125,802 research outputs found
Four-quark condensates in open-charm chiral QCD sum rules
Recently, in Hilger et al. (2011) [1] QCD sum rules for chiral partners in
the open-charm meson sector have been presented at nonzero baryon net density
or temperature up to and including mass dimension 5. Referring to this, details
concerning the cancelation of infrared divergences are presented and important
technical and conceptional ingredients for an incorporation of four-quark
condensates beyond factorization and of other mass dimension 6 condensates are
collected.Comment: 7 pages, 5 figures, conference proceedin
Lifted rule injection for relation embeddings
Methods based on representation learning currently hold the state-of-the-art in many natural language processing and knowledge base inference tasks. Yet, a major challenge is how to efficiently incorporate commonsense knowledge into such models. A recent approach regularizes relation and entity representations by propositionalization of first-order logic rules. However, propositionalization does not scale beyond domains with only few entities and rules. In this paper we present a highly efficient method for incorporating implication rules into distributed representations for automated knowledge base construction. We map entity-tuple embeddings into an approximately Boolean space and encourage a partial ordering over relation embeddings based on implication rules mined from WordNet. Surprisingly, we find that the strong restriction of the entity-tuple embedding space does not hurt the expressiveness of the model and even acts as a regularizer that improves generalization. By incorporating few commonsense rules, we achieve an increase of 2 percentage points mean average precision over a matrix factorization baseline, while observing a negligible increase in runtime
Special Lagrangians, stable bundles and mean curvature flow
We make a conjecture about mean curvature flow of Lagrangian submanifolds of
Calabi-Yau manifolds, expanding on \cite{Th}. We give new results about the
stability condition, and propose a Jordan-H\"older-type decomposition of
(special) Lagrangians. The main results are the uniqueness of special
Lagrangians in hamiltonian deformation classes of Lagrangians, under mild
conditions, and a proof of the conjecture in some cases with symmetry: mean
curvature flow converging to Shapere-Vafa's examples of SLags.Comment: 36 pages, 4 figures. Minor referee's correction
Impact of Four-Quark Condensates on In-Medium Effects of Hadrons
Spectral properties of hadrons in nuclear matter are treated in the framework
of QCD sum rules. The influence of the ambient strongly interacting medium is
encoded in various condensates. Especially, the structure of different
four-quark condensates and their density dependencies in light quark systems
are exemplified for the omega meson and the nucleon.Comment: Contribution to Quark Confinement and the Hadron Spectrum VII,
02.-07.09.2006, Ponta Delgada, Portuga
Studies of low-energy ionic collisions Final report, 1 Oct. 1965 - 30 Sep. 1967
Ionic-molecular collisions, and collision induced dissociation of ion
QCD sum rules for D and B mesons in nuclear matter
QCD sum rules for D and B mesons embedded in cold nuclear matter are
evaluated. We quantify the mass splitting of D - D-bar and B - B-bar mesons as
a function of the nuclear matter density; extrapolated to saturation density it
is in the order of 60 and 130 MeV driven essentially by the condensates
, and . The genuine chiral
condensate , amplified by heavy-quark masses, enters the Borel
transformed sum rules for the mass splitting beyond linear density dependence.
Including strange quark condensates reveals a umerically smaller and opposite
effect for the Ds - Ds-bar mass splitting.Comment: 16 pages, 8 figures, to be published; a broader range of condensate
values is discussed (v2
A consistent spatial differencing scheme for the transonic full-potential equation in three dimensions
A full-potential steady transonic wing flow solver has been modified so that freestream density and residual are captured in regions of constant velocity. This numerically precise freestream consistency is obtained by slightly altering the differencing scheme without affecting the implicit solution algorithm. The changes chiefly affect the fifteen metrics per grid point, which are computed once and stored. With this new method, the outer boundary condition is captured accurately, and the smoothness of the solution is especially improved near regions of grid discontinuity
A study to identify and compare airborne systems for in-situ measurements of launch vehicle effluents
An in-situ system for monitoring the concentration of HCl, CO, CO2, and Al2O3 in the cloud of reaction products that form as a result of a launch of solid propellant launch vehicle is studied. A wide array of instrumentation and platforms are reviewed to yield the recommended system. An airborne system suited to monitoring pollution concentrations over urban areas for the purpose of calibrating remote sensors is then selected using a similar methodology to yield the optimal configuration
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