Infinite Quantum Group Symmetry of Fields in Massive 2D Quantum Field Theory

Starting from a given S-matrix of an integrable quantum field theory in $1+1$ dimensions, and knowledge of its on-shell quantum group symmetries, we describe how to extend the symmetry to the space of fields. This is accomplished by introducing an adjoint action of the symmetry generators on fields, and specifying the form factors of descendents. The braiding relations of quantum field multiplets is shown to be given by the universal \CR-matrix. We develop in some detail the case of infinite dimensional Yangian symmetry. We show that the quantum double of the Yangian is a Hopf algebra deformation of a level zero Kac-Moody algebra that preserves its finite dimensional Lie subalgebra. The fields form infinite dimensional Verma-module representations; in particular the energy-momentum tensor and isotopic current are in the same multiplet.Comment: 29 page

The Scattering Theory of Oscillator Defects in an Optical Fiber

We examine harmonic oscillator defects coupled to a photon field in the environs of an optical fiber. Using techniques borrowed or extended from the theory of two dimensional quantum fields with boundaries and defects, we are able to compute exactly a number of interesting quantities. We calculate the scattering S-matrices (i.e. the reflection and transmission amplitudes) of the photons off a single defect. We determine using techniques derived from thermodynamic Bethe ansatz (TBA) the thermodynamic potentials of the interacting photon-defect system. And we compute several correlators of physical interest. We find the photon occupancy at finite temperature, the spontaneous emission spectrum from the decay of an excited state, and the correlation functions of the defect degrees of freedom. In an extension of the single defect theory, we find the photonic band structure that arises from a periodic array of harmonic oscillators. In another extension, we examine a continuous array of defects and exactly derive its dispersion relation. With some differences, the spectrum is similar to that found for EM wave propagation in covalent crystals. We then add to this continuum theory isolated defects, so as to obtain a more realistic model of defects embedded in a frequency dependent dielectric medium. We do this both with a single isolated defect and with an array of isolated defects, and so compute how the S-matrices and the band structure change in a dynamic medium.Comment: 32 pages, TeX with harvmac macros, three postscript figure

Variabilité de la morphologie et des structures sédimentaires du lit d’un confluent de cours d’eau discordant en période d’étiage

Les confluents de cours d'eau discordants sont des milieux fluviaux particulièrement turbulents dont la morphologie se caractérise par un banc d'accumulation à l'embouchure du tributaire et présente une importante variabilité temporelle. Cette étude souligne le rôle actif de l'étiage dans la dynamique des interrelations entre les conditions hydrauliques, la morphologie et la sédimentologie au confluent des rivières Bayonne et Berthier, comté de Lanaudière, Québec. Les résultats d'un suivi quasi-hebdomadaire durant deux étés successifs à ce confluent de cours d'eau sablonneux et d'inégales profondeurs montrent que des variations morphologiques se produisent sur l'ensemble du lit malgré des hauteurs d'eau se situant autour de 1/20 à 1/5 du niveau plein-bord durant la majorité du temps. La nature de chacun des deux bassins-versants confère à chaque cours d'eau des conditions d'étiage qui font varier temporellement leur importance relative. Ces fluctuations entraînent une migration latérale du plan de mélange entre les deux masses d'eau. Elles touchent aussi la morphologie du banc d'accumulation à l'embouchure du tributaire qui avance et recule à l'intérieur du confluent. Les faciès sédimentaires prélevés illustrent les différents modes de construction du banc d'accumulation. Nous présentons un modèle en trois phases qui souligne le rôle de ce banc d'accumulation comme figure dominante de la dynamique du confluent. Selon la morphologie du banc (en régression, en construction ou en pleine expansion dans le chenal), le développement du plan de mélange est plus ou moins retardé et la dynamique spécifique de l'écoulement détermine alors en partie les épisodes de dépôt ou d'érosion dans les autres zones du confluent.Discordant river channel confluences are highly turbulent environments. Their morphology, which is caracterized by a tributary mouth bar, shows great temporal variability. In this study, we examine the relationships between hydraulics, bed morphology and sediment transport at a discordant river channel confluence at low flow stage. During two consecutive summers, we surveyed almost weekly the confluence of the Bayonne and the Berthier rivers, Lanaudière, Québec. Significant morphological changes occurred on almost the entire channel bed even if flow stages were most of the time between 1/20 and 1/5 bankfull level. Sedimentary facies illustrate particularly well the tributary mouth bar progradation due to each watershed characteristics. Low flow conditions for each river varied considerably and incongruently. These variations resulted in changes in the location of the mixing layer between the joining flows and the extent of progradation of the tributary mouth bar into the main channel. We propose a three-phase model showing that the position of the tributary mouth bar, and whether it is receding from, prograding or fully extending into the confluence, is closely related to the development and lateral expansion of the mixing layer between the two streams. Zones of deposition and erosion in the confluence are then associated with the position and dynamics of the mixing layer.Die Zusammenflùsse ungleichsohiiger Wasserlàufe sind besonders turbulente Flussmilieus, deren Morphologie sich durch eine Aufschùttungsbank an der Mùndung des Zuflusses auszeichnet und eine bedeutende zeitliche Variabilitàt zeigt. Dièse Studie betont die aktive RoIIe des Niedrigwassers in der Dynamik der Beziehungen zwischen hydraulischen Bedingungen, der Morphologie und der Sédimentologie am Zusammenfluss des Bayonne- und Berthier-Flusses, Lanaudière, Québec. Zwei aufeinander folgende Sommer lang hat man fast wôchentlich an diesem Zusammenfluss sandhaltiger Wasserlàufe ungleicher Tiefe Messungen durchgefùhrt. Die Ergebnisse zeigen, dass morphologische Variationen sich im ganzen Flussbett ergeben, trotz der Wasserhôhen, die meist bei 1/20 bis 1/5 des ufervollen Standes Iiegen. Die Natur jedes der beiden Flussbecken verleiht jedem Wasserlauf Niedrigwasserbedingungen, die ihre relative Bedeutung zeitweilig ândern. Dièse Fluktuationen fùhren zu einer lateralen Verschiebung der Mischungsschicht zwischen den beiden Wassermassen. Sie beeinflussen auch die Morphologie der Aufschùttungsbank an der Mùndung des Zuflusses, der sich im Innem des Zusammenflusses vorwàrts und rùckwàrts bewegt. Die entnommenen Sediment-Fazies illustrieren die verschiedenen Arten des Baus der Aufschùttungsbank. Wir stellen ein Modell in drei Phasen vor, das die dominierende RoIIe dieser Aufschùttungsbank in der Dynamik des Zusammenflusses hervorhebt. Entsprechend der Morphologie der Bank (zurùckweichend, im Aufbau oder voll expandierend im Kanal) ist die Entwicklung der Mischungsschicht mehr oder weniger verzôgert und die spezifische Dynamik des Abflusses bestimmt dann zum Teil die Episoden der Ablagerung oder Erosion in den anderen Zonen des Zusammenflusses

The Maxwell-Bloch Theory in Quantum Optics and the Kondo Model

In this letter, the problem of radiation in a fiber geometry interacting with a two level atom is mapped onto the anisotropic Kondo model. Thermodynamical and dynamical properties are then computed exploiting the integrability of this latter system. We compute some correlation functions, decay rates and Lamb shifts. In turn this leads to an analysis of the classical limit of the anisotropic Kondo model.Comment: 4 pages, 1 figure. In Latex. Uses Revte

Super Spin-Charge Separation for class A, C, and D disorder

We prove versions of super spin-charge separation for all three of the symmetry groups SU(N), Sp(2N), and SO(N) of disordered Dirac fermions in 2+1 dimensions, which involve the supercurrent-algebras gl (1|1)_{N}, osp(2|2)_{-2N}, and osp(2|2)_N respectively. For certain restricted classes of disordered potentials, the latter supercurrent algebra based conformal field theories can arise as non-trivial low energy fixed points. For all cases with such a fixed point, we compute the density of states exponents as a function of N.Comment: 10 pages; section 3 adde

Form-factors computation of Friedel oscillations in Luttinger liquids

We show how to analytically determine for $g\leq 1/2$ the "Friedel oscillations" of charge density by a single impurity in a 1D Luttinger liquid of spinless electrons.Comment: Revtex, epsf, 4pgs, 2fig

Finite temperature spectral function of Mott insulators and CDW States

We calculate the low temperature spectral function of one-dimensional incommensurate charge density wave (CDW) states and half-filled Mott insulators (MI). At $T=0$ there are two dispersing features associated with the spin and charge degrees of freedom respectively. We show that already at very low temperatures (compared to the gap) one of these features gets severely damped. We comment on implications of this result for photoemission experiments.Comment: 4 pages, 2 figures, published versio

Finite temperature correlations in the one-dimensional quantum Ising model

We extend the form-factors approach to the quantum Ising model at finite temperature. The two point function of the energy is obtained in closed form, while the two point function of the spin is written as a Fredholm determinant. Using the approach of \Korbook, we obtain, starting directly from the continuum formulation, a set of six differential equations satisfied by this two point function. Four of these equations involve only spacetime derivatives, of which three are equivalent to the equations obtained earlier in \mccoy,\perk. In addition, we obtain two new equations involving a temperature derivative. Some of these results are generalized to the Ising model on the half line with a magnetic field at the origin.Comment: 37 pages, uses harvmac, minor changes in the last two paragraphs, updating some conjecture

Complex Role of Secondary Electron Emissions in Dust Grain Charging in Space Environments: Measurements on Apollo 11 and 17 Dust Grains

Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions. Knowledge of the dust grain charges and equilibrium potentials is important for understanding of a variety of physical and dynamical processes in the interstellar medium (ISM), and heliospheric, interplanetary, planetary, and lunar environments. The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. It has been well recognized that the charging properties of individual micron/submicron size dust grains are expected to be substantially different from the corresponding values for bulk materials and theoretical models. In this paper we present experimental results on charging of individual dust grains selected from Apollo 11 and Apollo 17 dust samples by exposing them to mono-energetic electron beams in the 10- 400 eV energy range. The charging rates of positively and negatively charged particles of approximately 0.2 to 13 microns diameters are discussed in terms of the secondary electron emission (SEE) process, which is found to be a complex charging process at electron energies as low as 10-25 eV, with strong particle size dependence. The measurements indicate substantial differences between dust charging properties of individual small size dust grains and of bulk materials

Boundary flows in minimal models

We discuss in this paper the behaviour of minimal models of conformal theory perturbed by the operator $\Phi_{13}$ at the boundary. Using the RSOS restriction of the sine-Gordon model, adapted to the boundary problem, a series of boundary flows between different set of conformally invariant boundary conditions are described. Generalizing the "staircase" phenomenon discovered by Al. Zamolodchikov, we find that an analytic continuation of the boundary sinh-Gordon model provides a flow interpolation not only between all minimal models in the bulk, but also between their possible conformal boundary conditions. In the particular case where the bulk sinh-Gordon coupling is turned to zero, we obtain a boundary roaming trajectory in the $c=1$ theory that interpolates between all the possible spin $S$ Kondo models.Comment: 13pgs, harvmac, 2 fig