Interpolating Action for Strings and Membranes - a Study of Symmetries in the Constrained Hamiltonian Approach

A master action for bosonic strings and membranes, interpolating between the Nambu--Goto and Polyakov formalisms, is discussed. The role of the gauge symmetries vis-\`{a}-vis reparametrization symmetries of the various actions is analyzed by a constrained Hamiltonian approach. This analysis reveals the difference between strings and higher branes, which is essentially tied to a degree of freedom count. The cosmological term for membranes follows naturally in this scheme. The conncetion of our aproach with the Arnowitt--Deser--Misner representation in general relativity is illuminated.Comment: LaTex, 23 pages; discussion on ADM representation included and new references adde

Dual Projection and Selfduality in Three Dimensions

We discuss the notion of duality and selfduality in the context of the dual projection operation that creates an internal space of potentials. Contrary to the prevailing algebraic or group theoretical methods, this technique is applicable to both even and odd dimensions. The role of parity in the kernel of the Gauss law to determine the dimensional dependence is clarified. We derive the appropriate invariant actions, discuss the symmetry groups and their proper generators. In particular, the novel concept of duality symmetry and selfduality in Maxwell theory in (2+1) dimensions is analysed in details. The corresponding action is a 3D version of the familiar duality symmetric electromagnetic theory in 4D. Finally, the duality symmetric actions in the different dimensions constructed here manifest both the SO(2) and $Z_2$ symmetries, contrary to conventional results.Comment: 20 pages, late

Characteristics of polar coronal hole jets

High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be $\approx$ 27 km s$^{-1}$. The average outward speed of the first jet is $\approx 171$ km s$^{-1}$, well below the escape speed, hence if simple ballistic motion is considered, the plasma will not escape the Sun. The second jet was observed in the south polar coronal hole with three XRT filters, namely, C$_{-}$poly, Al$_{-}$poly, and Al$_{-}$mesh filters. We observed that the second jet drifted at all altitudes along the jet with the same drift speed of $\simeq$ 7 km s$^{-1}$. The enhancement in the light curves of low-temperature EIS lines in the later phase of the jet lifetime and the shape of the jet's stack plots suggests that the jet material is falls back, and most likely cools down. To support this conclusion, the observed drifts were interpreted within a scenario where reconnection progressively shifts along a magnetic structure, leading to the sequential appearance of jets of about the same size and physical characteristics. On this basis, we also propose a simple qualitative model that mimics the observations.Comment: Accepted Astronomy and Astrophysic

Propagating waves in polar coronal holes as seen by SUMER and EIS

To study the dynamics of coronal holes and the role of waves in the acceleration of the solar wind, spectral observations were performed over polar coronal hole regions with the SUMER spectrometer on SoHO and the EIS spectrometer on Hinode. Using these observations, we aim to detect the presence of propagating waves in the corona and to study their properties. The observations analysed here consist of SUMER spectra of the Ne VIII 770 A line (T = 0.6 MK) and EIS slot images in the Fe XII 195 A line (T = 1.3 MK). Using the wavelet technique, we study line radiance oscillations at different heights from the limb in the polar coronal hole regions. We detect the presence of long period oscillations with periods of 10 to 30 min in polar coronal holes. The oscillations have an amplitude of a few percent in radiance and are not detectable in line-of-sight velocity. From the time distance maps we find evidence for propagating velocities from 75 km/s (Ne VIII) to 125 km/s (Fe XII). These velocities are subsonic and roughly in the same ratio as the respective sound speeds. We interpret the observed propagating oscillations in terms of slow magneto-acoustic waves. These waves can be important for the acceleration of the fast solar wind.Comment: 5 pages, 7 figures Accepted as Astronomy and Astrophysics Lette

Batalin-Tyutin Quantization of the Self-Dual Massive Theory in Three Dimensions

We quantize the self-dual massive theory by using the Batalin-Tyutin Hamiltonian method, which systematically embeds second class constraint system into first class one in the extended phase space by introducing the new fields. Through this analysis we obtain simultaneously the St\"uckelberg scalar term related to the explicit gauge-breaking effect and the new type of Wess-Zumino action related to the Chern-Simons term.Comment: 17 pages, SOGANG-HEP 191/9

Spectroscopic Observations of Propagating Disturbances in a Polar Coronal Hole: Evidence of Slow Magneto-acoustic Waves

We focus on detecting and studying quasi-periodic propagating features that have been interpreted both in terms of slow magneto-acoustic waves and of high speed upflows. We analyze long duration spectroscopic observations of the on-disk part of the south polar coronal hole taken on 1997 February 25 by the SUMER spectrometer aboard SOHO. We calibrated the velocity with respect to the off-limb region and obtain time--distance maps in intensity, Doppler velocity and line width. We also perform a cross correlation analysis on different time series curves at different latitudes. We study average spectral line profiles at the roots of propagating disturbances and along the propagating ridges, and perform a red-blue asymmetry analysis. We find the clear presence of propagating disturbances in intensity and Doppler velocity with a projected propagation speed of about $60\pm 4.8$ km s$^{-1}$ and a periodicity of $\approx$14.5 min. To our knowledge, this is the first simultaneous detection of propagating disturbances in intensity as well as in Doppler velocity in a coronal hole. During the propagation, an intensity enhancement is associated with a blue-shifted Doppler velocity. These disturbances are clearly seen in intensity also at higher latitudes (i.e. closer to the limb), while disturbances in Doppler velocity becomes faint there. The spectral line profiles averaged along the propagating ridges are found to be symmetric, to be well fitted by a single Gaussian, and have no noticeable red-blue asymmetry. Based on our analysis, we interpret these disturbances in terms of propagating slow magneto-acoustic waves.Comment: accepted for publication by A&

Fluctuating local moments, itinerant electrons and the magnetocaloric effect: the compositional hypersensitivity of FeRh

We describe an ab-initio Disordered Local Moment Theory for materials with quenched static compositional disorder traversing first order magnetic phase transitions. It accounts quantitatively for metamagnetic changes and the magnetocaloric effect. For perfect stoichiometric B2-ordered FeRh, we calculate the transition temperature of the ferromagnetic-antiferromagnetic transition to be $T_t =$ 495K and a maximum isothermal entropy change in 2 Tesla of $|\Delta S|= 21.1$ J~K$^{-1}$~kg$^{-1}$. A large (40\%) component of $|\Delta S|$ is electronic. The transition results from a fine balance of competing electronic effects which is disturbed by small compositional changes - e.g. swapping just 2\% Fe of `defects' onto the Rh sublattice makes $T_t$ drop by 290K. This hypersensitivity explains the narrow compositional range of the transition and impurity doping effects.Comment: 11 pages, 4 figure

Komar energy and Smarr formula for noncommutative Schwarzschild black hole

We calculate the Komar energy $E$ for a noncommutative Schwarzschild black hole. A deformation from the conventional identity $E=2ST_H$ is found in the next to leading order computation in the noncommutative parameter $\theta$ (i.e. $\mathcal{O}(\sqrt{\theta}e^{-M^2/\theta})$) which is also consistent with the fact that the area law now breaks down. This deformation yields a nonvanishing Komar energy at the extremal point $T_{H}=0$ of these black holes. We then work out the Smarr formula, clearly elaborating the differences from the standard result $M=2ST_H$, where the mass ($M$) of the black hole is identified with the asymptotic limit of the Komar energy. Similar conclusions are also shown to hold for a deSitter--Schwarzschild geometry.Comment: 5 pages Late

Enhancing Synchrony in Chaotic Oscillators by Dynamic Relaying

In a chain of mutually coupled oscillators, the coupling threshold for synchronization between the outermost identical oscillators decreases when a type of impurity (in terms of parameter mismatch) is introduced in the inner oscillator(s). The outer oscillators interact indirectly via dynamic relaying, mediated by the inner oscillator(s). We confirm this enhancing of critical coupling in the chaotic regimes of R\"ossler system in absence of coupling delay and in Mackey-Glass system with delay coupling. The enhancing effect is experimentally verified in electronic circuit of R\"ossler oscillators.Comment: 4 pages, 9 figure

Logarithmic corrections to black hole and black ring entropy in tunneling approach

The tunneling approach beyond semiclassical approximation has been used to calculate the corrected Hawking temperature and entropy for various black holes and FRW universe model. We examine their derivations, and prove that the quantity $H$ in the corrected temperature is the explicit function of the only free parameter $\mathcal{A}$ (which is an auxiliary parameter defined by $\mathcal{A}=\hbar S_{BH}$). Our analysis improves previous calculations, and indicates that the leading order logarithmic correction to entropy is a natural result of the corrected temperature and the first law of thermodynamics. Additionally, we apply the tunneling approach beyond semiclassical approximation to neutral black rings. Based on the analysis, we show that the entropy of neutral black rings also has a logarithmic leading order correction.Comment: 13 pages, rewritte