The production of pairs of entangled photons simply by focusing a laser beam onto a crystal with a non-linear optical response was used to test quantum mechanics and to open new approaches in imaging. The development of the latter was enabled by the emergence of single photon sensitive cameras able to characterize spatial correlations and high-dimensional entanglement. Thereby new techniques emerged such as the ghost imaging of objectswhere the quantum correlations between photons reveal the image from photons that have never interacted with the object -or the imaging with undetected photons by using nonlinear interferometers. Additionally, quantum approaches in imaging can also lead to an improvement in the performance of conventional imaging systems. These improvements can be obtained by means of image contrast, resolution enhancement that exceed the classical limit and acquisition of sub-shot noise phase or amplitude images. In this review we discuss the application of quantum states of light for advanced imaging techniques.
Chapter 3. The Contragredient Case 3.1. Introduction 3.2. Results on modules for three-dimensional Lie algebras 3.3. Primitive vectors in g 1 and g −1 3.4. Subalgebras with a balanced grading 3.5. Algebras with an unbalanced grading Chapter 4. The Noncontragredient Case 4.1. General assumptions and notation 4.2. Brackets of weight vectors in opposite gradation spaces 4.3. Determining g 0 and its representation on g −1 4.4. Additional assumptions 4.5. Computing weights of b − -primitive vectors in g 1 4.6. Determination of the local Lie algebra 4.7. The irreducibility of g 1 4.8. Determining the negative part when g 1 is irreducible 4.9. Determining the negative part when g 1 is reducible 4.10. The case that g 0 is abelian 4.11. Completion of the proof of the Main Theorem Bibliography
The contrast of an image can be degraded by the presence of background light and sensor noise.To overcome this degradation, quantum illumination protocols have been theorised (Science 321 (2008), Physics Review Letters 101 (2008)) that exploit the spatial correlations between photonpairs. Here we demonstrate the first full-field imaging system using quantum illumination, by an enhanced detection protocol. With our current technology we achieve a rejection of background and stray light of order 5 and also report an image contrast improvement up to a factor of 5.5, which is resilient to both environmental noise and transmission losses. The quantum illumination protocol differs from usual quantum schemes in that the advantage is maintained even in the presence of noise and loss. Our approach may enable laboratory-based quantum imaging to be applied to real-world applications where the suppression of background light and noise is important, such as imaging under low-photon flux and quantum LIDAR.Conventional illumination uses a spatially and temporally random sequence of photons to illuminate an object, whereas quantum illumination can use spatial correlations between pairs of photons to achieve performance enhancements in the presence of noise and/or losses. This enhancement is made possible by using detection techniques that preferentially select photon-pair events over isolated background events.The quantum illumination protocol was introduced by Lloyd , and generalized to Gaussian states by Tan et al. , where they proposed a practical version of the protocol. Quantum illumination has applications in the context of quantum information protocol such as secure communication [3,4] where it secures communication against passive eavesdropping techniques that take advantage of noise and losses. The protocol has also been proposed to be useful for detecting the presence of a target object embedded within a noisy background, despite environmental perturbations and losses destroying the initial entanglement [5,6,7].In 2013, Lopaeva et al. performed an experimental demonstration of the quantum illumination principle, to determine the presence or absence of a semi-transparent object, by exploiting intensity correlations of a quantum origin in the presence of thermal light . Additionally, a quantum illumination protocol has been experimentally demonstrated in the microwave domain  and a further demonstration in which joint detection of the signal and idler is not required . However, these previous demonstrations were restricted 1 to simply detecting the presence or absence of a target, rather than performing any form of spatially resolved imaging. The acquisition of an image using quantum illumination has recently been reported , but that demonstration was performed using a mono-mode source of correlations and by raster-scanning the object within this single-mode beam. The aforementioned demonstration may be seen as a qualitative assessment of the method but a full field imaging implementation of the qua...
BackgroundThe success of Total Shoulder Arthroplasty (TSA) is believed to depend on the restoration of the natural anatomy of the joint and a key development has been the introduction of modular humeral components to more accurately restore the patient’s anatomy. However, there are no peer-reviewed studies that have reported the degree of glenoid component mal-position achieved in clinical practice and the clinical outcome of such mal-position. The main purpose of this study was to assess the accuracy of glenoid implant positioning during TSA and to relate it to the radiological (occurrence of radiolucent lines and osteolysis on CT) and clinical outcomes.Methods68 TSAs were assessed with a mean follow-up of 38+/−27 months. The clinical evaluation consisted of measuring the mobility as well as of the Constant Score. The radiological evaluation was performed on CT-scans in which metal artefacts had been eliminated. From the CT-scans radiolucent lines and osteolysis were assessed. The positions of the glenoid and humeral components were also measured from the CT scans.ResultsFour position glenoid component parameters were calculated The posterior version (6°±12°; mean ± SD), the superior tilt (12°±17°), the rotation of the implant relative to the scapular plane (3°±14°) and the off-set distance of the centre of the glenoid implant from the scapular plane (6±4 mm). An inferiorly inclined implant was found to be associated with higher levels of radiolucent lines while retroversion and non-neutral rotation were associated with a reduced range of motion.Conclusionthis study demonstrates that glenoid implants of anatomic TSA are poorly positioned and that this malposition has a direct effect on the clinical and radiological outcome. Thus, further developments in glenoid implantation techniques are required to enable the surgeon to achieve a desired implant position and outcome.
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