THEME01-3-1030-99/2003

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01-3-1030-99/2003

Priority:

Status:

In-progress

Theory of Condensed Matter

Leader:

N. Plakida
V. Priezzhev

Scientific Programme:
Multi-particle 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

SR method will be used.

  Nonlinear problems in multi-particle 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 multi-particle 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 for 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 2002:

Calculation of the electronic structure for the three-band Hubbard model of copper oxides within a cell cluster representation. Investigation of charge, orbital, and magnetic ordering for manganite compounds by applying the symmetry analysis and comparing it with a microscopic theory. Calculation of the spin excitation spectrum for layered manganites within the double-exchange model with strong electron correlations. Investigation of the role of the crystal structure for layered superconducting systems. Calculation of thermoelectric effects in complex oxides and cuprates.
Further development of the Bethe-ansatz method for solution of one-dimensional problems of quantum statistical mechanics and kinetic equations. Evaluation of kinetic coefficients in one-dimensional avalanche processes.
Calculation of the spectrum of local vibrations near wedge disclination dipoles and their contribution to the specific heat of crystals. Investigation of topological effects in graphitic microstructures (cones, fullerenes, nanotubes). Study of electric field effects on thermal conductivity of granular superconductors. Calculation of the thermal expansion coefficient of the Josephson junction array in an applied magnetic field.
Development of the theory of nonlinear coherent modes of atoms in traps and a device of their nonresonant excitation. Determination of the polaron properties in a quantum wire.
Derivation of an exact formula for a pair interatomic helium interaction for liquid He-4. Estimation of the shift of Bose-Einstein condensation temperature in atomic traps by the gravitational field.

List of Activities
	Activity or project	Spokespersons	Principal researchers
1.	Strongly Correlated Systems	N. Plakida G. Repke
			W. Kleinig A. Kuzemsky V. Moskalenko V. Oudovenko N. Perkins J. Schmelzer V. Shakhmatov V. Yushankhai
2.	Dynamic Systems: chaos, integrability and self-organization	V. Priezzhev
			L. Alexsandrov V. Mel'nikov V. Inozemtsev T. Ivanova E. Ivashkevich A. Povolotskiy V. Plechko K. Rerikh P. Zhidkov
3.	Disorded Structures: glasses, topological defects, nanostructures and Josephson junction	V. Osipov
			E. Kochetov S. Krasavin S. Sergeenkov
4.	Mesoscopic and Coherent Phenomena in Quantum Systems	M. Smondyrev V. Yarunin
			E. Bukina A. Cherny A. Chizhov V. Dubovik A. Shanenko V. Yukalov

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

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Theory of Condensed Matter

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