@article{19053, abstract = {Building on previous works by Bilu, Chambert-Loir and Loeser, we study the asymptotic behaviour of the moduli space of sections of a given family over a smooth projective curve, assuming that the generic fiber is an equivariant compactification of a finite dimensional vector space. Working in a suitable Grothendieck ring of varieties, we show that the class of these moduli spaces converges, modulo an adequate normalisation, to a non-zero effective element, when the class of the sections goes arbitrary far from the boundary of the dual of the effective cone. The limit can be interpreted as a motivic Euler product in the sense of Bilu’s thesis. This result provides a positive answer to a motivic version of the Batyrev–Manin–Peyre conjectures in this particular setting.}, author = {Faisant, Loïs}, issn = {2191-0383}, journal = {Beiträge zur Algebra und Geometrie / Contributions to Algebra and Geometry}, number = {3}, pages = {783--850}, publisher = {Springer Nature}, title = {{Geometric Batyrev–Manin–Peyre for equivariant compactifications of additive groups}}, doi = {10.1007/s13366-022-00656-w}, volume = {64}, year = {2023}, } @misc{19308, abstract = {This Dataset contains the raw data from the following publication: "Optical and electronic signal stabilization of plasmonic fiber optic gate electrodes: towards improved real-time dual-mode biosensing" (DOI 10.3389/fphy.2023.1202132)}, author = {Hasler, Roger and Polt, Marie-Helene and Reiner-Rozman, Ciril and Fossati, Stefan and Lee, Seungho and Aspermair, Patrik and Kleber, Christoph and Ibáñez, Maria and Dostalek, Jakub and Knoll, Wolfgang}, publisher = {Zenodo}, title = {{Optical and electronic signal stabilization of plasmonic fiber optic gate electrodes: Towards improved real-time dual-mode biosensing}}, doi = {10.5281/ZENODO.7716920}, year = {2023}, } @article{19471, abstract = {Fasting initiates a multitude of adaptations to allow survival. Activation of the hypothalamic–pituitary–adrenal (HPA) axis and subsequent release of glucocorticoid hormones is a key response that mobilizes fuel stores to meet energy demands1,2,3,4,5. Despite the importance of the HPA axis response, the neural mechanisms that drive its activation during energy deficit are unknown. Here, we show that fasting-activated hypothalamic agouti-related peptide (AgRP)-expressing neurons trigger and are essential for fasting-induced HPA axis activation. AgRP neurons do so through projections to the paraventricular hypothalamus (PVH), where, in a mechanism not previously described for AgRP neurons, they presynaptically inhibit the terminals of tonically active GABAergic afferents from the bed nucleus of the stria terminalis (BNST) that otherwise restrain activity of corticotrophin-releasing hormone (CRH)-expressing neurons. This disinhibition of PVHCrh neurons requires γ-aminobutyric acid (GABA)/GABA-B receptor signalling and potently activates the HPA axis. Notably, stimulation of the HPA axis by AgRP neurons is independent of their induction of hunger, showing that these canonical ‘hunger neurons’ drive many distinctly different adaptations to the fasted state. Together, our findings identify the neural basis for fasting-induced HPA axis activation and uncover a unique means by which AgRP neurons activate downstream neurons: through presynaptic inhibition of GABAergic afferents. Given the potency of this disinhibition of tonically active BNST afferents, other activators of the HPA axis, such as psychological stress, may also work by reducing BNST inhibitory tone onto PVHCrh neurons.}, author = {Douglass, Amelia May Barnett and Resch, Jon M. and Madara, Joseph C. and Kucukdereli, Hakan and Yizhar, Ofer and Grama, Abhinav and Yamagata, Masahito and Yang, Zongfang and Lowell, Bradford B.}, issn = {1476-4687}, journal = {Nature}, number = {7972}, pages = {154--162}, publisher = {Springer Nature}, title = {{Neural basis for fasting activation of the hypothalamic–pituitary–adrenal axis}}, doi = {10.1038/s41586-023-06358-0}, volume = {620}, year = {2023}, } @article{19487, abstract = {Fix a non-square integer 𝑘≠0. We show that the number of curves 𝐸𝐵:𝑦^2=𝑥^3+𝑘𝐵^2 containing an integral point, where B ranges over positive integers less than N, is bounded by ≪𝑘𝑁(log𝑁)−1/2+𝜖. In particular, this implies that the number of positive integers 𝐵≤𝑁 such that −3𝑘𝐵^2 is the discriminant of an elliptic curve over 𝑄 is o(N). The proof involves a discriminant-lowering procedure on integral binary cubic forms.}, author = {Chan, Yik Tung}, issn = {1432-1807}, journal = {Mathematische Annalen}, number = {3}, pages = {2275--2288}, publisher = {Springer Nature}, title = {{Integral points on cubic twists of Mordell curves}}, doi = {10.1007/s00208-023-02578-x}, volume = {388}, year = {2023}, } @article{19803, abstract = {Eu⁢Cd2⁢P2 is notable for its unconventional transport: upon cooling the metallic resistivity changes slope and begins to increase, ultimately 100-fold, before returning to its metallic value. Surprisingly, this giant peak occurs at 18 K, well above the Néel temperature (𝑇𝑁) of 11.5 K. Using a suite of sensitive probes of magnetism, including resonant x-ray scattering and magneto-optical polarimetry, we have discovered that ferromagnetic order onsets above 𝑇𝑁 in the temperature range of the resistivity peak. The observation of inverted hysteresis in this regime shows that ferromagnetism is promoted by coupling of localized spins and itinerant carriers. The resulting carrier localization is confirmed by optical conductivity measurements.}, author = {Sunko, Veronika and Sun, Y. and Vranas, M. and Homes, C. C. and Lee, C. and Donoway, E. and Wang, Z.-C. and Balguri, S. and Mahendru, M. B. and Ruiz, A. and Gunn, B. and Basak, R. and Blanco-Canosa, S. and Schierle, E. and Weschke, E. and Tafti, F. and Frano, A. and Orenstein, J.}, issn = {2469-9969}, journal = {Physical Review B}, number = {14}, publisher = {American Physical Society}, title = {{Spin-carrier coupling induced ferromagnetism and giant resistivity peak in EuCd2P2}}, doi = {10.1103/physrevb.107.144404}, volume = {107}, year = {2023}, } @article{19821, abstract = {The adiabatic elastocaloric effect measures the temperature change of a given system with strain and provides a thermodynamic probe of the entropic landscape in the temperature-strain space. Here, we demonstrate that the DC bias strain-dependence of AC elastocaloric effect allows decomposition of the latter into symmetric (rotation-symmetry-preserving) and antisymmetric (rotation-symmetry-breaking) strain channels, using a tetragonal -electron intermetallic DyB2C2—whose antiferroquadrupolar order breaks local fourfold rotational symmetries while globally remaining tetragonal—as a showcase example. We capture the strain evolution of its quadrupolar and magnetic phase transitions using both singularities in the elastocaloric coefficient and its jumps at the transitions, and the latter we show follows a modified Ehrenfest relation. We find that antisymmetric strain couples to the underlying order parameter in a biquadratic (linear-quadratic) manner in the antiferroquadrupolar (canted antiferromagnetic) phase, which are attributed to a preserved (broken) global tetragonal symmetry, respectively. The broken tetragonal symmetry in the magnetic phase is further evidenced by elastocaloric strain-hysteresis and optical birefringence. Additionally, within the staggered quadrupolar order, the observed elastocaloric response reflects a quadratic increase of entropy with antisymmetric strain, analogous to the role magnetic field plays for Ising antiferromagnetic orders by promoting pseudospin flips. Our results demonstrate AC elastocaloric effect as a compact and incisive thermodynamic probe into the coupling between electronic degrees of freedom and strain in free energy, which holds the potential for investigating and understanding the symmetry of a wide variety of ordered phases in broader classes of quantum materials.}, author = {Ye, Linda and Sun, Yue and Sunko, Veronika and Rodriguez-Nieva, Joaquin F. and Ikeda, Matthias S. and Worasaran, Thanapat and Sorensen, Matthew E. and Bachmann, Maja D. and Orenstein, Joseph and Fisher, Ian R.}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {35}, publisher = {National Academy of Sciences}, title = {{Elastocaloric signatures of symmetric and antisymmetric strain-tuning of quadrupolar and magnetic phases in DyB2C2}}, doi = {10.1073/pnas.2302800120}, volume = {120}, year = {2023}, } @article{19828, abstract = {We describe an optical method to directly measure the position-dependent thermal diffusivity of reflective single crystal samples across a broad range of temperatures for condensed matter physics research. Two laser beams are used, one as a source to locally modulate the sample temperature, and the other as a probe of sample reflectivity, which is a function of the modulated temperature. Thermal diffusivity is obtained from the phase delay between source and probe signals. We combine this technique with a microscope setup in an optical cryostat, in which the sample is placed on a three-axis piezo-stage, allowing for spatially resolved measurements. Furthermore, we demonstrate experimentally and mathematically that isotropic in-plane diffusivity can be obtained when overlapping the two laser beams instead of separating them in the traditional way, which further enhances the spatial resolution to a micron scale, especially valuable when studying inhomogeneous or multidomain samples. We discuss in detail the experimental conditions under which this technique is valuable and demonstrate its performance on two stoichiometric bilayer ruthenates: Sr3Ru2O7 and Ca3Ru2O7. The spatial resolution allowed us to study the diffusivity in single domains of the latter, and we uncovered a temperature-dependent in-plane diffusivity anisotropy. Finally, we used the enhanced spatial resolution enabled by overlapping the two beams to measure the temperature-dependent diffusivity of Ti-doped Ca3Ru2O7, which exhibits a metal–insulator transition. We observed large variations of transition temperature over the same sample, originating from doping inhomogeneity and pointing to the power of spatially resolved techniques in accessing inherent properties.}, author = {Sun, F. and Mishra, S. and McGuinness, P. H. and Filipiak, Z. H. and Marković, I. and Sokolov, D. A. and Kikugawa, N. and Orenstein, J. W. and Hartnoll, S. A. and Mackenzie, A. P. and Sunko, Veronika}, issn = {1089-7623}, journal = {Review of Scientific Instruments}, number = {4}, publisher = {AIP Publishing}, title = {{A spatially resolved optical method to measure thermal diffusivity}}, doi = {10.1063/5.0098800}, volume = {94}, year = {2023}, } @inproceedings{19985, abstract = {We consider a natural problem dealing with weighted packet selection across a rechargeable link, which e.g., finds applications in cryptocurrency networks. The capacity of a link (u, v) is determined by how much nodes u and v allocate for this link. Specifically, the input is a finite ordered sequence of packets that arrive in both directions along a link. Given (u, v) and a packet of weight x going from u to v, node u can either accept or reject the packet. If u accepts the packet, the capacity on link (u, v) decreases by x. Correspondingly, v’s capacity on (u, v) increases by x. If a node rejects the packet, this will entail a cost affinely linear in the weight of the packet. A link is “rechargeable” in the sense that the total capacity of the link has to remain constant, but the allocation of capacity at the ends of the link can depend arbitrarily on the nodes’ decisions. The goal is to minimise the sum of the capacity injected into the link and the cost of rejecting packets. We show that the problem is NP-hard, but can be approximated efficiently with a ratio of (1 + E) . (1 + square3) for some arbitrary E>0.}, author = {Schmid, Stefan and Svoboda, Jakub and Yeo, Michelle X}, booktitle = {30th International Colloquium on Structural Information and Communication Complexity}, isbn = {9783031327322}, issn = {1611-3349}, location = {Alcalá de Henares, Spain}, pages = {576--594}, publisher = {Springer Nature}, title = {{Weighted acket selection for rechargeable links in cryptocurrency networks: Complexity and approximation}}, doi = {10.1007/978-3-031-32733-9_26}, volume = {13892}, year = {2023}, } @unpublished{20572, abstract = {We present an elementary non-recursive formula for the multivariate moments of the Dirichlet distribution on the standard simplex, in terms of the pattern inventory of the moments' exponents. We obtain analog formulas for the multivariate moments of the Dirichlet-Ferguson and Gamma measures. We further introduce a polychromatic analogue of Ewens sampling formula on colored integer partitions, discuss its relation with suitable extensions of Hoppe's urn model and of the Chinese restaurant process, and prove that it satisfies an adapted notion of consistency in the sense of Kingman.}, author = {Dello Schiavo, Lorenzo and Quattrocchi, Filippo}, booktitle = {arXiv}, keywords = {Dirichlet distribution, Ewens sampling formula, Hoppe urn model, colored partitions}, title = {{Multivariate Dirichlet moments and a polychromatic Ewens sampling formula}}, doi = {10.48550/arXiv.2309.11292}, year = {2023}, } @unpublished{20624, abstract = {We describe a sequence of smooth quotients of the Deligne-Mumford moduli space ${\mathbb R}\overline{\mathcal M}_{0,\ell+1}$ of real rational curves with $\ell\!+\!1$ conjugate pairs of marked points that terminates at ${\mathbb R}\overline{\mathcal M}_{0,\ell}\!\times\!{\mathbb C}{\mathbb P}^1$. This produces an analogue of Keel's blowup construction of the Deligne-Mumford moduli spaces $\overline{\mathcal M}_{\ell+1}$ of rational curves with $\ell\!+\!1$ marked points, but with an explicit description of the intermediate spaces and the blowups of three different types. The same framework readily adapts to the real moduli spaces with real points. In a sequel, we use this inductive construction of ${\mathbb R}\overline{\mathcal M}_{0,\ell+1}$ to completely determine the rational (co)homology ring of ${\mathbb R}\overline{\mathcal M}_{0,\ell}$.}, author = {Chen, Xujia and Zinger, Aleksey}, booktitle = {arXiv}, title = {{Blowdowns of the Deligne-Mumford spaces of real rational curves}}, doi = {10.48550/ARXIV.2305.08811}, year = {2023}, } @unpublished{20625, abstract = {It is a long-established and heavily-used fact that the integral cohomology ring of the Deligne-Mumford moduli space of (complex) rational curves is the polynomial ring on the boundary divisors modulo the ideal generated by the obvious geometric relations between them. We show that the rational cohomology ring of the Deligne-Mumford moduli space of real rational curves with conjugate marked points only is the polynomial ring on certain (``complex") boundary divisors and real boundary hypersurfaces modulo the ideal generated by the obvious geometric relations between them and the geometric relation in positive dimension and codimension identified in a previous paper.}, author = {Chen, Xujia and Georgieva, Penka and Zinger, Aleksey}, booktitle = {arXiv}, title = {{The cohomology ring of the Deligne-Mumford moduli space of real rational curves with conjugate marked points}}, doi = {10.48550/ARXIV.2305.08798}, year = {2023}, } @unpublished{20626, abstract = {Kontsevich's characteristic classes are invariants of framed smooth fiber bundles with homology sphere fibers. It was shown by Watanabe that they can be used to distinguish smooth $S^4$-bundles that are all trivial as topological fiber bundles. In this article we show that this ability of Kontsevich's classes is a manifestation of the following principle: the ``real blow-up'' construction on a smooth manifold essentially depends on its smooth structure and thus, given a smooth manifold (or smooth fiber bundle) $M$, the topological invariants of spaces constructed from $M$ by real blow-ups could potentially differentiate smooth structures on $M$. The main theorem says that Kontsevich's characteristic classes of a smooth framed bundle $π$ are determined by the topology of the 2-point configuration space bundle of $π$ and framing data.}, author = {Chen, Xujia}, booktitle = {arXiv}, title = {{Kontsevich's characteristic classes as topological invariants of configuration space bundles}}, doi = {10.48550/ARXIV.2302.03021}, year = {2023}, } @article{20759, abstract = {Recent advances in single-atom insertion reactions have opened up new synthetic approaches for molecular diversification. Developing innovative strategies to directly transform biologically relevant molecules, without any prefunctionalization, is key to further expanding the scope and utility of such transformations. Herein, the direct access to quinazolines and pyrimidines from the corresponding unprotected 1H-indoles and 1H-pyrroles is reported, relying on the implementation of lithium bis(trimethylsilyl)amide (LiHMDS) as a novel nitrogen atom source in combination with commercially available hypervalent iodine reagents. Further application of this strategy in late-stage settings demonstrates its potential in lead structure diversification campaigns.}, author = {Reisenbauer, Julia and Paschke, Ann-Sophie K. and Krizic, Jelena and Botlik, Bence B. and Finkelstein, Patrick and Morandi, Bill}, issn = {1523-7052}, journal = {Organic Letters}, number = {47}, pages = {8419--8423}, publisher = {American Chemical Society}, title = {{Direct access to quinazolines and pyrimidines from unprotected indoles and pyrroles through nitrogen atom insertion}}, doi = {10.1021/acs.orglett.3c03264}, volume = {25}, year = {2023}, } @article{20760, abstract = {The implementation of HCN-free transfer hydrocyanation reactions on laboratory scales has recently been achieved by using HCN donor reagents under nickel- and Lewis acid co-catalysis. More recently, malononitrile-based HCN donor reagents were shown to undergo the C(sp3)–CN bond activation by the nickel catalyst in the absence of Lewis acids. However, there is a lack of detailed mechanistic understanding of the challenging C(sp3)–CN bond cleavage step. In this work, in-depth kinetic and computational studies using alkynes as substrates were used to elucidate the overall reaction mechanism of this transfer hydrocyanation, with a particular focus on the activation of the C(sp3)–CN bond to generate the active H–Ni–CN transfer hydrocyanation catalyst. Comparisons of experimentally and computationally derived 13C kinetic isotope effect data support a direct oxidative addition mechanism of the nickel catalyst into the C(sp3)–CN bond facilitated by the coordination of the second nitrile group to the nickel catalyst.}, author = {Reisenbauer, Julia and Finkelstein, Patrick and Ebert, Marc-Olivier and Morandi, Bill}, issn = {2155-5435}, journal = {ACS Catalysis}, number = {17}, pages = {11548--11555}, publisher = {American Chemical Society}, title = {{Mechanistic investigation of the nickel-catalyzed transfer hydrocyanation of alkynes}}, doi = {10.1021/acscatal.3c02977}, volume = {13}, year = {2023}, } @article{20761, abstract = {We report a convenient protocol for a nitrogen atom insertion into indenes to afford isoquinolines. The reaction uses a combination of commercially available phenyliodine(III) diacetate (PIDA) and ammonium carbamate as the nitrogen source to furnish a wide range of isoquinolines. Various substitution patterns and commonly used functional groups are well tolerated. The operational simplicity renders this protocol broadly applicable and has been successfully extended towards the direct interconversion of cyclopentadienes into the corresponding pyridines. Furthermore, this strategy enables the facile synthesis of 15N labelled isoquinolines, using 15NH4Cl as a commercial 15N source.}, author = {Finkelstein, Patrick and Reisenbauer, Julia and Botlik, Bence B. and Green, Ori and Florin, Andri and Morandi, Bill}, issn = {2041-6539}, journal = {Chemical Science}, number = {11}, pages = {2954--2959}, publisher = {Royal Society of Chemistry}, title = {{Nitrogen atom insertion into indenes to access isoquinolines}}, doi = {10.1039/d2sc06952k}, volume = {14}, year = {2023}, } @article{20762, abstract = {A metal-free deaminative coupling of non-prefunctionalised benzylamines and arylboronic acids is reported. In this operationally simple reaction, a primary amine in benzylamine is converted into a good leaving group in situ using inexpensive and commercially available isoamyl nitrite as a nitrosating reagent. Lewis-acidic arylboronic acids are shown to replace mineral acids such as HCl or HBF4 that are conventionally used in the preparation of aryl diazonium salts. This unlocked the formation of the corresponding diarylmethanes by forging a new C–C bond in good yields. }, author = {Sirvinskaite, Giedre and Reisenbauer, Julia and Morandi, Bill}, issn = {2041-6539}, journal = {Chemical Science}, number = {7}, pages = {1709--1714}, publisher = {Royal Society of Chemistry}, title = {{Deaminative coupling of benzylamines and arylboronic acids}}, doi = {10.1039/d2sc06055h}, volume = {14}, year = {2023}, } @article{10145, abstract = {We study direct integrals of quadratic and Dirichlet forms. We show that each quasi-regular Dirichlet space over a probability space admits a unique representation as a direct integral of irreducible Dirichlet spaces, quasi-regular for the same underlying topology. The same holds for each quasi-regular strongly local Dirichlet space over a metrizable Luzin σ-finite Radon measure space, and admitting carré du champ operator. In this case, the representation is only projectively unique.}, author = {Dello Schiavo, Lorenzo}, issn = {1572-929X}, journal = {Potential Analysis}, pages = {573--615}, publisher = {Springer Nature}, title = {{Ergodic decomposition of Dirichlet forms via direct integrals and applications}}, doi = {10.1007/s11118-021-09951-y}, volume = {58}, year = {2023}, } @article{10173, abstract = {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.}, author = {Clozeau, Nicolas}, issn = {2194-0401}, journal = {Stochastics and Partial Differential Equations: Analysis and Computations}, pages = {1254–1378}, publisher = {Springer Nature}, title = {{Optimal decay of the parabolic semigroup in stochastic homogenization for correlated coefficient fields}}, doi = {10.1007/s40072-022-00254-w}, volume = {11}, year = {2023}, } @article{10174, abstract = {Quantitative stochastic homogenization of linear elliptic operators is by now well-understood. In this contribution we move forward to the nonlinear setting of monotone operators with p-growth. This first work is dedicated to a quantitative two-scale expansion result. Fluctuations will be addressed in companion articles. By treating the range of exponents 2≤p<∞ in dimensions d≤3, we are able to consider genuinely nonlinear elliptic equations and systems such as −∇⋅A(x)(1+|∇u|p−2)∇u=f (with A random, non-necessarily symmetric) for the first time. When going from p=2 to p>2, the main difficulty is to analyze the associated linearized operator, whose coefficients are degenerate, unbounded, and depend on the random input A via the solution of a nonlinear equation. One of our main achievements is the control of this intricate nonlinear dependence, leading to annealed Meyers' estimates for the linearized operator, which are key to the quantitative two-scale expansion result.}, author = {Clozeau, Nicolas and Gloria, Antoine}, issn = {1432-0673}, journal = {Archive for Rational Mechanics and Analysis }, number = {4}, publisher = {Springer Nature}, title = {{Quantitative nonlinear homogenization: Control of oscillations}}, doi = {10.1007/s00205-023-01895-4}, volume = {247}, year = {2023}, } @article{10405, abstract = {We consider large non-Hermitian random matrices X with complex, independent, identically distributed centred entries and show that the linear statistics of their eigenvalues are asymptotically Gaussian for test functions having 2+ϵ derivatives. Previously this result was known only for a few special cases; either the test functions were required to be analytic [72], or the distribution of the matrix elements needed to be Gaussian [73], or at least match the Gaussian up to the first four moments [82, 56]. We find the exact dependence of the limiting variance on the fourth cumulant that was not known before. The proof relies on two novel ingredients: (i) a local law for a product of two resolvents of the Hermitisation of X with different spectral parameters and (ii) a coupling of several weakly dependent Dyson Brownian motions. These methods are also the key inputs for our analogous results on the linear eigenvalue statistics of real matrices X that are presented in the companion paper [32]. }, author = {Cipolloni, Giorgio and Erdös, László and Schröder, Dominik J}, issn = {1097-0312}, journal = {Communications on Pure and Applied Mathematics}, number = {5}, pages = {946--1034}, publisher = {Wiley}, title = {{Central limit theorem for linear eigenvalue statistics of non-Hermitian random matrices}}, doi = {10.1002/cpa.22028}, volume = {76}, year = {2023}, }