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1. First Frequency Phase Transfer from the 3 mm to the 1 mm Band on an Earth-sized Baseline

   https://doi.org/10.3847/1538-3881/adbb55  

   Issaoun, Sara; Pesce, Dominic W; Rioja, María J; Dodson, Richard; Blackburn, Lindy; Keating, Garrett K; Doeleman, Sheperd S; Sohn, Bong Won; Jiang_江, Wu 悟; Hoak, Dan; et al (March 2025, The Astronomical Journal)

   Abstract Frequency phase transfer (FPT) is a technique designed to increase coherence and sensitivity in radio interferometry by making use of the nondispersive nature of the troposphere to calibrate high-frequency data using solutions derived at a lower frequency. While the Korean very long baseline interferometry (VLBI) network has pioneered the use of simultaneous multiband systems for routine FPT up to an observing frequency of 130 GHz, this technique remains largely untested in the (sub)millimeter regime. A recent effort has been made to outfit dual-band systems at (sub)millimeter observatories participating in the Event Horizon Telescope (EHT) and to test the feasibility and performance of FPT up to the observing frequencies of the EHT. We present the results of simultaneous dual-frequency observations conducted in 2024 January on an Earth-sized baseline between the IRAM 30-m in Spain and the James Clerk Maxwell Telescope (JCMT) and Submillimeter Array (SMA) in Hawai‘i. We performed simultaneous observations at 86 and 215 GHz on the bright sources J0958+6533 and OJ 287, with strong detections obtained at both frequencies. We observe a strong correlation between the interferometric phases at the two frequencies, matching the trend expected for atmospheric fluctuations and demonstrating for the first time the viability of FPT for VLBI at a wavelength of  ∼1 millimeter. We show that the application of FPT systematically increases the 215 GHz coherence on all averaging timescales. In addition, the use of the colocated JCMT and SMA as a single dual-frequency station demonstrates the feasibility of paired-antenna FPT for VLBI for the first time, with implications for future array capabilities (e.g., Atacama Large Millimeter/submillimeter Array subarraying and ngVLA calibration strategies). 

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2. High-Efficiency, 80 mm Aperture Metalens Telescope

   https://doi.org/10.1021/acs.nanolett.2c03561  

   Zhang, Lidan; Chang, Shengyuan; Chen, Xi; Ding, Yimin; Rahman, Md Tarek; Duan, Yao; Stephen, Mark; Ni, Xingjie (January 2023, Nano Letters)
3. Photonics-Aided Mm-Wave Communication for 5G

   https://doi.org/10.1364/OFC.2019.Th1F.1  

   Li, Xinying; Yu, Jianjun; Chang, Gee-Kung (January 2019, Photonics-Aided Mm-Wave Communication for 5G)
4. On the Consistency strength of MM(\omega_1)

   Dobrinen, Natasha; Krueger, John; Mota, Miguel Angel; Marun, Pedro; Zapletal, Jindrich (March 2024, Proceedings of the American Mathematical Society)

   We prove that the consistency of Martin's Maximum restricted to partial orders of cardinality \omega_1 follows from the consistency of ZFC. 

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5. Analysis of the conformational properties of amine ligands at the gold/water interface with QM, MM and QM/MM simulations

   https://doi.org/10.1039/C7CP06709G  

   Liang, Dongyue; Hong, Jiewei; Fang, Dong; Bennett, Joseph W.; Mason, Sara E.; Hamers, Robert J.; Cui, Qiang (January 2018, Physical Chemistry Chemical Physics)

   We describe a strategy of integrating quantum mechanical (QM), hybrid quantum mechanical/molecular mechanical (QM/MM) and MM simulations to analyze the physical properties of a solid/water interface. This protocol involves using a correlated ab initio (CCSD(T)) method to first calibrate Density Functional Theory (DFT) as the QM approach, which is then used in QM/MM simulations to compute relevant free energy quantities at the solid/water interface using a mean-field approximation of Yang et al. that decouples QM and MM thermal fluctuations; gas-phase QM/MM and periodic DFT calculations are used to determine the proper QM size in the QM/MM simulations. Finally, the QM/MM free energy results are compared with those obtained from MM simulations to directly calibrate the force field model for the solid/water interface. This protocol is illustrated by examining the orientations of an alkyl amine ligand at the gold/water interface, since the ligand conformation is expected to impact the chemical properties ( e.g. , charge) of the solid surface. DFT/MM and MM simulations using the INTERFACE force field lead to consistent results, suggesting that the effective gold/ligand interactions can be adequately described by a van der Waals model, while electrostatic and induction effects are largely quenched by solvation. The observed differences among periodic DFT, QM/MM and MM simulations, nevertheless, suggest that explicitly including electronic polarization and potentially charge transfer in the MM model can be important to the quantitative accuracy. The strategy of integrating multiple computational methods to cross-validate each other for complex interfaces is applicable to many problems that involve both inorganic/metallic and organic/biomolecular components, such as functionalized nanoparticles. 

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