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Topic: Skyrmions

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	Theory Group : Quantum Hall effect, Spin-excitons and Skyrmions
		In this limit, the shape of the spin distribution within the core of Skyrmion is not affected, neither by the Zeeman splitting nor by the Coulomb energy, and is the same as that of an ideal Skyrmion.
		In the paper [6] another approach to the problem of Skyrmions is offered by using transformation induced by application of a non-reduced to the same Landau level states rotation matrix and considering the full Schrodinger equation obtained by means of ordinary perturbation theory applied to the gradients of this matrix.
		The propagation of spin waves in the presence of a single Skyrmion in the framework of the proposed approach was considered.
	www.magniel.com /group/r_qhe.html (3127 words)

	Theoretical Physics Research Group
		The skyrmions are not point particles, so it is not immediately obvious how to construct a Hamiltonian, or a Schrodinger equation for them.
		The `skyrmions' are twists in the magnetisation of the system, and their influence on the - linear - spin waves will be investigated.
		Then a variational approach to the quantum case will be considered, where approximate momentum eigenstates of the skyrmions will be constructed and their energy as a function of wave vector investigated.
	www.th.ph.bham.ac.uk /ug_courses/projects/quantsky.htm (270 words)

	Research Interests (Site not responding. Last check: 2007-10-10)
		Skyrmions are three-dimensional and the number of Skyrmions is conventionally called B.
		Skyrmions are interesting both from a mathematical point of view and as a way of gaining a better understanding of nuclear physics.
		The first problem is to understand the structure of Skyrmions, in particular the occurrence of folds and cusps which is predicted by the theory of singularities of differentiable maps.
	www.kent.ac.uk /IMS/personal/sk68/research.html (637 words)

	BlueSci Online - Scheming with Skyrmions
		Named for their inventor Tony Skyrme, skyrmions are a mathematical description of what physicists believe particles to be.
		Skyrmions are a mathematical description of this idea; they are used to describe how groups of such ‘particles’ would arrange themselves.
		Solving the skyrmion equations for this predicts a tetrahedral arrangement, which is indeed what is observed.
	www.bluesci.org /content/view/362/265 (447 words)

	Institute for Solid State Physics
		Skyrmions (excitations with a topologically nontrivial configuration) are relevant in various physical systems.
		We examined the possibility of a Skyrmion in isotropic Bose-Einstein condensates with (pseudo-) spin 1/2.
		We found that there is no stable Skyrmions in the free space in either 2 or 3 dimensions.
	www.issp.u-tokyo.ac.jp /cgi-bin/edetail.cgi?c=society_table::344 (112 words)

	Creation of Skyrmions in a Spinor Bose-Einstein Condensate (Site not responding. Last check: 2007-10-10)
		A Skyrmion is a collective state of a BEC with internal structure.
		A Skyrmion has a vortex flow but no vortex core, i.e., the density does not vanish at the vortex line (if you like to know more about vortex states click here).
		Skyrmions in condensates composed of alkali atoms are related to corresponding defects in the A phase of
	qis.ucalgary.ca /~pmarzlin/paper/pra62-13602 (106 words)

	Spontaneous skyrmion ground states in magnetic metals : Abstract : Nature
		Skyrmionic states have been found under non-equilibrium conditions, or when stabilized by external fields or the proliferation of topological defects.
		Here, we show theoretically that this assumption is wrong and that skyrmion textures may form spontaneously in condensed-matter systems with chiral interactions without the assistance of external fields or the proliferation of defects.
		Our model implies that spontaneous skyrmion lattice ground states may exist generally in a large number of materials, notably at surfaces and in thin films, as well as in bulk compounds, where a lack of space inversion symmetry leads to chiral interactions.
	www.nature.com /nature/journal/v442/n7104/abs/nature05056.html (361 words)

	W. Apel, A. Bychkov: Hopf term and the effective Lagrangian for the Skyrmions in a two-dimensional electron gas at ... (Site not responding. Last check: 2007-10-10)
		Skyrmions appeared originally in Condensed Matter physics as solutions of the O(3) non-linear sigma model in two dimensions for non-zero values of the topological charge [7].
		It is determined by the ``Hopf term'' [20,9] which is topological in nature and, obviously, cannot be found by a simple generalization of the classical model but rather needs to be derived from the microscopic Hamiltonian of the electrons.
		In (20), a total derivative in spatial coordinates was omitted which in all cases we checked was non-singular and thus did not contribute to (20).
	www.magniel.com /hmtj/papers/ab97/ab.html (2190 words)

	Nuggets 2000-Large Skyrmions in an A10.13Ga0.87As Quantum Well
		Such a spin texture is termed a skyrmion.
		The size s of a skyrmion is gauged by the number of flipped spins which comprise one skyrmion excitation.
		Interestingly, although consistent with the skyrmion size observed, theoretical calculations significantly overestimate the excitation gaps over the entire range of measured data (the dashed curve in Fig.
	www.princeton.edu /~pccm/past/Nuggets2000-MRSEC-Skyrmions.htm (432 words)

	Judah Eisenberg's latter papers
		Kälbermann, The nucleon in the nucleus as given by skyrmions, lecture given at the International Conference on Nuclear Physics at the Turn of Millennium, Wilderness, South Africa, 10-16 March 1996, published in Structure of Vacuum and Elementary Matter, ed.
		Kälbermann, The nucleon-nucleon force from skyrmions, talk delivered at the Seventeenth Course of the International School on Nuclear Physics: Quarks in Hadrons and Nuclei, September, 1995, Erice, Sicily, Italy, published in Progress in Particle and Nuclear Physics 36 (1996) 321.
		Within the skyrmion approach for the nucleon-nucleon force, difficulties have been experienced in obtaining an isoscalar attractive spin-orbit potential, in parallel to the problems of finding attraction in the isoscalar central potential.
	julian.tau.ac.il /~bqs/jmepubs (2266 words)

	Session W3 - Skyrmions and Spin Dynamics in Quantum Hall Ferromagnets.
		The data are consistent with the nuclear Schottky heat capacity of Ga and As atoms in the quantum wells except for a remarkably sharp peak in heat capacity vs temperature, suggestive of a phase transition in the electronic system.
		We argue that the enhanced diffusion may be a result of the liquid-to-solid transition of the Skyrmions at very low temperatures.
		Finite densities of skyrmions may be introduced into the groundstate of the quantum Hall system by adjusting the filling fraction away from unity.
	flux.aps.org /meetings/YR98/BAPSMAR98/abs/S4330.html (625 words)

	Skyrmions 3D (Site not responding. Last check: 2007-10-10)
		When submitted to a space or iso-space rotation (greater spin or iso-spin), the skyrmion gets distorted.
		This deformation is greater for larger spin or iso-spin rotation energy.
		We propose an oblate shaped solution in the reference frame of the skyrmion.
	feynman.phy.ulaval.ca /marleau/skyrmion3D_1.htm (132 words)

	UCL/CERMIN - Heat Capacity of 2DEGs
		Even though the physics of the 2DES that causes the peak in C vs T is not yet understood, we showed that it is due to a sudden nuclear spin diffusion from the GaAs QWs into the AlGaAs barriers.
		We conclude that heat capacity is a sensitive probe of the presence or the absence of Skyrmions in 2DESs.
		One important theoretical prediction is that a transition from Skyrmions to single spin-flip excitations is expected above a critical ratio gc between Zeeman and Coulomb energies.
	www.cermin.ucl.ac.be /HeatCap.html (475 words)

	[No title] (Site not responding. Last check: 2007-10-10)
		I present results of numerical work on the classical dynamics of Skyrmions stabilized by a singlet vector field (the omega).
		Depending on the impact parameter and the relative grooming, the skyrmions either simply scatter, or form an N=2 state which may or may not decay.
		Recently we were able to simulate through the annihilation of a Skyrmion and an anti-Skyrmion to the point when the bulk of the energy is carried by outgoing pion and omega radiation.
	www.phy.duke.edu /TNT/coll/abstracts/halasz.html (113 words)

	Citebase - On the interactions of Skyrmions with domain walls
		The model possesses Skyrmion solutions as well as stable domain walls that connect different vacua of the theory.
		We show also that, when the mass term is of a special type, the model possesses bound states of Skyrmions and of the domain wall.
		For more conventional choices of the mass term of the model in the model the attraction between the Skyrmions and the wall leads to the capture of the Skyrmions which are then turned into topological waves which spread out on the wall.
	citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:hep-th/9907197 (268 words)

	Session G17 - QHE V: Skyrmions, Spin Effects, and Magnetoresistance.
		We report the study of the temperature dependence of this peak, as well as its dependence on the total magnetic field (with the sample tilted to maintain the \nu=1 condition).
		The low temperature spectra appear to be in the ``frozen'' limit consistent with the localization of skyrmions as T\rightarrow0.
		A remarkable correlation between the resistance relaxation and the hysteretic behavior suggests that the ferromagnetic \nu = 2/5 FQHE state exhibits a slow reconfiguration of its multi-domain structure.
	flux.aps.org /meetings/YR00/MAR00/abs/S2160.html (1692 words)

	Paul Sutcliffe
		Skyrmions are candidates for a solitonic description of nuclei, where the number of solitons is identified with baryon number.
		However, it is possible to use an approximation in which Skyrmions can be constructed from rational maps between Riemann spheres and this has proved useful in understanding the structure of Skyrmions.
		Monopoles often resemble Skyrmions and although this is not yet well understood, monopoles can also be described by rational maps, so there are some hints at a connection.
	www.kent.ac.uk /ims/personal/pms4/index.htm (726 words)

	CLASSICAL TOPOLOGY AND QUANTUM STATES (Site not responding. Last check: 2007-10-10)
		It is also an introduction to topological solitons with special emphasis on Skyrmions.
		As regards the first aspect, several issues of current interest are dealt with at a reasonably elementary level.
		Readership: Mathematical physicists and physicists interested in topological concepts, soliton and skyrmion theory and foundations of quantum theory.
	www.worldscibooks.com /physics/1180.html (250 words)

	string intercommuntation
		We study the intercommuting of semilocal strings and Skyrmions, for a wide range of internal parameters, velocities and intersection angles by numerically evolving the equations of motion.
		We find that the collisions of strings and strings, strings and Skyrmions, and Skyrmions and Skyrmions, all lead to intercommuting for any set of parameters.
		Even the collisions of unstable Skyrmions and strings leads to intercommuting, demonstrating that the phenomenon of intercommuting is very robust, extending to dissimilar field configurations that are not stationary solutions.
	wwwrel.ph.utexas.edu /Members/vishnu/new (216 words)

	Citebase - Dynamics of Baby Skyrmions
		Authors: Piette, B. Schroers, B. Zakrzewski, W. Baby Skyrmions are topological solitons in a (2+1)-dimensional field theory which resembles the Skyrme model in important respects.
		We apply some of the techniques and approximations commonly used in discussions of the Skyrme model to the dynamics of baby Skyrmions and directly test them against numerical simulations.
		Specifically we study the effect of spin on the shape of a single baby Skyrmion, the dependence of the forces between two baby Skyrmions on the baby Skyrmions' relative orientation and the forces between two baby Skyrmions when one of them is spinning.
	citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:hep-ph/9410256 (163 words)

	Barrett Lab - Publications & Talks (Site not responding. Last check: 2007-10-10)
		Novel spin textures called skyrmions are predicted(S. Sondhi, A. Karlhede, S. Kivelson, and E. Rezayi, Phys.
		At "high" temperatures, the spectra provide evidence for delocalized skyrmions.
		The frozen limit spectra appear to rule out a 2D lattice of conventional skyrmions.
	opnmr.physics.yale.edu /Publications/Publications.html (564 words)

	e-Prints Soton - Creating vortex rings and three-dimensional Skyrmions in Bose-Einstein condensates
		This population can be removed, or it can be made to flow around the torus (i.e.
		If this flow has unit topological winding number, the entire structure formed by the two condensates is an example of a three-dimensional skyrmion texture.
		In the future it will become an official university service, but until then should be considered volatile.
	eprints.soton.ac.uk /29347 (158 words)

	Skyrmion - Wikipedia, the free encyclopedia
		In theoretical physics, a skyrmion, conceived by Tony Skyrme, is a homotopically non-trivial classical solution of a nonlinear sigma model with a non-trivial target manifold topology i.e.
		This results in superselection sectors in the quantized model.
		This page was last modified 15:03, 22 November 2006.
	en.wikipedia.org /wiki/Skyrmion (154 words)

	Freie Universität Berlin - EUCLID graduate lectures - Departmental News - Department of Mathematics - University of ...
		Moreover, following Skyrme's work in the 1960s, solitons have been recognised as being important entities in quantum field theory, especially as sources of ideas and insight.
		Examples are skyrmions, magnetic flux tubes or magnetic monopoles; and the language of solitons has penetrated gauge theory, string theory and its generalisations.
		Recent work has concentrated on the behaviour of classical solitons, or their quantum counterparts, in field theories defined on restricted domains and has led to a number of interesting, sometimes unexpected, new insights.
	maths.york.ac.uk /modules/news/article.php?storyid=24 (271 words)

	IngentaConnect Baby Skyrme models for a class of potentials (Site not responding. Last check: 2007-10-10)
		= -1 [/iopmath] the configurations corresponding to the baby skyrmions lying `on top of each other' are the minima of the energy.
		= -1)0 [/iopmath] the lowest field configurations correspond to separated baby skyrmions.
		We determine the energy distributions for skyrmions of degrees between one and eight and discuss their geometrical shapes and binding energies.
	www.ingentaconnect.com /content/iop/non/2000/00000013/00000005/art00322 (278 words)

	Robert Tycko, Ph.D. : Faculty : NIDDK Laboratories (Site not responding. Last check: 2007-10-10)
		At Bell Labs, Dr. Tycko continued his work on NMR methodology and theory, and additionally carried out NMR studies of novel materials such as fullerenes and superconducting alkali fullerides.
		Using optically pumped NMR, he carried out the first experimental studies of skyrmions in semiconductor quantum wells.
		In 1994, Dr. Tycko moved to the Laboratory of Chemical Physics, a physical chemistry and biophysics research department in NIDDK.
	intramural.niddk.nih.gov /research/faculty.asp?People_ID=1573 (1230 words)

	The baby Skyrme models and their multi-skyrmions
		The simplest holomorphic baby Skyrme model has no known stable minimal-energy solution for n greater than one.
		The other baby Skyrme model studied in the literature possesses non-radially-symmetric minimal-energy configurations that look like `skyrmion lattices' formed by skyrmions with n = 2.
		We discuss a baby Skyrme model with a potential that has two vacua.
	stacks.iop.org /0951-7715/12/1489 (330 words)

	brains in natural phenomena ? (Site not responding. Last check: 2007-10-10)
		discovery that the behaviour of the statistical particles skyrmions
		Sure, since thought and mind are the epiphenomena of peer-peer
		Phew, I would not call that radical, it reminds me of a conversation I
	www.groupsrv.com /science/about181158.html (865 words)

	ACQAO
		Numerical study of the stability of skyrmions in Bose-Einstein condensates.
		Energetically stable particle-like Skyrmions in a trapped Bose-Einstein condensate.
		ACQAO work published without ACQAO affiliation prior to finalisation of the ARC funding agreement.
	www.acqao.org /publications.htm (1939 words)

	Herbert A. Fertig, Univ of Kentucky , Skyrmions and Skryme Crystals in Quantum Hall Ferromagnets
		Herbert A. Fertig, Univ of Kentucky, Skyrmions and Skryme Crystals in Quantum Hall Ferromagnets
		Skyrmions and Skryme Crystals in Quantum Hall Ferromagnets
		Audio for this talk requires sound hardware, and RealPlayer or RealAudio by RealNetworks.
	online.itp.ucsb.edu /online/qhall_c98/fertig (53 words)

	HEP Institutes in UNITED KINGDOM
		QCD sum rules, gauge theories, skyrmions, quantum mechanics, superstrings.
		SPS-WA69, LEP-OPAL (built muon chambers and involved with analysis) HERA-H1 (built chambers and data-collection systems), design of trigger and preparation for analysis.
		High-energy quark-gluon phenomenology, superstring theory and phenomenology, gauge theories on the lattice, hadronic spectroscopy from QCD, quark matter, skyrmions, topological field theories, hypernuclear physics.
	greybook.cern.ch /institutes/countries/GB.html (473 words)

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