@article{2193, abstract = {We show that weakly bound molecules can be probed by "shaking" in a pulsed nonresonant laser field. The field introduces a centrifugal term which expels the highest vibrational level from the potential that binds it. Our numerical simulations applied to the Rb2 and KRb Feshbach molecules indicate that shaking by feasible laser pulses can be used to accurately recover the square of the vibrational wave function and, by inversion, also the long-range part of the molecular potential.}, author = {Mikhail Lemeshko and Friedrich, Břetislav}, journal = {Physical Review Letters}, number = {5}, publisher = {American Physical Society}, title = {{Probing weakly bound molecules with nonresonant light}}, doi = {10.1103/PhysRevLett.103.053003}, volume = {103}, year = {2009}, } @article{228, abstract = {Let X be a projective non-singular quartic hypersurface of dimension 39 or more, which is defined over . We show that X() is non-empty provided that X() is non-empty and X has p-adic points for every prime p.}, author = {Timothy Browning and Heath-Brown, Roger}, journal = {Journal fur die Reine und Angewandte Mathematik}, number = {629}, pages = {37 -- 88}, publisher = {Walter de Gruyter}, title = {{Rational points on quartic hypersurfaces}}, doi = {10.1515/CRELLE.2009.026}, year = {2009}, } @article{229, abstract = {An upper bound of the expected order of magnitude is established for the number of ℚ-rational points of bounded height on Châtelet surfaces defined over ℚ.}, author = {Timothy Browning}, journal = {Mathematische Annalen}, number = {1}, pages = {41 -- 50}, publisher = {Springer Nature}, title = {{Linear growth for Châtelet surfaces}}, doi = {10.1007/s00208-009-0383-z}, volume = {346}, year = {2009}, } @article{2384, abstract = {We prove the Lee-Huang-Yang formula for the ground state energy of the 3D Bose gas with repulsive interactions described by the exponential function, in a simultaneous limit of weak coupling and high density. In particular, we show that the Bogoliubov approximation is exact in an appropriate parameter regime, as far as the ground state energy is concerned.}, author = {Giuliani, Alessandro and Robert Seiringer}, journal = {Journal of Statistical Physics}, number = {5-6}, pages = {915 -- 934}, publisher = {Springer}, title = {{The ground state energy of the weakly interacting Bose gas at high density}}, doi = {10.1007/s10955-009-9718-0}, volume = {135}, year = {2009}, } @article{2385, abstract = {We consider an ultracold rotating Bose gas in a harmonic trap close to the critical angular velocity, so that the system can be considered to be confined to the lowest Landau level. With this assumption we prove that the Gross-Pitaevskii energy functional accurately describes the ground-state energy of the corresponding N -body Hamiltonian with contact interaction provided the total angular momentum L is much less than N2. While the Gross-Pitaevskii energy is always an obvious variational upper bound to the ground-state energy, a more refined analysis is needed to establish it as an exact lower bound. We also discuss the question of Bose-Einstein condensation in the parameter range considered. Coherent states together with inequalities in spaces of analytic functions are the main technical tools.}, author = {Lieb, Élliott H and Robert Seiringer and Yngvason, Jakob}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, number = {6}, publisher = {American Physical Society}, title = {{Yrast line of a rapidly rotating Bose gas: Gross-Pitaevskii regime}}, doi = {10.1103/PhysRevA.79.063626}, volume = {79}, year = {2009}, } @article{2386, abstract = {We prove exponential decay of the off-diagonal correlation function in the two-dimensional homogeneous Bose gas when a2 ρ is small and the temperature T satisfies T> 4πρ ln | ln (a2 ρ) |. Here, a is the scattering length of the repulsive interaction potential and ρ is the density. To the leading order in a2 ρ, this bound agrees with the expected critical temperature for superfluidity. In the three-dimensional Bose gas, exponential decay is proved when T- Tc (0) Tc (0) >5 a ρ1/3, where Tc (0) is the critical temperature of the ideal gas. While this condition is not expected to be sharp, it gives a rigorous upper bound on the critical temperature for Bose-Einstein condensation.}, author = {Robert Seiringer and Ueltschi, Daniel}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {1}, publisher = {American Physical Society}, title = {{Rigorous upper bound on the critical temperature of dilute Bose gases}}, doi = {10.1103/PhysRevB.80.014502}, volume = {80}, year = {2009}, } @article{2387, abstract = {We consider a system of trapped spinless bosons interacting with a repulsive potential and subject to rotation. In the limit of rapid rotation and small scattering length, we rigorously show that the ground state energy converges to that of a simplified model Hamiltonian with contact interaction projected onto the Lowest Landau Level. This effective Hamiltonian models the bosonic analogue of the Fractional Quantum Hall Effect (FQHE). For a fixed number of particles, we also prove convergence of states; in particular, in a certain regime we show convergence towards the bosonic Laughlin wavefunction. This is the first rigorous justification of the effective FQHE Hamiltonian for rapidly rotating Bose gases. We review previous results on this effective Hamiltonian and outline open problems.}, author = {Lewin, Mathieu and Robert Seiringer}, journal = {Journal of Statistical Physics}, number = {5}, pages = {1040 -- 1062}, publisher = {Springer}, title = {{Strongly correlated phases in rapidly rotating Bose gases}}, doi = {10.1007/s10955-009-9833-y}, volume = {137}, year = {2009}, } @article{2388, abstract = {This paper provides self-contained proof of a theorem relating probabilistic coherence of forecasts to their non-domination by rival forecasts with respect to any proper scoring rule. The theorem recapitulates insights achieved by other investigators, and clarifies the connection of coherence and proper scoring rules to Bregman divergence.}, author = {Predd, Joel B and Robert Seiringer and Lieb, Élliott H and Osherson, Daniel N and Poor, Harold V and Kulkarni, Sanjeev R}, journal = {IEEE Transactions on Information Theory}, number = {10}, pages = {4786 -- 4792}, publisher = {IEEE}, title = {{Probabilistic coherence and proper scoring rules}}, doi = {10.1109/TIT.2009.2027573}, volume = {55}, year = {2009}, } @inproceedings{2433, abstract = {Let EMBEDk→d be the following algorithmic problem: Given a finite simplicial complex K of dimension at most k, does there exist a (piecewise linear) embedding of K into ℝd? Known results easily imply polynomiality of EMBEDk→2 (k = 1, 2; the case k = 1, d = 2 is graph planarity) and of EMBEDk→2k for all k ≥ 3 (even if k is not considered fixed). We show that the celebrated result of Novikov on the algorithmic unsolvability of recognizing the 5-sphere implies that EMBED d→d and EMBED(d-1)→d are undecidable for each d ≥ 5. Our main result is NP-hardness of EMBED2→4 and, more generally, of EMBEDk→d for all k, d with d ≥ 4 and d ≥ k ≥ (2d - 2)/3.}, author = {Matoušek, Jiří and Martin Tancer and Uli Wagner}, pages = {855 -- 864}, publisher = {SIAM}, title = {{Hardness of embedding simplicial complexes in ℝd}}, year = {2009}, } @inproceedings{4569, abstract = {Most specification languages express only qualitative constraints. However, among two implementations that satisfy a given specification, one may be preferred to another. For example, if a specification asks that every request is followed by a response, one may prefer an implementation that generates responses quickly but does not generate unnecessary responses. We use quantitative properties to measure the “goodness” of an implementation. Using games with corresponding quantitative objectives, we can synthesize “optimal” implementations, which are preferred among the set of possible implementations that satisfy a given specification. In particular, we show how automata with lexicographic mean-payoff conditions can be used to express many interesting quantitative properties for reactive systems. In this framework, the synthesis of optimal implementations requires the solution of lexicographic mean-payoff games (for safety requirements), and the solution of games with both lexicographic mean-payoff and parity objectives (for liveness requirements). We present algorithms for solving both kinds of novel graph games.}, author = {Bloem, Roderick and Chatterjee, Krishnendu and Henzinger, Thomas A and Jobstmann, Barbara}, location = {Grenoble, France}, pages = {140 -- 156}, publisher = {Springer}, title = {{Better quality in synthesis through quantitative objectives}}, doi = {10.1007/978-3-642-02658-4_14}, volume = {5643}, year = {2009}, } @inproceedings{4580, abstract = {Alpaga is a solver for two-player parity games with imperfect information. Given the description of a game, it determines whether the first player can ensure to win and, if so, it constructs a winning strategy. The tool provides a symbolic implementation of a recent algorithm based on antichains.}, author = {Berwanger, Dietmar and Krishnendu Chatterjee and De Wulf, Martin and Doyen, Laurent and Thomas Henzinger}, pages = {58 -- 61}, publisher = {Springer}, title = {{Alpaga: A tool for solving parity games with imperfect information}}, doi = {10.1007/978-3-642-00768-2_7}, volume = {5505}, year = {2009}, } @misc{5392, abstract = {We consider probabilistic automata on infinite words with acceptance defined by safety, reachability, Büchi, coBüchi and limit-average conditions. We consider quantitative and qualitative decision problems. We present extensions and adaptations of proofs of [GO09] and present a precise characterization of the decidability and undecidability frontier of the quantitative and qualitative decision problems.}, author = {Chatterjee, Krishnendu}, issn = {2664-1690}, pages = {17}, publisher = {IST Austria}, title = {{Probabilistic automata on infinite words: Decidability and undecidability results}}, doi = {10.15479/AT:IST-2009-0004}, year = {2009}, } @misc{5393, abstract = {Gist is a tool that (a) solves the qualitative analysis problem of turn-based probabilistic games with ω-regular objectives; and (b) synthesizes reasonable environment assumptions for synthesis of unrealizable specifications. Our tool provides efficient implementations of several reduction based techniques to solve turn-based probabilistic games, and uses the analysis of turn-based probabilistic games for synthesizing environment assumptions for unrealizable specifications.}, author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Jobstmann, Barbara and Radhakrishna, Arjun}, issn = {2664-1690}, pages = {12}, publisher = {IST Austria}, title = {{Gist: A solver for probabilistic games}}, doi = {10.15479/AT:IST-2009-0003}, year = {2009}, } @misc{5394, abstract = {We consider two-player games played on graphs with request-response and finitary Streett objectives. We show these games are PSPACE-hard, improving the previous known NP-hardness. We also improve the lower bounds on memory required by the winning strategies for the players.}, author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Horn, Florian}, issn = {2664-1690}, pages = {11}, publisher = {IST Austria}, title = {{Improved lower bounds for request-response and finitary Streett games}}, doi = {10.15479/AT:IST-2009-0002}, year = {2009}, } @misc{5395, abstract = {We study observation-based strategies for partially-observable Markov decision processes (POMDPs) with omega-regular objectives. An observation-based strategy relies on partial information about the history of a play, namely, on the past sequence of observa- tions. We consider the qualitative analysis problem: given a POMDP with an omega-regular objective, whether there is an observation-based strategy to achieve the objective with probability 1 (almost-sure winning), or with positive probability (positive winning). Our main results are twofold. First, we present a complete picture of the computational complexity of the qualitative analysis of POMDPs with parity objectives (a canonical form to express omega-regular objectives) and its subclasses. Our contribution consists in establishing several upper and lower bounds that were not known in literature. Second, we present optimal bounds (matching upper and lower bounds) on the memory required by pure and randomized observation-based strategies for the qualitative analysis of POMDPs with parity objectives and its subclasses.}, author = {Chatterjee, Krishnendu and Doyen, Laurent and Henzinger, Thomas A}, issn = {2664-1690}, pages = {20}, publisher = {IST Austria}, title = {{Qualitative analysis of partially-observable Markov decision processes}}, doi = {10.15479/AT:IST-2009-0001}, year = {2009}, } @article{599, abstract = {The human CDK8 subcomplex (CDK8, cyclin C, Med12, and Med13) negatively regulates transcription in ways not completely defined; past studies suggested CDK8 kinase activity was required for its repressive function. Using a reconstituted transcription system together with recombinant or endogenous CDK8 subcomplexes, we demonstrate that, in fact, Med12 and Med13 are critical for subcomplex-dependent repression, whereas CDK8 kinase activity is not. A hallmark of activated transcription is efficient reinitiation from promoter-bound scaffold complexes that recruit a series of pol II enzymes to the gene. Notably, the CDK8 submodule strongly represses even reinitiation events, suggesting a means to fine tune transcript levels. Structural and biochemical studies confirm the CDK8 submodule binds the Mediator leg/tail domain via the Med13 subunit, and this submodule-Mediator association precludes pol II recruitment. Collectively, these results reveal the CDK8 subcomplex functions as a simple switch that controls the Mediator-pol II interaction to help regulate transcription initiation and reinitiation events. As Mediator is generally required for expression of protein-coding genes, this may reflect a common mechanism by which activated transcription is shut down in human cells.}, author = {Knuesel, Matthew and Meyer, Krista and Bernecky, Carrie A and Taatjes, Dylan}, journal = {Genes and Development}, number = {4}, pages = {439 -- 451}, publisher = {Cold Spring Harbor Laboratory Press}, title = {{The human CDK8 subcomplex is a molecular switch that controls Mediator coactivator function}}, doi = {10.1101/gad.1767009}, volume = {23}, year = {2009}, } @article{9147, abstract = {As part of an ongoing effort to develop a parameterization of wave-induced abyssal mixing, the authors derive an heuristic model for nonlinear wave breaking and energy dissipation associated with internal tides. Then the saturation and dissipation of internal tides for idealized and observed topography samples are investigated. One of the main results is that the wave-induced mixing could be more intense and more confined to the bottom than previously assumed in numerical models. Furthermore, in this model wave breaking and mixing clearly depend on the small scales of the topography below 10 km or so, which is below the current resolution of global bathymetry. This motivates the use of a statistical approach to represent the unresolved topography when addressing the role of internal tides in mixing the deep ocean.}, author = {Muller, Caroline J and Bühler, Oliver}, issn = {1520-0485}, journal = {Journal of Physical Oceanography}, keywords = {Oceanography}, number = {9}, pages = {2077--2096}, publisher = {American Meteorological Society}, title = {{Saturation of the internal tides and induced mixing in the abyssal ocean}}, doi = {10.1175/2009jpo4141.1}, volume = {39}, year = {2009}, } @article{9148, abstract = {Several observational studies have shown a tight relationship between tropical precipitation and column‐integrated water vapor. We show that the observed relationship in the tropics between column‐integrated water vapor, precipitation, and its variance can be qualitatively reproduced by a simple and physically motivated two‐layer model. It has previously been argued that features of this relationship could be explained by analogy with the theory of continuous phase transitions. Instead, our model explicitly assumes that the onset of precipitation is governed by a stability threshold involving boundary‐layer water vapor. This allows us to explain the precipitation‐humidity relationship over a broader range of water vapor values, and may explain the observed temperature dependence of the relationship.}, author = {Muller, Caroline J and Back, Larissa E. and O'Gorman, Paul A. and Emanuel, Kerry A.}, issn = {0094-8276}, journal = {Geophysical Research Letters}, keywords = {General Earth and Planetary Sciences, Geophysics}, number = {16}, publisher = {American Geophysical Union}, title = {{A model for the relationship between tropical precipitation and column water vapor}}, doi = {10.1029/2009gl039667}, volume = {36}, year = {2009}, } @article{9453, abstract = {Parent-of-origin-specific (imprinted) gene expression is regulated in Arabidopsis thaliana endosperm by cytosine demethylation of the maternal genome mediated by the DNA glycosylase DEMETER, but the extent of the methylation changes is not known. Here, we show that virtually the entire endosperm genome is demethylated, coupled with extensive local non-CG hypermethylation of small interfering RNA–targeted sequences. Mutation of DEMETER partially restores endosperm CG methylation to levels found in other tissues, indicating that CG demethylation is specific to maternal sequences. Endosperm demethylation is accompanied by CHH hypermethylation of embryo transposable elements. Our findings demonstrate extensive reconfiguration of the endosperm methylation landscape that likely reinforces transposon silencing in the embryo.}, author = {Hsieh, Tzung-Fu and Ibarra, Christian A. and Silva, Pedro and Zemach, Assaf and Eshed-Williams, Leor and Fischer, Robert L. and Zilberman, Daniel}, issn = {1095-9203}, journal = {Science}, keywords = {Multidisciplinary}, number = {5933}, pages = {1451--1454}, publisher = {American Association for the Advancement of Science}, title = {{Genome-wide demethylation of Arabidopsis endosperm}}, doi = {10.1126/science.1172417}, volume = {324}, year = {2009}, } @article{1038, abstract = {One possible way to produce ultra-cold, high-phase-space-density quantum gases of molecules in the rovibronic ground state is given by molecule association from quantum-degenerate atomic gases on a Feshbach resonance and subsequent coherent optical multi-photon transfer into the rovibronic ground state. In ultra-cold samples of Cs2 molecules, we observe two-photon dark resonances that connect the intermediate rovibrational level |v=73,J=2 with the rovibrational ground state |v=0,J=0 of the singlet X 1 ∑ g + ground-state potential. For precise dark resonance spectroscopy we exploit the fact that it is possible to efficiently populate the level |v=73,J=2 by two-photon transfer from the dissociation threshold with the stimulated Raman adiabatic passage (STIRAP) technique. We find that at least one of the two-photon resonances is sufficiently strong to allow future implementation of coherent STIRAP transfer of a molecular quantum gas to the rovibrational ground state |v=0,J=0.}, author = {Mark, Manfred and Danzl, Johann G and Haller, Elmar and Gustavsson, Mattias and Bouloufa, Nadia and Dulieu, Olivier and Salami, Houssam and Bergeman, Thomas and Ritsch, Helmut and Hart, Russell and Nägerl, Hanns}, journal = {Applied Physics B: Lasers and Optics}, number = {2}, pages = {219 -- 225}, publisher = {Springer}, title = {{Dark resonances for ground-state transfer of molecular quantum gases}}, doi = {10.1007/s00340-009-3407-1}, volume = {95}, year = {2009}, }