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MaGiV-1 is a candidate triple ellipsoidal star system in Vulpecula at coordinates RA(J2000) 19:52:19.13 DEC(J2000) +23:29:59.7 classified as ELL+ELL, number 2344411 in AAVSO VSX database. Through photometry from the TESS Space Telescope, two significant periods describing the orbital times of the components were identified using the Fourier transform. The analysis led to determining P(A-BC) = 4.269d the orbital period of A-BC pair, the primary component with the secondary component described by another pair, and P(BC) = 0.610d the orbital period of B-C pair, the inner ellipsoidal system. However, it cannot be completely ruled out that the shorter period can be explained by pulsations of one of the two components (e.g. by the GDOR type).

The red giant MaCoMP_V1 in Cepheus at coordinates RA (J2000) 22:49:05:49 and DEC (J2000) +57:52:41:6 is a semiregular variable star classified as SRS, number 2225960 in the AAVSO VSX database. Using the Fourier transform, the period P = 24.751(0.062)d was evaluated and, with the support of the ASAS-SN and ZTF surveys, a well-defined light curve was made. The analysis resulted in the fundamental physical parameters of MaCoMP_V1, such as the mass M = 4.97(0.38)M(Sun) and radius R = 40.5(6.7)R(Sun), with consistent values suggesting the characteristics of a semiregular red giant. In addition, the effective temperature Teff = 4500(135)K from the Gaia catalog and the stellar evolution based on the Schoenberg-Chandraskehar limit was estimated.

We present a simple method to obtain the solution of a few orbital problems: the Kepler problem, the modified Kepler problem by the addition of an inverse square potential and linear force., Comment: To appear in Revista Braileira de Ensino de F\'isica

We characterise the origin and evolution of a mesoscale wave pattern in Jupiter's North Equatorial Belt (NEB), detected for the first time at 5 $\mu$m using a 2016-17 campaign of `lucky imaging' from the VISIR instrument on the Very Large Telescope and the NIRI instrument on the Gemini observatory, coupled with M-band imaging from Juno's JIRAM instrument during the first seven Juno orbits. The wave is compact, with a $1.1-1.4^\circ$ longitude wavelength (wavelength 1,300-1,600 km, wavenumber 260-330) that is stable over time, with wave crests aligned largely north-south between $14$ and $17^\circ$N (planetographic). The waves were initially identified in small ($10^\circ$ longitude) packets immediately west of cyclones in the NEB at $16^\circ$N, but extended to span wider longitude ranges over time. The waves exhibit a 7-10 K brightness temperature amplitude on top of a $\sim210$-K background at 5 $\mu$m. The thermal structure of the NEB allows for both inertio-gravity waves and gravity waves. Despite detection at 5 $\mu$m, this does not necessarily imply a deep location for the waves, and an upper tropospheric aerosol layer near 400-800 mbar could feature a gravity wave pattern modulating the visible-light reflectivity and attenuating the 5-$\mu$m radiance originating from deeper levels. Strong rifting activity appears to obliterate the pattern, which can change on timescales of weeks. The NEB underwent a new expansion and contraction episode in 2016-17 with associated cyclone-anticyclone formation, which could explain why the mesoscale wave pattern was more vivid in 2017 than ever before., Comment: 17 pages, 9 figures, published in Astronomical Journal

Stochastic partial differential equations can be used to model second order thermodynamical phase transitions, as well as a number of critical out-of-equilibrium phenomena. In (2+1) dimensions, many of these systems are conjectured (and some are indeed proved) to be described by conformal field theories. We advance, in the framework of the Martin-Siggia-Rose field theoretical formalism of stochastic dynamics, a general solution of the translation Ward identities, which yields a putative conformal energy-momentum tensor. Even though the computation of energy-momentum correlators is obstructed, in principle, by dimensional reduction issues, these are bypassed by the addition of replicated fields to the original (2+1)-dimensional model. The method is illustrated with an application to the Kardar-Parisi-Zhang (KPZ) model of surface growth. The consistency of the approach is checked by means of a straightforward perturbative analysis of the KPZ ultraviolet region, leading, as expected, to its $c=1$ conformal fixed point., Comment: Title, abstract and part of the text have been rewritten. To be published in Physical Review E.

In this paper, we present an exact procedure to deal with Dirac strings or worldsheets in gauge theories containing ensembles of monopoles interacting with charged fields. For SU(2) Yang-Mills theory, initially we construct the appropriate change of variables of the charged fields (including charged ghosts and auxiliary fields) so that the only change in the integrand of the partition function, in the Maximal Abelian gauge, is the addition of given closed Dirac worldsheets. Next, we derive our main result, namely, we show that it is always possible to choose them in such a manner that the total (open plus closed) Dirac worldsheets explicitly decouple from the charged sector, leaving only the effect of their associated gauge invariant borders (where the monopoles are placed), without missing any information about the center vortex sector. This procedure serves as a simplifying basis to deal with ensembles of monopoles and center vortices in the framework of the Cho-Faddeev-Niemi gauge field decomposition, by writing the partition function only in terms of the physical part of the defects to be integrated., Comment: 27 pages, accepted for publication in Jour. Phys. A, improved discussion

We show how to obtain the first multipole contributions to the electromagnetic radiation emited by an arbitrary localized source directly from the Jefimenko equation for the magnetic field and the Panofsky-Phillips equation for the electric field. This procedure avoids the unnecessary calculation of the electromagnetic potentials., Comment: 12 pages, no figures

We give a simple argument to show that the $n$th wavefunction for the one-dimensional Schr\"odinger equation has $n-1$ nodes. We also show that if $n_1 < n_2$, then between two consecutive zeros of $\psi_{n_1}$, there is a zero of $\psi_{n_2}$., Comment: 5 pages

We present the special theory of relativity taking the Doppler effect as the starting point, and derive several of its main effects, such as time dilation, length contraction, addition of velocities, and the mass-energy relation, and assuming energy and momentum conservation, we discuss how to introduce the 4-momentum in a natural way. We also use the Doppler effect to explain the "twin paradox", and its version on a cylinder. As a by-product we discuss Bell's spaceship paradox, and the Lorentz transformation for arbitrary velocities in one dimension., Comment: 20 pages, 1 figure

We investigate the problem of backscattering off a time-dependent impurity in a one-dimensional electron gas. By combining the Schwinger-Keldysh method with an adiabatic approximation in order to deal with the corresponding out of equilibrium Dirac equation, we compute the total energy density (TED) of the system. We show how the free fermion TED is distorted by the backscattering amplitude and the geometry of the impurity., Comment: 5 pages, 2 figures, RevTex4. Appendix and some text added. Results and conclusions did not change. Version accepted for publication in Phys. Rev. B

We study a two-dimensional bosonic field theory with a random defect line. The theory has a background field coupled to the field variables at the defect line, which renders the model non-integrable. However, as the background field is random, and the disorder is implemented through the replica trick, the model becomes integrable, allowing us to use the form-factor method to compute the exact correlation functions of the quenched model., Comment: 13 pages, 1 figure

A large class of quantum and statistical field theoretical models, encompassing relevant condensed matter and non-abelian gauge systems, are defined in terms of complex actions. As the ordinary Monte-Carlo methods are useless in dealing with these models, alternative computational strategies have been proposed along the years. The Langevin technique, in particular, is known to be frequently plagued with difficulties such as strong numerical instabilities or subtle ergodic behavior. Regarding the chirally decomposed version of the sine-Gordon model as a prototypical case for the failure of the Langevin approach, we devise a truncation prescription in the stochastic differential equations which yields numerical stability and is assumed not to spoil the Berezinskii-Kosterlitz-Thouless transition. This conjecture is supported by a finite size scaling analysis, whereby a massive phase ending at a line of critical points is clearly observed for the truncated stochastic model., Comment: 6 pages, 4 figures

We study the noncommutative extensions of certain integrable field theories, namely the sine- and sinh-Gordon (sG and shG) models, and the U(N) principal chiral model (pcm). We argue that the Moyal deformations of the sG and shG models are not integrable, by looking at tree-level amplitudes where there is particle production. By considering the noncommutative generalization of the zero-curvature method, it is possible to define integrable versions of the noncommutative sG and shG models, which introduce extra constraints. The noncommutative pcm is shown to be integrable and we discuss the existence of non-trivial non-local conserved charges, and the associated noncommutative zero-curvature condition., Comment: 9 pages, 1 figure, talk given at the Workshop on Integrable Theories, Solitons and Dualities, IFT Sao Paulo, July 2002

We study the noncommutative generalization of (euclidean) integrable models in two-dimensions, specifically the sine- and sinh-Gordon and the U(N) principal chiral models. By looking at tree-level amplitudes for the sinh-Gordon model we show that its na\"\i ve noncommutative generalization is {\em not} integrable. On the other hand, the addition of extra constraints, obtained through the generalization of the zero-curvature method, renders the model integrable. We construct explicit non-local non-trivial conserved charges for the U(N) principal chiral model using the Brezin-Itzykson-Zinn-Justin-Zuber method., Comment: 18 pages, 1 figure; v2: references added

We discuss the new integrable boundary conditions for the O(N) nonlinear $\sigma$ model and related solutions of the boundary Yang-Baxter equation, which were presented in our previous paper hep-th/0108039., Comment: 9 pages. To appear in the proceedings of the NATO Advanced Research Workshop on "Statistical Field Theories", Como, Italy, 18-23 June 2001. v2: typos corrected

We find new integrable boundary conditions, depending on a free parameter $g$, for the O(N) nonlinear $\sigma$ model, which are of nondiagonal type, that is, particles can change their ``flavor'' through scattering off the boundary. These boundary conditions are derived from a microscopic boundary lagrangian, which is used to establish their integrability, and exhibit integrable flows between diagonal boundary conditions investigated earlier. We solve the boundary Yang-Baxter equation, connect these solutions to the boundary conditions, and examine the corresponding integrable flows., Comment: 21 pages, 2 figures. v2: References added, typos corrected, few comments added

By making use of current-algebra Ward identities we study renormalization of general anisotropic current-current interactions in 2D. We obtain a set of algebraic conditions that ensure the renormalizability of the theory to all orders. In a certain minimal prescription we compute the beta function to all orders., Comment: 7 pages, 6 figures. v2: References added and typos corrected; v3: cancellation of finite parts more accurately stated

We study the scattering theory for the Gross-Neveu model on the half-line. We find the reflection matrices for the elementary fermions, and by fusion we compute the ones for the two-particle bound-states, showing that they satisfy non-trivial bootstrap consistency conditions. We also compute more general reflection matrices for the Gross-Neveu model and the nonlinear sigma model, and argue that they correspond to the integrable boundary conditions we identified in our previous paper hep-th/9809178., Comment: 13 pages, latex file, final version to appear in PLB

We study the quantum integrability of the O(N) nonlinear $\sigma$ (nls) model and the O(N) Gross-Neveu (GN) model on the half-line. We show that the \nls model is integrable with Neumann, Dirichlet and a mixed boundary condition, and that the GN model is integrable if $\psi_+^a\x=\pm\psi_-^a\x$. We also comment on the boundary condition found by Corrigan and Sheng for the O(3) nls model., Comment: 11 pages, Latex file, minor changes, one reference added

We study the integrable and supersymmetric massive $\hat\phi_{(1,3)}$ deformation of the tricritical Ising model in the presence of a boundary. We use constraints from supersymmetry in order to compute the exact boundary $S$-matrices, which turn out to depend explicitly on the topological charge of the supersymmetry algebra. We also solve the general boundary Yang-Baxter equation and show that in appropriate limits the general reflection matrices go over the supersymmetry preserving solutions. Finally, we briefly discuss the possible connection between our reflection matrices and boundary perturbations within the framework of perturbed boundary conformal field theory., Comment: 21 pages, 3 figures, Latex file

The physical properties induced by a quenched surface magnetic field in the Ising model are investigated by means of boundary quantum field theory in replica space. Exact boundary scattering amplitudes are proposed and used to study the averaged quenched correlation functions., Comment: 37 pages (Latex), including 16 figures, one reference added

We briefly review the general structure of integrable particle theories in 1+1 dimensions having N=1 supersymmetry. Examples are specific perturbed superconformal field theories (of Yang-Lee type) and the N=1 supersymmetric sine-Gordon theory. We comment on the modifications that are required when the N=1 supersymmetry algebra contains non-trivial topological charges., Comment: 7 pages, Revtex, 2 figures, talk given at the International Seminar on Supersymmetry and Quantum Field Theory, dedicated to the memory of D.V.Volkov, Kharkov (Ukraine), January 5-7, 1997

We study two-dimensional integrable $N=1$ supersymmetric theories (without topological charges) in the presence of a boundary. We find a universal ratio between the reflection amplitudes for particles that are related by supersymmetry and we propose exact reflection matrices for the supersymmetric extensions of the multi-component Yang-Lee models and for the breather multiplets of the supersymmetric sine-Gordon theory. We point out the connection between our reflection matrices and the classical boundary actions for the supersymmetric sine-Gordon theory as constructed by Inami, Odake and Zhang \cite{IOZ}., Comment: 29 pages, Revtex, 4 figures

We briefly review results on two-dimensional supersymmetric quantum field theories that exhibit factorizable particle scattering. Our particular focus is on a series of $N\!=\!1$ supersymmetric theories, for which exact $S$-matrices have been obtained. A Thermodynamic Bethe Ansatz (TBA) analysis for these theories has confirmed the validity of the proposed $S$-matrices and has pointed at an interesting `folding' relation with a series of $N\!=\!2$ supersymmetric theories., Comment: 3 pages, wstwocl.sty, epsfig.sty, talk delivered at the HEP95 Conference of the EPS, Brussels, July/August 1995

We study a series of $N\!=\!1$ supersymmetric integrable particle theories in $d=1+1$ dimensions. These theories are represented as integrable perturbations of specific $N\!=\!1$ superconformal field theories. Starting from the conjectured $S$-matrices for these theories, we develop the Thermodynamic Bethe Ansatz (TBA), where we use that the 2-particle $S$-matrices satisfy a free fermion condition. Our analysis proves a conjecture by E.~Melzer, who proposed that these $N\!=\!1$ supersymmetric TBA systems are ``folded'' versions of $N\!=\!2$ supersymmetric TBA systems that were first studied by P.~Fendley and K.~Intriligator., Comment: 24 pages, Revtex