Remarks on non-gaussian fluctuations of the inflaton and constancy of \zeta outside the horizon

We point out that the non-gaussianity arising from cubic self interactions of the inflaton field is proportional to \xi N_e where \xi ~ V"' and N_e is the number of e-foldings from horizon exit till the end of inflation. For scales of interest N_e = 60, and for models of inflation such as new inflation, natural inflation and running mass inflation \xi is large compared to the slow roll parameter \epsilon ~ V'^{2}. Therefore the contribution from self interactions should not be outrightly ignored while retaining other terms in the non-gaussianity parameter f_{NL}. But the N_e dependent term seems to imply the growth of non-gaussianities outside the horizon. Therefore we briefly discuss the issue of the constancy of correlations of the curvature perturbation \zeta outside the horizon. We then calculate the 3-point function of the inflaton fluctuations using the canonical formalism and further obtain the 3-point function of \zeta_k. We find that the N_e dependent contribution to f_{NL} from self interactions of the inflaton field is cancelled by contributions from other terms associated with non-linearities in cosmological perturbation theory.Comment: 16 pages, Minor changes, matches the published version. v3: Minor typo correcte

Two-fluid temperature-dependent relativistic waves in magnetized streaming pair plasmas

A relativistic two-fluid temperature-dependent approach for a streaming magnetized pair plasma is considered. Such a scenario corresponds to secondary plasmas created at the polar caps of pulsar magnetospheres. In the model the generalized vorticity rather than the magnetic field is frozen into the fluid. For parallel propagation four transverse modes are found. Two are electromagnetic plasma modes which at high temperature become light waves. The remaining two are Alfveacutenic modes split into a fast and slow mode. The slow mode is cyclotron two-stream unstable at large wavelengths and is always subluminous. We find that the instability cannot be suppressed by temperature effects in the limit of large (finite) magnetic field. The fast Alfveacuten mode can be superluminous only at large wavelengths, however it is always subluminous at high temperatures. In this incompressible approximation only the ordinary mode is present for perpendicular propagation. For oblique propagation the dispersion relation is studied for finite and large strong magnetic fields and the results are qualitatively described.Institute for Fusion Studie

The Optical Hygrometer and its Working

In this paper, the description of the construction of the optical hygrometer is given. It works on the principle of a balance in the form of a rod supported by two loose screws and at right angles to it there is another rod having two pans on its ends, rigidly Attached with it. One pan contains the substance having high power of absorption and desorption of moisture and the other pan balancing weights. the rotation of the rod which is proportional to the change in humidity is measured by the lamp and scale arrangement. The theory, its sensitiveness and working are discussed in detail. A few observations recorded with this instrument are compared with those of the other kinds of hygrometers

Multidimensional Binary Vector Assignment problem: standard, structural and above guarantee parameterizations

In this article we focus on the parameterized complexity of the Multidimensional Binary Vector Assignment problem (called \BVA). An input of this problem is defined by $m$ disjoint sets $V^1, V^2, \dots, V^m$, each composed of $n$ binary vectors of size $p$. An output is a set of $n$ disjoint $m$-tuples of vectors, where each $m$-tuple is obtained by picking one vector from each set $V^i$. To each $m$-tuple we associate a $p$ dimensional vector by applying the bit-wise AND operation on the $m$ vectors of the tuple. The objective is to minimize the total number of zeros in these $n$ vectors. mBVA can be seen as a variant of multidimensional matching where hyperedges are implicitly locally encoded via labels attached to vertices, but was originally introduced in the context of integrated circuit manufacturing. We provide for this problem FPT algorithms and negative results ($ETH$-based results, $W$[2]-hardness and a kernel lower bound) according to several parameters: the standard parameter $k$ i.e. the total number of zeros), as well as two parameters above some guaranteed values.Comment: 16 pages, 6 figure

Tunable temperature induced magnetization jump in a GdVO3 single crystal

We report a novel feature of the temperature induced magnetization jump observed along the a-axis of the GdVO3 single crystal at temperature TM = 0.8 K. Below TM, the compound shows no coercivity and remanent magnetization indicating a homogenous antiferromagnetic structure. However, we will demonstrate that the magnetic state below TM is indeed history dependent and it shows up in different jumps in the magnetization only when warming the sample through TM. Such a magnetic memory effect is highly unusual and suggesting different domain arrangements in the supposedly homogenous antiferromagnetic phase of the compound.Comment: 17 pages, 8 Figure