Quantum Communication and Computing With Atomic Ensembles Using Light-Shift Imbalance Induced Blockade

Recently, we have shown that for conditions under which the so-called light-shift imbalance induced blockade (LSIIB) occurs, the collective excitation of an ensemble of a multi-level atom can be treated as a closed two level system. In this paper, we describe how such a system can be used as a quantum bit (qubit) for quantum communication and quantum computing. Specifically, we show how to realize a C-NOT gate using the collective qubit and an easily accessible ring cavity, via an extension of the so-called Pellizzari scheme. We also describe how multiple, small-scale quantum computers realized using these qubits can be linked effectively for implementing a quantum internet. We describe the details of the energy levels and transitions in 87Rb atom that could be used for implementing these schemes.Comment: 16 pages, 9 figures. Accepted in Phys. Rev.

User Perceived Service Quality of mHealth Services in Developing Countries

Health challenges present arguably the most significant barrier to sustainable global development. The introduction of ICT in healthcare, especially the application of mobile communications, has created the potential to transform healthcare delivery by making it more accessible, affordable and effective across the developing world. However, there is growing concerns about the quality of such services with regard to the robustness of the service delivery platform, knowledge and competence of the provider, privacy and security of information and above all, their effects on satisfaction, future use intentions and quality of life. The aim of this paper is to explore, analyze and critically assess the use of existing service quality theories in the light of evolving and ubiquitous healthcare services and their underlying technologies. The conceptual model of the study identifies that there are three primary quality dimensions (platform quality, interaction quality and outcome quality) and ten subdimensions (System reliability, system efficiency, system availability, system adaptability, system privacy, assurance, responsivness, empathy, functional benefits and emotinal benefits) which play a vital role in capturing users’ overall perceptions of mobile health services. Finally, the study identifies future research directions and highlights the managerial implications in the context of developing countries

Development and validation of an instrument to measure user perceived service quality of mHealth

The role of service quality in fostering the growth of mHealth services has gained much attention in the academic and practitioner communities. However, empirical research in this area has been beset by inadequate conceptualization and the lack of a validated scale. This study addresses these limitations by theoretically conceptualizing and empirically validating a multidimensional service quality scale in the mHealth context. The findings show that mHealth service quality is a hierarchical, multidimensional, and reflective construct, which consists of three primary dimensions and eight subdimensions. The results also confirm that the mHealth service quality scale is more effective at predicting satisfaction and continuance in a nomological network

Modeling Quality Dynamics in IT Services Management

The increasing importance of information technology (IT) services in the global economy prompts IS researchers to focus on service quality dynamics to capture the critical interaction between human behavior and IT. The purpose of this study is to develop and validate a user perceived IT service quality model for mHealth using a cross-disciplinary approach. The conceptual model is rooted in the traditional cognition (service quality) – affective (satisfaction)– conation (continuance intentions) chain but explicitly identifies three primary dimensions (i.e., system quality, interaction quality and outcome quality) and eight subdimensions (system reliability, system efficiency, system privacy, responsiveness, assurance, empathy, utilitarian benefits and hedonic benefits) of IT service quality in mHealth. The findings of the study show that IT service quality is the third-order, reflective, hierarchical construct with strong positive effects on satisfaction and continuance intentions in a nomological network

AN EVALUATION OF PLS BASED COMPLEX MODELS: THE ROLES OF POWER ANALYSIS, PREDICTIVE RELEVANCE AND GOF INDEX

Structural equation modeling (SEM) is an important tool to estimate a network of causal relationships linking two or morecomplex concepts. The PLS approach to SEM, also known as component based SEM, is becoming more prominent forestimating large complex models due to its soft modeling assumptions. This ‘soft modeling’ refers to the greater flexibility ofPLS technique in developing and validating the complex models. However, to establish rigor in such complex modeling, thisstudy highlights the critical roles of power analysis, predictive relevance and GoF index. The findings of the study show thatpower analysis is essential to establish conjectures based on IT artifacts, predictive relevance is vital to measure how wellobserved values are reproduced by the model and finally, GoF index is crucial for assessing the global validity of a complexmodel

Commentary on using the SF-36 or MOS-HIV in studies of persons with HIV disease

The purpose was to compare and comment on use of the SF-36 and MOS-HIV instruments in studies of persons with HIV disease. Three medical information databases were searched to identify examples of HIV studies that included the MOS-HIV or SF-36. Thirty-nine and 14 published articles were identified for illustration in comparing the use of the MOS-HIV and SF-36 in HIV disease, respectively. Support for the reliability and construct validity of the MOS-HIV and SF-36 was found. Ceiling and floor effects were reported for both the MOS-HIV and SF-36; however, ceiling effects were more common for the MOS-HIV, in part due to fewer items in the physical, social, and role functioning domains. The MOS-HIV measures three domains hypothesized to be associated with the health deterioration of HIV disease not measured by the SF-36; however, these domains may not assess aspects of HIV disease that typify the majority of the persons with HIV disease today. National norms for the U.S. adult population (and other nations) are available for the SF-36. In addition, the SF-36 has been used in a wide variety of patient populations, enabling comparisons of HIV-infected persons with persons with other health conditions. No national norms for the MOS-HIV are available. We conclude that there is currently insufficient evidence in the literature to recommend the use of the MOS-HIV over the SF-36 in HIV-infected persons. Although the SF-36 is not targeted at HIV, it may be preferable to use the SF-36 over the MOS-HIV due to fewer ceiling effects, availability of national norms, and the vast amount of data for other populations in the U.S. and around the world. Head-to-head comparisons demonstrating the unique value of the MOS-HIV over the SF-36 are clearly needed. More importantly, additional work needs to be directed at comparing the MOS-HIV and other putatively HIV-targeted instruments to one another to help demarcate aspects of HRQOL that are truly generic versus specific to HIV disease. Using both a generic and targeted HRQOL measure is a good general strategy, but this has not been a typical practice in studies of HIV because the MOS-HIV is so similar in content to the SF-36

Beyond the Petermann Limit: Prospect of Increasing Sensor Precision near Exceptional Points

Experiments near the lock-in region in maximally dissipative non-Hermitian systems, e.g., conventional laser gyroscopes near the deadband, have run up against the Petermann limit, where excess noise exactly cancels any scale-factor enhancement resulting in no overall enhancement in precision. As a result, one might be tempted to conclude that exceptional points (EPs) generally cannot be used to increase the precision of laser sensors. Indeed, using a linear eigenmode analysis we show that the Petermann limit applies not just to maximally dissipative systems, but for any type of EP, owing to the fact that EPs are rotationally invariant. It turns out, however, that this restriction comes from the assumption of linearity. We find that nonlinearity breaks the rotation symmetry such that the different types of EPs are no longer equivalent above threshold. In particular, EPs in conservatively coupled systems can lead to an increase in the fundamental precision beyond the Petermann limit as a result of gain saturation. Importantly, we find that only one mode lases under these conditions. We show that the beat note can be recovered by interference with an auxiliary mode, but that this has consequences for the quantum and classical noise that depend on the recovery scheme. Thus, it remains to be seen whether practical experiments can be designed that can take advantage of this enhancement

Enhanced Optoelectronic Response in Bilayer Lateral Heterostructures of Transition Metal Dichalcogenides

Two-dimensional lateral heterojunctions are basic components for low-power and flexible optoelectronics. In contrast to monolayers, devices based on few-layer lateral heterostructures could offer superior performance due to their lower susceptibility to environmental conditions. Here, we report the controlled synthesis of multi-junction bilayer lateral heterostructures based on MoS2-WS2 and MoSe2-WSe2, where the hetero-junctions are created via sequential lateral edge-epitaxy that happens simultaneously in both the first and the second layer. With respect to their monolayer counterparts, bilayer lateral heterostructures yield nearly one order of magnitude higher rectification currents. They also display a clear photovoltaic response, with short circuit currents ~103 times larger than those extracted from the monolayers, in addition to room-temperature electroluminescence. The superior performance of bilayer heterostructures significantly expands the functionalities of 2D crystals

Surface band bending in as-grown and plasma-treated n-type GaN films using surface potential electric force microscopy

The surface band bending, as well as the effect of plasma-induced damage on band bending, on GaN surfaces, was investigated. The upward band bending, measured by surface potentialelectric force microscopy (a variant of atomic force microscopy), for the as-grown n -type GaNwas about 1.0 eV which increased to ∼1.4 eV after reactive ion etching (RIE). UV illuminationdecreased the band bending by 0.3 eV with time constants on the order of seconds and hundreds of seconds for the as-grown and RIE treated GaN, respectively. This implies that there is a higher density of the surface states in the samples subjected to the RIE process. After the RIE treatment, the shape of the photoluminescence spectrum remained unchanged, but the intensity dropped by a factor of 3. This effect can be attributed to nonradiative defects created near the surface by the RIE treatment