7,937 research outputs found
PMC34 INTERNATIONAL SURVEY ONWTP FOR ONE ADDITIONAL QALY GAIN—HOW MUCH IS THE THRESHOLD OF COST-EFFECTIVENESS ANALYSIS
PCV93 DISCRETE EVENT SIMULATION OF CARDIAC HOSPITALS PERFORMING PERCUTANEOUS CORONARY INTERVENTIONS
Extending the Real-Time Maude Semantics of Ptolemy to Hierarchical DE Models
This paper extends our Real-Time Maude formalization of the semantics of flat
Ptolemy II discrete-event (DE) models to hierarchical models, including modal
models. This is a challenging task that requires combining synchronous
fixed-point computations with hierarchical structure. The synthesis of a
Real-Time Maude verification model from a Ptolemy II DE model, and the formal
verification of the synthesized model in Real-Time Maude, have been integrated
into Ptolemy II, enabling a model-engineering process that combines the
convenience of Ptolemy II DE modeling and simulation with formal verification
in Real-Time Maude.Comment: In Proceedings RTRTS 2010, arXiv:1009.398
Enhanced quantum coherence in exchange coupled spins via singlet-triplet transitions
Manipulation of spin states at the single-atom scale underlies spin-based quantum information processing and spintronic devices. These applications require protection of the spin states against quantum decoherence due to interactions with the environment. While a single spin is easily disrupted, a coupled-spin system can resist decoherence by using a subspace of states that is immune to magnetic field fluctuations. Here, we engineered the magnetic interactions between the electron spins of two spin-1/2 atoms to create a “clock transition” and thus enhance their spin coherence. To construct and electrically access the desired spin structures, we use atom manipulation combined with electron spin resonance (ESR) in a scanning tunneling microscope. We show that a two-level system composed of a singlet state and a triplet state is insensitive to local and global magnetic field noise, resulting in much longer spin coherence times compared with individual atoms. Moreover, the spin decoherence resulting from the interaction with tunneling electrons is markedly reduced by a homodyne readout of ESR. These results demonstrate that atomically precise spin structures can be designed and assembled to yield enhanced quantum coherence
Efficient range alignment algorithm for real-time range-Doppler algorithm
When deriving a range-Doppler image or a time-frequency image of a fast-maneuvering target at long range, existing range alignment methods yield poor results due to the large numbers of range profiles (RPs) and range bins that are required for this task. This paper proposes a three-step range alignment method to overcome the problems of these existing methods and to yield focused images: (1) coarse alignment using the interpolated center of mass of each RP, (2) fine alignment with an integer step using an entropy cost function, and (3) fine-tuning using particle swarm optimization. Compared to existing methods, the proposed method is computationally more efficient and provides better image focus. © 2017, Electromagnetics Academy. All rights reserved.11Yscopu
Radion Dynamics and Phenomenology in the Linear Dilaton Model
We investigate the properties of the radion in the 5D linear dilaton model
arising from Little String Theory. A Goldberger-Wise type mechanism is used to
stabilise a large interbrane distance, with the dilaton now playing the role of
the stabilising field. We consider the coupled fluctuations of the metric and
dilaton fields and identify the physical scalar modes of the system. The
wavefunctions and masses of the radion and Kaluza-Klein modes are calculated,
giving a radion mass of order the curvature scale. As a result of the direct
coupling between the dilaton and Standard Model fields, the radion couples to
the SM Lagrangian, in addition to the trace of the energy-momentum tensor. The
effect of these additional interaction terms on the radion decay modes is
investigated, with a notable increase in the branching fraction to photons. We
also consider the effects of a non-minimal Higgs coupling to gravity, which
introduces a mixing between the Higgs and radion modes. Finally, we calculate
the production cross section of the radion at the LHC and use the current Higgs
searches to place constraints on the parameter space.Comment: 28 pages, 7 figures; v2: error in radion-gauge boson Feynman rules
corrected, version published in JHE
Light Higgsino from Axion Dark Radiation
The recent observations imply that there is an extra relativistic degree of
freedom coined dark radiation. We argue that the QCD axion is a plausible
candidate for the dark radiation, not only because of its extremely small mass,
but also because in the supersymmetric extension of the Peccei-Quinn mechanism
the saxion tends to dominate the Universe and decays into axions with a sizable
branching fraction. We show that the Higgsino mixing parameter mu is bounded
from above when the axions produced at the saxion decays constitute the dark
radiation: mu \lesssim 300 GeV for a saxion lighter than 2m_W, and mu less than
the saxion mass otherwise. Interestingly, the Higgsino can be light enough to
be within the reach of LHC and/or ILC even when the other superparticles are
heavy with mass about 1 TeV or higher. We also estimate the abundance of axino
produced by the decays of Higgsino and saxion.Comment: 18 pages, 1 figure; published in JHE
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