Search results for "Fidelity"
showing 10 items of 79 documents
Quantum benchmark for teleportation and storage of squeezed states.
2007
We provide a quantum benchmark for teleportation and storage of single-mode squeezed states with zero displacement and a completely unknown degree of squeezing along a given direction. For pure squeezed input states, a fidelity higher than 81.5% has to be attained in order to outperform any classical strategy based on an estimation of the unknown squeezing and repreparation of squeezed states. For squeezed thermal input states, we derive an upper and a lower bound on the classical average fidelity which tighten for moderate degree of mixedness. These results enable a critical discussion of recent experiments with squeezed light.
Cloning transformations in spin networks without external control
2004
In this paper we present an approach to quantum cloning with unmodulated spin networks. The cloner is realized by a proper design of the network and a choice of the coupling between the qubits. We show that in the case of phase covariant cloner the XY coupling gives the best results. In the 1->2 cloning we find that the value for the fidelity of the optimal cloner is achieved, and values comparable to the optimal ones in the general N->M case can be attained. If a suitable set of network symmetries are satisfied, the output fidelity of the clones does not depend on the specific choice of the graph. We show that spin network cloning is robust against the presence of static imperfection…
Information geometry of Gaussian channels
2009
We define a local Riemannian metric tensor in the manifold of Gaussian channels and the distance that it induces. We adopt an information-geometric approach and define a metric derived from the Bures-Fisher metric for quantum states. The resulting metric inherits several desirable properties from the Bures-Fisher metric and is operationally motivated from distinguishability considerations: It serves as an upper bound to the attainable quantum Fisher information for the channel parameters using Gaussian states, under generic constraints on the physically available resources. Our approach naturally includes the use of entangled Gaussian probe states. We prove that the metric enjoys some desir…
Spin chains for two-qubit teleportation
2019
Generating high-quality multi-particle entanglement between communicating parties is the primary resource in quantum teleportation protocols. To this aim, we show that the natural dynamics of a single spin chain is able to sustain the generation of two pairs of Bell states - possibly shared between a sender and a distant receiver - which can in turn enable two-qubit teleportation. In particular, we address a spin-1/2 chain with XX interactions, connecting two pairs of spins located at its boundaries, playing the roles of sender and receiver. In the regime where both end pairs are weakly coupled to the spin chain, it is possible to generate at predefinite times a state that has vanishing inf…
Exploring Training Options for RF Sensing Using CSI
2018
This work analyzes human behavior recognition approaches using WiFi channel state information from the perhaps less usual point of view of training and calibration needs. With the help of selected literature examples, as well as with more detailed experimental insights on our own Doppler spectrum-based approach for physical motion/presence/cardinality detection, we first classify the diverse forms of training so far employed into three main categories (trained, trained-once, and training-free). We further discuss under which conditions it is possible to move toward lighter forms of calibration or even succeed in devising fully untrained model-based solutions. Our take home messages are main…
Research protocol: Technology-supported guidance to increase flexibility, quality and efficiency in the clinical practicum of nursing education
2020
Abstract This paper presents the protocol for a randomized controlled trial aimed at studying the effects of a technology-supported guidance model delivered by smartphone and intended to strengthen the follow-up of nursing students during their clinical practicum. The research outcomes will reflect students’ critical thinking, learning outcomes, and satisfaction. The results will be compared before and after the intervention and between control and intervention groups. In the control group, the clinical practicum period will be performed as usual. In the intervention group, students will monitor their day by filling in daily electronic reports. Based on students’ reports and the day’s exper…
The Effects of Using High-Fidelity Simulation in Undergraduate Nursing Education: A Multicenter Randomized Controlled Trial with a Process Evaluation
2021
Abstract The overall aim of this study was to examine the effects of a high-fidelity simulation on the knowledge and self-confidence of a total of 177 undergraduate nursing students in recognizing and responding to hypovolemia. A randomized experimental pre- and post-test research design with a process evaluation was employed. A significantly larger proportion of students in the intervention group than in the control group increased the number of correct responses in their knowledge and levels of self-confidence postintervention. As enablers for the successful implementation of the intervention, a need for a safe environment, fidelity, and learning in different roles were identified.
Data-based modeling of vehicle collision by LPV-ARMAX model approach
2013
Vehicle crash are considered to be events with high complexity from the mathematical points of view. The high experiment cost and huge time-consumption make the establishment of a mathematical model of vehicle crash which can simplify the analysis process in great demand. In this work, we present the application of LPV-ARMAX model to simulate the car-to-pole collision with different initial impact velocities. The parameters of the LPV-ARMAX are assumed to be functions of the initial impact velocities. Instead of establishing a set of LTI models for vehicle crashes with various impact velocities, the LPV-ARMAX model is comparatively simple and applicable to predict the responses of new colli…
SHARP: Environment and Person Independent Activity Recognition with Commodity IEEE 802.11 Access Points
2022
In this article we present SHARP, an original approach for obtaining human activity recognition (HAR) through the use of commercial IEEE 802.11 (Wi-Fi) devices. SHARP grants the possibility to discern the activities of different persons, across different time-spans and environments. To achieve this, we devise a new technique to clean and process the channel frequency response (CFR) phase of the Wi-Fi channel, obtaining an estimate of the Doppler shift at a radio monitor device. The Doppler shift reveals the presence of moving scatterers in the environment, while not being affected by (environment-specific) static objects. SHARP is trained on data collected as a person performs seven differe…
Fidelity and influencing factors in the Systemic Practice Model of children's social care in Finland
2020
Given that multiple countries have recently adopted social work practice models in children’s services, it is striking that only a few studies have systematically analysed both the level of fidelity and potential implementation barriers and facilitators. The aim of this study is to provide an in-depth analysis of how and why the Reclaiming Social Work (RSW) model works in different settings. The study context was the implementation in Finland of an adaptation of the model, the Systemic Practice Model (SPM). This mixed-methods study evaluates 1) fidelity to the SPM and 2) the possible influencing factors. The results reveal high variability in the extent of fidelity in 23 implementation site…