161 research outputs found
Twist deformation of doubly enlarged Newton-Hooke Hopf algebra
We provide fifteen twist-deformed doubly enlarged Newton-Hooke quantum
space-times. In approaching infinity limit the twisted doubly enlarged
Galilei spaces are obtained as well.Comment: 11 pages, no figures. arXiv admin note: substantial text overlap with
arXiv:1007.465
Braided algebras and the kappa-deformed oscillators
Recently there were presented several proposals how to formulate the binary
relations describing kappa-deformed oscillator algebras. In this paper we shall
consider multilinear products of kappa-deformed oscillators consistent with the
axioms of braided algebras. In general case the braided triple products are
quasi-associative and satisfy the hexagon condition depending on the
coassociator . We shall consider only the products
of kappa-oscillators consistent with co-associative braided algebra, with Phi
=1. We shall consider three explicite examples of binary kappa-deformed
oscillator algebra relations and describe briefly their multilinear
coassociative extensions satisfying the postulates of braided algebras. The
third example, describing kappa-deformed oscillators in group manifold approach
to kappa-deformed fourmomenta, is a new result.Comment: v2, 13 pages; Proc. of 2-nd Corfu School on Quantum Gravity and
Quantum Geometry, September 2009, Corfu; Gen. Rel. Grav. (2011),special
Proceedings issue; version in pres
Dy8SnS13.61O0.39 from single-crystal data
Crystals of the title dysprosium tin sulfide oxide, Dy8SnS13S1−xOx [x = 0.39 (4)], were obtained unintentionally from the Dy–Sn–S system. A statistical mixture of sulfur and oxygen was assumed for one position in the structure. S and O atoms surround each of the eight symmetrically non-equivalent dysprosium atoms. The Sn atoms are located in tetrahedral surroundings of sulfur atoms. Trigonal prisms and tetrahedra are connected to each other by their edges. All atoms are situated in mirror planes
Star Product and Invariant Integration for Lie type Noncommutative Spacetimes
We present a star product for noncommutative spaces of Lie type, including
the so called ``canonical'' case by introducing a central generator, which is
compatible with translations and admits a simple, manageable definition of an
invariant integral. A quasi-cyclicity property for the latter is shown to hold,
which reduces to exact cyclicity when the adjoint representation of the
underlying Lie algebra is traceless. Several explicit examples illuminate the
formalism, dealing with kappa-Minkowski spacetime and the Heisenberg algebra
(``canonical'' noncommutative 2-plane).Comment: 21 page
Twist deformations of Newton-Hooke Hopf algebras
We construct five new quantum Newton-Hooke Hopf algebras with the use of
Abelian twist procedure. Further we demonstrate that the corresponding deformed
space-times with quantum space and classical time are periodic or expanding in
time.Comment: 11 pages, no figures, the paper accepted for publication in
Mod.Phys.Lett.
Scalar field theory on -Minkowski space-time and Doubly Special Relativity
In this paper we recall the construction of scalar field action on
-Minkowski space-time and investigate its properties. In particular we
show how the co-product of -Poincar\'e algebra of symmetries arises
from the analysis of the symmetries of the action, expressed in terms of
Fourier transformed fields. We also derive the action on commuting space-time,
equivalent to the original one. Adding the self-interaction term we
investigate the modified conservation laws. We show that the local interactions
on -Minkowski space-time give rise to 6 inequivalent ways in which
energy and momentum can be conserved at four-point vertex. We discuss the
relevance of these results for Doubly Special Relativity.Comment: 17 pages; some editing done, final version to be published in Int. J.
Mod. Phys.
Asteroseismology of massive stars with the TESS mission: the runaway Beta Cep pulsator PHL 346 = HN Aqr
We report an analysis of the first known Beta Cep pulsator observed by the
TESS mission, the runaway star PHL 346 = HN Aqr. The star, previously known as
a singly-periodic pulsator, has at least 34 oscillation modes excited, 12 of
those in the g-mode domain and 22 p modes. Analysis of archival data implies
that the amplitude and frequency of the dominant mode and the stellar radial
velocity were variable over time. A binary nature would be inconsistent with
the inferred ejection velocity from the Galactic disc of 420 km/s, which is too
large to be survivable by a runaway binary system. A kinematic analysis of the
star results in an age constraint (23 +- 1 Myr) that can be imposed on
asteroseismic modelling and that can be used to remove degeneracies in the
modelling process. Our attempts to match the excitation of the observed
frequency spectrum resulted in pulsation models that were too young. Hence,
asteroseismic studies of runaway pulsators can become vital not only in tracing
the evolutionary history of such objects, but to understand the interior
structure of massive stars in general. TESS is now opening up these stars for
detailed asteroseismic investigation.Comment: accepted for ApJ
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