TY - JOUR
AB - We establish the dimension and irreducibility of the moduli space of rational curves (of fixed degree) on arbitrary smooth hypersurfaces of sufficiently low degree. A spreading out argument reduces the problem to hypersurfaces defined over finite fields of large cardinality, which can then be tackled using a function field version of the Hardy-Littlewood circle method, in which particular care is taken to ensure uniformity in the size of the underlying finite field.
AU - Timothy Browning
AU - Vishe, Pankaj
ID - 265
IS - 7
JF - Geometric Methods in Algebra and Number Theory
TI - Rational curves on smooth hypersurfaces of low degree
VL - 11
ER -
TY - JOUR
AB - We generalise Birch's seminal work on forms in many variables to handle a system of forms in which the degrees need not all be the same. This allows us to prove the Hasse principle, weak approximation, and the Manin-Peyre conjecture for a smooth and geometrically integral variety X Pm, provided only that its dimension is large enough in terms of its degree.
AU - Timothy Browning
AU - Heath-Brown, Roger
ID - 266
IS - 2
JF - Journal of the European Mathematical Society
TI - Forms in many variables and differing degrees
VL - 19
ER -
TY - JOUR
AB - Building on recent work of Bhargava, Elkies and Schnidman and of Kriz and Li, we produce infinitely many smooth cubic surfaces defined over the field of rational numbers that contain rational points.
AU - Timothy Browning
ID - 267
IS - 3
JF - Mathematika
TI - Many cubic surfaces contain rational points
VL - 63
ER -
TY - JOUR
AB - We show that any subset of the squares of positive relative upper density contains nontrivial solutions to a translation-invariant linear equation in five or more variables, with explicit quantitative bounds. As a consequence, we establish the partition regularity of any diagonal quadric in five or more variables whose coefficients sum to zero. Unlike previous approaches, which are limited to equations in seven or more variables, we employ transference technology of Green to import bounds from the linear setting.
AU - Timothy Browning
AU - Prendiville, Sean M
ID - 268
IS - 7
JF - International Mathematics Research Notices
TI - A transference approach to a Roth-type theorem in the squares
VL - 2017
ER -
TY - JOUR
AU - Browning, Timothy D
AU - Loughran, Daniel
ID - 269
IS - 3-4
JF - Mathematische Zeitschrift
TI - Varieties with too many rational points
VL - 285
ER -
TY - JOUR
AB - Given a symmetric variety Y defined over Q and a non-zero polynomial with integer coefficients, we use techniques from homogeneous dynamics to establish conditions under which the polynomial can be made r-free for a Zariski dense set of integral points on Y . We also establish an asymptotic counting formula for this set. In the special case that Y is a quadric hypersurface, we give explicit bounds on the size of r by combining the argument with a uniform upper bound for the density of integral points on general affine quadrics defined over Q.
AU - Timothy Browning
AU - Gorodnik, Alexander
ID - 270
IS - 6
JF - Proceedings of the London Mathematical Society
TI - Power-free values of polynomials on symmetric varieties
VL - 114
ER -
TY - JOUR
AB - We show that a non-singular integral form of degree d is soluble non-trivially over the integers if and only if it is soluble non-trivially over the reals and the p-adic numbers, provided that the form has at least (d-\sqrt{d}/2)2^d variables. This improves on a longstanding result of Birch.
AU - Timothy Browning
AU - Prendiville, Sean M
ID - 271
IS - 731
JF - Journal fur die Reine und Angewandte Mathematik
TI - Improvements in Birch's theorem on forms in many variables
VL - 2017
ER -
TY - JOUR
AB - Given a number field K/Q and a polynomial P ε Q [t], all of whose roots are Q, let X be the variety defined by the equation NK (x) = P (t). Combining additive combinatiorics with descent we show that the Brauer-Manin obstruction is the only obstruction to the Hesse principle and weak approximation on any smooth and projective model of X.
AU - Timothy Browning
AU - Matthiesen, Lilian
ID - 272
IS - 6
JF - Annales Scientifiques de l'Ecole Normale Superieure
TI - Norm forms for arbitrary number fields as products of linear polynomials
VL - 50
ER -
TY - CONF
AB - We consider the problem of estimating the partition function Z(β)=∑xexp(−β(H(x)) of a Gibbs distribution with a Hamilton H(⋅), or more precisely the logarithm of the ratio q=lnZ(0)/Z(β). It has been recently shown how to approximate q with high probability assuming the existence of an oracle that produces samples from the Gibbs distribution for a given parameter value in [0,β]. The current best known approach due to Huber [9] uses O(qlnn⋅[lnq+lnlnn+ε−2]) oracle calls on average where ε is the desired accuracy of approximation and H(⋅) is assumed to lie in {0}∪[1,n]. We improve the complexity to O(qlnn⋅ε−2) oracle calls. We also show that the same complexity can be achieved if exact oracles are replaced with approximate sampling oracles that are within O(ε2qlnn) variation distance from exact oracles. Finally, we prove a lower bound of Ω(q⋅ε−2) oracle calls under a natural model of computation.
AU - Kolmogorov, Vladimir
ID - 274
T2 - Proceedings of the 31st Conference On Learning Theory
TI - A faster approximation algorithm for the Gibbs partition function
VL - 75
ER -
TY - JOUR
AB - We present the fabrication and characterization of an aluminum transmon qubit on a silicon-on-insulator substrate. Key to the qubit fabrication is the use of an anhydrous hydrofluoric vapor process which selectively removes the lossy silicon oxide buried underneath the silicon device layer. For a 5.6 GHz qubit measured dispersively by a 7.1 GHz resonator, we find T1 = 3.5 μs and T∗2 = 2.2 μs. This process in principle permits the co-fabrication of silicon photonic and mechanical elements, providing a route towards chip-scale integration of electro-opto-mechanical transducers for quantum networking of superconducting microwave quantum circuits. The additional processing steps are compatible with established fabrication techniques for aluminum transmon qubits on silicon.
AU - Keller, Andrew J
AU - Dieterle, Paul
AU - Fang, Michael
AU - Berger, Brett
AU - Fink, Johannes M
AU - Painter, Oskar
ID - 796
IS - 4
JF - Applied Physics Letters
SN - 00036951
TI - Al transmon qubits on silicon on insulator for quantum device integration
VL - 111
ER -
TY - JOUR
AB - Phasenübergänge helfen beim Verständnis von Vielteilchensystemen in der Festkörperphysik und Fluiddynamik bis hin zur Teilchenphysik. Unserer internationalen Kollaboration ist es gelungen, einen neuartigen Phasenübergang in einem Quantensystem zu beobachten [1]. In einem Mikrowellenresonator konnte erstmals die spontane Zustandsänderung von undurchsichtig zu transparent nachgewiesen werden.
AU - Fink, Johannes M
ID - 797
IS - 3
JF - Physik in unserer Zeit
TI - Photonenblockade aufgelöst
VL - 48
ER -
TY - JOUR
AB - Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. Here we demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanic interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electro-mechanical signal conversion paths. The presented circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. With a high dynamic range, a tunable bandwidth of up to 30 MHz and an in situ reconfigurability as beam splitter or wavelength converter, it could pave the way for superconducting qubit processors with multiplexed on-chip signal processing and readout.
AU - Barzanjeh, Shabir
AU - Wulf, Matthias
AU - Peruzzo, Matilda
AU - Kalaee, Mahmoud
AU - Dieterle, Paul
AU - Painter, Oskar
AU - Fink, Johannes M
ID - 798
IS - 1
JF - Nature Communications
SN - 20411723
TI - Mechanical on chip microwave circulator
VL - 8
ER -
TY - CHAP
AB - In this part, the use of polysaccharides, either directly through composite approaches, or by carbonization will be described. In many cases, materials are obtained which are competitive in terms of capacitance and cycle lifetime. In this part, the use of polysaccharides, either directly through composite approaches, or by carbonization will be described. In many cases, materials are obtained which are competitive in terms of capacitance and cycle lifetime. The following part will focus mainly on cellulosic composites with conductive polymers since cellulose is most abundant and therefore has attracted much more research interest in this field whereas in the second part also other polysaccharides, such as chitin, xylans, alginates, pectins, dextrans and caragenaans have been used in carbonization experiments.
AU - Yee Liew, Soon
AU - Thielemans, Wim
AU - Freunberger, Stefan Alexander
AU - Spirk, Stefan
ED - Yee Liew, Soon
ED - Thielemans, Wim
ED - Freunberger, Stefan Alexander
ED - Spirk, Stefan
ID - 7980
SN - 2191-5407
T2 - Polysaccharide Based Supercapacitors
TI - Polysaccharides in supercapacitors
ER -
TY - JOUR
AB - Aprotische Natrium‐O2‐Batterien basieren auf der reversiblen Bildung und Auflösung von Natriumsuperoxid (NaO2) während des Zellbetriebs. Nebenreaktionen des Elektrolyten und der Elektrode mit dem stark nukleophilen und basischen NaO2 führen zu mangelhafter Zyklenstabilität. Seine Reaktivität allein kann die Nebenreaktionen und schlechte Reversibilität jedoch nicht schlüssig erklären. Hier wird gezeigt, dass Singulett‐Sauerstoff (1O2) in allen Phasen des Betriebs entsteht und eine Hauptursache für Nebenreaktionen ist. 1O2 wurde in situ und ex situ mit einem 1O2‐Fänger detektiert, der schnell und selektiv ein Addukt mit 1O2 bildet. Mechanistisch betrachtet entsteht 1O2 entweder durch protonenunterstützte Disproportionierung von Superoxid während des Entladens, Lagerns und Ladens unter ca. 3.3 V oder durch direkte elektrochemische 1O2‐Entwicklung über ca. 3.3 V. Spuren von Wasser ermöglichen hohe Kapazitäten, beschleunigen aber auch Nebenreaktionen. Daher muss das hochreaktive 1O2 unbedingt kontrolliert werden, um die Zelle reversibel zu betreiben.
AU - Schafzahl, Lukas
AU - Mahne, Nika
AU - Schafzahl, Bettina
AU - Wilkening, Martin
AU - Slugovc, Christian
AU - Borisov, Sergey M.
AU - Freunberger, Stefan Alexander
ID - 7981
IS - 49
JF - Angewandte Chemie
SN - 0044-8249
TI - Singulett-Sauerstoff in der aprotischen Natrium-O2-Batterie
VL - 129
ER -
TY - JOUR
AB - Beyond-intercalation batteries promise a step-change in energy storage compared to intercalation-based lithium-ion and sodium-ion batteries. However, only performance metrics that include all cell components and operation parameters can tell whether a true advance over intercalation batteries has been achieved.
AU - Freunberger, Stefan Alexander
ID - 7982
IS - 7
JF - Nature Energy
SN - 2058-7546
TI - True performance metrics in beyond-intercalation batteries
VL - 2
ER -
TY - JOUR
AU - Mahne, Nika
AU - Schafzahl, Bettina
AU - Leypold, Christian
AU - Leypold, Mario
AU - Grumm, Sandra
AU - Leitgeb, Anita
AU - Strohmeier, Gernot A.
AU - Wilkening, Martin
AU - Fontaine, Olivier
AU - Kramer, Denis
AU - Slugovc, Christian
AU - Borisov, Sergey M.
AU - Freunberger, Stefan Alexander
ID - 7986
IS - 5
JF - Nature Energy
SN - 2058-7546
TI - Singlet oxygen generation as a major cause for parasitic reactions during cycling of aprotic lithium–oxygen batteries
VL - 2
ER -
TY - JOUR
AB - Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to a fungal toxin brefeldin A (BFA), which is known to inhibit guanine-nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM. However, the molecular details of the BFA-sensitive trafficking pathway have not been revealed fully. In a previous study, we have identified an Arabidopsis mutant BFA-visualized endocytic trafficking defective 3 (ben3) which exhibited reduced sensitivity to BFA in terms of BFA-induced intracellular PIN1 agglomeration. Here, we show that BEN3 encodes a member of BIG family ARF GEFs, BIG2. Fluorescent proteins tagged BEN3/BIG2 co-localized with markers for TGN / early endosome (EE). Inspection of conditionally induced de novo synthesized PIN1 confirmed that its secretion to the PM is BFA-sensitive and established BEN3/BIG2 as a crucial component of this BFA action at the level of TGN/EE. Furthermore, ben3 mutation alleviated BFA-induced agglomeration of another TGN-localized ARF GEF BEN1/MIN7. Taken together our results suggest that BEN3/BIG2 is an ARF GEF component, which confers BFA sensitivity to the TGN/EE in Arabidopsis.
AU - Kitakura, Saeko
AU - Adamowski, Maciek
AU - Matsuura, Yuki
AU - Santuari, Luca
AU - Kouno, Hirotaka
AU - Arima, Kohei
AU - Hardtke, Christian
AU - Friml, Jirí
AU - Kakimoto, Tatsuo
AU - Tanaka, Hirokazu
ID - 799
IS - 10
JF - Plant and Cell Physiology
SN - 00320781
TI - BEN3/BIG2 ARF GEF is involved in brefeldin a-sensitive trafficking at the trans-Golgi network/early endosome in Arabidopsis thaliana
VL - 58
ER -
TY - JOUR
AB - Gamma oscillations (30–150 Hz) in neuronal networks are associated with the processing and recall of information. We measured local field potentials in the dentate gyrus of freely moving mice and found that gamma activity occurs in bursts, which are highly heterogeneous in their spatial extensions, ranging from focal to global coherent events. Synaptic communication among perisomatic-inhibitory interneurons (PIIs) is thought to play an important role in the generation of hippocampal gamma patterns. However, how neuronal circuits can generate synchronous oscillations at different spatial scales is unknown. We analyzed paired recordings in dentate gyrus slices and show that synaptic signaling at interneuron-interneuron synapses is distance dependent. Synaptic strength declines whereas the duration of inhibitory signals increases with axonal distance among interconnected PIIs. Using neuronal network modeling, we show that distance-dependent inhibition generates multiple highly synchronous focal gamma bursts allowing the network to process complex inputs in parallel in flexibly organized neuronal centers.
AU - Strüber, Michael
AU - Sauer, Jonas
AU - Jonas, Peter M
AU - Bartos, Marlene
ID - 800
IS - 1
JF - Nature Communications
SN - 20411723
TI - Distance-dependent inhibition facilitates focality of gamma oscillations in the dentate gyrus
VL - 8
ER -
TY - JOUR
AB - Long-term modifications of neuronal connections are critical for reliable memory storage in the brain. However, their locus of expression—pre- or postsynaptic—is highly variable. Here we introduce a theoretical framework in which long-term plasticity performs an optimization of the postsynaptic response statistics toward a given mean with minimal variance. Consequently, the state of the synapse at the time of plasticity induction determines the ratio of pre- and postsynaptic modifications. Our theory explains the experimentally observed expression loci of the hippocampal and neocortical synaptic potentiation studies we examined. Moreover, the theory predicts presynaptic expression of long-term depression, consistent with experimental observations. At inhibitory synapses, the theory suggests a statistically efficient excitatory-inhibitory balance in which changes in inhibitory postsynaptic response statistics specifically target the mean excitation. Our results provide a unifying theory for understanding the expression mechanisms and functions of long-term synaptic transmission plasticity.
AU - Costa, Rui Ponte
AU - Padamsey, Zahid
AU - D’Amour, James A.
AU - Emptage, Nigel J.
AU - Froemke, Robert C.
AU - Vogels, Tim P
ID - 8016
IS - 1
JF - Neuron
SN - 0896-6273
TI - Synaptic transmission optimization predicts expression loci of long-term plasticity
VL - 96
ER -
TY - JOUR
AB - nhibitory neurons, although relatively few in number, exert powerful control over brain circuits. They stabilize network activity in the face of strong feedback excitation and actively engage in computations. Recent studies reveal the importance of a precise balance of excitation and inhibition in neural circuits, which often requires exquisite fine-tuning of inhibitory connections. We review inhibitory synaptic plasticity and its roles in shaping both feedforward and feedback control. We discuss the necessity of complex, codependent plasticity mechanisms to build nontrivial, functioning networks, and we end by summarizing experimental evidence of such interactions.
AU - Hennequin, Guillaume
AU - Agnes, Everton J.
AU - Vogels, Tim P
ID - 8017
IS - 1
JF - Annual Review of Neuroscience
SN - 0147-006X
TI - Inhibitory plasticity: Balance, control, and codependence
VL - 40
ER -