7,758 research outputs found
Generation of Superposition States and Charge-Qubit Relaxation Probing in a Circuit
We demonstrate how a superposition of coherent states can be generated for a
microwave field inside a coplanar transmission line coupled to a single
superconducting charge qubit, with the addition of a single classical magnetic
pulse for chirping of the qubit transition frequency. We show how the qubit
dephasing induces decoherence on the field superposition state, and how it can
be probed by the qubit charge detection. The character of the charge qubit
relaxation process itself is imprinted in the field state decoherence profile.Comment: 6 pages, 4 figure
Wave polarizations for a beam-like gravitational wave in quadratic curvature gravity
We compute analytically the tidal field and polarizations of an exact
gravitational wave generated by a cylindrical beam of null matter of finite
width and length in quadratic curvature gravity. We propose that this wave can
represent the gravitational wave that keep up with the high energy photons
produced in a gamma ray burst (GRB) source.Comment: 5 pages, 3 figures, minor corrections, to appear in CQ
Temperature Measurement and Phonon Number Statistics of a Nanoelectromechanical Resonator
Measuring thermodynamic quantities can be easy or not, depending on the
system that is being studied. For a macroscopic object, measuring temperatures
can be as simple as measuring how much a column of mercury rises when in
contact with the object. At the small scale of quantum electromechanical
systems, such simple methods are not available and invariably detection
processes disturb the system state. Here we propose a method for measuring the
temperature on a suspended semiconductor membrane clamped at both ends. In this
method, the membrane is mediating a capacitive coupling between two
transmission line resonators (TLR). The first TLR has a strong dispersion, that
is, its decaying rate is larger than its drive, and its role is to pump in a
pulsed way the interaction between the membrane and the second TLR. By
averaging the pulsed measurements of the quadrature of the second TLR we show
how the temperature of the membrane can be determined. Moreover the statistical
description of the state of the membrane, which is directly accessed in this
approach is significantly improved by the addition of a Josephson Junction
coupled to the second TLR.Comment: 9 pages, 5 figures. To appear in New Journal of Physic
Capacitive Coupling of Two Transmission Line Resonators Mediated by the Phonon Number of a Nanoelectromechanical Oscillator
Detection of quantum features in mechanical systems at the nanoscale
constitutes a challenging task, given the weak interaction with other elements
and the available technics. Here we describe how the interaction between two
monomodal transmission-line resonators (TLRs) mediated by vibrations of a
nano-electromechanical oscillator can be described. This scheme is then
employed for quantum non-demolition detection of the number of phonons in the
nano-electromechanical oscillator through a direct current measurement in the
output of one of the TLRs. For that to be possible an undepleted field inside
one of the TLR works as a amplifier for the interaction between the mechanical
resonator and the remaining TLR. We also show how how the non-classical nature
of this system can be used for generation of tripartite entanglement and
conditioned mechanical coherent superposition states, which may be further
explored for detection processes.Comment: 6 pages, 5 figure
The 12 prophets dataset
The "Ajeijadinho 3D" project is an initiative supported by the University of
S\~ao Paulo (Museum of Science and Dean of Culture and Extension), which
involves the 3D digitization of art works of Brazilian sculptor Antonio
Francisco Lisboa, better known as Aleijadinho. The project made use of advanced
acquisition and processing of 3D meshes for preservation and dissemination of
the cultural heritage. The dissemination occurs through a Web portal, so that
the population has the opportunity to meet the art works in detail using 3D
visualization and interaction. The portal address is
http://www.aleijadinho3d.icmc.usp.br. The 3D acquisitions were conducted over a
week at the end of July 2013 in the cities of Ouro Preto, MG, Brazil and
Congonhas do Campo, MG, Brazil. The scanning was done with a special equipment
supplied by company Leica Geosystems, which allowed the work to take place at
distances between 10 and 30 meters, defining a non-invasive procedure,
simplified logistics, and without the need for preparation or isolation of the
sites. In Ouro Preto, we digitized the churches of Francisco of Assis, Our Lady
of Carmo, and Our Lady of Mercy; in Congonhas do Campo we scanned the entire
Sanctuary of Bom Jesus de Matosinhos and his 12 prophets. Once scanned, the art
works went through a long process of preparation, which required careful
handling of meshes done by experts from the University of S\~ao Paulo in
partnership with company Imprimate.Comment: Full dataset online at http://aleijadinho3d.icmc.usp.br/data.htm
Híbridos de milho em consórcio com populações de Brachiaria ruziziensis na safra 2009/2010, em Dourados, MS
Trabalho também publicado no Livro de resumos
- …