5 research outputs found
Exact results on decoherence and entanglement in a system of N driven atoms and a dissipative cavity mode
We solve the dynamics of an open quantum system where N strongly driven
two-level atoms are equally coupled on resonance to a dissipative cavity mode.
Analytical results are derived on decoherence, entanglement, purity, atomic
correlations and cavity field mean photon number. We predict decoherence-free
subspaces for the whole system and the N-qubit subsystem, the monitoring of
quantum coherence and purity decay by atomic populations measurements, the
conditional generation of atomic multi-partite entangled states and of cavity
cat-like states. We show that the dynamics of atoms prepared in states
invariant under permutation of any two components remains restricted within the
subspace spanned by the completely symmetric Dicke states. We discuss examples
and applications in the cases N=3,4.Comment: 7 pages, 4 figures, accepted in EPJ
Comparison of Cervical Disk Implants and Cervical Disk Fusion Treatments in Human Cadaveric Models
Decoherence in the solvable dynamics of N strongly driven atoms coupled to a cavity mode
An assessment of catches and harvest of recreational shore angling in the north of Portugal
Recreational shore angling in the Atlantic Ocean between Moledo and Aveiro (Portugal) was examined using roving creel surveys (March/September 2001). Cooperation was high (90% of 2310 anglers approached). At least 39 species of fish were caught at a rate of approximately 0.5 fish angler h(-1). An estimated 7319 kg of Dicentrarchus labrax (L.), with 45.6% below the minimum legal size, and 2040 kg of sea breams (genus Diplodus), correspond to 5.75% and 1.19% of the commercial landings in the same geographical area, respectively. The results shed light on a number of issues relevant to integrated coastal management, including temporal and spatial distribution of fishing effort, species caught, sizes of fish, catch rates, and factors influencing catches and angler satisfaction. Whilst the results suggest that the catches of sea breams and sea bass by day-time recreational shore angling in northern Portugal are small compared with commercial fishing, other recreational activities, such as boat fishing and spear-fishing, must be assessed