Dynamical Casimir Effect in two-atom cavity QED

We study analytically and numerically the dynamical Casimir effect in a cavity containing two stationary 2-level atoms that interact with the resonance field mode via the Tavis-Cummings Hamiltonian. We determine the modulation frequencies for which the field and atomic excitations are generated and study the corresponding dynamical behaviors in the absence of damping. It is shown that the two-atom setup allows for monitoring of photon generation without interrupting the growth, and different entangled states can be generated during the process.Comment: 4+ pages, 2 figure

Approximate analytical results on the cavity dynamical Casimir effect in the presence of a two-level atom

We study analytically the photon generation from vacuum due to the Dynamical Casimir effect in a cavity with a two-level atom, prepared initially in an arbitrary pure state. Performing small unitary transformations we obtain closed analytical expressions for the probability amplitudes and other important quantities in the resonant/dispersive regimes.Comment: 5 pages, 2 figure

DURANTA REPENS LINN. (VERBENACEAE): A COMPREHENSIVE REVIEW OF PHARMACOGNOSTIC, ETHNOMEDICINAL, PHARMACOLOGICAL, AND PHYTOCHEMICAL ASPECTS

Objective: This review is intended to investigate the published report regarding phytochemical, ethnomedicinal, and pharmacological activities and put forth the therapeutic potential of Duranta repens Linn. (D. repens). It belongs to the family Verbenaceae, one of the therapeutically important plants, broadly distributed all throughout the world. It is commonly referred as golden dewdrop, angel whisper, pigeon berry, or skyflower.Methods: I utilized logical writing and scientific literature regarding D. repens by referring search engine such as Springerlink, ScienceDirect, SciFinder, PubMed, Scopus, Google Scholar, and BioMed Central as well as relevant books, websites, scientific publications, and dissertations as a source of information that provided an up-to-date review. My work on morphology and extraction of various phytochemicals and their evaluation has helped to provide an insightful account of D. repens.Results: Phytochemical profiling of these species revealed the presence of some imperative phytochemicals such as alkaloids, flavonoids, glycosides, phenolics, saponins, steroids, tannins and terpenoids as the basis of its valuable therapeutic properties. The other imperative phytoconstituents which contribute to the therapeutic properties are durantol, repennoside, repenins, and scutellarein. The pharmacological activities exhibited by D. repens as antimicrobial, antioxidant, and insecticide properties are attributed to the presence of valuable bioactive phytoconstituents.Conclusion: Considering these facts, I endeavored to present a comprehensive review enlightening the phytochemistry and pharmacological activities of plant D. repens. Future research can be directed to an extensive investigation about phytochemistry, clinical trials, pharmacokinetics, and acquiring safety data so as to add new dimensions to the therapeutic utilization of D. repens and other Duranta species

QUANTITATIVE PHYTOCHEMICAL SCREENING, THIN-LAYER CHROMATOGRAPHY ANALYSIS, HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHY FINGERPRINTING, AND ANTIOXIDANT ACTIVITY OF LEAVES OF DIOSPYROS MONTANA (ROXB.)

Objective: The objective of this study was to investigate important phytochemical constituents and antioxidant potential of Diospyros montana Roxb. leaves belonging to the family Ebenaceae. Methods: Leaves were exhaustively extracted with ethanol and fractionated into petroleum ether, chloroform, and ethyl acetate extracts. The various fractions were further analyzed for phytochemical composition and concentration-dependent antioxidant activity using conventional methods and high-performance thin-layer chromatography (HPTLC) fingerprinting. Since leaves contained phenolic compounds, extracts were evaluated for total phenolic content, flavonoids contents, and in-vitro antioxidant activity. Antioxidant potential was assessed using parameters such as superoxide radical scavenging, nitric oxide inhibition, and β-carotene/linoleic acid antioxidant activity. Results: Primitive phytochemical investigation highlighted the presence of steroids, saponins, flavonoids, alkaloids, and tannins which were confirmed by TLC and HPTLC fingerprinting. The antioxidant activity of leaf extracts decreased in the following order ethyl acetate > ethanolic > chloroform > petroleum ether and it was comparable with standards such as ascorbic acid and butylated hydroxytoluene. Conclusion: The present study concludes that the ethanolic extract and fractions of D. montana (Roxb.) leaves have prominent antioxidant activity comparable to standards. Therefore, D. montana (Roxb.) leaves may be used as a probable source of natural antioxidants in the pharmaceutical industry

ARTABOTRYS HEXAPETALUS (L. F.) BHANDARI: A PLANT WITH ENORMOUS BIOMEDICAL POTENTIAL

This review is intended to investigate the published report regarding phytochemical, ethnomedicinal, and pharmacological activities and put forth the therapeutic potential of Artabotrys hexapetalus (L. f.) Bhandari. (A. hexapetalus). It belongs to the family Annonaceae, one of the therapeutically important plants, broadly distributed throughout the world. An extensive review of the literature available in various recognized databases including logical writing and scientific literature, search engines such as Springerlink, ScienceDirect, SciFinder, PubMed, Scopus, Google Scholar, and BioMed Central as well as relevant books, websites, scientific publications, and dissertations were utilized as a source of information that provided an up-to-date review. Phytochemical profiling of these species revealed the presence of some imperative phytochemicals alkaloids, terpenoids, anthraquinones, butyrolactones, flavonoids, neolignans, phenolic compounds, and leucoanthocyanins as the basis of its valuable therapeutic properties. The other imperative phytoconstituents which contribute to the therapeutic properties are isoamericanin A, isoamericanol, americanin, artabotricinol and artabotriol, β-unsaturated-β-butyrolactones, arapetaloside taxifolin, apigenin-7-O-apiosylglucoside, glucoluteolin, and artabotrine. The pharmacological activities exhibited by Artabotrys hexapetalus as antimicrobial, antileishmanial, antioxidant, antifungal, antifertility, and anthelmintic properties are attributed to the presence of valuable bioactive phytoconstituents. Considering these facts an effort was made to present a comprehensive review enlightening the taxonomical, phytochemical, and pharmacological activities of plant Artabotrys hexapetalus. Future research can be directed to an extensive investigation about phytochemistry, clinical trials, pharmacokinetics, and acquiring safety data to add new dimensions to the therapeutic utilization of Artabotrys hexapetalus and other Artabotrys species

Amplification of Fluctuations in Unstable Systems with Disorder

We study the early-stage kinetics of thermodynamically unstable systems with quenched disorder. We show analytically that the growth of initial fluctuations is amplified by the presence of disorder. This is confirmed by numerical simulations of morphological phase separation (MPS) in thin liquid films and spinodal decomposition (SD) in binary mixtures. We also discuss the experimental implications of our results.Comment: 15 pages, 4 figure

Smooth quantum-classical transition in photon subtraction and addition processes

Recently Parigi et al. [Science 317, 1890 (2007)] implemented experimentally the photon subtraction and addition processes from/to a light field in a conditional way, when the required operations were produced successfully only upon the positive outcome of a separate measurement. It was verified that for a low intensity beam (quantum regime) the bosonic annihilation operator does indeed describe a single photon subtraction, while the creation operator describes a photon addition. Nonetheless, the exact formal expressions for these operations do not always reduce to these simple identifications, and in this connection here we deduce the general superoperators for multiple photons subtraction and addition processes and analyze the statistics of the resulting states for classical field states having an arbitrary intensity. We obtain closed analytical expressions and verify that for classical fields with high intensity (classical regime) the operators that describe photon subtraction and addition processes deviate significantly from simply annihilation and creation operators. Complementarily, we analyze in details such a smooth quantum-classical transition as function of beam intensity for both processes.Comment: 7 pages, 5 figures. To appear in Phys. Rev.

Microscopic models of quantum jump super-operators

We discuss the quantum jump operation in an open system, and show that jump super-operators related to a system under measurement can be derived from the interaction of that system with a quantum measurement apparatus. We give two examples for the interaction of a monochromatic electromagnetic field in a cavity (the system) with 2-level atoms and with a harmonic oscillator (representing two different kinds of detectors). We show that derived quantum jump super-operators have `nonlinear' form which depends on assumptions made about the interaction between the system and the detector. A continuous transition to the standard Srinivas--Davies form of the quantum jump super-operatoris shown

Economic Aseismic Design of Rigid Retaining Wall

Rigid retaining walls experience significant displacements during earthquakes. Several investigators have developed 1- D and 2-D models to predict displacements. A critical review of the state of the art shows that these model may not predict realistic displacements Wu (1999). A new 2-D model, which considers strain dependant soil stiffness and material damping, sliding and rocking motions, and practical field water conditions behind the wall as per Eurocode (1994) has been developed (Wu 1999). This model represents a considerable advance over the existing solutions and is easily useable by the practicing engineer. It has been shown that walls inclined on the back fill offer several technical advantage