1,298 research outputs found

    Detection of Bosenovae with Quantum Sensors on Earth and in Space

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    In a broad class of theories, the accumulation of ultralight dark matter (ULDM) with particles of mass 10−22 eV<mϕ<1 eV10^{-22}~\textrm{eV} < m_{\phi} < 1~\textrm{eV} leads the to formation of long-lived bound states known as boson stars. When the ULDM exhibits self-interactions, prodigious bursts of energy carried by relativistic bosons are released from collapsing boson stars in bosenova explosions. We extensively explore the potential reach of terrestrial and space-based experiments for detecting transient signatures of emitted relativistic bursts of scalar particles, including ULDM coupled to photons, electrons, and gluons, capturing a wide range of motivated theories. For the scenario of relaxion ULDM, we demonstrate that upcoming experiments and technology such as nuclear clocks as well as space-based interferometers will be able to sensitively probe orders of magnitude in the ULDM coupling-mass parameter space, challenging to study otherwise, by detecting signatures of transient bosenova events. Our analysis can be readily extended to different scenarios of relativistic scalar particle emission.Comment: 16 pages, 9 figure

    The effect of inventory leanness on firms’ credit ratings: The case of Pakistan

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    Inventory leanness requires that firms minimize inventory mistreatment and misuse. A firm performance deteriorates because of high inventory misuse, and because of such an issue, the effect on the firm’s credit rating can also be seen. This study examines the effect of inventory leanness on firms’ credit ratings. It aims to create an understanding of the relationship between inventory leanness and the firm’s financial performance and provides insight into the credit rating system of Pakistan. We analyze secondary Pakistan data between 2008 and 2017. Among the sixty firms on Pakistan Stock Exchange that are rated by PACRA, only thirty-eight have complete data available on their respective websites. By using panel data analysis, the results indicate that inventory leanness and credit ratings are positively related. In an added analysis, we evaluate the financial performance in the context of credit rating by using control variables (size, leverage, and capital intensity ratio) and dummy variables (loss and subordinate debt). Our results are consistent with earlier studies.info:eu-repo/semantics/publishedVersio

    Physician-based availability of psychotherapy in Ontario : a population-based retrospective cohort study

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    BACKGROUND: Psychotherapy is recommended as a first-line treatment for the management of common psychiatric disorders. The objective of this study was to evaluate the availability of publicly funded psychotherapy provided by physicians in Ontario by describing primary care physicians (PCPs) and psychiatrists whose practices focus on psychotherapy and comparing them to PCPs and psychiatrists whose practices do not. METHODS: This was a population-based retrospective cohort study. We included all PCPs and psychiatrists in Ontario who submitted at least 1 billing claim to the Ontario Health Insurance Plan between Apr. 1, 2015, and Mar. 31, 2016, and categorized them as psychotherapists if at least 50% of their outpatient billings were related to the provision of psychotherapy. We measured practice characteristics such as total number of patients and new patients, and average visit frequency for 4 physician categories: PCP nonpsychotherapists, PCP psychotherapists, psychiatrist nonpsychotherapists and psychiatrist psychotherapists. We also measured access to care for people with urgent need for mental health services. RESULTS: Of 12 772 PCPs, 404 (3.2%) were PCP psychotherapists; of 2150 psychiatrists, 586 (27.3%) were psychotherapists. Primary care physician nonpsychotherapists had the highest number of patients and number of new patients, followed by psychiatrist nonpsychotherapists, PCP psychotherapists and psychiatrist psychotherapists. Primary care physician nonpsychotherapists had the lowest average annual number of visits per patient, whereas both types of psychotherapists had a much greater number of visits per patient. Primary care physician and psychiatrist nonpsychotherapists saw about 25% of patients with urgent needs for mental health services, whereas PCP and psychiatrist psychotherapists saw 1%-3% of these patients. INTERPRETATION: Physicians who provide publicly funded psychotherapy in Ontario see a small number of patients, and they see few of those with urgent need for mental health services. Our findings suggest that improving access to psychotherapy will require the development of alternative strategies

    Effect of temperature anisotropy on various modes and instabilities for a magnetized non-relativistic bi-Maxwellian plasma

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    Using kinetic theory for homogeneous collisionless magnetized plasmas, we present an extended review of the plasma waves and instabilities and discuss the anisotropic response of generalized relativistic dielectric tensor and Onsager symmetry properties for arbitrary distribution functions. In general, we observe that for such plasmas only those electromagnetic modes whose magnetic field perturbations are perpendicular to the ambient magneticeld, i.e.,B1 \perp B0, are effected by the anisotropy. However, in oblique propagation all modes do show such anisotropic effects. Considering the non-relativistic bi-Maxwellian distribution and studying the relevant components of the general dielectric tensor under appropriate conditions, we derive the dispersion relations for various modes and instabilities. We show that only the electromagnetic R- and L- waves, those derived from them and the O-mode are affected by thermal anisotropies, since they satisfy the required condition B1\perpB0. By contrast, the perpendicularly propagating X-mode and the modes derived from it (the pure transverse X-mode and Bernstein mode) show no such effect. In general, we note that the thermal anisotropy modifies the parallel propagating modes via the parallel acoustic effect, while it modifies the perpendicular propagating modes via the Larmor-radius effect. In oblique propagation for kinetic Alfven waves, the thermal anisotropy affects the kinetic regime more than it affects the inertial regime. The generalized fast mode exhibits two distinct acoustic effects, one in the direction parallel to the ambient magnetic field and the other in the direction perpendicular to it. In the fast-mode instability, the magneto-sonic wave causes suppression of the firehose instability. We discuss all these propagation characteristics and present graphic illustrations

    Revival-collapse phenomenon in the fluctuations of quadrature field components of the multiphoton Jaynes-Cummings model

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    In this paper we consider a system consisting of a two-level atom, initially prepared in a coherent superposition of upper and lower levels, interacting with a radiation field prepared in generalized quantum states in the framework of multiphoton Jaynes-Cummings model. For this system we show that there is a class of states for which the fluctuation factors can exhibit revival-collapse phenomenon (RCP) similar to that exhibited in the corresponding atomic inversion. This is shown not only for normal fluctuations but also for amplitude-squared fluctuations. Furthermore, apart from this class of states we generally demonstrate that the fluctuation factors associated with three-photon transition can provide RCP similar to that occurring in the atomic inversion of the one-photon transition. These are novel results and their consequence is that RCP occurred in the atomic inversion can be measured via a homodyne detector. Furthermore, we discuss the influence of the atomic relative phases on such phenomenon.Comment: 17 pages, 4 figure

    Casimir interaction: pistons and cavity

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    The energy of a perfectly conducting rectangular cavity is studied by making use of pistons' interactions. The exact solution for a 3D perfectly conducting piston with an arbitrary cross section is being discussed.Comment: 10 pages, 2 figures, latex2

    On the evolution of superposition of squeezed displaced number states with the multiphoton Jaynes-Cummings model

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    In this paper we discuss the quantum properties for superposition of squeezed displaced number states against multiphoton Jaynes-Cummings model (JCM). In particular, we investigate atomic inversion, photon-number distribution, purity, quadrature squeezing, Mandel QQ parameter and Wigner function. We show that the quadrature squeezing for three-photon absorption case can exhibit revivals and collapses typical to those occurring in the atomic inversion for one-photon absorption case. Also we prove that for odd number absorption parameter there is a connection between the evolution of the atomic inversion and the evolution of the Wigner function at the origin in phase space. Furthermore, we show that the nonclassical states whose the Wigner functions values at the origins are negative will be always nonclassical when they are evolving through the JCM with even absorption parameter. Also we demonstrate that various types of cat states can be generated via this system.Comment: 27 pages, 10 figure

    Isolation and identification of phosphate solubilizer Azospirillum, Bacillus and Enterobacter strains by 16SrRNA sequence analysis and their effect on growth of wheat (Triticum aestivum L.)

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    The aim of the present study was to isolate phosphate solubilizing bacteria from wheat rhizosphere and investigate their potential for plant growth promotion. Three phosphate solubilizing bacterial strains were isolated by serial dilution method from the rhizosphere of wheat grown under wheat-cotton and wheat-rice crop rotation. 16S rRNA gene sequence of the isolates WS-1, T-34 and T-41 showed 98% similarity to those of Azospirillum, Bacillus and Enterobacter sequences in NCBI data base, respectively. The bacterial strain WS-1 clustered with Azospirillum brasilense strains in the phylogenetic tree constructed using NCBI data base sequences of the genus Azospirillum. The bacterial isolate T-34 formed cluster with Bacillus licheniformis strains in the phylogenetic tree constructed using 16S rRNA sequences of the genera Bacillus and Paenibacillus. In the phylogenetic tree constructed using 16S rRNA gene sequences of genus Enterobacter, the isolate T-41 clustered with Enterobacter amnigenus strains. Phosphate solubilizing activity of the bacterial strains in Pikovskaya medium was investigated by molybdate blue color method using spectrophotometer while organic acids produced in the medium were detected on HPLC. In a growth medium containing insoluble tri-calcium phosphate and supplemented with sucrose, maltose, glucose or galactose as single C-source, all the three isolates produced organic acids like acetic acid, citric acid and gluconic acid for phosphate solubilization. Among the organic acids detected, acetic acid was produced in highest amounts by all strains tested in the media containing different sugars. Maximum acetic acid (56.7 mug/ml) was produced by Bacillus strain T-34 in medium supplemented with sucrose and citric acid (36.2 mug/ml) by the same strain on glucose supplemented medium. Oxalic acid was produced by Bacillus strain T-34 (2.89 mug/ml) and Enterobacter strain T-41 (5.93 mug/ml) only in the medium containing galactose as C-source. Maximum amount of gluconic acid (25.4 mug/ml) was produced by Azospirillum strain WS-1 in the medium containing glucose as C-source. Highest P solubilization activity (298.3 mug/ml) was observed in Bacillus strain T-34 grown on sucrose supplemented medium. Maximum P solubilization was detected in Enterobacter strain T-41 (292.2 mug/ml) in medium containing maltose. Azospirillum strain WS-1 showed maximum P solubilization (218.1 mug/ml) in medium containing glucose as single C-source. All the three bacterial strains produced growth hormone IAA in the growth medium supplemented with tryptophan. Quantification on HPLC indicated maximum IAA production (31.15 mug/ml) by Bacillus strain T-34. A pot experiment conducted to study the effect of bacterial isolates on growth of wheat showed that inoculation with Azospirillum, Bacillus and Enterobacter strains increased the grain yield of wheat by 9.3%, 14.8%, 13.1%, respectively over non-inoculated control. Under field conditions, increase in grain yield of plants inoculated with Azospirillum, Bacillus and Enterobacter was 11.2%, 15.7% and 5.6%, respectively compared with non-inoculated plants.These results indicated that bacterial isolates having plant-beneficial traits like phosphate solubilization and IAA production and capable of improving growth of wheat when used as inoculants qualify for production of biofertilizer for wheat cro

    Dynamics, correlations and phases of the micromaser

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    The micromaser possesses a variety of dynamical phase transitions parametrized by the flux of atoms and the time-of-flight of the atom within the cavity. We discuss how these phases may be revealed to an observer outside the cavity using the long-time correlation length in the atomic beam. Some of the phase transitions are not reflected in the average excitation level of the outgoing atom, which is the commonly used observable. The correlation length is directly related to the leading eigenvalue of the time evolution operator, which we study in order to elucidate the phase structure. We find that as a function of the time-of-flight the transition from the thermal to the maser phase is characterized by a sharp peak in the correlation length. For longer times-of-flight there is a transition to a phase where the correlation length grows exponentially with the flux. We present a detailed numerical and analytical treatment of the different phases and discuss the physics behind them.Comment: 60 pages, 18 figure files, Latex + \special{} for the figures, (some redundant figures are eliminated and others are changed

    Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes-Cummings model: interference and entanglement

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    In this paper we study the evolution of the two two-level atoms interacting with a single-mode quantized radiation field, namely, two-atom multiphoton Jaynes-Cummings model when the radiation field and atoms are initially prepared in the superpostion of displaced number states and excited atomic states, respectively. For this system we investigate the atomic inversion, Wigner function, phase distribution and entanglement.Comment: 18 pages, 17 figure
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