The neutrino-antineutrino annihilation to electron-positron pair around a Schwarzschild black hole in asymptotic safety

We research on the neutrino pair annihilation $\nu+\overline{\nu}\longrightarrow e^{-}+e^{+}$ around a massive source in asymptotic safety. The ratio $\frac{\dot{Q}}{\dot{Q}_{Newt}}$ corresponding to the energy deposition per unit time over that in the Newtonian case is derived and calculated. We find that the quantum corrections to the black hole spacetime affect the emitted energy rate ratio for the annihilation. It is interesting that the more considerable quantum effect reduces the ratio value slightly. The corrected annihilation process can become a source of gamma ray burst. We also investigate the derivative $\frac{d\dot{Q}}{dr}$ relating to the star's radius $r$ to show that the quantum effect for the black hole will drop the ratio. The more manifest quantum gravity influence leads the weaker neutrino pair annihilation.Comment: 10 pages, 2 figures. arXiv admin note: text overlap with arXiv:2206.0067

Analyzing and Optimizing AED Placement Locations in Big Cites—A Geographical Information System Analysis

Out-of-Hospital Cardiac Arrest (OHCA) has been identified as a significant public health issue in China. Numerous studies have demonstrated that using automated external defibrillators (AEDs) can significantly improve the survival rate of OHCA patients, but their low utilization rate is partly due to the accessibility of AED deployment sites. This study collects the location information of AED devices in three representative cities in China: Beijing, Shanghai, and Shenzhen and then combines the kilometer population grid data (2021) with the AED geographic location data for visualization and data analysis through QGIS and Kepler.GL. Our model considers population distribution, subway, and road traffic factors and proposes a new method for AED index measurement. Through empirical analysis, we discovered that the existing AED distribution has an issue with unequal resource allocation. Thus, we have proposed specific suggestions on quantity and specific zones for AED deployment. Furthermore, this study proposes three specific suggestions for the problems currently in developing AEDs in China

Genetic Analysis of Prostate Cancer with Computer Science Methods

Metastatic prostate cancer is one of the most common cancers in men. In the advanced stages of prostate cancer, tumours can metastasise to other tissues in the body, which is fatal. In this thesis, we performed a genetic analysis of prostate cancer tumours at different metastatic sites using data science, machine learning and topological network analysis methods. We presented a general procedure for pre-processing gene expression datasets and pre-filtering significant genes by analytical methods. We then used machine learning models for further key gene filtering and secondary site tumour classification. Finally, we performed gene co-expression network analysis and community detection on samples from different prostate cancer secondary site types. In this work, 13 of the 14,379 genes were selected as the most metastatic prostate cancer related genes, achieving approximately 92% accuracy under cross-validation. In addition, we provide preliminary insights into the co-expression patterns of genes in gene co-expression networks. Project code is available at https://github.com/zcablii/Master_cancer_project

Integrated circularly polarized OAM generator and multiplexer for fiber transmission

Unlike linearly polarized modes in fiber, modes exploiting orbital angular momentum (OAM) are circularly polarized when propagating in fiber. The use of OAM modes for spatial multiplexing requires efficient, low cost mode generators and multiplexers. We propose such a device based on the standard 220-nm silicon-on-insulator platform, taking multiple single-mode data-modulated signals, and imprinting these signals on right- and left-circularly polarized OAM channels on a single, multiplexed output. The device is designed to easily couple to an OAM fiber with a ring shaped core. This approach treating circular polarization within the multiplexer allows us to avoid the losses associated with filtering out unwanted polarization to create a single polarization. Designing the device to have an output matched to the OAM fiber mode profile also avoids mode size conversion. We describe our design methodology and optimization techniques using a transfer-matrix model and the finite-difference time-domain method. A candidate design is simulated and modal crosstalk is examined, showing that lowcrosstalk OAM multiplexing can be achieved through direct fiberto-chip coupling

Integrated phased array for scalable vortex beam multiplexing

Orbital angular momentum (OAM) modes have low model interactions during fiber propagation at data center distances, and thus are suitable for ultra-high capacity systems at low digital signal processing. Generating OAM modes using free-space setups is useful for proof-of-concept experiments, but is not a scalable solution. We use an optical phased array (OPA) with two-dimensional antennas for on-chip circularly polarized OAM beam generation. Our previous work demonstrated an OAM multiplexer for lower-order modes. In this work, we demonstrate an OAM multiplexer that supports a record of 46 (23 per polarization) simultaneous spatial modes up to OAM order 11. We also improve the crosstalk performance of our multiplexer. We incorporate an intensity tuning capability that substantially improves the OAM quality by enabling a uniform power distribution across the antennas. The worst-case crosstalk for the supported OAM5 to OAM11 are found experimentally to be better than -12 dB, with OAM10 achieving -17.2 dB

Optimal ultra-miniature polarimeters in silicon photonic integrated circuits

Measurement of the state of polarization of light is essential in a vast number of applications, such as quantum and classical communications, remote sensing, astronomy, and biomedical diagnostics. Nanophotonic structures and integrated photonic circuits can, in many circumstances, replace conventional discrete optical components for miniature polarimeters and chip-scale polarimetry systems and thus significantly improve robustness while minimizing the footprint and cost. We propose and experimentally demonstrate two silicon photonic four-photodetector (PD) division-of-amplitude polarimeters (4PD-DOAPs) using a complementary metal–oxide–semiconductor-compatible photonic fabrication process. The first design targets minimizing the number of optical components. The second design makes use of a slightly more complex circuit design to achieve an optimal frame for measurements; this measurement frame minimizes and equalizes estimation variances in the presence of the additive white Gaussian noise and the signal dependent shot noise. Further theoretical examination reveals that within the optimal measurement frames for Stokes polarimeters, the DOAP with four PDs has the minimal equally weighted variance compared to those with a greater number of PDs

A Chip-scale, Full-Stokes Polarimeter

The polarization of light conveys unique information that can be exploited by crucial applications. The bulky and costly discrete optical components used in conventional polarimeters limit their broad adoption. A compact, low-cost polarimeter would bring this functionality into a myriad of new scenarios and revolutionize its exploitation. Here we present a high-performance, full-Stokes polarimeter on a silicon chip. A surface polarization splitter and on-chip optical interferometer circuit produce the analysis matrix of an optimally conditioned polarimeter. This solid-state polarimeter is a system-on-a-chip with exceptional compactness, stability, and speed that could be used singly or in integrated arrays. Large arrays can increase the speed and resolution of full-Stokes imaging; therefore, our design provides a scalable polarimeter solution.Comment: 5 figure

On-chip circular polarization splitter using silicon photonic nanoantenna array

Control and sorting of quantum states of photons through the manipulation of polarization and spatial modes of light in integrated photonic circuits contributes important applications in optical communications and quantum-optical systems. We design and demonstrate a novel structure for a silicon nanoantenna array that can split the circular polarization states and couple them to separate single-mode silicon waveguides. Implemented using a CMOS-compatible photonic fabrication process, the array can be monolithically integrated with other photonic components for chip-scale optical signal processing. We also show that the polarization sorting property of the nanoantenna array can be flexibly controlled (by adjusting design parameters at subwavelength scale) to split any two arbitrary orthogonal polarization states