2001) 183-195)
Tatiana A. Ivanova and Olaf Lechtenfeld:
Hidden symmetries of the open N=2 string
hep-th/0007049 (Int. J. Mod. Phys. A 16 (2001) 303-329)
Evgeny Ivanov, Sergey Krivonos and Olaf Lechtenfeld:
Double-vector multiplet and partially broken N=4, d=3 supersymmetry
hep-th/0006017 (Phys. Lett. B 487 (2000) 192-200)
Sergei V. Ketov:
Anomalous N=2 superconformal Ward identities
hep-th//0003245 (Nucl. Phys. B 582 (2000) 119-138)
Thomas Böttner, Sergei V. Ketov and Thomas Lau:
Manifestly N=3 supersymmetric Euler-Heisenberg action in light-cone superspace
hep-th/0002134 (Mod. Phys. Lett. A 15 (2000) 587-594)
Sergei V. Ketov:
Superconformal hypermultiplets from superspace
hep-th/0001109 (Nucl. Phys. B 582 (2000) 95-118)
Olaf Lechtenfeld:
Mathematics and physics of N=2 strings
hep-th/9912281
(Talk at JINR workshop ``Supersymmetries and Quantum Symmetries'', Dubna, Russia, 27-31 July 1999;
Proceedings 2000: SQS'99, pp. 79-89)
Olaf Lechtenfeld and Alexander D. Popov:
Closed N=2 strings: picture-changing, hidden symmetries and SDG hierarchy
hep-th/9912154 (Int. J. Mod. Phys. A 15 (2000) 4191-4237)
Olaf Lechtenfeld and Alexander Sorin:
Real forms of the complex twisted N=2 supersymmetric Toda chain hierarchy in real N=1 and twisted N=2 superspaces
solv-int/9912010 (J. Nonlinear Math. Phys. 7 (2000) 433-444)
Klaus Jünemann and Olaf Lechtenfeld:
Ward identities and the vanishing theorem for loop amplitudes of the closed N=2 string
hep-th/9912016 (Phys. Lett. B 474 (2000) 58-66)
Sergei V. Ketov:
Exact low-energy effective actions for hypermultiplets in four dimensions
hep-th/9909177 (unpublished)
Olaf Lechtenfeld and A. Sorin:
Supersymmetric KP hierarchy in N=1 superspace and its N=2 reductions
solv-int/9907021 (Nucl. Phys. B 566 [PM] (2000) 489-510)
Sergei V. Ketov:
Exact hypermultiplet dynamics in four dimensions
hep-th/9904196 (Phys. Lett. B 469 (1999) 136-144)
Anton Galajinsky and Olaf Lechtenfeld:
Towards a stringy extension of self-dual super Yang-Mills
hep-th/9903149 (Phys. Lett. B 460 (1999) 288-294)
Klaus Jünemann, Olaf Lechtenfeld and Alexander D. Popov:
Non-local symmetries of the closed N=2 string
hep-th/9901164 (Nucl. Phys. B 548 (1999) 449-474)
Olaf Lechtenfeld and Boris Zupnik:
Manifestly invariant actions for harmonic self-dual gauge theory
hep-th/9812244 (unpublished)
Sergei V. Ketov:
AdS/CFT correspondence and coincident D-6-branes
hep-th/9812079 (Fortsch. Phys. 48 (2000) 147-150)
Sergei V. Ketov:
Born-Infeld-Goldstone superfield actions for gauge-fixed D-5- and D-3-branes in 6d
hep-th/9812051 (Nucl. Phys. B 553 (1999) 250-282)
Olaf Lechtenfeld and Alexander Sorin:
Fermionic flows and tau function of the N=(1|1) superconformal Toda lattice hierarchy
solv-int/9810009 (Nucl. Phys. B 557 [PM] (1999) 535-547)
Sergei V. Ketov:
A manifestly N=2 supersymmetric Born-Infeld action
hep-th/9809121 (Mod. Phys. Lett. A 14 (1999) 501-510)
Sergei V. Ketov:
Dynamical generation of gauge and Higgs bosons in N=2 supersymmetric non-linear sigma-models
hep-th/9808187 (Nucl. Phys. B 544 (1999) 181-217)
Chandrashekar Devchand and Olaf Lechtenfeld:
String-induced Yang-Mills coupling to self-dual gravity
hep-th/9808053 (Nucl. Phys. B 539 (1999) 309-328)
Sergei V. Ketov:
Making manifest the symmetry enhancement for coinciding BPS branes
hep-th/9806130
(presented at the International Conference STRINGS'98 in Santa Barbara, USA, 22-26 June 1998, and the International Conference ``Problems of Quantum Field Theory'' in Dubna, Russia, 13-17 July 1998)
Sergei V. Ketov:
Analytic tools to brane technology in N=2 gauge theories with matter
hep-th/9806009 (Fortsch. Phys. 47 (1999) 643-703)
Chandrashekar Devchand and Olaf Lechtenfeld:
On the self-dual geometry of N=2 strings
hep-th/9801117
(Talk given at the 31st International Ahrenshoop Symposium on the Theory of Elementary Particles in Buckow, Germany, 2-6 September 1997, at the International Conference ``Methods in Field Theory'' in Stara Lesna, Slovakia, 22-26 September 1997, and the String Workshop in Wittenberg, Germany, 14-15 November, 1997)
S.V. Ketov:
The hypermultiplet low-energy effective action, N=2 supersymmetry breaking and confinement
hep-th/9712152
(Talk given at the 31st International Ahrenshoop Symposium on the Theory of Elementrary Particles in Buckow, Germany, 2-6 September 1997, and the String Workshop in Wittenberg, Germany, 14-15 November, 1997)
S. Karnas and S.V. Ketov:
An action of N=8 self-dual supergravity in ultra-hyperbolic harmonic superspace
hep-th/9712151 (Nucl. Phys. B 526 (1998) 597)
Klaus Jünemann and Olaf Lechtenfeld:
Chiral BRST cohomology of the N=2 string at arbitrary ghost and picture number
hep-th/9712182 (Comm. Math. Phys. 203 (1999) 53)
Chandrashekar Devchand and Olaf Lechtenfeld:
Extended self-dual Yang-Mills from the N=2 string
hep-th/9712043 (Nucl. Phys. B 516 (1998) 255)
Sergei Ketov and Christine Unkmeir:
Induced scalar potentials for hypermultiplets
hep-th/9710185 (Phys. Lett. B 422 (1998) 179)
I. L. Buchbinder, S. M. Kuzenko and B. A. Ovrut:
On the D=4, N=2 non-renormalization theorem
hep-th/9710142 (Phys. Lett. B 433 (1998) 335)
Sergei Ketov:
Do the critical (2,2) strings know about a supergravity in 2+10 dimensions ?
hep-th/9710086
(Talk at the XII International Congress of Mathematical Physics, 13-19 July, 1997, in Brisbane, Australia, and the 2nd International Conference on Quantum Field Theory and Gravity, July 29 - August 2, 1997, in Tomsk, Russia)
Sergei Ketov:
On the exact solutions to quantum N=2 gauge theories: a guide to instantons, superspace and M theory
hep-th/9710085 (unpublished)
Norbert Dragon and Sergei M. Kuzenko:
Self-interacting vector-tensor multiplet
hep-th/9709088 (Phys. Lett. B 420 (1998) 64)
Norbert Dragon, Sergei M. Kuzenko and Ulrich Theis:
The vector-tensor multiplet in harmonic superspace
hep-th/9706169 (Eur. Phys. J. C 4 (1998) 717)
Sergei Ketov:
On the next-to-leading-order correction to the effective action in N=2 gauge theories
hep-th/9706079 (Phys. Rev. D 57 (1998) 1277)
Evgeni Ivanov, Sergei Ketov and Boris Zupnik:
Induced hypermultiplet self-interactions in N=2 gauge theories
hep-th/9706078 (Nucl.Phys. B509 (1998) 53)
Norbert Dragon and Sergei M. Kuzenko:
The Higgs Mechanism in N=2 Superspace
hep-th/9705027 (Nucl. Phys. B 508 (1997) 229)
I.L. Buchbinder, E.I. Buchbinder, S.M. Kuzenko and B.A. Ovrut:
The background field method for N = 2 super Yang-Mills theories in harmonic superspace
hep-th/9704214 (Phys.Lett. B 417 (1998) 61)
Sergei M. Kuzenko :
The off-shell massive hypermultiplets revisited
hep-th/9704002 (Class. Quantum Grav. 14 (1997) L157)
I.L. Buchbinder, E.I. Buchbinder, E.A. Ivanov, S.M. Kuzenko and B.A. Ovrut:
Effective action of N=2 Maxwell multiplet in harmonic superspace
hep-th/9703147 (Phys. Lett. B 412 (1997) 309)
Sergei Ketov:
The effective hyper-Kähler potential in N=2 supersymmetric QCD
hep-th/9701158 (Phys. Lett. B 399 (1997) 83)
Sergei Ketov:
SOLITONS, MONOPOLES, AND DUALITY: from Sine-Gordon to Seiberg-Witten
hep-th/9611209 (Review, unpublished)
J.S. Gates Jr., S.M. Kuzenko and A.G. Sibiryakov:
Towards a unified theory of massless superfields of all superspins
hep-th/9611193 (Phys. Lett. B 394 (1997) 343)