THEME01-3-1030-99/2008

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01-3-1030-99/2008

Priority:

Status:

Extended

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 2004:

Theoretical description of phase transitions between antiferromagnetic state and singlet or triplet supercoductivity for strongly correlated electrons. Calculation of dynamical spin susceptibility in normal and superconducting states for high-temperature superconductors. Development of a theory of metal-insulator phase transitions for mixed-valence transition metal oxides.
The stationary and nonstationary properties of nonequilibrium stochastic processes will be studied for three basic models admitting exact solutions:
a) one-dimensional asymmetric exclusion process;
b) one-dimensional avalanche process;
c) one-dimensional zero-range process.
Investigation of the low-temperature properties of materials with the structural disorder (amorphous bodies, glasses, quasicrystals). Study of electronic properties of variously shaped carbon nanostructures. Analysis of the role of the topological term in the quantum 1D t-J model.
Calculations of polaron characteristics in a quantum wire with a potential of finite height.

The polariton (electron-hole-photon quasiparticle) theory will be developed in view of the recent optical experiments with the semiconductor films on a metallic background.

Investigation of a Raman-type model for a three-level atom interacting with cavity electromagnetic fields in the presence of dispersing and absorbing surroundings.

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.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 V.I. Yukalov
			E.V. Bukina A.Yu. Cherny A.V. Chizhov V.M. Dubovik A.A. Shanenko

Collaboration
Country or international organization	City	Institute or Laboratory
Armenia	Yerevan	YerPhI
Azerbaijan	Baku	IP ANAS
Belarus	Minsk	IMAP NASB
Belgium	Antwerp	UIA
Brazil	Brasilia, DF	UnB
	San Paulo, SP	USP
Bulgaria	Sofia	ISSP BAS
		SU
Canada	Montreal	CU
Czech Republic	Rez	NPI ASCR
France	Marseille	CPT
	Nice	UNSA
Germany	Bremen	Univ.
	Brunswick	TU
	Dortmund	Univ.
	Dresden	TUD
		IFW
	Duisburg	Univ.
	Hamburg	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	IONCh 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 UD RAS
Serbia and Montenegro	Belgrade	INS "VINCA"
Slovak Republic	Bratislava	IP SAS
	Kosice	IEP SAS
Slovenia	Ljubljana	UL
Switzerland	Villigen	PSI
Taiwan	Taipei	IP ASN
The United Kingdom	Cambridge	Univ.
Ukraine	Kharkov	KFTI NASU
The USA	New York, NY	CUNY
	Rochester, NY	UR
Uzbekistan	Tashkent	Assoc."P.-S." PTI
Vietnam	Hanoi	IP NCNST

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