We demonstrate polarization entanglement in highly non-degenerate photon pairs, generated through Type-0 spontaneous parametric down conversion (SPDC) using bulk periodically poled Lithium Niobate (PPLN) crystals. Through the utilization of both a beam displacer interferometer scheme and a Sagnac interferometer, we ensure high polarisation contrast and stable interference of the highly non-degenerate photon pairs, which however causes substantial spatial and temporal walk-offs of the photon paths which poses a formidable challenge. We introduce an effective compensation method using birefringent crystal wedges to eliminate spatial and temporal walkoffs simultaneously. This method is implemented in our entangled photon source (EPS) designed specifically for testing entanglement-based quantum key distribution (EBQKD) between ground and satellite, as part of the Quantum Encryption and Science Satellite (QEYSSat) mission funded by the Canadian Space Agency (CSA). We observed a coincidence rate of N = (33.33+-0.05)kHz, a significant improvement compared to the absence of the spatial compensation. We also observed an estimated pair generation rate of (2.92+-0.12)MHz and an entanglement visibility of (96.6+-0.3)% from only 1.0mW of pump power, making it a promising source for long-distance quantum communication for ground-to-satellite and fiber optic links.
Entanglement certification in bulk nonlinear crystals for degenerate and non-degenerate SPDC: spectral filter effects on transverse spatial correlations
Qatar Center for Quantum Computing, College of Science and Engineering, Hamad Bin Khalifa University（卡塔尔量子计算中心，科学与工程学院，哈马德·本·哈利法大学）
Collective Chirped STIRAP in a Pair of Three-Level Atoms: Dressed-Manifold Dynamics and Compensation of the Rydberg-Rydberg Interaction-Induced Detuning
From spectral structure to sensing limits in quantum thermometry
Abdelmalek Essaadi University（阿卜杜勒马利克·埃萨迪大学）；Università di Modena e Reggio Emilia（摩德纳和雷焦艾米利亚大学）；CNR-Istituto di Nanoscienze（国家研究委员会纳米科学研究所）；Università di Milano（米兰大学）
Integrability and Chaos via fractal analysis of Spectral Form Factors: Gaussian approximations and exact results
Università degli Studi di Napoli Federico II（那不勒斯费德里科二世大学）；University of Southern California（南加州大学）；Istituto Nazionale di Fisica Nucleare (INFN)（意大利国家核物理研究所）；Scuola Superiore Meridionale（南方高等学院）
Long time dynamics of a single particle extended quantum walk on a one dimensional lattice with complex hoppings: a generalized hydrodynamic description
