346 research outputs found
Partial Disorder in the Periodic Anderson Model on a Triangular Lattice
We report our theoretical results on the emergence of a partially-disordered
state at zero temperature and its detailed nature in the periodic Anderson
model on a triangular lattice at half filling. The partially-disordered state
is characterized by coexistence of a collinear antiferromagnetic order on an
unfrustrated honeycomb subnetwork and nonmagnetic state at the remaining sites.
This state appears with opening a charge gap between a noncollinear
antiferromagnetic metal and Kondo insulator while changing the hybridization
and Coulomb repulsion. We also find a characteristic crossover in the
low-energy excitation spectrum as a result of coexistence of magnetic order and
nonmagnetic sites. The result demonstrates that the partially-disordered state
is observed distinctly even in the absence of spin anisotropy, in marked
contrast to the partial Kondo screening state found in the previous study for
the Kondo lattice model.Comment: 4 pages, 4 figures, accepted for publication in J. Phys. Soc. Jp
CoSMo: a Framework for Implementing Conditioned Process Simulation Models
Process simulation is an analysis tool in process mining that allows users to
measure the impact of changes, prevent losses, and update the process without
risks or costs. In the literature, several process simulation techniques are
available and they are usually built upon process models discovered from a
given event log or learned via deep learning. Each group of approaches has its
own strengths and limitations. The former is usually restricted to the
control-flow but it is more interpretable, whereas the latter is not
interpretable by nature but has a greater generalization capability on large
event logs. Despite the great performance achieved by deep learning approaches,
they are still not suitable to be applied to real scenarios and generate value
for users. This issue is mainly due to fact their stochasticity is hard to
control. To address this problem, we propose the CoSMo framework for
implementing process simulation models fully based on deep learning. This
framework enables simulating event logs that satisfy a constraint by
conditioning the learning phase of a deep neural network. Throughout
experiments, the simulation is validated from both control-flow and data-flow
perspectives, demonstrating the proposed framework's capability of simulating
cases while satisfying imposed conditions
A meta-learning configuration framework for graph-based similarity search indexes
Similarity searches retrieve elements in a dataset with similar characteristics to the input query element. Recent works show that graph-based methods have outperformed others in the literature, such as tree-based and hash-based methods. However, graphs are highly parameter-sensitive for indexing and searching, which usually demands extra time for finding a suitable trade-off for specific user requirements. Current approaches to select parameters rely on observing published experimental results or Grid Search procedures. While the former has no guarantees that good settings for a dataset will also perform well on a different one, the latter is computationally expensive and limited to a small range of values. In this work, we propose a meta-learning-based recommender framework capable of providing a suitable graph configuration according to the characteristics of the input dataset. We present two instantiations of the framework: a global instantiation that uses the whole meta-database to train meta-models and a dataset-similarity-based instantiation that relies on clustering to generate meta-models tailored to datasets with similar characteristics. We also developed generic and tuned versions of the instantiations. The generic versions can satisfy user requirements in orders of magnitude faster than the traditional Grid Search. The tuned versions provide more accurate predictions at a higher cost. Our results show that the tuned methods outperform the Grid Search for most cases, providing recommendations close to the optimal one and being a suitable alternative, particularly for more challenging datasets
Thermal Properties of Heavy Fermion Compound YbP
Low-temperature specific heat and its field-dependence up to 16 T was
measured in a stoichiometric single crystal of YbP. A sharp peak was observed
at {\it T} = 0.53 K in zero magnetic field. Application of external
field seems to induce a new magnetic phase above 11 T. The field dependence of
the transition temperature in the high-field phase is different from that of
the low field phase. The linear coefficient of the electronic specific heat is
estimated as 120 mJ/mole K from low temperature specfic heat, suggesting
heavy Fermion state in YbP.Comment: to be published in J.Phys.Soc.Jpn on May, 200
Inner-shell ionization by ultrarelativistic electronsInner-shell ionization by ultrarelativistic electrons
Optimum Arrangement of Resonator in Micro-bunch Free Electron Laser(III. Accelerator, Synchrotron Radiation, and Instrumentation)
Using a short-bunched beam of electrons from a linear accelator, the output of the micro-bunch FEL has been studied experimentally to clarify the optimum arrangement of an open resonator on the electron orbit. The output depends sharply on the arrangement, and the maximum output is observed when the resonator axis intersects the electron orbit with the angle of 3°
Photo-production of neutral kaons on 12C in the threshold region
Kaon photo-production process on C has been studied by measuring
neutral kaons in a photon energy range of 0.81.1 GeV. Neutral kaons were
identified by the invariant mass constructed from two charged pions emitted in
the decay channel. The differential cross sections
as well as the integrated ones in the threshold photon energy region were
obtained. The obtained momentum spectra were compared with a Spectator model
calculation using elementary amplitudes of kaon photo-production given by
recent isobar models. Present result provides, for the first time, the
information on reaction which is expected to play an
important role to construct models for strangeness production by the
electromagnetic interaction. Experimental results show that cross section of
is of the same order to that of and suggest that slightly backward angular distribution
is favored in the process.Comment: 6 pages, 8 figure
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