22,759 research outputs found
An open quantum system approach to the B-mesons system
In this talk we consider a non standard evolution for the neutral B-mesons
system, namely, an evolution in the open quantum systems framework. Such
approach is justified by the very high sensitivity of experiments studying
CP-violating phenomena in the B-mesons sector, very near to the one required to
test some possible scenarios induced by quantum gravity at the Planck scale,
whose effects at low energy can be described by a heat bath. We adopt a
phenomenological point of view, introducing six new parameters that fully
describe this kind of evolution without referring to a specific model for the
microscopic interaction. We outline the main differences between this approach
and the usual one in the description of evolution and decay of single mesons or
correlated pairs.Comment: Proceedings of the IV Workshop on Time Asymmetric Quantum Theory
(Jaca, Spain - June 2001), accepted for IJTP 2003.10, Latex, 9 page
Incoherent control and entanglement for two-dimensional coupled systems
We investigate accessibility and controllability of a quantum system S
coupled to a quantum probe P, both described by two-dimensional Hilbert spaces,
under the hypothesis that the external control affects only P. In this context
accessibility and controllability properties describe to what extent it is
possible to drive the state of the system S by acting on P and using the
interaction between the two systems. We give necessary and sufficient
conditions for these properties and we discuss the relation with the entangling
capability of the interaction between S and P. In particular, we show that
controllability can be expressed in terms of the SWAP operator, acting on the
composite system, and its square root.Comment: Latex, 13 page
Complete positivity and dissipative factorized dynamics
We show that any Hermiticity and trace preserving continuous semigroup
gamma_t in d dimensions is completely positive if and only if the semigroup
gamma_t otimes gamma_t is positivity preserving.Comment: 7 page
Potensi Produksi dan Kinerja Investasi Industri Pengolahan Kelapa Terpadu di Provinsi Aceh
. The Province of Aceh has the large potential of palm plant development with high production value, when supported by an integrated coconut industry. Today with potential expansion of coconut in 8 point production centers has 210.400 ha, we needs the processing technology that can utilize a by product and product primer, such as coir and coconut shell. Research has been conducted in four districts of Aceh by using census method. The results showed the coefficient of technology produced from 12 unit integrated coconut processing industry is 0.6806. With an investment of between Rp 342 million to Rp 825 million to produce a value of Rp 1,543,707,300 to Rp 3,721,320,000 in industrial economic life of 10 years. Efficiency of integrated technology is still relatively low oil caused a number of factors and allocation of equipment investment. There are still residual value (salvage value) is still a waste in the benefits component of coconut that has not been exploited by employers
Elongated theropod tracks from the Cretaceous Apenninic Carbonate Platform of southern Latium (central Italy)
New dinosaur footprints were recently discovered in southern Latium (Italy). The
tracks all appear slightly differently preserved and are characterized by elongated
metatarsal impressions, recording the complex locomotor behaviour of a medium-sized
theropod. The spatial distribution and the features of the footprints indicate that the
trackmaker adopted a “crouched” position as part of an activity as well as a resting
phase suggested by sub-parallel, calcigrade tracks. These new data once again highlight
the great potential of ichnological evidence in the study of the biology and
behaviour of extinct tetrapods
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