TY - JOUR AB - We present a low-scaling diagrammatic Monte Carlo approach to molecular correlation energies. Using combinatorial graph theory to encode many-body Hugenholtz diagrams, we sample the Møller-Plesset (MPn) perturbation series, obtaining accurate correlation energies up to n=5, with quadratic scaling in the number of basis functions. Our technique reduces the computational complexity of the molecular many-fermion correlation problem, opening up the possibility of low-scaling, accurate stochastic computations for a wide class of many-body systems described by Hugenholtz diagrams. AU - Bighin, Giacomo AU - Ho, Quoc P AU - Lemeshko, Mikhail AU - Tscherbul, T. V. ID - 13966 IS - 4 JF - Physical Review B SN - 2469-9950 TI - Diagrammatic Monte Carlo for electronic correlation in molecules: High-order many-body perturbation theory with low scaling VL - 108 ER - TY - JOUR AU - Madani, Amiera AU - Sletten, Eric T. AU - Cavedon, Cristian AU - Seeberger, Peter H. AU - Pieber, Bartholomäus ID - 13970 JF - Organic Syntheses SN - 0078-6209 TI - Visible-light-mediated oxidative debenzylation of 3-O-Benzyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose VL - 100 ER - TY - JOUR AB - Cooperative disease defense emerges as group-level collective behavior, yet how group members make the underlying individual decisions is poorly understood. Using garden ants and fungal pathogens as an experimental model, we derive the rules governing individual ant grooming choices and show how they produce colony-level hygiene. Time-resolved behavioral analysis, pathogen quantification, and probabilistic modeling reveal that ants increase grooming and preferentially target highly-infectious individuals when perceiving high pathogen load, but transiently suppress grooming after having been groomed by nestmates. Ants thus react to both, the infectivity of others and the social feedback they receive on their own contagiousness. While inferred solely from momentary ant decisions, these behavioral rules quantitatively predict hour-long experimental dynamics, and synergistically combine into efficient colony-wide pathogen removal. Our analyses show that noisy individual decisions based on only local, incomplete, yet dynamically-updated information on pathogen threat and social feedback can lead to potent collective disease defense. AU - Casillas Perez, Barbara E AU - Bod'Ová, Katarína AU - Grasse, Anna V AU - Tkačik, Gašper AU - Cremer, Sylvia ID - 13127 JF - Nature Communications TI - Dynamic pathogen detection and social feedback shape collective hygiene in ants VL - 14 ER - TY - THES AB - High-performance semiconductors rely upon precise control of heat and charge transport. This can be achieved by precisely engineering defects in polycrystalline solids. There are multiple approaches to preparing such polycrystalline semiconductors, and the transformation of solution-processed colloidal nanoparticles is appealing because colloidal nanoparticles combine low cost with structural and compositional tunability along with rich surface chemistry. However, the multiple processes from nanoparticle synthesis to the final bulk nanocomposites are very complex. They involve nanoparticle purification, post-synthetic modifications, and finally consolidation (thermal treatments and densification). All these properties dictate the final material’s composition and microstructure, ultimately affecting its functional properties. This thesis explores the synthesis, surface chemistry and consolidation of colloidal semiconductor nanoparticles into dense solids. In particular, the transformations that take place during these processes, and their effect on the material’s transport properties are evaluated. AU - Calcabrini, Mariano ID - 12885 SN - 2663-337X TI - Nanoparticle-based semiconductor solids: From synthesis to consolidation ER - TY - JOUR AB - Following up on the recent work on lower Ricci curvature bounds for quantum systems, we introduce two noncommutative versions of curvature-dimension bounds for symmetric quantum Markov semigroups over matrix algebras. Under suitable such curvature-dimension conditions, we prove a family of dimension-dependent functional inequalities, a version of the Bonnet–Myers theorem and concavity of entropy power in the noncommutative setting. We also provide examples satisfying certain curvature-dimension conditions, including Schur multipliers over matrix algebras, Herz–Schur multipliers over group algebras and generalized depolarizing semigroups. AU - Wirth, Melchior AU - Zhang, Haonan ID - 12087 JF - Annales Henri Poincare SN - 1424-0637 TI - Curvature-dimension conditions for symmetric quantum Markov semigroups VL - 24 ER - TY - JOUR AB - In 1998 Burago and Kleiner and (independently) McMullen gave examples of separated nets in Euclidean space which are non-bilipschitz equivalent to the integer lattice. We study weaker notions of equivalence of separated nets and demonstrate that such notions also give rise to distinct equivalence classes. Put differently, we find occurrences of particularly strong divergence of separated nets from the integer lattice. Our approach generalises that of Burago and Kleiner and McMullen which takes place largely in a continuous setting. Existence of irregular separated nets is verified via the existence of non-realisable density functions ρ:[0,1]d→(0,∞). In the present work we obtain stronger types of non-realisable densities. AU - Dymond, Michael AU - Kaluza, Vojtech ID - 9652 JF - Israel Journal of Mathematics KW - Lipschitz KW - bilipschitz KW - bounded displacement KW - modulus of continuity KW - separated net KW - non-realisable density KW - Burago--Kleiner construction TI - Highly irregular separated nets VL - 253 ER - TY - JOUR AB - The power factor of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film can be significantly improved by optimizing the oxidation level of the film in oxidation and reduction processes. However, precise control over the oxidation and reduction effects in PEDOT:PSS remains a challenge, which greatly sacrifices both S and σ. Here, we propose a two-step post-treatment using a mixture of ethylene glycol (EG) and Arginine (Arg) and sulfuric acid (H2SO4) in sequence to engineer high-performance PEDOT:PSS thermoelectric films. The high-polarity EG dopant removes the excess non-ionized PSS and induces benzenoid-to-quinoid conformational change in the PEDOT:PSS films. In particular, basic amino acid Arg tunes the oxidation level of PEDOT:PSS and prevents the films from over-oxidation during H2SO4 post-treatment, leading to increased S. The following H2SO4 post-treatment further induces highly orientated lamellar stacking microstructures to increase σ, yielding a maximum power factor of 170.6 μW m−1 K−2 at 460 K. Moreover, a novel trigonal-shape thermoelectric device is designed and assembled by the as-prepared PEDOT:PSS films in order to harvest heat via a vertical temperature gradient. An output power density of 33 μW cm−2 is generated at a temperature difference of 40 K, showing the potential application for low-grade wearable electronic devices. AU - Zhang, Li AU - Liu, Xingyu AU - Wu, Ting AU - Xu, Shengduo AU - Suo, Guoquan AU - Ye, Xiaohui AU - Hou, Xiaojiang AU - Yang, Yanling AU - Liu, Qingfeng AU - Wang, Hongqiang ID - 12113 JF - Applied Surface Science KW - Surfaces KW - Coatings and Films KW - Condensed Matter Physics KW - Surfaces and Interfaces KW - General Physics and Astronomy KW - General Chemistry SN - 0169-4332 TI - Two-step post-treatment to deliver high performance thermoelectric device with vertical temperature gradient VL - 613 ER - TY - JOUR AB - We study the large scale behavior of elliptic systems with stationary random coefficient that have only slowly decaying correlations. To this aim we analyze the so-called corrector equation, a degenerate elliptic equation posed in the probability space. In this contribution, we use a parabolic approach and optimally quantify the time decay of the semigroup. For the theoretical point of view, we prove an optimal decay estimate of the gradient and flux of the corrector when spatially averaged over a scale R larger than 1. For the numerical point of view, our results provide convenient tools for the analysis of various numerical methods. AU - Clozeau, Nicolas ID - 10173 JF - Stochastics and Partial Differential Equations: Analysis and Computations SN - 2194-0401 TI - Optimal decay of the parabolic semigroup in stochastic homogenization for correlated coefficient fields VL - 11 ER - TY - JOUR AB - Following E. Wigner’s original vision, we prove that sampling the eigenvalue gaps within the bulk spectrum of a fixed (deformed) Wigner matrix H yields the celebrated Wigner-Dyson-Mehta universal statistics with high probability. Similarly, we prove universality for a monoparametric family of deformed Wigner matrices H+xA with a deterministic Hermitian matrix A and a fixed Wigner matrix H, just using the randomness of a single scalar real random variable x. Both results constitute quenched versions of bulk universality that has so far only been proven in annealed sense with respect to the probability space of the matrix ensemble. AU - Cipolloni, Giorgio AU - Erdös, László AU - Schröder, Dominik J ID - 11741 JF - Probability Theory and Related Fields SN - 0178-8051 TI - Quenched universality for deformed Wigner matrices VL - 185 ER - TY - JOUR AB - High carrier mobility is critical to improving thermoelectric performance over a broad temperature range. However, traditional doping inevitably deteriorates carrier mobility. Herein, we develop a strategy for fine tuning of defects to improve carrier mobility. To begin, n-type PbTe is created by compensating for the intrinsic Pb vacancy in bare PbTe. Excess Pb2+ reduces vacancy scattering, resulting in a high carrier mobility of ∼3400 cm2 V–1 s–1. Then, excess Ag is introduced to compensate for the remaining intrinsic Pb vacancies. We find that excess Ag exhibits a dynamic doping process with increasing temperatures, increasing both the carrier concentration and carrier mobility throughout a wide temperature range; specifically, an ultrahigh carrier mobility ∼7300 cm2 V–1 s–1 is obtained for Pb1.01Te + 0.002Ag at 300 K. Moreover, the dynamic doping-induced high carrier concentration suppresses the bipolar thermal conductivity at high temperatures. The final step is using iodine to optimize the carrier concentration to ∼1019 cm–3. Ultimately, a maximum ZT value of ∼1.5 and a large average ZTave value of ∼1.0 at 300–773 K are obtained for Pb1.01Te0.998I0.002 + 0.002Ag. These findings demonstrate that fine tuning of defects with <0.5% impurities can remarkably enhance carrier mobility and improve thermoelectric performance. AU - Wang, Siqi AU - Chang, Cheng AU - Bai, Shulin AU - Qin, Bingchao AU - Zhu, Yingcai AU - Zhan, Shaoping AU - Zheng, Junqing AU - Tang, Shuwei AU - Zhao, Li Dong ID - 12331 IS - 2 JF - Chemistry of Materials SN - 0897-4756 TI - Fine tuning of defects enables high carrier mobility and enhanced thermoelectric performance of n-type PbTe VL - 35 ER -