Phase estimation and compensation is one of the enabling functionalities in continous-variable quantum key distribution (CVQKD). Recently, a novel CVQKD scheme has been independently proposed to combat the local oscillator (LO) side channel attacks. Furthermore, we have carried out a proof-of-principle experimental study on the feasibility of the CVQKD without sending a LO. However, this scheme contains a serious weakness: The phase noise caused by the two different lasers between the sender and the receiver would severely destroy the quantum signal and finally reduce the secure distance. In this paper, we investigate the optical phase noise and explore the optimal approach to estimate and compensate such kind of noise with appropriate data overhead. Numerical simulations show that our scheme can successfully reconstruct the phase drifts even at low signal-to-noise ratio conditions. We also suggest that a higher accuracy of phase estimation could be achieved by using the frequency division multiplexing scheme. This opens an opportunity to employ advanced pilot-aided phase estimation techniques in quantum communication system.
The crystal structure, electronic structure, and superconductivity of copper hydrides at high pressure have been studied by ab initio calculation. Consistent with experimental report, results show that the predicted stoichiometry Cu2H with the P-3m1 space group is stable above 16.8 GPa. The stoichiometry of CuH with the Fm-3m space group is predicted to be synthesized above 30 GPa, but it is metastable and dynamical instable up to 120 GPa. The electronic band calculations reveal that Cu2H is a good metal at a stable pressure range, whereas CuH is an insulator. Moreover, the other hydrogenrich compounds CuH2 and CuH3 are thermodynamically and dynamically unstable, respectively. The calculated superconducting transition temperature (Tc) of Cu2H at 40 GPa is 0.028 K by using the Allen-Dynes modified McMillan equation. 相似文献
Biocompatible skin wound dressing materials with long-term therapeutic windows and anti-infection properties have attracted great attention all over the world. The cooperation between essential oil and non-toxic or bio-based polymers was a promising strategy. However, the inherent volatility and chemical instability of most ingredients in essential oils make the sustained pharmacological activity of essential oil-based biomaterials a challenge. In this study, a kind of film nanocomposite loaded with patchouli essential oil (PEO-FNC) was fabricated. PEO-loaded mesoporous silica nanoparticles (PEO-MSNs) with drug load higher than 40 wt% were firstly prepared using supercritical CO2 cyclic impregnation (SCCI), and then combined with the film matrix consisting of polyvinyl alcohol and chitosan. The morphology of PEO-MSNs and PEO-FNC was observed by transmission and scanning electron microscope. The mechanical properties, including hygroscopicity, tensile strength and elongation at break (%), were tested. The release behavior of PEO from the film nanocomposite showed that PEO could keep releasing for more than five days. PEO-FNC exhibited good long-term (>48 h) antibacterial effect on Staphylococcus aureus and non-toxicity on mouse fibroblast (L929 cells), making it a promising wound dressing material. 相似文献
The morphology and size dependence of silver microstructures in a novel microfabrication process, fatty salts-assisted multiphoton
photoreduction (MPR), were investigated by using the fatty salts with different carbon chain lengths (Cn: n=4,5,7,9) under varied powers and irradiation times of a femtosecond near-infrared laser with the wavelength of 800 nm. Not
only the feature size of the silver structures was reduced but also the surface smoothness was improved by increasing the
chain length of the fatty salts. The highest resolution of a silver line was obtained to be 285 nm, which exceeded the diffraction
limit. The fatty salts-assisted MPR microfabrication approach would provide an efficient protocol for fabricating metallic
micro/nanostructures with fine morphology and size and could play an important role in the fabrication of the metallic micro/nanostructures
for applications in photonics and electronics as well as in sensors. 相似文献
The Short term frequency stability characteristics of 2 μm single frequency Solid-state lasers was investigated. The two laser
systems of 2 μm single longitudinal mode oscillation Tm, Ho:YLF microchip laser and Ho:YAG NPRO laser were designed and constructed.
The Short term frequency stability of these two laser were measured with the fiber delay self-beating heterodyne method. The
3dB width of the relative frequency fluctuation of Tm, Ho:YLF microchip laser and Ho:YAG NPRO laser were measured to be 895
and 736 Hz with 500 m fiber optical (2.5 μs delay). The proportional relation between the lasing fluctuation and the delay
time were 358 and 263 Hz/μs, respectively. The vibration experiment was presented and it indicated that the NPRO Ho:YAG was
more terrible to the influence of vibration, which is important in the practical application of wind measurement lidar. 相似文献