Growth and reproduction studies on gilthead seabream (Sparus aurata) in Beymelek Lagoon, Turkey

In the present study, age, growth, length-weight relationship and reproduction were investigated in gilthead seabream (Sparus aurata L., 1758) collected from Beymelek Lagoon (Antalya, Turkey) between February 2006 and July 2007. The age, total length and weight of samples ranged from 0+ to 4 years, 10.6 to 35.5cm, and 18 to 928g, respectively. Growth was described by the standard form of the von Bertalanffy growth equation and the estimated parameters were L∞ = 44.6cm, k = 0.394yr^-1 and t0 = -1.331yr. Length-weight relationship was determined as W=0.0174TL^2.9769 (R^2=0.965), and weight increased with size isometrically (b = 2.9769) for all fish. Sex inversion occurred mainly at 26 cm in total length and females reached sexual maturity at 28.5 cm. The spawning period was from December to February, while the gamete emission peaked in December

Precision spectroscopy with two correlated atoms

We discuss techniques that allow for long coherence times in laser spectroscopy experiments with two trapped ions. We show that for this purpose not only entangled ions prepared in decoherence-free subspaces can be used but also a pair of ions that are not entangled but subject to the same kind of phase noise. We apply this technique to a measurement of the electric quadrupole moment of the 3d D5/2 state of 40Ca+ and to a measurement of the linewidth of an ultrastable laser exciting a pair of 40Ca+ ions

Quantum control, quantum information processing, and quantum-limited metrology with trapped ions

We briefly discuss recent experiments on quantum information processing using trapped ions at NIST. A central theme of this work has been to increase our capabilities in terms of quantum computing protocols, but we have also applied the same concepts to improved metrology, particularly in the area of frequency standards and atomic clocks. Such work may eventually shed light on more fundamental issues, such as the quantum measurement problem.Comment: Proceedings of the International Conference on Laser Spectroscopy (ICOLS), 10 pages, 5 figure

Diffusion Resonances in Action Space for an Atom Optics Kicked Rotor with Decoherence

We numerically investigate momentum diffusion rates for the pulse kicked rotor across the quantum to classical transition as the dynamics are made more macroscopic by increasing the total system action. For initial and late time rates we observe an enhanced diffusion peak which shifts and scales with changing kick strength, and we also observe distinctive peaks around quantum resonances. Our investigations take place in the context of a system of ultracold atoms which is coupled to its environment via spontaneous emission decoherence, and the effects should be realisable in ongoing experiments.Comment: 4 Pages, RevTeX 4, 5 Figures. Updated Figures, Minor Changes to text, Corrected Reference

'Designer atoms' for quantum metrology

Entanglement is recognized as a key resource for quantum computation and quantum cryptography. For quantum metrology, the use of entangled states has been discussed and demonstrated as a means of improving the signal-to-noise ratio. In addition, entangled states have been used in experiments for efficient quantum state detection and for the measurement of scattering lengths. In quantum information processing, manipulation of individual quantum bits allows for the tailored design of specific states that are insensitive to the detrimental influences of an environment. Such 'decoherence-free subspaces' protect quantum information and yield significantly enhanced coherence times. Here we use a decoherence-free subspace with specifically designed entangled states to demonstrate precision spectroscopy of a pair of trapped Ca+ ions; we obtain the electric quadrupole moment, which is of use for frequency standard applications. We find that entangled states are not only useful for enhancing the signal-to-noise ratio in frequency measurements - a suitably designed pair of atoms also allows clock measurements in the presence of strong technical noise. Our technique makes explicit use of non-locality as an entanglement property and provides an approach for 'designed' quantum metrology

Nanofabrication by magnetic focusing of supersonic beams

We present a new method for nanoscale atom lithography. We propose the use of a supersonic atomic beam, which provides an extremely high-brightness and cold source of fast atoms. The atoms are to be focused onto a substrate using a thin magnetic film, into which apertures with widths on the order of 100 nm have been etched. Focused spot sizes near or below 10 nm, with focal lengths on the order of 10 microns, are predicted. This scheme is applicable both to precision patterning of surfaces with metastable atomic beams and to direct deposition of material.Comment: 4 pages, 3 figure

Squeezing of Atoms in a Pulsed Optical Lattice

We study the process of squeezing of an ensemble of cold atoms in a pulsed optical lattice. The problem is treated both classically and quantum-mechanically under various thermal conditions. We show that a dramatic compression of the atomic density near the minima of the optical potential can be achieved with a proper pulsing of the lattice. Several strategies leading to the enhanced atomic squeezing are suggested, compared and optimized.Comment: Latex, 9 pages, 10 figures, submitted to PR

Maturity of dispersed organic matter in bituminous formations of the Ionian Zone (Epirus region, NW Greece)

Σκοπός της εργασίας είναι η μελέτη της ωριμότητας της οργανικής ύλης ορισμένων σχηματισμών της Ιόνιας Ζώνης, όπως οι αργιλικοί σχίστες του ανώτερου και κατώτερου Ιουρασικού, ο Ανώτερος Πυριτικός Ορίζοντας της Βίγλας του Κρητιδικού και οι βιτουμενιούχοι Ψαμμίτες του Τριτογενούς, χρησιμοποιώντας τεχνικές Οργανικής Πετρολογίας. Τα δείγματα συλλέχθηκαν από επιφανειακές εμφανίσεις στην Ήπειρο. Αρχικά χρησιμοποιήθηκαν οξέα (HCl-HF) για να απομακρυνθεί το μεγαλύτερο μέρος των ανθρακικών και πυριτικών ορυκτών. Το συμπύκνωμα που προέκυψε, αναμίχθηκε με ZnCl2 συγκεκριμένης πυκνότητας, ώστε να επέλθει βαρυτικός διαχωρισμός του πετρώματος σε ελαφρύ και βαρύ κλάσμα. Το οργανικό μέρος οξειδώθηκε χημικά για να υπολογιστεί η περιεκτικότητa σε Ολικό Οργανικό Άνθρακα. Στιλπνές τομές παρασκευάστηκαν με ανάμιξη του οργανικού υλικού με διάλυμα εποξικής ρητίνης και μελετήθηκαν στο ανθρακοπετρογραφικό μικροσκόπιο. Έμφαση δόθηκε στην ανακλαστικότητα βιτρινίτη και τον προσδιορισμό των maceral. Εφαρμόστηκε επίσης περιθλασιμετρία ακτίνων Χ. Διαπιστώθηκε ότι οι αργιλικοί σχίστες του κατώτερου Ιουρασικού περιέχουν οργανική ύλη (TOC: 4,74%), ο βαθμός ωριμότητας (Rr 0,68%) της οποίας βρίσκεται εντός του παραθύρου πετρελαίου. Ωστόσο περαιτέρω έρευνα εστιασμένη στους Κατω-Ιουρασικούς αργιλικούς σχίστες με Posidonia, με τη βοήθεια της Οργανικής Πετρολογίας και της πυρόλυσης Rock-Eval είναι αναγκαία, προκειμένου να διαπιστωθεί η ποιότητά τους ως μητρικά πετρώματα υδρογονανθράκων.The main objective of this paper is to study by means of Organic Petrology techniques, the maturity of the dispersed organic matter from certain sedimentary formations of the Ionian Zone, such as the Bituminous Shale, the Upper Siliceous Vigla Formation and the Bituminous Sandstone. The samples were collected from outcropping sites located in the region of Epirus. Initially they were treated with acids (HCl-HF) to remove most of the carbonate and silicate minerals. Then a ZnCl2 solution was used to concentrate the organic-rich fraction. Total Organic Carbon (TOC) content was determined applying dichromate oxidation. Polished blocks were prepared from the concentrated organic matter mounted in epoxy resin and examined under the coal-petrography microscope. Emphasis was given to maceral identification and vitrinite reflectance (R) measurements, which provide information regarding the quality and the maturity of the organic matter respectively, with implications for the petroleum generation potential regardless the level of alteration. The TOC and Rr values (4.74% and 0.68%, respectively) confirm to the oil potential of the Lower Jurassic Posidonia Shale. Nevertheless, it is suggested that detailed and higher resolution sampling focusing on the Lower Posidonia Shale, as well as organic petrography analyses coupled with Rock-Eval pyrolysis should be carried out in order to accurately determine its quality as petroleum source rocks