Entanglement--one of the most delicate phenomena in nature--is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit ...entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfigurable optics to generate a path-entangled two-qubit state and analyse its entanglement. We show that ring-resonator-based spontaneous four-wave mixing photon-pair sources can be made highly indistinguishable and that their spectral correlations are small. We use on-chip frequency demultiplexers and reconfigurable optics to perform both quantum state tomography and the strict Bell-CHSH test, both of which confirm a high level of on-chip entanglement. This work demonstrates the integration of high-performance components that will be essential for building quantum devices and systems to harness photonic entanglement on the large scale.
We report the observation of the signature of a localization phase transition for light in one-dimensional quasiperiodic photonic lattices, by directly measuring wave transport inside the lattice. ...Below the predicted transition point an initially narrow wave packet expands as it propagates, while above the transition expansion is fully suppressed. In addition, we measure the effect of focusing nonlinear interaction on the propagation and find it increases the width of the localized wave packets.
A unique feature shared by all plant viruses of the Potyviridae family is the induction of characteristic pinwheel-shaped inclusion bodies in the cytoplasm of infected cells. These cylindrical ...inclusions are composed of the viral-encoded cylindrical inclusion helicase (CI protein). Its helicase activity was characterized and its involvement in replication demonstrated through different reverse genetics approaches. In addition to replication, the CI protein is also involved in cell-to-cell and long-distance movements, possibly through interactions with the recently discovered viral P3N-PIPO protein. Studies over the past two decades demonstrate that the CI protein is present in several cellular compartments interacting with viral and plant protein partners likely involved in its various roles in different steps of viral infection. Furthermore, the CI protein acts as an avirulence factor in gene-for-gene interactions with dominant-resistance host genes and as a recessive-resistance overcoming factor. Although a significant amount of data concerning the potential functions and subcellular localization of this protein has been published, no synthetic review is available on this important multifunctional protein. In this review, we compile and integrate all information relevant to the current understanding of this viral protein structure and function and present a mode of action for CI, combining replication and movement.
We examine the problem of restoration from multiple images degraded by camera motion blur. We consider scenes with significant depth variations resulting in space-variant blur. The proposed algorithm ...can be applied if the camera moves along an arbitrary curve parallel to the image plane, without any rotations. The knowledge of camera trajectory and camera parameters is not necessary. At the input, the user selects a region where depth variations are negligible. The algorithm belongs to the group of variational methods that estimate simultaneously a sharp image and a depth map, based on the minimization of a cost functional. To initialize the minimization, it uses an auxiliary window-based depth estimation algorithm. Feasibility of the algorithm is demonstrated by three experiments with real images.
Cylindrical vector (CV) beams have sparked considerable interest due to their extraordinary vectorial properties, desirable for applications ranging from microscopy to high energy physics. Increasing ...demand for cost-effective, small-footprint photonics has fueled the development of photonic integrated circuits (PICs) capable of generating structured light beams in recent years. This technology however suffers from low reconfigurability, limiting the variety of CV beams that can be generated from these devices. In this article, we propose a novel design to overcome this limitation, which exploits the polarization-dependent response of annular gratings embedded into a microring resonator to generate re-configurable CV beams. We demonstrate the viability of the device in a proof-of-principle experiment including spatially resolved Stokes measurements.
Abstract STUDY QUESTION Do women with endometriosis who achieve a live birth (LB) after HRT-frozen embryo transfer (HRT-FET) have different progesterone levels on the day of transfer compared to ...unaffected women? SUMMARY ANSWER In women achieving a LB after HRT-FET, serum progesterone levels on the day of the transfer did not differ between patients with endometriosis and unaffected patients. WHAT IS KNOWN ALREADY In HRT-FET, several studies have highlighted the correlation between serum progesterone levels at the time of FET and LB rates. In the pathophysiology of endometriosis, progesterone resistance is typically described in the eutopic endometrium. This has led to the hypothesis that women with endometriosis may require higher progesterone levels to achieve a LB, especially in HRT-FET cycles without a corpus luteum. STUDY DESIGN, SIZE, DURATION We conducted an observational cohort study at the university-based reproductive medicine center of our institution, focusing on women who underwent a single autologous frozen blastocyst transfer after HRT using exogenous estradiol and micronized vaginal progesterone for endometrial preparation between January 2019 and December 2021. Women were included only once during the study period. Serum progesterone levels were measured on the morning of the FET by a single laboratory. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients were divided into groups based on whether they had endometriosis or not and whether they achieved a LB. The diagnosis of endometriosis was based on published imaging criteria (transvaginal sonography/magnetic resonance imaging) and/or confirmed histology. The primary outcome was progesterone levels on the day of the HRT-FET leading to a LB in patients with endometriosis compared to unaffected women. Subgroup analyses were performed based on the presence of deep infiltrating endometriosis or adenomyosis. MAIN RESULTS AND THE ROLE OF CHANCE A total of 1784 patients were included. The mean age of the women was 35.1 ± 4.1 (SD) years. Five hundred and sixty women had endometriosis, while 1224 did not. About 179/560 (32.0%) with endometriosis and 381/1224 (31.2%) without endometriosis achieved a LB. Among women who achieved a LB after HRT-FET, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (13.6 ± 4.3 ng/ml vs 13.2 ± 4.4 ng/ml, respectively; P = 0.302). In the subgroup of women with deep infiltrating endometriosis (n = 142) and adenomyosis (n = 100), the mean progesterone level was 13.1 ± 4.1 ng/ml and 12.6 ± 3.7 ng/ml, respectively, with no significant difference compared to endometriosis-free patients. After adjusting for BMI, parity, duration of infertility, tobacco use, and geographic origin, neither the presence of endometriosis (coefficient 0.38; 95% CI: −0.63 to 1.40; P = 0.457) nor the presence of adenomyosis (coefficient 0.97; 95% CI: −0.24 to 2.19; P = 0.114) was associated with the progesterone level on the day of HRT-FET. Among women who did not conceive, there was no significant difference in the mean progesterone level on the day of the HRT-FET between those with endometriosis and those without (P = 0.709). LIMITATIONS, REASONS FOR CAUTION The primary limitation of our study is associated with its observational design. Extrapolating our results to other laboratories or different routes and/or dosages of administering progesterone also requires validation. WIDER IMPLICATIONS OF THE FINDINGS This study shows that patients diagnosed with endometriosis do not require higher progesterone levels on the day of a frozen blastocyst transfer to achieve a LB in hormonal replacement therapy cycles. STUDY FUNDING/COMPETING INTEREST(S) None declared. TRIAL REGISTRATION NUMBER N/A.
Entanglement is a fundamental property of quantum mechanics, and is a primary resource in quantum information systems. Its manipulation remains a central challenge in the development of quantum ...technology. In this work, we demonstrate a device which can generate, manipulate, and analyse two-qubit entangled states, using miniature and mass-manufacturable silicon photonics. By combining four photon-pair sources with a reconfigurable six-mode interferometer, embedding a switchable entangling gate, we generate two-qubit entangled states, manipulate their entanglement, and analyse them, all in the same silicon chip. Using quantum state tomography, we show how our source can produce a range of entangled and separable states, and how our switchable controlled-Z gate operates on them, entangling them or making them separable depending on its configuration.
Aluminum Gallium Arsenide (AlGaAs) is an attractive platform for the development of integrated optical circuits for all-optical signal processing thanks to its large nonlinear coefficients in the ...1.55-μm telecommunication spectral region. In this paper we discuss the results of the nonlinear continuous-wave optical characterization of AlGaAs waveguides at a wavelength of 1.55 μm. We also report the highest value ever reported in the literature for the real part of the nonlinear coefficient in this material (Re(γ) ≈521 W(-1)m(-1)).
A four-orbital angular momentum (OAM) modes converter consisting of the cascade of an OAM demultiplexer and an OAM multiplexer is implemented and characterized. The OAM multiplexer is realized with ...an integrated photonic circuit based on four tunable OAM emitters, i.e. the order of the emitted OAM mode can be selected by thermal tuning. It works on linearly polarized signals. The OAM demultiplexer, completely passive, consists of the cascade of two patterned refractive elements followed by a lens and can work independently of the polarization of the input signals. The proposed OAM converter can receive at its input a bundle of spatially multiplexed beams mapped on different OAM modes, each one carrying a set of wavelength division multiplexed (WDM) channels. Each WDM channel can be independently converted to a different OAM mode and all the OAM beams are multiplexed at the converter output. The performance of the proposed scheme is assessed as a function of the order of the OAM beam before and after the conversion, as well as of the wavelength of the input signal. The measurements show a power penalty on the bit error-rate (BER) curves of less than 1 dB in all the considered cases. The scheme is tested also with 100 Gb/s real data-traffic generated with commercial network cards, showing full operability. The cascading ability of the proposed scheme is also investigated in an experiment where the signal to be converted is generated by an OAM multiplexer, i.e. the output stage of the OAM converter, showing a penalty of less than 2 dB. Moreover, considerations on scalability, bandwidth and power consumption are also included along with a possible application of OAM conversion within add/drop nodes in an OAM-wavelength multiplexed transmission scenario.
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