38,265 research outputs found
Existence uniqueness and ratio decomposition for Gibbs states via duality
We give an elementary proof of existence and uniqueness of Gibbs states for Hölder weight systems on subshifts of finite type. This uses a notion of duality for such subshifts. The approach of Paterson [2] is used to construct a measure with a prescribed Jacobian and the duality is used to produce an invariant measure from this
Smoothness of holonomies for codimension 1 hyperbolic dynamics
Hyperbolic invariant sets {Lambda} of C1+{gamma} diffeomorphisms where either the stable or unstable leaves are 1-dimensional are considered in this paper. Under the assumption that the {Lambda} has local product structure, the authors prove that the holonomies between the 1-dimensional leaves are C1+{alpha} for some 0 < {alpha} < 1
Teichmüller spaces and HR structures for hyperbolic surface dynamics
We construct a Teichmüller space for the C^{1+}-conjugacy classes of hyperbolic dynamical systems on surfaces. After introducing the notion of an HR structure which associates an affine structure with each of the stable and unstable laminations, we show that there is a one-to-one correspondence between these HR structures and the C^{1+}-conjugacy classes. As part of the proof we construct a canonical representative dynamical system for each HR structure. This has the smoothest holonomies of any representative of the corresponding C^{1+}-conjugacy class. Finally, we introduce solenoid functions and show that they provide a good Teichmüller space
Monitoring of Iberian wolf expansion in Sabugal: Malcata Region
Relatório de projecto no âmbito de Bolsa Universidade de Lisboa/Fundação Amadeu Dias (2008/2009)Departamento de Biologia Animal, Faculdade de Ciências da Universidade de LisboaScholarship Fundação Amadeu Dias/Universidade de LisboaWind farm construction may cause an effect of repulse on the wildlife. Sabugal – Malcata region has a new
wind farm in a zone where the situation of the Iberian wolf (Canis lupus signatus, Cabrera 1907) is considered as
precarious. In this context a monitoring project was begun to assess the impact of this infrastructure on the Iberian wolf
population. Here are presented the results of eight months of monitoring and some information received during the
project about the wolf presence in this region. Every month, signs of wolf presence were prospected in twelve transects
in the wind farm adjacent area and fourteen inquires were done to people that can contact with this predator. In all the
eight months only two scats were detected and two wolf tracks after a snowfall. The presence of wolves was referred in
the inquires as constant before 1990. However, some recent livestock damages were reported. The Roe deer
(Capreolus capreolus) seems to be in expansion in this area, being reported in more than half of the inquires. This
situation may reveal a new opportunity for settlement of dispersing wolves. The occurrence of the Iberian Wolf in
Sabugal – Malcata region continues not to be confirmed, but the designation of probable presence is reinforced.Universidade de Lisboa; Fundação Amadeu Dia
Quantum localized modes in capacitively coupled Josephson junctions
We consider the quantum dynamics of excitations in a system of two
capacitively coupled Josephson junctions. Quantum breather states are found in
the middle of the energy spectrum of the confined nonescaping states of the
system. They are characterized by a strong excitation of one junction. These
states perform slow tunneling motion from one junction to the other, while
keeping their coherent nature. The tunneling time sensitively depends on the
initial excitation energy. By using an external bias as a control parameter,
the tunneling time can be varied with respect to the escape time and the
experimentally limited coherence time. Thus one can control the flow of quantum
excitations between the two junctions.Comment: 5 pages, 3 figures. Improved version, title was slightly changed.
Accepted in Europhysics Letters (http://www.iop.org/EJ/journal/EPL
Quantum discrete breathers
We review recent studies about quantum discrete breathers. We describe their
basic properties in comparison with their classical counterparts, and the ways
they may be addressed theoretically in different quantum lattice models
including either bosonic or fermionic excitations. We also review recent
experimental work in the field.Comment: 49 pages, 36 figures, some corrected typos, and the section
"Conclusions and outlook" was added. Chapter for a book edited by S.
Keshavamurthy and P. Schlagheck with title "Dynamical Tunneling: Theory and
Experiment
Quantum breathers in capacitively coupled Josephson junctions: Correlations, number conservation, and entanglement
We consider the classical and quantum dynamics of excitations in a system of
two capacitively coupled Josephson junctions. In the classical case the
equations of motion admit discrete breather solutions, which are time periodic
and localized predominantly on one of the junctions. In the quantum case
breather states are found in the central part of the energy spectrum of the
confined nonescaping states of the system. We perform a systematic analysis of
their tunneling frequency, site correlations, fluctuations of the number of
quanta, and entanglement. Quantum breather states show strong site correlation
of quanta and are characterized by a strong excitation of quanta on one
junction which perform slow coherent tunneling motion from one junction to the
other. They suppress fluctuations of the total number of excited quanta.
Quantum breather states are the least entangled states among the group of
eigenstates in the same range of the energy spectrum. We describe how quantum
breather excitations could be experimentally observed by employing the already
developed techniques for quantum information processing using Josephson
junctions.Comment: 10 pages, 9 figures. Improved version with further discussions.
Accepted in Physical Review
- …