Global Minimum Depth In Edwards-Anderson Model

In the literature the most frequently cited data are quite contradictory, and there is no consensus on the global minimum value of 2D Edwards-Anderson (2D EA) Ising model. By means of computer simulations, with the help of exact polynomial Schraudolph-Kamenetsky algorithm, we examined the global minimum depth in 2D EA-type models. We found a dependence of the global minimum depth on the dimension of the problem N and obtained its asymptotic value in the limit $N\to\infty$. We believe these evaluations can be further used for examining the behavior of 2D Bayesian models often used in machine learning and image processing.Comment: 10 pages, 4 figures, 2 tables, submitted to conference on Engineering Applications of Neural Networks (EANN 2019

Quantum theory of resonantly enhanced four-wave mixing: mean-field and exact numerical solutions

We present a full quantum analysis of resonant forward four-wave mixing based on electromagnetically induced transparency (EIT). In particular, we study the regime of efficient nonlinear conversion with low-intensity fields that has been predicted from a semiclassical analysis. We derive an effective nonlinear interaction Hamiltonian in the adiabatic limit. In contrast to conventional nonlinear optics this Hamiltonian does not have a power expansion in the fields and the conversion length increases with the input power. We analyze the stationary wave-mixing process in the forward scattering configuration using an exact numerical analysis for up to $10^3$ input photons and compare the results with a mean-field approach. Due to quantum effects, complete conversion from the two pump fields into the signal and idler modes is achieved only asymptotically for large coherent pump intensities or for pump fields in few-photon Fock states. The signal and idler fields are perfectly quantum correlated which has potential applications in quantum communication schemes. We also discuss the implementation of a single-photon phase gate for continuous quantum computation.Comment: 10 pages, 11 figure

Full quantum solutions to the resonant four-wave mixing of two single-photon wave packets

We analyze both analytically and numerically the resonant four-wave mixing of two co-propagating single-photon wave packets. We present analytic expressions for the two-photon wave function and show that soliton-type quantum solutions exist which display a shape-preserving oscillatory exchange of excitations between the modes. Potential applications including quantum information processing are discussed.Comment: 7 pages, 3 figure

Исследование протекторных свойств агониста TrkA-рецептора ГК-2 на модели окислительного стресса в культуре клеток сосудистого эндотелия человека (HUVEC)

Oxidative stress resulted to decrease in cells viability compared to the control (78 ± 5 % and 100 ± 6 %, respectively, р < 0,05). GK-2 and NGF prevented H2O2-induced HUVEC cells damages (95 ± 3 % for HA-2 and 97 ± 4 % for NGF vs. 78 ± 5 % for H2O2, p < 0.05). In control the number of cells with condensed chromatin was 9 ± 2, after the addition of H2O2 78 ± 9 (p < 0.05 compared with the control). The addition of NGF or GK-2 after H2O2 significantly reduced the number of such cells (44 ± 9 and 41 ± 8, respectively) (p < 0.05 compared to hydrogen peroxide) and prevented the development of morphological changes in nuclear chromatin. Thus GK-2, like NGF, in human endothelial cell culture HUVEC prevented the apoptosis development caused by hydrogen peroxide.Окислительный стресс приводил к достоверному снижению жизнеспособности клеток по сравнению с контролем (78±5 % и 100±6 % соответственно, р &lt; 0,05). Внесение как ГК-2, так и NGF предотвращало снижение жизнеспособности клеток HUVEC под действием H2O2 (95±3 % для ГК-2 и 97±4 % для NGF против 78±5 % для H2O2, р &lt; 0,05). В контроле количество клеток с конденсированным хроматином составило 9±2, после внесения Н2О2 78±9 (р &lt; 0,05 по сравнению с контролем). Внесение NGF или ГК-2 после Н2О2 достоверно снижало число таких клеток (44±9 и 41±8 соответственно) (р &lt; 0,05 по сравнению с перекисью водорода) и препятствовало развитию морфологических изменений ядерного хроматина. Таким образом, ГК-2, подобно NGF, в культуре клеток эндотелия человека HUVEC препятствует развитию процесса апоптоза, вызванного окислительным стрессом

Generation of entangled coherent states via cross phase modulation in a double electromagnetically induced transparency regime

The generation of an entangled coherent state is one of the most important ingredients of quantum information processing using coherent states. Recently, numerous schemes to achieve this task have been proposed. In order to generate travelling-wave entangled coherent states, cross phase modulation, optimized by optical Kerr effect enhancement in a dense medium in an electromagnetically induced transparency (EIT) regime, seems to be very promising. In this scenario, we propose a fully quantized model of a double-EIT scheme recently proposed [D. Petrosyan and G. Kurizki, {\sl Phys. Rev. A} {\bf 65}, 33833 (2002)]: the quantization step is performed adopting a fully Hamiltonian approach. This allows us to write effective equations of motion for two interacting quantum fields of light that show how the dynamics of one field depends on the photon-number operator of the other. The preparation of a Schr\"odinger cat state, which is a superposition of two distinct coherent states, is briefly exposed. This is based on non-linear interaction via double-EIT of two light fields (initially prepared in coherent states) and on a detection step performed using a $50:50$ beam splitter and two photodetectors. In order to show the entanglement of a generated entangled coherent state, we suggest to measure the joint quadrature variance of the field. We show that the entangled coherent states satisfy the sufficient condition for entanglement based on quadrature variance measurement. We also show how robust our scheme is against a low detection efficiency of homodyne detectors.Comment: 15 pages, 9 figures; extensively revised version; added Section