Orbit and spin evolution of the synchronous binary stars on the main sequence phase

The sets of the synchronous equations are derived from the sets of non-synchronous equations The analytical solutions are given by solving the set of differential equations. The results of the evolutionary tendency of the orbit-spin are that the semi-major axis shrinks gradually with time: the orbital eccentricity dereacses gradually with time until the orbital circularization; the orbital period shortens gradually with time and the rotational angular velocity of primary component speed up with time gradually before the orbit-rotation achieved the circularization The theoretical results are applied to evolution of the orbit and spin of synchronous binary stars Algol A, B on the main sequence phase The circularization time and life time (age) and the evolutional numerical solutions of orbit and spin when circularization time are estimeted for Algol A, B. The results are discussed and concluded.Comment: 8 pages, accepted for publication in RA

The excitation spectrum of rotating strings with masses at the ends

We compute the spectrum of excitations of the rotating Nambu-Goto string with masses at the ends. We find interesting quasi-massless modes in the limit of slow rotation and comment on the nontrivial relation between world-sheet and target space energy.Comment: 13 pages, 1 figure, v2: Typos corrected, v3: fina

Divergences in QFT on the Noncommutative Minkowski Space with Grosse-Wulkenhaar potential

We study quantum field theory on the two-dimensional Noncommutative Minkoswki space with a Grosse-Wulkenhaar potential. We explicitly construct the retarded propagator and show that it is not a tempered distribution. This leads to problems when trying to define planar products of such distributions, as they appear in the Yang-Feldman series. At and above the self-dual point, these can no longer be defined, not even at different points. This shows that we do not deal with an ordinary ultraviolet divergence.Comment: 8 pages, Contribution to the proceedings of the Corfu Summer Institute on Elementary Particles and Physics 201

Locally covariant chiral fermions and anomalies

We define chiral fermions in the presence of non-trivial gravitational and gauge background fields in the framework of locally covariant field theory. This allows to straightforwardly compute the chiral anomalies on non-compact Lorentzian space-times, without recourse to a weak field approximation.Comment: 19 page