8,854 research outputs found
Exponential Convergence Rates of Second Quantization Semigroups and Applications
Exponential convergence rates in the -tail norm and entropy are
characterized for the second quantization semigroups by using the corresponding
base Dirichlet form. This supplements the well known result on the
-exponential convergence rate of second quantization semigroups. As
applications, birth-death type processes on Poisson spaces and the path space
of L\'evy processes are investigated.Comment: 20 page
Demystify the mixed-parity pairing of attractive fermions with spin-orbit coupling in optical lattice
The admixture of spin-singlet and spin-triplet pairing states in
superconductors can be typically induced by breaking spatial inversion
symmetry. Employing the {\it numerically exact} auxiliary-field Quantum Monte
Carlo method, we study such mixed-parity pairing phenomena of attractive
fermions with Rashba spin-orbit coupling (SOC) in two-dimensional optical
lattice at finite temperature. We systematically demystify the evolution of the
essential pairing structure in both singlet and triplet channels versus the
temperature, fermion filling, SOC and interaction strengths, via computing the
condensate fraction and pair wave function. Our numerical results reveal that
the singlet channel dominates in the fermion pairing and the triplet pairing
has relatively small contribution to the superfluidity for physically relevant
parameters. In contrast to the singlet channel mainly consisted of the on-site
Cooper pairs, the triplet pairing has plentiful patterns in real space with the
largest contributions from several nearest neighbors. As the SOC strengh
increases, the pairing correlation is firstly enhanced and then suppressed for
triplet pairing while it's simply weakened in singlet channel. We have also
obtained the Berezinskii-Kosterlitz-Thouless transition temperatures through
the finite-size analysis of condensate fraction. Our results can serve as
quantitative guide for future optical lattice experiments as well as accurate
benchmarks for theories and other numerical methods.Comment: 14 pages, 11+5 figure
Semantic lifting and reasoning on the personalised activity big data repository for healthcare research
The fast growing markets of smart health monitoring devices and mobile applications provide opportunities for common citizens to have capability for understanding and managing their own health situations. However, there are many challenges for data engineering and knowledge discovery research to enable efficient extraction of knowledge from data that is collected from heterogonous devices and applications with big volumes and velocity. This paper presents research that initially started with the EC MyHealthAvatar project and is under continual improvement following the project’s completion. The major contribution of the work is a comprehensive big data and semantic knowledge discovery framework which integrates data from varied data resources. The framework applies hybrid database architecture of NoSQL and RDF repositories with introductions for semantic oriented data mining and knowledge lifting algorithms. The activity stream data is collected through Kafka’s big data processing component. The motivation of the research is to enhance the knowledge management, discovery capabilities and efficiency to support further accurate health risk analysis and lifestyle summarisation
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