Search

It is well known that environmental decoherence is a crucial barrier in realizing various quantum information processing tasks; on the other hand, it plays a pivotal role in explaining how a quantum system's fragile state leads to a robust classical state. Zurek (Nat Phys 5(3):181–188, 2009) was the first to develop the theory which successfully describes the emergence of classical objectivity of quantum systems using decoherence, introduced by the environment. Here, we consider an n-qubit generalized quantum circuit for the quantum system–environment interaction model, where the first qubit represents the quantum system, and the rest are for the environmental fragments. This quantum circuit is implemented on ibmq_athens and ibmq_16_melbourne for n = 2 , 3 , 4 , 5 , 6 . Its accuracy is checked using quantum state tomography and enhanced using the quantum error mitigation procedure. The reconstructed density matrices are used to investigate quantum-classical correlation and the mutual information between the quantum system and the environment. The investigation proves the quantum Darwinism principle when the quantum circuits are executed on the noise-less simulator; however, it shows the unaccountable behavior when implemented on the real quantum devices. The results via the noise-less simulator successfully prove that the environmental fragment size and the interaction strength play a crucial role in the emergence of classicality. [ABSTRACT FROM AUTHOR]

Electrical charges originate at most solid surfaces in contact with aqueous electrolytes which result in the formation of an electrical double layer. If an external electric field is tangentially applied to the double layer, an electroosmotic flow is induced which can be employed for various applications such as microfluidic pumps. Here, highly porous materials are especially suitable since they generate significant flow rates along with high pump pressures. The models which are currently used to describe the electroosmotic flow through porous substrates are based on the so-called parallel capillary flow model. In terms of packed beds of granular materials, these models have the disadvantages of oversimplifying the geometry to tortuous capillaries while neglecting intra- and inter-pore connections, varying pore cross-sectional geometries as well as the influence of the packed bed walls. In the current research, we employ dimensional reasoning (Buckingham $$\Pi$$ theorem) to derive a phenomenological model which relates the electroosmotic flow to the averaged parameters of the packed bed as well as to the relevant physicochemical parameters. A comprehensive set of experiments is carried out to infer a semiempirical correlation which can be universally applied to packed beds of arbitrary granular materials. Additionally, we derive a dynamic model of the center-of-mass motion of the fluidic parts of the experimental setup. The model allows for an evaluation of the influence of Joule heating without monitoring the temperature in the bed. [ABSTRACT FROM AUTHOR]

The present study documents the long-term trends in the temperature and precipitation of a poorly represented region, the Sikkim, eastern Himalaya using the Mann–Kendall non-parametric test and the Sen's slope estimator. Additionally, the normal distribution curves and Cusum charts have been used to identify the shifts in extreme events and to detect the points of change in the climatic data series for robust analysis. The minimum temperatures recorded a positive trend in Gangtok (0.036 ˚C year−1 from 1961 to 2017) as well as in Tadong (0.065 ˚C year−1 from 1981 to 2010) stations, while the maximum temperatures showed no trend in Tadong station from 1981 to 2010 which is consistent with the trend in Gangtok station for the overlapped period. However, it was negative for the overall assessed period (− 0.027 ˚C year−1 from 1961 to 2017) in Gangtok. The average temperatures in Gangtok recorded no trend whereas a positive trend (0.035 ˚C year−1 from 1981 to 2010) was observed at Tadong station. A similar positive trend in the average temperatures has been detected at Gangtok also for the overlapped period. Accelerated warming was noticed during the last two decades with an increase in the probability of extreme events of temperatures (minimum, maximum, average) at the higher end. Precipitation was found to be more variable across the observed period and suggested no trend in the study area. [ABSTRACT FROM AUTHOR]