Sharif Digital Repository

In this study, we have proposed a method based on non-equilibrium effects to generate the superposition of macroscopically distinguishable quantum states, known as Schrödinger cat states, by using a Mach-Zehnder interferometry type experiment. The interaction of the input number state with a Kerr medium in the presence of a couple of heat baths in different temperatures in the interaction picture and without imposing a Markov assumption is considered. We have shown that the study of dynamics of the cat states under non-equilibrium condition opens up a way for the robustness of quantum features against the destructive role of the environment, even at high temperature limits. It is verified... 

In this work a generalized non-equilibrium model of three-phase flow in porous media including gravity as well as capillary terms is developed and used for analysis of Riemann's problem in several three-phase systems. The proposed model uses the extension of Barenblatt model to three-phase systems considering dynamic effects in both relative permeability and capillary pressure functions. We compare the solution of the Riemann's problem when non-equilibrium effects are included. While equilibrium formulation develops unstable oscillatory solution in the elliptic region, non-equilibrium solution is smooth and stable. The results of this work might be helpful to better understanding the... 

We demonstrate theoretically by density functional non-equilibrium Green's function method that a much simplest two-terminal wire can exhibit switching, and we present a realistic theory of its behavior. We consider a C20-bowl molecular wire sandwiched between an Au (1 0 0) substrate and a monatomic Au scanning tunneling microscope (STM) tip. Lateral motion of the tip over the pentagon ring causes it to change from one conformation class to the other and to switch between a strongly and a weakly conducting state. Thus, surprisingly, despite their apparent simplicity, these Au/C20/Au nanowires are shown to be a convenient switch, the simplest two-terminal molecular switches to date.... 

We study the dynamics of a macroscopic superconducting qubit coupled to two independent non-stationary reservoirs by using time-dependent perturbation theory. We show that an equilibrium environment surpasses the coherent evolution of the macroscopic qubit completely. When the qubit couples to two different reservoirs, exemplifying a non-equilibrium environment, the short-time dynamics is affected by the interference between two reservoirs, implying the non-additivity of effects of two reservoirs. The non-additivity can be traced back to a non-Markovian effect, even though two reservoirs are independently assumed to be Markovian. Explicitly, the non-equilibrium environment intensifies both... 

Using non-equilibrium Green’s function method and density functional theory, we study the effect of line structural defects on the electron transport of zigzag molybdenum disulfide (MoS 2 ) nanoribbons. Here, the various types of non-stoichiometric line defects greatly affect the electron conductance of MoS 2 nanoribbons. Although such defects would be lead to the electron scattering, they can increase the transmission of charge carriers by creating new channels. In addition, the presence of S bridge defect in the zigzag MoS 2 nanoribbon leads to more the transmission of charge carriers in comparison with the Mo–Mo bond defect. Also, we find that the different atomic orbitals and their... 

We examine the effect of local thermal non-equilibrium on the evolution of the stagnant temperature field in a semi-infinite porous medium. When local thermal equilibrium pertains, the temperature field which is induced by a step change in the temperature of a plane boundary is given by the classical conduction solution involving the complementary error function. When thermal local equilibrium does not apply, then conduction takes place more rapidly in one phase than in the other, although local thermal equilibrium is always approached as time increases. This note examines the evolution of the temperature field in each phase in detail using numerical methods, and the numerical solutions are... 

This work concerns with developing a non-equilibrium model of gravity drainage in a single block. The proposed model which considers both non-equilibrium effects of capillary pressure and relative permeabilities is used for prediction of oil recovery by gravity drainage from a single block. Close agreement observed between the model results and experimental data disclosed that the non-equilibrium assumption is completely reliable for modeling of gravity drainage. The results revealed that when the characteristic time of the saturation variation is comparable with the time required to establish capillary equilibrium, the non-equilibrium effects in gravity drainage must be considered. The... 

This work concerns with developing a non-equilibrium model of gravity drainage in a single block. The proposed model which considers both non-equilibrium effects of capillary pressure and relative permeabilities is used for prediction of oil recovery by gravity drainage from a single block. Close agreement observed between the model results and experimental data disclosed that the non-equilibrium assumption is completely reliable for modeling of gravity drainage. The results revealed that when the characteristic time of the saturation variation is comparable with the time required to establish capillary equilibrium, the non-equilibrium effects in gravity drainage must be considered. The... 

In this paper, a novel structure for a dual-gated graphene nanoribbon field-effect transistor (GNRFET) is offered, which combines the advantages of high and low dielectric constants. In the proposed Two Different Insulators GNRFET (TDI-GNRFET), the gate dielectric at the drain side is a material with low dielectric constant to form smaller capacitances, while in the source side, there is a material with high dielectric constant to improve On-current and reduce the leakage current. Simulations are performed based on self-consistent solutions of the Poisson equation coupled with Non-Equilibrium Green's Function (NEGF) formalism in the ballistic regime. We assume a tight-binding Hamiltonian in... 

We introduce a 'high probability' framework for repeated games with incomplete information. In our non-equilibrium setting, players aim to guarantee a certain payoff with high probability, rather than in expected value. We provide a high probability counterpart of the classical result of Mertens and Zamir for the zero-sum repeated games. Any payoff that can be guaranteed with high probability can be guaranteed in expectation, but the reverse is not true. Hence, unlike the average payoff case where the payoff guaranteed by each player is the negative of the payoff by the other player, the two guaranteed payoffs would differ in the high probability framework. One motivation for this framework... 

The present study addresses a new effort to improve the prediction of the thermal field in separating-reattaching flows by making modifications in a low-Reynolds-number (LRN) version of HOGGDH heat-flux model proposed by Suga and Abe (2000). The modifications are based on introducing non-equilibrium effects of hydrodynamic flow field in the heat-flux model. Using an analytical approach, we have implemented P/ε, ignored in the base version, to the modified version. To do so, the model structure was changed and a damping function which is more sensitive to non-equilibrium flow features is also applied to the model. The modified heat-flux formulation along with a second moment closure... 

In this paper, transient depressurization of high pressure pipelines containing initially subcooled liquid is simulated numerically by using thermodynamic non-equilibrium and choking condition model. The numerical method relies on finite volume. The convective terms of cell boundaries are discretized by Advection Upstream Splitting Method (AUSM+ - up) with a proposal of partially implicit approach for source terms. Different void fraction correlations are applied to simulate two phase shock tubes as well as the depressurization process. By comparison between the present results and previous experimental data, the best void fraction correlation is introduced. The results indicate that the...