THEME01-3-1030-99/2003

Next theme	Prev. theme
to field of reseach	to contents

01-3-1030-99/2003

Priority:

Status:

Approved for completion
in 2003

Theory of Condensed Matter

Leader:

N.M. Plakida
V.B. Priezzhev

Scientific Programme:
Multiparticle models of solids taking into consideration strong electron correlations, electron-lattice and spin interactions to describe spectra of quasiparticle excitations, phase transitions and kinetic phenomena in solids. In equilibrium and nonequilibrium media with strong correlations such as liquids and nuclear matter, the processes of multifragmentation, clusterization in phase transitions and the influence of surface effects on properties of clusters. In the theory of superconductivity, nonstandard mechanisms of pairing in metal-oxides, the problem of bipolaron stability in a polaron gas environment, the influence of strong electric fields and temperature gradients on elastic, magnetic, and thermal properties of granular superconductors. For the study of mechanisms of phase transitions caused by charge, orbital, and magnetic ordering in magnetic semiconductors and in metals with a large magnetoresistance, experimental data obtained at the Frank Laboratory of Neutron Physics, JINR, by neutron scattering and the µSR method will be used.

Nonlinear problems in multiparticle theory will be studied by using modern methods of the renormalization group theory, the inverse scattering problem, fractal geometry, and the conformal field theory. The main subjects of the study are integrable systems, equilibrium systems of the statistical mechanics and dissipative systems far from the thermodynamic equilibrium. The aim of these investigations is to reveal the common properties of the multiparticle systems associated with the ideas of self-similarity and universality.

The microstructure of amorphous state will be studied in the framework of the theoretical model where topological disorder is introduced via arrays of disclination dipoles and loops. The thermal properties of disclinated media are of primary interest. The electronic spectrum of carbon materials, fullerenes and nanotubes, will be examined within the field-theory model adapted to account for nontrivial geometry of these nanostructures. The model of random Josephson junction arrays will be studied and applied to the description of the high-temperature granular superconductors.

In the theory of finite quantum systems, local and low-dimensional states of matter obtained in modern experiments will be investigated. In particular, properties of quasiparticles in mesoscopic systems and the Bose-Einstein condensation in atomic traps will be studied.

Expected main results in 2003:

Calculation of electronic spectra in high-temperature superconductors with impurities. To study a new mechanism of superconducting pairing mediated by the exchange of phonon clouds surrounding polarons in models with strong electronic correlations. Calculation of transport properties of layered mercury high-temperature superconductors. Calculation of optical and transport properties of real materials (such as titanites, vanadetes etc.) where strong correlations play a major role. Calculation of the ground state of vanadate oxide compounds allowing for the spin-orbital coupling.
The Bethe integral equation for one-dimensional directed avalanche process will be investigated in the whole domain of parameters. Macroscopic characteristics of the avalanche process will be determined in the critical and supercritical regimes.
Investigation of topological effects in graphitic microstructures and in crystals having a Mobius structure.
Study of topological properties of quantum computers within the model of Josephson junction arrays.
Calculation of the phonon spectrum due to wedge disclination dipoles and their contribution to the thermodynamical characteristics of crystals.
Development of a model of photons and electrons interacting with the walls of a micro cavity. Construction of the theory of nonlinear coherent modes in the gas of trapped atoms. The study of the influence of pressure on the critical temperature in MgB₂ crystal. The generalization of the Gross-Pitaevskii equation for accurate evaluation of the coupling constant; consideration of the crossover 3D-2D.

List of Activities
	Activity or project	Spokespersons	Principal researchers
1.	Strongly Correlated Systems	N.M. Plakida G. Repke
			W. Kleinig A.L. Kuzemsky V.A. Moskalenko V.S. Oudovenko N.B. Perkins J. Schmelzer V.S. Shakhmatov V.Yu. Yushankhai
2.	Dynamic Systems: chaos, integrability and self-organization	V.B. Priezzhev
			L. Aleksandrov V.K. Mel'nikov V.I. Inozemtsev E.V. Ivashkevich A.M. Povolotsky V.N. Plechko K.V. Rerikh P.E. Zhidkov
3.	Disorded Structures: glasses, topological defects, nanostructures and Josephson junction	V.A. Osipov
			E.A. Kochetov S.E. Krasavin S.A. Sergeenkov
4.	Mesoscopic and Coherent Phenomena in Quantum Systems	M.A. Smondyrev V.S. Yarunin
			E.V. Bukina A.Yu. Cherny A.V. Chizhov V.M. Dubovik A.A. Shanenko V.I. Yukalov

Collaboration
Country or international organization	City	Institute or Laboratory
Armenia	Yerevan	YerPhI
Azerbaijan	Baku	IP AAS
Belarus	Minsk	IMAP NASB
Belgium	Antwerpen	UIA
Brazil	Brasilia, DF	Univ.
	San Paulo, SP	USP
Bulgaria	Sofia	ISSP BAS
		SU
Canada	Montreal	CU
Czech Republic	Rez	NPI ASCR
France	Marseille	CNRS
	Nice	Univ.
Germany	Bremen	Univ.
	Braunschweig	TUCW
	Dortmund	UNIDO
	Dresden	TUD
		IFW
	Duisburg	GMU
	Hamburg	Univ.
	Leipzig	Univ.
	Magdeburg	TU
	Rostock	Univ.
	Stuttgart	MPI-FKF
Hungary	Budapest	KFKI RMKI
ICTP
India	Mumbai	TIFR
Ireland	Dublin	DIAS
Italy	Catania	Univ.
	Salerno	Univ.
JINR	Dubna	FLNP
		LIT
		VBLHE
Poland	Cracow	JU
	Poznan	IP AMU
Romania	Bucharest	IFIN-HH
Russia	Moscow	KIGICh RAS
		LPI RAS
		MEPhI
		PFUR
		SMI RAS
		SINP MSU
		SSC RRC KI
	Irkutsk	ISU
	Perm	PSU
	St. Petersburg	POMI RAS
	Troitsk	VIHPP RAS
	Voronezh	VSU
	Yekaterinburg	IMP RAS-UD
Slovak Republic	Bratislava	IP SAS
	Kosice	IEP SAS
Slovenia	Ljubljana	Univ.
Switzerland	Villigen	PSI
Taiwan	Taipei	IP ASN
United Kingdom	Cambridge	Univ.
Ukraine	Kharkov	KFTI NASU
USA	New York, NY	CUNY
	Rochester, NY	UR
Uzbekistan	Tashkent	Assoc."P.-S." PTI
Vietnam	Hanoi	IP NCNST
Yugoslavia	Belgrade	INS "Vinca"

Next theme	Prev. theme
to field of reseach	to contents