THEME01-3-1030-99/2008

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01-3-1030-99/2008

Priority:

Status:

In-progress

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 a 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 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 describe 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 2006:

Calculation of the dynamical spin susceptibility in cuprates within the t-J model to explain magnetic inelastic neutron scattering experiments. Evaluation of the electronic structure of copper-oxide materials on the basis of the p-d-s Hubbard model.

Evaluation of electronic structure of icosahedral fullerenes in a uniform magnetic field. Study of quantum anomalies in spin systems. Calculation of the electronic spectrum of semiconductors in the presence of topological defects.
To develop a general theory of nonlinear spin relaxation in strongly nonequilibrium magnets and to apply this theory for describing the coherent spin relaxation in molecular nanomagnets.

To develop a modified semiclassical approximation for describing the properties of cold trapped atoms.

List of Activities
	Activity or Experiment	Leader	Principal researchers
1.	Physical properties of complex materials and nanostructures	N.M. Plakida V.A. Osipov G. Repke
			W. Kleinig E.A. Kochetov S.E. Krasavin A.L. Kuzemsky V.A. Moskalenko V.S. Oudovenko N.B. Perkins J. Schmelzer S.A. Sergeenkov V.S. Shakhmatov V.Yu. Yushankhai
2.	Mathematical problems of many-particle systems	V.B. Priezzhev M.A. Smondyrev V.I. Yukalov
			L. Aleksandrov E.V. Bukina A.Yu. Cherny A.V. Chizhov V.M. Dubovik V.I. Inozemtsev A.E. Patrik A.M. Povolotsky V.N. Plechko K.V. Rerikh A.A. Shanenko P.E. Zhidkov

Collaboration
Country or international organization	City	Institute or Laboratory
Armenia	Yerevan	YerPhI
Belarus	Minsk	IMAP NASB
Belgium	Antwerp	UIA
Brazil	Brasilia, DF	UnB
	San Paulo, SP	USP
Bulgaria	Sofia	ISSP BAS
		SU
Canada	Montreal	Concordia
Czech Republic	Rez	NPI ASCR
France	Marseille	CPT
	Nice	UNSA
Germany	Bremen	Univ.
	Brunswick	TU
	Dortmund	Univ.
	Dresden	TUD
		IFW
	Duisburg	Univ.
	Leipzig	Univ.
	Magdeburg	OvGU
	Rostock	Univ.
	Stuttgart	MPI-FKF
Hungary	Budapest	KFKI RMKI
ICTP	Trieste
India	Bombey	TIFR
Ireland	Dublin	DIAS
Italy	Catania	Univ.
	Salerno	Univ.
JINR	Dubna	FLNP
		LIT
Poland	Cracow	JU
	Poznan	IP AMU
Romania	Bucharest	IFIN-HH
Russia	Moscow	IGIC RAS
		LPI RAS
		MEPhI
		PFUR
		SMI RAS
		SINP MSU
		SSC RRC KI
	Irkutsk	ISU
	Perm	PSU
	St. Petersburg	POMI
	Troitsk	HPPI RAS
	Voronezh	VSU
	Yekaterinburg	INP RAS UB
Serbia and Montenegro	Podgorica	Univ.
Slovak Republic	Bratislava	IP SAS
	Kosice	IEP SAS
Slovenia	Ljubljana	UL
Switzerland	Villigen	PSI
Taiwan	Taipei	IP ASN
Ukraine	Kharkov	KFTI NASU
USA	New York, NY	CUNY
	Rochester, NY	UR
Uzbekistan	Tashkent	Assoc."P.-S." PTI
Vietnam	Hanoi	IP NCST

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