9,516 research outputs found

    Nonfactorization in Hadronic Two-body Cabibbo-favored decays of D^0 and D^+

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    With the inclusion of nonfactorized amplitudes in a scheme with Nc=3N_c=3, we have studied Cabibbo-favored decays of D0D^0 and D+D^+ into two-body hadronic states involving two isospins in the final state. We have shown that it is possible to understand the measured branching ratios and determined the sizes and signs of nonfactorized amplitudes required.Comment: 15 pages, Late

    Non-degenerate, three-wave mixing with the Josephson ring modulator

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    The Josephson ring modulator (JRM) is a device, based on Josephson tunnel junctions, capable of performing non-degenerate mixing in the microwave regime without losses. The generic scattering matrix of the device is calculated by solving coupled quantum Langevin equations. Its form shows that the device can achieve quantum-limited noise performance both as an amplifier and a mixer. Fundamental limitations on simultaneous optimization of performance metrics like gain, bandwidth and dynamic range (including the effect of pump depletion) are discussed. We also present three possible integrations of the JRM as the active medium in a different electromagnetic environment. The resulting circuits, named Josephson parametric converters (JPC), are discussed in detail, and experimental data on their dynamic range are found to be in good agreement with theoretical predictions. We also discuss future prospects and requisite optimization of JPC as a preamplifier for qubit readout applications.Comment: 21 pages, 16 figures, 4 table

    Femtosecond Photoionization of Atoms under Noise

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    We investigate the effect of incoherent perturbations on atomic photoionization due to a femtosecond mid-infrared laser pulse by solving the time-dependent stochastic Schr\"odinger equation. For a weak laser pulse which causes almost no ionization, an addition of a Gaussian white noise to the pulse leads to a significantly enhanced ionization probability. Tuning the noise level, a stochastic resonance-like curve is observed showing the existence of an optimum noise for a given laser pulse. Besides studying the sensitivity of the obtained enhancement curve on the pulse parameters, such as the pulse duration and peak amplitude, we suggest that experimentally realizable broadband chaotic light can also be used instead of the white noise to observe similar features. The underlying enhancement mechanism is analyzed in the frequency-domain by computing a frequency-resolved atomic gain profile, as well as in the time-domain by controlling the relative delay between the action of the laser pulse and noise.Comment: 10 pages, 10 figure

    Optimal Stochastic Enhancement of Photoionization

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    The effect of noise on the nonlinear photoionization of an atom due to a femtosecond pulse is investigated in the framework of the stochastic Schr\"odinger equation. A modest amount of white noise results in an enhancement of the net ionization yield by several orders of magnitude, giving rise to a form of quantum stochastic resonance. We demonstrate that this effect is preserved if the white noise is replaced by broadband chaotic light.Comment: 4 pages, 4 figure

    Perbandingan Model Estimasi Kandungan Nitrogen Padi Menggunakan Citra Hiperspektral dan Multispektral Sebagian Wilayah Kabupaten Sleman

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    Penelitian ini memiliki tujuan untuk mengetahui kemampun citra hipersepektral dan multispektral dalam mengestimasi kandungan nitrogen padi di sebagian wilayah Kabupaten Sleman menggunakan pendekatan semi-empiris. Bersamaan dengan itu juga menghitung besarnya akurasi pemetaan yang didapatkan. Diukur pula kemampuan data penginderaan multisensor untuk memetakan penggunaan lahan, sawah irigasi, yang menjadi dasar pengambilan data. Citra Hyperion dan citra Landsat 8 OLI digunakan sebagai data rujukan untuk pembuatan model estimasi.Hasil penelitian menunjukkan bahwa citra Hyperion dapat menyajikan informasi penggunaan lahan lebih baik dibandingkan dengan citra Landsat 8 OLI dengan akurasi pemetaan sebesar 87,78%. Model estimasi nitrogen padi terbaik dimiliki oleh NDNI (Hyperion) dengan nilai RMSE 0,45 dan r 0,53. Diikuti oleh OSAVI (Hyperion) RMSE=0,50, OSAVI (Landsat 8 OLI) RMSE=0,67 dan NDNI (Landsat 8 OLI) RMSE=0,80. Berdasarkan informasi tersebut, citra hiperspektral mampu menggambarkan informasi nitrogen padi di wilayah kajian lebih baik dibandingkan dengan citra Landsat 8 OLI. Hal ini disebabkan oleh karakteristik spektral citra

    Heisenberg-limited qubit readout with two-mode squeezed light

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    We show how to use two-mode squeezed light to exponentially enhance cavity-based dispersive qubit measurement. Our scheme enables true Heisenberg-limited scaling of the measurement, and crucially, is not restricted to small dispersive couplings or unrealistically long measurement times. It involves coupling a qubit dispersively to two cavities, and making use of a symmetry in the dynamics of joint cavity quadratures (a so-called quantum-mechanics-free subsystem). We discuss the basic scaling of the scheme and its robustness against imperfections, as well as a realistic implementation in circuit quantum electrodynamics.Comment: 5 pages, 4 figures, Supplemental Materia

    On some generalized ageing orderings

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    Some partial orderings which compare probability distributions with the expo- nential distribution, are found to be very useful to understand the phenomenon of ageing. Here, we introduce some new generalized partial orderings which de- scribe the same kind of characterization of some generalized ageing classes. We give some equivalent conditions for each of the orderings. Inter-relations among the generalized orderings have also been discussed

    Inelastic Final-State Interactions and Two-body Hadronic B decays into Single-Isospin channels

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    The role of inelastic final-state interactions in CP asymmetries and branching ratios is investigated in certain chosen single isospin two-body hadronic B decays. Treating final-state interactions through Pomeron and Regge exchanges, we demonstrate that inelastic final state interactions could lead to sizeable effects on the CP asymmetry.Comment: 23 pages, Latex, 1 eps-figur

    Depth Images-based Human Detection, Tracking and Activity Recognition Using Spatiotemporal Features and Modified HMM

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    Human activity recognition using depth information is an emerging and challenging technology in computer vision due to its considerable attention by many practical applications such as smart home/office system, personal health care and 3D video games. This paper presents a novel framework of 3D human body detection, tracking and recognition from depth video sequences using spatiotemporal features and modified HMM. To detect human silhouette, raw depth data is examined to extract human silhouette by considering spatial continuity and constraints of human motion information. While, frame differentiation is used to track human movements. Features extraction mechanism consists of spatial depth shape features and temporal joints features are used to improve classification performance. Both of'these features are fused together to recognize different activities using the modified hidden Markov model (M-HMM). The proposed approach is evaluated on two challenging depth video datasets. Moreover, our system has significant abilities to handle subject's body parts rotation and body parts missing which provide major contributions in human activity recognition.1165Ysciescopuskc
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