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Maternal severe zinc (Zn) deficiency resulted in growth retardation and high mortality during embryonic development in human. Therefore, this study is aimed at evaluating the effect of maternal marginal Zn deficiency on the development and redox status to avoid severe Zn deficiency using an avian model. A total of 324 laying duck breeders at 214 days old were randomly allotted into 3 dietary Zn levels with 6 replicates of 18 ducks per replicate. The birds were fed experimental diets including 3 dietary supplemental Zn levels of 0 mg/kg (maternal Zn-deficient group, 29.2 mg Zn/kg diet), 60 mg/kg (maternal Zn-adequate group), and 120 mg/kg (maternal Zn-high group) for 6 weeks. Dietary Zn levels had on effect on egg production and fertility ( P > 0.05 ), whereas dietary Zn deficiency decreased breeder plasma Zn concentration and erythrocytic alkaline phosphatase activity at week 6 and inhibited erythrocytic 5 ′ -nucleotidase (5 ′ -NT) activity at weeks 2, 4, and 6 ( P < 0.05 ), indicating that marginal Zn-deficient status occurred after Zn depletion. Maternal marginal Zn deficiency increased embryonic mortality and contents of superoxide anion radical, MDA, and PPC and reduced MT content and CuZnSOD activity in duck embryonic livers on E29. The MDA content was positively correlated with embryonic mortality. Maternal marginal Zn deficiency increased BCL2-associated X protein and Caspase-9 mRNA expressions as well as decreased B-cell lymphoma-2 and MT1 mRNA and signal AKT1 and ERK1 protein expressions ( P < 0.05 ). Breeder plasma Zn concentration and erythrocytic 5 ′ -NT activities at week 6 were positively correlated with GSH-Px activity and GPx, MT1, and BCL2 mRNA expressions in embryonic livers on E29. In conclusion, erythrocytic 5 ′ -NT activity could be more rapid and reliable to monitor marginal Zn-deficient status. Marginal Zn deficiency impaired hatchability and antioxidant defense system and then induced oxidative damage and apoptosis in the embryonic liver, contributing to the greater loss of duck embryonic death.

Quantum sensor network with multipartite entanglement offers a sensitivity advantage in optical phase estimation over classical scheme. In order to tackle richer sensing problems, we construct a distributed sensor network with four nodes via four partite entanglements, unveil the estimation of the higher order derivative of radio-frequency signal phase, and unlock the potential of quantum target ranging and space positioning. Therefore, taking phased-array radar as an example, we demonstrate the optimal quantum advantages for space positioning and target ranging missions. Without doubt, the demonstration that endows innovative physical conception opens up a widespread application of quantum sensor network.

Background Cystic echinococcosis is one of the most severe helminth zoonosis with a drastic impact on human health and livestock industry. Investigating optimal control strategy and assessing the crucial factors are essential for developing countermeasures to mitigate this disease. Methods Two compartment models were formulated to study the dynamics of cystic echinococcosis transmission, to evaluate the effectiveness of various control measures, and to find the optimal control strategy. Sensitive analyses were conducted by obtaining PRCCs and contour plot was used to evaluate the effect of key parameters on the basic reproduction number. Based on forward–backward sweep method, numerical simulations were employed to investigate effects of key factors on the transmission of cystic echinococcosis and to obtain the optimal control strategy. Results The food resources of stray dog and invalid sheep vaccination rate, which are always neglected, were significant to the transmission and control of cystic echinococcosis. Numerical simulations suggest that, the implementation of optimal control strategy can significantly reduce the infections. Improving the cost of health education and domestic dog deworming could not decrease human infections. Conclusions Our study showed that only a long-term use of the optimal control measures can eliminate the disease. Meanwhile, during the intervention, sheep vaccination and stray dogs disposing should be emphasized ahead of domestic dogs deworming to minimize the control cost. Simultaneously reducing other wild intermediate hosts and strengthening the sheep vaccination as well as disposing the stray dogs would be most effective.

The distribution of the quantum states to remote receivers is an indispensable technology in quantum communication, quantum networks, and quantum information processing. Perfect distribution does not allow any quantum information loss of the distributed quantum state. Quantum telecloning, which is made up of quantum cloning and quantum teleportation, is a remote quantum information distribution protocol. Here, we experimentally demonstrate unconditional $1\ensuremath{\rightarrow}3$ quantum telecloning of coherent states, and the fidelities of the cloned states are $0.64\ifmmode\pm\else\textpm\fi{}0.01, 0.64\ifmmode\pm\else\textpm\fi{}0.01$, and $0.49\ifmmode\pm\else\textpm\fi{}0.01$, respectively. No information about the unknown state is lost during the telecloning process by exploiting the quadripartite entangled modes as an auxiliary resource. Deterministic $1\ensuremath{\rightarrow}3$ quantum telecloning has great potential for applications in advanced quantum technology.

Einstein-Podolsky-Rosen (EPR) entangled states can significantly enhance the secret key rate and secure distance of continuous-variable quantum key distribution (CV-QKD). In practical imperfections always exist in the preparation of two-mode squeezing (entangled states), which present an asymmetrical variance for the two quadratures. The imperfections induced by the bias effect of the entangled states are commonly treated as part of the untrusted channel to decrease the performance of the system. Here, we theoretically quantify the influence of bias effect on the secret key rate and secure distance, and propose a solution of generating unbiased entangled states protocol. The results demonstrated that the unbiased entangled states protocol guarantees the longest secure distance and highest key rate compared to that of coherent and biased entangled states.

High-fidelity quantum teleportation is necessary to configure a cubic phase gate that enables the processing of the nonclassicality in an input quantum state. The noise variance of the antisqueezing component, which increases rapidly with a higher pump factor, contaminates the squeezing component due to the phase fluctuation and results in a reduction of the fidelity. Here, we balance the influence of the extraction loss and phase fluctuation on the fidelity and optimize the performance of quantum teleportation. As a result, a fidelity $F=0.905\ifmmode\pm\else\textpm\fi{}0.022$ is experimentally achieved. The ultrahigh fidelity is expected to configure a cubic phase gate involving four-time sequential teleportation to perform universal continuous-variable quantum information processing.

Squeezed state light is a fundamental resource for many quantum optics experiments. Important applications like quantum-enhanced magnetometer and quantum key distribution, require the squeezing level as high as possible. In balanced homodyne detection, the detector output is directly proportional to the noise of the squeezed beam. The detected quadrature is dependent on the relative phase between the squeezed beam and local oscillator. Here, we present a balanced homodyne detector (BHD) with independent phase control and noise detection branches. The independence between the phase control and noise detection branches is experimentally verified, the two branches are independently optimized according to the practical requirements. With the BHD, a bright squeezed light at 1550 nm with quantum noise reduction of 10.3 dB is directly detected. After stabilizing the relative phase between the squeezed states and local oscillator by the phase locking branch of the BHD, the fluctuation of the noise suppression is ±0.2 dB by 1-h testing time.

Quantum teleportation is a key primitive across a number of quantum information tasks and represents a fundamental ingredient for many quantum technologies. Channel capacity, other than the fidelity, becomes another focus of quantum communication. Here, we present a 5-channel multiplexing continuous-variable quantum teleportation protocol in the optical frequency comb system, exploiting five-order entangled sideband modes. Because of the resonant electro-optical modulation (EOM) that is specifically designed, the fidelities of five channels are greater than 0.78, which are superior to the no-cloning limit of 2 / 3 . This work provides a feasible scheme for implementing efficient quantum information processing.

To scale quantum information processing, quantum state distributors are an indispensable technology in quantum networks. We present a universal scheme of a continuous variable quantum state distributor that performs point-to-multipoint distributions via quantum teleportation with partially disembodied transport. The fidelity of the state at the output nodes can be conveniently manipulated as needed by engineering the correlation noise of the Einstein–Podolsky–Rosen (EPR) beam. For a 1 → 2 distributor, controllable distributions were demonstrated by manipulating the squeezing factor of EPR entanglement. The fidelities of the two receivers gradually changed from (2/3, 2/3) to (0.95, 0.17) corresponding to the transition from symmetric to asymmetric quantum cloning.

Supplemental document

BackgroundMaternal severe zinc (Zn) deficiency induced oxidative damage and apoptosis in embryos, resulting in growth retardation. Therefore, it is crucial to assess maternal marginal Zn nutritional status for poultry breeders to prevent embryos subjected to severe Zn deficiency. MethodsIn Exp. 1, twelve egg embryos were sampled at incubation day 17 (E17), E20, E23, E26, E29, and E32 (day of hatch) respectively, with 6 replicates of 2 embryo each. The developmental changes of Zn mobilization and Zn transport gene mRNA expression were determined. In Exp. 2, 324 laying duck breeders were randomly allotted into 3 dietary Zn levels (0, 60, and 120 mg Zn/kg diet) with 6 replicates of 18 ducks per replicate. Plasma Zn concentration and erythrocytic Zn metalloenzyme activities in breeders as well as the development, redox status, and gene expression related to oxidation and apoptosis in embryos were measured. Blood samples were collected at the 2th, 4th and 6th weeks of the experiment. ResultsIn Exp. 1, the overall Zn mobilization rates were increased in yolk sac and embryonic liver in response to the increased incubation period, associated with the decreased ZIP10, 13, and 14 mRNA expressions in embryonic liver (P < 0.05). In Exp. 2, with the prolonged dietary Zn depletion, maternal Zn deficiency decreased plasma Zn concentration and erythrocytic alkaline phosphatase activity at the 6th week and inhibited erythrocytic 5'-nucleotidase (5’-NT) activity at 2th week (P < 0.05). On E29 of the maximal rate of Zn mobilization, maternal marginal Zn deficiency increased middle and late embryonic mortality and contents of superoxide anion radical, MDA and PPC, as well as decreasedMT content, CuZnSOD activity, and MT1 mRNA expression in embryonic livers (P < 0.05). Additionally, maternal marginal Zn deficiency increased BCL2-associated X protein and Caspase-9 mRNA expression and decreased B-cell lymphoma-2 mRNA expression in embryonic liver (P < 0.05). ConclusionErythrocytic 5’-NT activity was more rapid and reliable to assess marginal Zn-deficient status in duck breeders. Marginal Zn deficiency impaired hatchability and antioxidant defense system and then induced the oxidative damage and apoptosis in embryonic liver, contributing to the greater loss of embryonic death.

Channel multiplexing quantum communication based on exploiting continuous-variable entanglement of optical modes offers great potential to enhance channel capacity and save quantum resource. Here, we present a frequency-comb-type control scheme for simultaneously extracting a lot of entangled sideband modes with arbitrary frequency detuning from a squeezed state of light. We experimentally demonstrate fourfold channel multiplexing quantum dense coding communication by exploiting the extracted four pairs of entangled sideband modes. Due to high entanglement and wide frequency separation between each entangled pairs, these quantum channels have large channel capacity and the cross talking effect can be avoided. The achieved channel capacities have surpassed that of all classical and quantum communication under the same bandwidth published so far. The presented scheme can be extended to more channels if more entangled sideband modes are extracted.

We demonstrate the experimental detection of an optical squeezing covering several higher resonances of the optical parametric amplifier (OPA) by adopting a bichromatic local oscillator (BLO). The BLO is generated from a waveguide electro-optic phase modulator (WGM) and subsequent optical mode cleaner (OMC), without the need of additional power balance and phase control. The WGM is used for generating the frequency-shifted sideband beams with equal power and certain phase difference, and the OMC is used for filtering the unwanted optical modes. Among a measurement frequency range from 0 to 16.64 GHz, the maximum squeezing factors are superior to 10 dB below the shot noise limit for the first three discrete odd-order resonances of the OPA.

We demonstrate experimentally the simultaneous generation and detection of two types of continuous variable nonclassical states from one type-0 phase-matching optical parametric amplification (OPA) and subsequent two ring filter cavities (RFCs). The output field of the OPA includes the baseband {\omega}0 and sideband modes {\omega}0+/-n{\omega}f subjects to the cavity resonance condition, which are separated by two cascaded RFCs. The first RFC resonates with half the pump wavelength {\omega}0 and the transmitted baseband component is a squeezed state. The reflected fields of the first RFC, including the sideband modes {\omega}0+/-{\omega}f, are separated by the second RFC, construct Einstein-Podolsky-Rosen entangled state. All freedoms, including the filter cavities for sideband separation and relative phases for the measurements of these sidebands, are actively stabilized. The noise variance of squeezed states is 10.2 dB below the shot noise limit (SNL), the correlation variances of both quadrature amplitude-sum and quadrature phase-difference for the entanglement state are 10.0 dB below the corresponding SNL., Comment: 7 pages, 3 figures

The injection of squeezed vacuum state is an indispensable technology for the next generation gravitational wave observatory, which will open up a much larger window to the universe. After analyzing the absorption and dispersion properties of the reflected field of the dual-recycled Michelson interferometer (DRMI), we propose the phase-sensitive manipulation scheme of squeezed vacuum by utilizing the coupled-resonator-induced transparency in a dual-recycled Michelson interferometer (DRMI). In this way, the rotation frequency of squeezing ellipse can be finely tuned by the coupling strength, which overcome the limitation of the current solution (with a fixed rotation frequency) that employs a Fabry-Perot optical cavity as phase-sensitive manipulation element. This work will unleash the potential applications for quantum metrology beyond the shot noise limit.

We report a control scheme of entangled sideband modes without coherent amplitude by employing a frequency-comb-type seed beam. In this scheme, each tooth of the frequency comb serves as a control field for the corresponding downconversion mode. Consequently, all the degrees of freedom can be actively controlled, and the entanglement degrees are higher than 6.7 dB for two pairs of sidebands. We believe that this scheme provides a simple solution for the control of sideband modes, which could be further applied to achieve compact channel multiplexing quantum communications.

The strength of the quantum correlations of a continuous-variable entangled state is determined by several relative phases in the preparation, transmission, and detection processes of entangled states. In this paper, we report the first experimental and theoretical demonstrations of the precision of relative phases associated with the strength of quadrature correlations. Based on the interrelations of the relative phases, three precisely phase-locking methodologies are established: ultralow RAM control loops for the lengths and relative phases stabilization of the DOPAs, difference DC locking for the relative phase between the two squeezed beams, and DC-AC joint locking for the relative phases in BHDs. The phase-locking loops ensure the total phase noise to be 9.7±0.32/11.1±0.36 mrad. Finally, all the relative phase deviations are controlled to be in the range of −35 to 35 mrad, which enhances the correlations of the amplitude and phase quadratures to −11.1 and −11.3 dB. The entanglement also exhibits a broadband squeezing bandwidth up to 100 MHz. This paves a valuable resource for experimental realization and applications in quantum information and precision measurement.

We present a method for determining the thermal focal length of periodically poled potassium titanyl phosphate (PPKTP) through measuring the variation in the mode-matching efficiency between the seed beam and the TEM00 eigenmode of an external optical cavity. The eigenmode size of the external optical cavity changes with the thermal focal length originating from the absorption of PPKTP inside the external optical cavity, whereas the fundamental wave injected into the external optical cavity keeps the geometrical size unchanged, which continuously deteriorates the mode-matching efficiency between the fundamental wave and external optical cavity’s eigenmode. Thus, we can obtain the thermal focal length at different power levels of a harmonic wave according to the corresponding mode-matching efficiency. The measurement is more sensitive to the absorbed power in the material, which can be of high precision under intense pumping. Finally, the uncertainty of the method is analyzed.

We report on a high conversion efficiency tunable laser at 426 nm by adopting an external frequency-doubling cavity pumped by a diode laser. For the frequency-doubling process at 426 nm, the major challenge of increasing the conversion efficiency is mode-match degradation originating from the severely thermal effect. Here, we find that the center of the equivalently thermal lens is not at the center of the nonlinear crystal. We minimize the variation of beam parameters of the Gaussian beam in the external cavity by optimizing the center of the thermal lens to beam waist. As a result, the mode-match degradation is reduced as the incident power is increased. Finally, a 405 mW blue light is obtained with the conversion efficiency of 81%.

We demonstrate the dependence of the squeezing and anti-squeezing factors on the seed beam power at different pump beam noise levels. The results indicate that a seed field injected into the optical parametric amplifier (OPA) dramatically degenerates the squeezing factor due to noise coupling between the pump and seed fields, even if both the pump and seed fields reach the shot noise limit. The squeezing and anti-squeezing factors are immune to the pump beam noise due to no noise coupling when the system operates for the generation of squeezed vacuum states. The squeezing factor degrades gradually as the pump beam intensity noise and seed beam power is increased. The influence of the two orthogonal quadrature variations is mutually independent of each other.

We theoretically analyze and experimentally investigate the dependence of residual amplitude modulation (RAM) on the beam radius within the electro-optic crystal (EOC), the wedge angle of the EOC and the overlap efficiency between the extraordinary and ordinary beams, and the overlap efficiency is determined by the distance from the wedge facet to the downstream polarizer. The results show that the RAM with the maximum optical path difference Δ at the edge of light spot presents a sinc-like curve,and the magnitude of Δ is directly proportional to the beam radius and the wedge angle. As a scaling factor, with the decrease of the overlap efficiency between the ordinary and extraordinary beams, the RAM can be further reduced.

In a continuous variable quantum key distribution (CV-QKD) system, strong Einstein–Podolsky–Rosen entangled states can significantly boost the robustness and distance for secure communication. However, an inevitable bias of two entanglement quadratures may degrade the secret key rate and distance during random quadrature base switching. The bias originates from several interdependent factors in the generation, propagation, and detection of entangled states, which faces a challenge to be completely eliminated. Here, we analyze in detail the origin of the bias effect and report on a scheme of generating unbiased entangled states, whereby a − 10.7 ± 0.1 dB quadrature noise unbiased entanglement is first generated experimentally with two single-mode squeezed states. The unbiased quadrature correlations within the measurement bandwidth are expected to immensely enhance the key rate and secure distance for CV-QKD.

Our previous work had proved pump field noise coupling in the seed field injected optical parametric amplifier (OPA) at a certain analysis frequency. Inspired by this noise coupling mechanism, the frequency dependent squeezing factor due to excess pump noise was experimentally demonstrated. Apart from a reduced squeezing level with an increased noise, the results also prove that a broadband squeezing noise spectrum is not frequency dependent on the amplitude modulated pump field, but limited by the bandwidth of the amplitude modulator and OPA resonator, and the effective measurement is carried out in the frequency range of 2–10 MHz. It provides a guidance to design a broader-bandwidth, higher-level bright squeezed light.

We report a low-noise, high-signal-to-noise-ratio (SNR) balanced homodyne detector based on the standard transimpedance amplifier circuit and the inductance and capacitance combination for the measurement of the bright squeezed state in the range from 1 kHz to 100 kHz. A capacitance is mounted at the input end of the AC branch to prevent the DC photocurrent from entering the AC branch and avoid AC branch saturation. By adding a switch at the DC branch, the DC branch can be flexibly turned on and off on different occasions. When the switch is on, the DC output provides a monitor signal for laser beam alignment. When the switch is off, the electronic noise of the AC branch is greatly reduced at audio-frequency band due to immunity to the impedance of the DC branch, hence the SNR of the AC branch is significantly improved. As a result, the electronic noise of the AC branch is close to −125 dBm, and the maximum SNR of the AC branch is 48 dB with the incident power of 8 mW in the range from 1 kHz to 100 kHz. The developed photodetector paves a path for measuring the bright squeezed state at audio-frequency band.

Location-semantic has become one of the key factors that lead to privacy disclosure in LBS. To solve this problem, we first propose sensitivity-fading algorithm (SFA). As there may be various semantics on a road, we design the semantic-influence vector for each road in the road networks. By calculating the sensitivity of each road based on the semantic-influence vector and selecting the road with the lowest sensitivity, SFA generates the cloaking set (CS) quickly. However, it is vulnerable to inference attack and replay attack. Thus, we also propose the weight-based sensitivity-fading algorithm (WB-SFA). It calculates the weight of each candidate road according to the distance between the candidate road and the road where the user located and gets the sensitivity of each candidate road based on the road's weight and semantic-influence vector. The road with the lowest sensitivity would be added into the CS. The experimental results show that both the two algorithms can guarantee a high success rate in generating CS. The SFA can generate CS at a faster speed while the WB-SFA has strong capability for resisting the inference attack and replay attack.