Quantum statistics in time-modulated exciton-photon system

We consider a system consisting of a large individual quantum dot with excitonic resonance coupled to a single mode photonic cavity in the nonlinear regime when exciton- exciton interaction becomes important. We show that in the presence of time-modulated external coherent pumping the system demonstrates essentially non classical behavior reflected in sub-Poissonian statistics of exciton- and photon-modes and the Wigner functions with negative values in phase-space for time-intervals exceeding the characteristic time of dissipative processes, $t\gg\gamma^{-1}$. It is shown that these results are cardinally different from the analogous results in the regime of the monomode continues-wave (cw) excitation.Comment: 8 pages, 6 figure

Selective excitations of a Kerr-nonlinear resonator: exactly solvable approach

We study Kerr nonlinear resonators (KNR) driven by a continuous wave field in quantum regimes where strong Kerr interactions give rise to selective resonant excitations of oscillatory modes. We use an exact quantum theory of KNR in the framework of the Fokker-Planck equation without any quantum state truncation or perturbation procedure. This approach allows non-perturbative consideration of KNR for various quantum operational regimes including cascaded processes between oscillatory states. We focus on understanding of multi-photon non-resonant and selective resonant excitations of introcavity mode depending on the detuning, the amplitude of the driving field and the strength of nonlinearity. The analysis is provided on the base of photon number distributions, the photon-number correlation function and the Wigner function.Comment: 8 pages, 9 figure

Bistability and chaos at low-level of quanta

We study nonlinear phenomena of bistability and chaos at a level of few quanta. For this purpose we consider a single-mode dissipative oscillator with strong Kerr nonlinearity with respect to dissipation rate driven by a monochromatic force as well as by a train of Gaussian pulses. The quantum effects and decoherence in oscillatory mode are investigated on the framework of the purity of states and the Wigner functions calculated from the master equation. We demonstrate the quantum chaotic regime by means of a comparison between the contour plots of the Wigner functions and the strange attractors on the classical Poincar\'e section. Considering bistability at low-limit of quanta, we analyze what is the minimal level of excitation numbers at which the bistable regime of the system is displayed? We also discuss the formation of oscillatory chaotic regime by varying oscillatory excitation numbers at ranges of few quanta. We demonstrate quantum-interference phenomena that are assisted hysteresis-cycle behavior and quantum chaos for the oscillator driven by the train of Gaussian pulses as well as we establish the border of classical-quantum correspondence for chaotic regimes in the case of strong nonlinearities.Comment: 10 pages, 14 figure

Phase-locking at low-level of quanta

We discuss phase-locking phenomena at low-level of quanta for parametrically driven nonlinear Kerr resonator (PDNR) in strong quantum regime. Oscillatory mode of PDNR is created in the process of a degenerate down-conversion of photons under interaction with a train of external Gaussian pulses. We calculate the Wigner functions of cavity mode showing two-fold symmetry in phase space and analyse formation of phase-locked states in the regular as well as the quantum chaotic regime.Comment: 6 pages, 4 figure

Clinical Endoscopic and Histological Characteristics of Helicobacter Pylori Positive and Negative Armenian Children with Recurrent Abdominal Pain and/or Dyspepsia

Recurrent abdominal pain (RAP) and dyspepsia are common complaints in children. These symptoms are often associated with Helicobacter pylori (Hp) infection. The aim of the present study was to prospectively analyze clinical, endoscopic, and histological characteristics of Hp+ and Hp- children with RAP and/or dyspepsia. Patients aged 2-18 years with RAP and/or dyspepsia, referred for an upper endoscopy to Arabkir Medical Center - Institute of Child and Adolescent Health (Arabkir MC-ICAH) from November 2015 to December 2017, were involved in the study. Histology was assessed according to the updated Sydney system. Gastric and duodenal specimens were stained by modified Giemsa staining for Hp infection. One antral biopsy was cultured in Hp selective media. 150 patients were included into the study: 70.7% Hp+, 29.3% Hp-. Nausea and vomiting were significantly more common in Hp+ patients (p<0.05). Gastric nodularity (p=0.02), erosions in the stomach (p=0.056), and duodenal erosions (p=0.019) were more common in Hp+. Chronic active (p=0.027) and non-active gastritis (p=0.002), cumulative findings of metaplasia/dysplasia/atrophy in the stomach (p=0.014) and chronic non-active duodenitis (p=0.016), were significantly more common in Hp+ patients. Hp infection prevalence is high in Armenian children with dyspepsia and/or RAP. Clinical symptoms, endoscopic findings, and histopathological findings were significantly different in Hp+ patients as compared to Hp- patients

Dissipative Chaos in Quantum Distributions

We discuss some problems of dissipative chaos for open quantum systems in the framework of semiclassical and quantum distributions. For this goal, we propose a driven nonlinear oscillator with time-dependent coefficients, i.e. with time-dependent Kerr-nonlinearity and time-modulated driving field. This model showing both regular and chaotic dynamics in the classical limit is realized in several experimental schemes. Quantum dissipative chaos is analyzed on the base of numerical method of quantum trajectories. Three quantities are studied: the Wigner function of oscillatory mode from the point of view of quantum-assemble theory and both semiclassical Poincare section and quantum Poincare section calculated on a single quantum trajectory. The comparatively analysis of these distributions for various operational chaotic regimes of the models is performed, as well as scaling invariance in dissipative chaos and quantum interference effects assisted by chaos are discussed.Comment: 17 pages, 3 figures, proceeding of Modern Optics And Photonic