Türkiye Cumhuriyeti ve halifelik

Taha Toros Arşivi, Dosya Adı: Son Halife Abdülmecit Efendi. Not: Gazetenin "Olaylar ve Görüşler" köşesinde yayımlanmıştır

Symplectic Partially Hyperbolic Automorphisms of 6-Torus

We study topological properties of automorphisms of a 6-dimensional torus generated by integer matrices symplectic with respect to either the standard symplectic structure in six-dimensional linear space or a nonstandard symplectic structure given by an integer skew-symmetric non-degenerate matrix. Such a symplectic matrix generates a partially hyperbolic automorphism of the torus, if it has eigenvalues both outside and on the unit circle. We study the case (2,2,2), numbers are dimensions of stable, center and unstable subspaces of the matrix. We study transitive and decomposable cases possible here and present a classification in both cases.Comment: 15 pages, 0 figures. arXiv admin note: text overlap with arXiv:2001.1072

Uncertainty Relations in Deformation Quantization

Robertson and Hadamard-Robertson theorems on non-negative definite hermitian forms are generalized to an arbitrary ordered field. These results are then applied to the case of formal power series fields, and the Heisenberg-Robertson, Robertson-Schr\"odinger and trace uncertainty relations in deformation quantization are found. Some conditions under which the uncertainty relations are minimized are also given.Comment: 28+1 pages, harvmac file, no figures, typos correcte

Variables in the Southern Polar Region Evryscope 2016 Dataset

The regions around the celestial poles offer the ability to find and characterize long-term variables from ground-based observatories. We used multi-year Evryscope data to search for high-amplitude (~5% or greater) variable objects among 160,000 bright stars (Mv < 14.5) near the South Celestial Pole. We developed a machine learning based spectral classifier to identify eclipse and transit candidates with M-dwarf or K-dwarf host stars - and potential low-mass secondary stars or gas giant planets. The large amplitude transit signals from low-mass companions of smaller dwarf host stars lessens the photometric precision and systematics removal requirements necessary for detection, and increases the discoveries from long-term observations with modest light curve precision. The Evryscope is a robotic telescope array that observes the Southern sky continuously at 2-minute cadence, searching for stellar variability, transients, transits around exotic stars and other observationally challenging astrophysical variables. In this study, covering all stars 9 < Mv < 14.5, in declinations -75 to -90 deg, we recover 346 known variables and discover 303 new variables, including 168 eclipsing binaries. We characterize the discoveries and provide the amplitudes, periods, and variability type. A 1.7 Jupiter radius planet candidate with a late K-dwarf primary was found and the transit signal was verified with the PROMPT telescope network. Further followup revealed this object to be a likely grazing eclipsing binary system with nearly identical primary and secondary K5 stars. Radial velocity measurements from the Goodman Spectrograph on the 4.1 meter SOAR telescope of the likely-lowest-mass targets reveal that six of the eclipsing binary discoveries are low-mass (.06 - .37 solar mass) secondaries with K-dwarf primaries, strong candidates for precision mass-radius measurements.Comment: 32 pages, 17 figures, accepted to PAS

Sequence Effects on DNA Entropic Elasticity

DNA stretching experiments are usually interpreted using the worm-like chain model; the persistence length A appearing in the model is then interpreted as the elastic stiffness of the double helix. In fact the persistence length obtained by this method is a combination of bend stiffness and intrinsic bend effects reflecting sequence information, just as at zero stretching force. This observation resolves the discrepancy between the value of A measured in these experiments and the larger ``dynamic persistence length'' measured by other means. On the other hand, the twist persistence length deduced from torsionally-constrained stretching experiments suffers no such correction. Our calculation is very simple and analytic; it applies to DNA and other polymers with weak intrinsic disorder.Comment: LaTeX; postscript available at http://dept.physics.upenn.edu/~nelson/index.shtm

A theoretical study on the mechanisms of formation of primal carbon clusters and nanoparticles in space

We present a computational study of assembling carbon clusters and nanophases in space from carbon aggregations. Geometry optimizations and Density-functional-based tight-binding (SCC-DFTB) dynamics methods are employed to predict carbon clusters, their time evolution, and their stability. The initial density of the aggregates is found to be of primary importance for the structural properties of the clusters. Aggregates with sufficiently low initial density yield clusters with approximately equal prevalence of sp and sp2 hybridized states and almost missing sp3 ones. The increase in the initial density results in sp2-dominant molecules that resemble the carbon skeleton of polycyclic aromatic hydrocarbons (PAHs). Larger initial aggregations with tetrahedral interatomic orientation result in sp2-dominant multi-dimensional polymers. Such materials are highly porous and resemble axially bound nanotubes. Some resultant clusters resemble fullerene building blocks. Spheroid nanoparticles resembling improper fullerenes are predicted by metadynamics, aimed at inter-fragment coupling reactions. One such structure has the lowest binding energy per atom among the studied molecules. All zero-dimensional forms, obtained by the simulations, conform to the experimentally detected types of molecules in space. The theoretical IR spectrum of the clusters closely resembles that of fullerene C70 and therefore such imperfect structures may be mistaken for known fullerenes in experimental infrared (IR) telescope studies

Purity-bounded uncertainty relations in multidimensional space -- generalized purity

Uncertainty relations for mixed quantum states (precisely, purity-bounded position-momentum relations, developed by Bastiaans and then by Man'ko and Dodonov) are studied in general multi-dimensional case. An expression for family of mixed states at the lower bound of uncertainty relation is obtained. It is shown, that in case of entropy-bounded uncertainty relations, lower-bound state is thermal, and a transition from one-dimensional problem to multi-dimensional one is trivial. Results of numerical calculation of the relation lower bound for different types of generalized purity are presented. Analytical expressions for general purity-bounded relations for highly mixed states are obtained.Comment: 12 pages, 2 figures. draft version, to appear in J. Phys. A Partially based on a poster "Multidimensional uncertainty relations for states with given generalized purity" presented on X Intl. Conf. on Quantum Optics'2004 (Minsk, Belarus, May 30 -- June 3, 2004) More actual report is to be presented on ICSSUR-2005, Besan\c{c}on, France and on EQEC'05, Munich. V. 5: amended article after referees' remark

Representations and Properties of Generalized ArA_r Statistics, Coherent States and Robertson Uncertainty Relations

The generalization of $A_r$ statistics, including bosonic and fermionic sectors, is performed by means of the so-called Jacobson generators. The corresponding Fock spaces are constructed. The Bargmann representations are also considered. For the bosonic $A_r$ statistics, two inequivalent Bargmann realizations are developed. The first (resp. second) realization induces, in a natural way, coherent states recognized as Gazeau-Klauder (resp. Klauder-Perelomov) ones. In the fermionic case, the Bargamnn realization leads to the Klauder-Perelomov coherent states. For each considered realization, the inner product of two analytic functions is defined in respect to a measure explicitly computed. The Jacobson generators are realized as differential operators. It is shown that the obtained coherent states minimize the Robertson-Schr\"odinger uncertainty relation.Comment: 16 pages, published in JP