Nonlinear coherent destruction of tunneling

We study theoretically two coupled periodically-curved optical waveguides with Kerr nonlinearity. We find that the tunneling between the waveguides can be suppressed in a wide range of parameters due to nonlinearity. Such suppression of tunneling is different from the coherent destruction of tunneling in a linear medium, which occurs only at the isolated degeneracy point of the quasienergies. We call this novel suppression nonlinear coherent destruction of tunneling.Comment: 4 pages,5 figure

Research on Environmental Crowdfunding Projects Based on Narrative Persuasion Theory

Creating a compelling narrative is critical for crowdfunding projects to convince potential supporters to support it. This paper is trying to introduce narrative persuasion theory to the study of environmental crowdfunding projects. We discuss the mechanism of the narrative persuasion on attitude, and study the influence of the narrative on the support of crowdfunding projects through an experiment. Research results show that the narrative have a positive impact on the attitudes of potential supporters towards environmental crowdfunding projects by mechanisms  of narrative understanding, attention focus, narrative presence and emotional engagement. Keywords: Crowdfunding, Narrative persuasion, Narrative engagement, Attitud

Coherent Destruction of Tunneling and Dark Floquet State

We study a system of three coherently coupled states, where one state is shifted periodically against the other two. We discover such a system possesses a dark Floquet state at zero quasienergy and always with negligible population at the intermediate state. This dark Floquet state manifests itself dynamically in terms of the suppression of inter-state tunneling, a phenomenon known as coherent destruction of tunneling. We suggest to call it dark coherent destruction of tunneling (DCDT). At high frequency limit for the periodic driving, this Floquet state reduces to the well-known dark state widely used for STIRAP. Our results can be generalized to systems with more states and can be verified with easily implemented experiments within current technologies.Comment: 5 pages, 3 figure

Quasi-energies and Floquet states of two weakly coupled Bose-Einstein condensates under periodic driving

We investigate the quasi-energies and Floquet states of two weakly coupled Bose-Einstein condensates driven by a periodic force. The quasi-energies and Floquet states of this system are computed within two different theoretical frameworks: the mean-field model and the second-quantized model. The mean-field approach reveals a triangular structure in the quasi-energy band. Our analysis of the corresponding Floquet states shows that this triangle signals the onset of a localization phenomenon, which can be regarded as a generalization of the well-known phenomenon called coherent destruction of tunneling. With the second quantized model, we find also a triangular structure in the quantum quasi-energy band, which is enveloped by the mean-field triangle. The close relation between these two sets of quasi-energies is further explored by a semi-classical method. With a Sommerfeld rule generalized to time-dependent systems, the quantum quasi-energies are computed by quantizing semiclassically the mean-field model and they are found to agree very well with the results obtained directly with the second-quantized model.Comment: 8pages,12figure

Ambidextrous Strategy and Firm Performance: The Moderating Effects of Organizational Slack and Organizational Life Cycle

The relationship between ambidexterity and firm performance holds a prominent place in the literature. However, studies that examine the conditions under which ambidexterity leads to success are relatively scarce. Based on a sample of 226 firms in China, this study examines the moderating effects of organizational slack and organizational life cycle on the relationship between balance dimension of ambidexterity and combined dimension of ambidexterity and firm performance. The empirical results reveal that pursuing a high level of combined dimension of organizational ambidexterity is only beneficial to firms with a high level of organizational slack or firms in maturity stage, while pursuing a high level of balance dimension of organizational ambidexterity is only beneficial to firms in growth stage, but not to firms in maturity stage

Effect of building gap to improve pedestrian comfort levels and ventilation

Rapid rates of urbanization have resulted into increased concerns of urban environment. Amongst them, wind and thermal comfort levels for pedestrians have attracted research interest. In this regards, urban wind environment is seen as a crucial components that can lead to improved thermal comfort levels for pedestrian population. High rise building in modern urban setting causes high levels of turbulence that renders discomfort to pedestrians. Additionally, a higher frequency of high ris e buildings at a particular region acts as a shield against the wind flow to the lower buildings beyond them resulting into higher levels of discomfort to users or residents. Studies conducted on developing wind flow models using Computational Fluid Dynami cs (CFD) simulations have revealed improvement in interval to height ratios can results into improved wind flow within the simulation grid. However, high value and demand for land in urban areas renders expansion to be an impractical solution. Nonetheless, innovative utilization of architectural concepts can be imagined to improve the pedestrian comfort levels through improved wind permeability. This paper assesses the possibility of through-building gaps being a solution to improve pedestrian comfort levels