TY - JOUR AB - Coherent control and manipulation of quantum degrees of freedom such as spins forms the basis of emerging quantum technologies. In this context, the robust valley degree of freedom and the associated valley pseudospin found in two-dimensional transition metal dichalcogenides is a highly attractive platform. Valley polarization and coherent superposition of valley states have been observed in these systems even up to room temperature. Control of valley coherence is an important building block for the implementation of valley qubit. Large magnetic fields or high-power lasers have been used in the past to demonstrate the control (initialization and rotation) of the valley coherent states. Here, the control of layer–valley coherence via strong coupling of valley excitons in bilayer WS2 to microcavity photons is demonstrated by exploiting the pseudomagnetic field arising in optical cavities owing to the transverse electric–transverse magnetic (TE–TM)mode splitting. The use of photonic structures to generate pseudomagnetic fields which can be used to manipulate exciton-polaritons presents an attractive approach to control optical responses without the need for large magnets or high-intensity optical pump powers. AU - Khatoniar, Mandeep AU - Yama, Nicholas AU - Ghazaryan, Areg AU - Guddala, Sriram AU - Ghaemi, Pouyan AU - Majumdar, Kausik AU - Menon, Vinod ID - 12836 IS - 13 JF - Advanced Optical Materials TI - Optical manipulation of Layer–Valley coherence via strong exciton–photon coupling in microcavities VL - 11 ER - TY - JOUR AB - This paper deals with the large-scale behaviour of dynamical optimal transport on Zd -periodic graphs with general lower semicontinuous and convex energy densities. Our main contribution is a homogenisation result that describes the effective behaviour of the discrete problems in terms of a continuous optimal transport problem. The effective energy density can be explicitly expressed in terms of a cell formula, which is a finite-dimensional convex programming problem that depends non-trivially on the local geometry of the discrete graph and the discrete energy density. Our homogenisation result is derived from a Γ -convergence result for action functionals on curves of measures, which we prove under very mild growth conditions on the energy density. We investigate the cell formula in several cases of interest, including finite-volume discretisations of the Wasserstein distance, where non-trivial limiting behaviour occurs. AU - Gladbach, Peter AU - Kopfer, Eva AU - Maas, Jan AU - Portinale, Lorenzo ID - 12959 IS - 5 JF - Calculus of Variations and Partial Differential Equations SN - 0944-2669 TI - Homogenisation of dynamical optimal transport on periodic graphs VL - 62 ER - TY - JOUR AB - Cu2–xS and Cu2–xSe have recently been reported as promising thermoelectric (TE) materials for medium-temperature applications. In contrast, Cu2–xTe, another member of the copper chalcogenide family, typically exhibits low Seebeck coefficients that limit its potential to achieve a superior thermoelectric figure of merit, zT, particularly in the low-temperature range where this material could be effective. To address this, we investigated the TE performance of Cu1.5–xTe–Cu2Se nanocomposites by consolidating surface-engineered Cu1.5Te nanocrystals. This surface engineering strategy allows for precise adjustment of Cu/Te ratios and results in a reversible phase transition at around 600 K in Cu1.5–xTe–Cu2Se nanocomposites, as systematically confirmed by in situ high-temperature X-ray diffraction combined with differential scanning calorimetry analysis. The phase transition leads to a conversion from metallic-like to semiconducting-like TE properties. Additionally, a layer of Cu2Se generated around Cu1.5–xTe nanoparticles effectively inhibits Cu1.5–xTe grain growth, minimizing thermal conductivity and decreasing hole concentration. These properties indicate that copper telluride based compounds have a promising thermoelectric potential, translated into a high dimensionless zT of 1.3 at 560 K. AU - Xing, Congcong AU - Zhang, Yu AU - Xiao, Ke AU - Han, Xu AU - Liu, Yu AU - Nan, Bingfei AU - Ramon, Maria Garcia AU - Lim, Khak Ho AU - Li, Junshan AU - Arbiol, Jordi AU - Poudel, Bed AU - Nozariasbmarz, Amin AU - Li, Wenjie AU - Ibáñez, Maria AU - Cabot, Andreu ID - 12915 IS - 9 JF - ACS Nano SN - 1936-0851 TI - Thermoelectric performance of surface-engineered Cu1.5–xTe–Cu2Se nanocomposites VL - 17 ER - TY - JOUR AB - Two notes separated by a doubling in frequency sound similar to humans. This “octave equivalence” is critical to perception and production of music and speech and occurs early in human development. Because it also occurs cross-culturally, a biological basis of octave equivalence has been hypothesized. Members of our team previousy suggested four human traits are at the root of this phenomenon: (1) vocal learning, (2) clear octave information in vocal harmonics, (3) differing vocal ranges, and (4) vocalizing together. Using cross-species studies, we can test how relevant these respective traits are, while controlling for enculturation effects and addressing questions of phylogeny. Common marmosets possess forms of three of the four traits, lacking differing vocal ranges. We tested 11 common marmosets by adapting an established head-turning paradigm, creating a parallel test to an important infant study. Unlike human infants, marmosets responded similarly to tones shifted by an octave or other intervals. Because previous studies with the same head-turning paradigm produced differential results to discernable acoustic stimuli in common marmosets, our results suggest that marmosets do not perceive octave equivalence. Our work suggests differing vocal ranges between adults and children and men and women and the way they are used in singing together may be critical to the development of octave equivalence. AU - Wagner, Bernhard AU - Šlipogor, Vedrana AU - Oh, Jinook AU - Varga, Marion AU - Hoeschele, Marisa ID - 12961 IS - 5 JF - Developmental Science SN - 1363-755X TI - A comparison between common marmosets (Callithrix jacchus) and human infants sheds light on traits proposed to be at the root of human octave equivalence VL - 26 ER - TY - JOUR AB - We consider billiards obtained by removing from the plane finitely many strictly convex analytic obstacles satisfying the non-eclipse condition. The restriction of the dynamics to the set of non-escaping orbits is conjugated to a subshift, which provides a natural labeling of periodic orbits. We show that under suitable symmetry and genericity assumptions, the Marked Length Spectrum determines the geometry of the billiard table. AU - De Simoi, Jacopo AU - Kaloshin, Vadim AU - Leguil, Martin ID - 12877 JF - Inventiones Mathematicae SN - 0020-9910 TI - Marked Length Spectral determination of analytic chaotic billiards with axial symmetries VL - 233 ER - TY - JOUR AB - Statistics of natural scenes are not uniform - their structure varies dramatically from ground to sky. It remains unknown whether these non-uniformities are reflected in the large-scale organization of the early visual system and what benefits such adaptations would confer. Here, by relying on the efficient coding hypothesis, we predict that changes in the structure of receptive fields across visual space increase the efficiency of sensory coding. We show experimentally that, in agreement with our predictions, receptive fields of retinal ganglion cells change their shape along the dorsoventral retinal axis, with a marked surround asymmetry at the visual horizon. Our work demonstrates that, according to principles of efficient coding, the panoramic structure of natural scenes is exploited by the retina across space and cell-types. AU - Gupta, Divyansh AU - Mlynarski, Wiktor F AU - Sumser, Anton L AU - Symonova, Olga AU - Svaton, Jan AU - Jösch, Maximilian A ID - 12349 JF - Nature Neuroscience SN - 1097-6256 TI - Panoramic visual statistics shape retina-wide organization of receptive fields VL - 26 ER - TY - DATA AB - Statistics of natural scenes are not uniform - their structure varies dramatically from ground to sky. It remains unknown whether these non-uniformities are reflected in the large-scale organization of the early visual system and what benefits such adaptations would confer. Here, by relying on the efficient coding hypothesis, we predict that changes in the structure of receptive fields across visual space increase the efficiency of sensory coding. We show experimentally that, in agreement with our predictions, receptive fields of retinal ganglion cells change their shape along the dorsoventral retinal axis, with a marked surround asymmetry at the visual horizon. Our work demonstrates that, according to principles of efficient coding, the panoramic structure of natural scenes is exploited by the retina across space and cell-types. AU - Gupta, Divyansh AU - Sumser, Anton L AU - Jösch, Maximilian A ID - 12370 TI - Research Data for: Panoramic visual statistics shape retina-wide organization of receptive fields ER - TY - JOUR AB - The deployment of direct formate fuel cells (DFFCs) relies on the development of active and stable catalysts for the formate oxidation reaction (FOR). Palladium, providing effective full oxidation of formate to CO2, has been widely used as FOR catalyst, but it suffers from low stability, moderate activity, and high cost. Herein, we detail a colloidal synthesis route for the incorporation of P on Pd2Sn nanoparticles. These nanoparticles are dispersed on carbon black and the obtained composite is used as electrocatalytic material for the FOR. The Pd2Sn0.8P-based electrodes present outstanding catalytic activities with record mass current densities up to 10.0 A mgPd-1, well above those of Pd1.6Sn/C reference electrode. These high current densities are further enhanced by increasing the temperature from 25 °C to 40 °C. The Pd2Sn0.8P electrode also allows for slowing down the rapid current decay that generally happens during operation and can be rapidly re-activated through potential cycling. The excellent catalytic performance obtained is rationalized using density functional theory (DFT) calculations. AU - Montaña-Mora, Guillem AU - Qi, Xueqiang AU - Wang, Xiang AU - Chacón-Borrero, Jesus AU - Martinez-Alanis, Paulina R. AU - Yu, Xiaoting AU - Li, Junshan AU - Xue, Qian AU - Arbiol, Jordi AU - Ibáñez, Maria AU - Cabot, Andreu ID - 12829 JF - Journal of Electroanalytical Chemistry SN - 1572-6657 TI - Phosphorous incorporation into palladium tin nanoparticles for the electrocatalytic formate oxidation reaction VL - 936 ER - TY - JOUR AB - We study a new discretization of the Gaussian curvature for polyhedral surfaces. This discrete Gaussian curvature is defined on each conical singularity of a polyhedral surface as the quotient of the angle defect and the area of the Voronoi cell corresponding to the singularity. We divide polyhedral surfaces into discrete conformal classes using a generalization of discrete conformal equivalence pioneered by Feng Luo. We subsequently show that, in every discrete conformal class, there exists a polyhedral surface with constant discrete Gaussian curvature. We also provide explicit examples to demonstrate that this surface is in general not unique. AU - Kourimska, Hana ID - 12764 JF - Discrete and Computational Geometry SN - 0179-5376 TI - Discrete yamabe problem for polyhedral surfaces VL - 70 ER - TY - THES AB - The extension of extremal combinatorics to the setting of exterior algebra is a work in progress that gained attention recently. In this thesis, we study the combinatorial structure of exterior algebra by introducing a dictionary that translates the notions from the set systems into the framework of exterior algebra. We show both generalizations of celebrated Erdös--Ko--Rado theorem and Hilton--Milner theorem to the setting of exterior algebra in the simplest non-trivial case of two-forms. AU - Köse, Seyda ID - 13331 SN - 2791-4585 TI - Exterior algebra and combinatorics ER -