This paper presents the Learning the Universe Implicit Likelihood Inference (LtU-ILI) pipeline, a codebase for rapid, user-friendly, and cutting-edge machine learning (ML) inference in astrophysics and cosmology. The ...
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We present a general framework for uncertainty quantification that is a mosaic of interconnected models. We define global first and second order structural and correlative sensitivity analyses for random counting meas...
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We prove a variable coefficient version of the square function estimate of Guth-Wang-Zhang. By a classical argument of Mockenhaupt-Seeger-Sogge, it implies the full range of sharp local smoothing estimates for 2 + 1 d...
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Highly charged ions (HCIs) are promising candidates for the next generation of atomic clocks, owing to their tightly bound electron cloud, which significantly suppresses the common environmental disturbances to the qu...
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Highly charged ions (HCIs) are promising candidates for the next generation of atomic clocks, owing to their tightly bound electron cloud, which significantly suppresses the common environmental disturbances to the quantum oscillator. Here we propose and pursue an experimental strategy that, while focusing on various HCIs of a single atomic element, keeps the number of candidate clock transitions as large as possible. Following this strategy, we identify four adjacent charge states of nickel HCIs that offer as many as six optical transitions. Experimentally, we demonstrated the essential capability of producing these ions in the low-energy compact Shanghai-Wuhan Electron Beam Ion Trap. We measured the wavelengths of four magnetic-dipole (M1) and one electric-quadrupole (E2) clock transitions with an accuracy of several ppm with an innovative calibration method. Compared to earlier determinations, our measurements improved wavelength accuracy by an order of magnitude. Such measurements are crucial for constraining the range of laser wavelengths for finding the “needle in a haystack” narrow lines. In addition, we calculated frequencies and quality factors, and evaluated sensitivity of these six transitions to the hypothetical variation of the electromagnetic fine structure constant α needed for fundamental physics applications. We argue that all the six transitions in nickel HCIs offer intrinsic immunity to all common perturbations of quantum oscillators, and one of them has the projected fractional frequency uncertainty down to the remarkable level of 10−19.
We have applied the model-mapped random phase approximation (RPA) [H. Sakakibara et al., J. Phys. Soc. Jpn. 86, 044714 (2017)] to the cuprate superconductors La2CuO4 and HgBa2CuO4, resulting in two-orbital Hubbard mod...
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We have applied the model-mapped random phase approximation (RPA) [H. Sakakibara et al., J. Phys. Soc. Jpn. 86, 044714 (2017)] to the cuprate superconductors La2CuO4 and HgBa2CuO4, resulting in two-orbital Hubbard models. All the model parameters are determined based on first-principles calculations. For the model Hamiltonians, we perform fluctuation exchange calculation. Results explain relative height of Tc observed in experiment for La2CuO4 and HgBa2CuO4. In addition, we give some analyses for the interaction terms in the model, especially comparisons with those of the constrained RPA.
Carbon nano-dots (CDs) are considered nowadays as one of the most interesting fluorescence nanomaterials with various technological applications in almost all aspects of needs e.g., in medicine, biology and engineerin...
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Carbon nano-dots (CDs) are considered nowadays as one of the most interesting fluorescence nanomaterials with various technological applications in almost all aspects of needs e.g., in medicine, biology and engineering. Yet, as reported in many previous works, un-doped CDs suffer from low quantum yield particularly when synthesized at relatively low temperatures. Here, we report on synthesis and characterization of a small size (4.7 nm in diameter) intentionally un-doped CDs with high fluorescence intensity, from Folic Acid as a single precursor, using hydrothermal process at relatively low temperature 200 °C. By attaching organics species of diamine-terminated oligomeric poly-ethylene glycol (PEG) to the surface of the derived CDs, a much stronger photoluminescence from the passivated dots was observed. Namely, we observe a strong enhancement of the CDs quantum yield from 44.4% to 67.5% by varying the PEG concentrations from 0 to 0.2 mM, respectively.
Deep learning has shown successful application in visual recognition and certain artificial intelligence tasks. Deep learning is also considered as a powerful tool with high flexibility to approximate functions. In th...
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Consensus has been reached that recollision, as the most important post-tunneling process, is responsible for nonsequential double ionization process in intense infrared laser field, however, its effect has been restr...
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DNA methylation is an epigenetic mechanism that introduces a methyl group at the C5 position of cytosine. This reaction is catalyzed by DNA methyltransferases (DNMTs) and is essential for the regulation of gene transc...
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