11,286 research outputs found
Dynamical Electron Mass in a Strong Magnetic Field
Motivated by recent interest in understanding properties of strongly
magnetized matter, we study the dynamical electron mass generated through
approximate chiral symmetry breaking in QED in a strong magnetic field. We
reliably calculate the dynamical electron mass by numerically solving the
nonperturbative Schwinger-Dyson equations in a consistent truncation within the
lowest Landau level approximation. It is shown that the generation of dynamical
electron mass in a strong magnetic field is significantly enhanced by the
perturbative electron mass that explicitly breaks chiral symmetry in the
absence of a magnetic field.Comment: 5 pages, 1 figure, published versio
The reinforcing influence of recommendations on global diversification
Recommender systems are promising ways to filter the overabundant information
in modern society. Their algorithms help individuals to explore decent items,
but it is unclear how they allocate popularity among items. In this paper, we
simulate successive recommendations and measure their influence on the
dispersion of item popularity by Gini coefficient. Our result indicates that
local diffusion and collaborative filtering reinforce the popularity of hot
items, widening the popularity dispersion. On the other hand, the heat
conduction algorithm increases the popularity of the niche items and generates
smaller dispersion of item popularity. Simulations are compared to mean-field
predictions. Our results suggest that recommender systems have reinforcing
influence on global diversification.Comment: 6 pages, 6 figure
Strategies for Leveraging IT-enabled Service Innovation in Intensively Competitive Market
Many studies have explored service innovations regarding the use of information technologies, yet few have addressed the strategic leveraging in IT investment for sustaining competitiveness. The objective of this paper is to examine different strategies that firms have applied in leveraging advanced information technologies for service innovation in highly competitive market. The analysis of strategy is developed based on two dimensions: (1) IT capability, referring to a firm’s ability to deploy IT-based resources, combined with (2) the firm’s complementary resources including customer and supplier relationships, financial capital. We investigate the convenience-store industry in Taiwan, where the intensity of convenience stores is ranked as the highest in the world and is observed to be in the intensive competitive market. The case analysis reveals that there are four types of strategies firms apply in leveraging IT for competitiveness: predator, inventor, follower, and hedger. Firms may apply multiple strategies toward different innovation initiatives
Extraction of Plumes in Turbulent Thermal Convection
We present a scheme to extract information about plumes, a prominent coherent
structure in turbulent thermal convection, from simultaneous local velocity and
temperature measurements. Using this scheme, we study the temperature
dependence of the plume velocity and understand the results using the equations
of motion. We further obtain the average local heat flux in the vertical
direction at the cell center. Our result shows that heat is not mainly
transported through the central region but instead through the regions near the
sidewalls of the convection cell.Comment: 4 pages, 4 figures, submitted to Physical Review Letter
Maximally entangled mixed states of two atoms trapped inside an optical cavity
In some off-resonant cases, the reduced density matrix of two atoms
symmetrically coupled with an optical cavity can very approximately approach to
maximally entangled mixed states or maximal Bell violation mixed states in
their evolution. The influence of phase decoherence on the generation of
maximally entangled mixed state is also discussed.
PACS numbers: 03.67.-a, 03.65.UdComment: 7 pages, 4 figures, Latex, have a major revision of content
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