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In the realm of quantum information processing, harnessing high-dimensional photonic systems provides a pathway to overcome limitations of traditional two-level systems. Orbital angular momentum (OAM) of light has emerged as a powerful tool for creating and manipulating high-dimensional entanglement, promising increased information capacity and enhanced security in quantum communication protocols. However, conventional methods like spontaneous parametric downconversion encounter challenges due to non-uniform production rates of Laguerre–Gaussian modes. This study explores the potential of spontaneous four-wave mixing in ring-core fibers (RCFs) as a viable platform for generating OAM photon pairs with tailored spectral and spatial properties. We show that by controlling the topological charge of pump photons, correlated, uncorrelated, and anti-correlated photon pairs can be engineered across arbitrary spectral ranges, essential for diverse quantum applications. Experimental noise characterization of the RCF-based source demonstrates a high coincidence-to-accidental ratio exceeding 4000, and a low heralded second-order correlation function (g_H⁽²⁾<0.005), which confirms its operation well into the single-photon regime. This work demonstrates the potential of RCFs as a versatile platform for generating structured photon pairs, paving the way for future high-dimensional quantum communication and information processing applications. 

Ebola virus (EBOV) matrix protein VP40 can assemble and bud as virus-like particles (VLPs) when expressed alone in mammalian cells. Nucleoprotein (NP) could be recruited to VLPs as inclusion body (IB) when co-expressed, and increase VLP production. However, the mechanism behind it remains unclear. Here, we use a computational approach to study NP-VP40 interactions. Our simulations indicate that NP may enhance VLP production through stabilizing VP40 filaments and accelerating the VLP budding step. Further, both the relative timing and amount of NP expression compared to VP40 are important for the effective production of IB-containing VLPs. We predict that relative NP/VP40 expression ratio and time are important for efficient production of IB-containing VLPs. We conclude that disrupting the expression timing and amount of NP and VP40 could provide new avenues to treat EBOV infection. This work provides quantitative insights into EBOV proteins interactions and how virion generation and drug efficacy could be influenced. 

The snowball Earth hypothesis predicts that continental chemical weathering diminished substantially during, but rebounded strongly after, the Marinoan ice age some 635 Mya. Defrosting the planet would result in a plume of fresh glacial meltwater with a different chemical composition from underlying hypersaline seawater, generating both vertical and lateral salinity gradients. Here, we test the plumeworld hypothesis using lithium isotope compositions in the Ediacaran Doushantuo cap dolostone that accumulated in the aftermath of the Marinoan snowball Earth along a proximal–distal (nearshore–offshore) transect in South China. Our data show an overall decreasing δ⁷Li trend with distance from the shoreline, consistent with the variable mixing of a meltwater plume with high δ⁷Li (due to incongruent silicate weathering on the continent) and hypersaline seawater with low δ⁷Li (due to synglacial distillation). The evolution of low δ⁷Li of synglacial seawater, as opposed to the modern oceans with high δ⁷Li, was likely driven by weak continental chemical weathering coupled with strong reverse weathering on the seafloor underneath silica-rich oceans. The spatial pattern of δ⁷Li is also consistent with the development and then collapse of the meltwater plume that occurred at the time scale of cap dolostone accumulation. Therefore, the δ⁷Li data are consistent with the plumeworld hypothesis, considerably reduced chemical weathering on the continent during the Marinoan snowball Earth, and enhanced reverse weathering on the seafloor of Precambrian oceans.