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1. Storing sunlight at low temperatures?

   https://doi.org/10.1016/j.joule.2021.08.012  

   Nguyen, Nghi P.; Moore, Gary F. (September 2021, Joule)
2. Borromean supercounterfluids at finite temperatures

   https://doi.org/10.1103/PhysRevResearch.7.013053  

   Golic, Alexandru; Timoshuk, Igor; Babaev, Egor; Svistunov, Boris (January 2025, Physical Review Research)

   While the properties of standard (single-component) superfluids are well understood, principal differences arise in a special type of multicomponent systems—the so-called Borromean supercounterfluids—in which (i) supertransport is possible only in the counterflow regime and (ii) there are three or more counterflowing components. Borromean supercounterfluids's correlation and topological properties distinguish them from their single- and two-component counterparts. The component-symmetric case characterized by a distinctively different universality class of the supercounterfluid-to-normal phase transition is especially interesting. Using the recently introduced concept of compact-gauge invariance as the guiding principle, we develop the finite-temperature description of Borromean supercounterfluids in terms of an asymptotically exact long-wave effective action. We formulate and study Borromean $XY$and loop statistical models, capturing the universal long-range properties and allowing us to perform efficient worm algorithm simulations. Numeric results demonstrate perfect agreement with analytic predictions. Particularly instructive is the two-dimensional case, where the Borromean nature of the system is strongly manifested while allowing for an asymptotically exact analytic description. 

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3. Yeast cells actively tune their membranes to phase separate at temperatures that scale with growth temperatures

   https://doi.org/10.1073/pnas.2116007119  

   Leveille, Chantelle L.; Cornell, Caitlin E.; Merz, Alexey J.; Keller, Sarah L. (January 2022, Proceedings of the National Academy of Sciences)

   Membranes of vacuoles, the lysosomal organelles of Saccharomyces cerevisiae (budding yeast), undergo extraordinary changes during the cell’s normal growth cycle. The cycle begins with a stage of rapid cell growth. Then, as glucose becomes scarce, growth slows, and vacuole membranes phase separate into micrometer-scale domains of two liquid phases. Recent studies suggest that these domains promote yeast survival by organizing membrane proteins that play key roles in a central signaling pathway conserved among eukaryotes (TORC1). An outstanding question in the field has been whether cells regulate phase transitions in response to new physical conditions and how this occurs. Here, we measure transition temperatures and find that after an increase of roughly 15 °C, vacuole membranes appear uniform, independent of growth temperature. Moreover, populations of cells grown at a single temperature regulate this transition to occur over a surprisingly narrow temperature range. Remarkably, the transition temperature scales linearly with the growth temperature, demonstrating that the cells physiologically adapt to maintain proximity to the transition. Next, we ask how yeast adjust their membranes to achieve phase separation. We isolate vacuoles from yeast during the rapid stage of growth, when their membranes do not natively exhibit domains. Ergosterol is the major sterol in yeast. We find that domains appear when ergosterol is depleted, contradicting the prevalent assumption that increases in sterol concentration generally cause membrane phase separation in vivo, but in agreement with previous studies using artificial and cell-derived membranes. 

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4. Optimal Algorithms for Computing Average Temperatures

   https://doi.org/10.1515/mcwf-2019-0003  

   Foucart, S.; Hielsberg, M.; Mullendore, G. L.; Petrova, G.; Wojtaszczyk, P. (April 2019, Mathematics of Climate and Weather Forecasting)

   Abstract A numerical algorithm is presented for computing average global temperature (or other quantities of interest such as average precipitation) from measurements taken at speci_ed locations and times. The algorithm is proven to be in a certain sense optimal. The analysis of the optimal algorithm provides a sharp a priori bound on the error between the computed value and the true average global temperature. This a priori bound involves a computable compatibility constant which assesses the quality of the measurements for the chosen model. The optimal algorithm is constructed by solving a convex minimization problem and involves a set of functions selected a priori in relation to the model. It is shown that the solution promotes sparsity and hence utilizes a smaller number of well-chosen data sites than those provided. The algorithm is then applied to canonical data sets and mathematically generic models for the computation of average temperature and average precipitation over given regions and given time intervals. A comparison is provided between the proposed algorithms and existing methods. 

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5. Air-Bridge Cells for Higher Emission Temperatures

   https://doi.org/10.1109/PVSC48320.2023.10359802  

   Roy-Layinde, Bosun; Rahman, Areefa; Lim, Jihun; Paul, Sritoma; Forrest, Stephen R.; Lenert, Andrej (June 2023, 2023 IEEE 50th Photovoltaic Specialists Conference (PVSC))

   Interest in thermal batteries for inexpensive grid-scale storage of renewable energy motivates the development of photovoltaics that efficiently convert very high temperature thermal emission to electrical energy. We have previously shown that InGaAs air-bridge cells can increase TPV efficiency by −30% compared to cells with more conventional back surface reflectors. In this study, we design and experimentally characterize airbridge cells with wider bandgaps for applications at higher emission temperatures. Parametric studies with varying bandgap and emitter temperature identify high performance regimes. At temperatures up to 2000K, predicted device efficiencies of single-junction air-bridge cells match that of record-holding multi-junction cells. Furthermore, a novel platform for device testing using porous graphite emitters is designed and experimentally demonstrated. 

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