Tomographic Characterization of Three-Qubit Pure States with Only Two-Qubit Detectors

A tomographic process for three-qubit pure states using only pairwise detections is presented.Comment: 3 pages; revtex4; v2: the focus on tomography was emphasized and the experimental procedure detailed; v3: the text was improved in clarity, some mistakes were correcte

Asymptotic Entanglement Dynamics and Geometry of Quantum States

A given dynamics for a composite quantum system can exhibit several distinct properties for the asymptotic entanglement behavior, like entanglement sudden death, asymptotic death of entanglement, sudden birth of entanglement, etc. A classification of the possible situations was given in [M. O. Terra Cunha, {\emph{New J. Phys}} {\bf{9}}, 237 (2007)] but for some classes there were no known examples. In this work we give a better classification for the possibile relaxing dynamics at the light of the geometry of their set of asymptotic states and give explicit examples for all the classes. Although the classification is completely general, in the search of examples it is sufficient to use two qubits with dynamics given by differential equations in Lindblad form (some of them non-autonomous). We also investigate, in each case, the probabilities to find each possible behavior for random initial states.Comment: 9 pages, 2 figures; revised version accepted for publication in J. Phys. A: Math. Theo

Long-distance remote comparison of ultrastable optical frequencies with 1e-15 instability in fractions of a second

We demonstrate a fully optical, long-distance remote comparison of independent ultrastable optical frequencies reaching a short term stability that is superior to any reported remote comparison of optical frequencies. We use two ultrastable lasers, which are separated by a geographical distance of more than 50 km, and compare them via a 73 km long phase-stabilized fiber in a commercial telecommunication network. The remote characterization spans more than one optical octave and reaches a fractional frequency instability between the independent ultrastable laser systems of 3e-15 in 0.1 s. The achieved performance at 100 ms represents an improvement by one order of magnitude to any previously reported remote comparison of optical frequencies and enables future remote dissemination of the stability of 100 mHz linewidth lasers within seconds.Comment: 7 pages, 4 figure

Os espíritos imundos nos sinóticos e o Mito dos Vigilantes

A obra compósita conhecida como 1 Enoque, formada por cinco livros, logrou muita importância no(s) Judaísmo(s) do segundo templo, como também no(s) Cristianismo(s) dos primeiros quatro séculos. Por isso, a intenção deste trabalho é testar a contribuição do Mito dos Vigilantes (1 Enoque 6-11) para o imaginário do demoníaco nos sinóticos, em especial enquanto espírito imundo. Com o acúmulo de imagens dos seres malignos no período do segundo templo e a sua próxima relação com o Mito dos Vigilantes, concluímos ser possível a hipótese de que o demoníaco ao ser chamado de espírito impuro no Novo Testamento trás indícios e ecos do desenvolvimento, nas tradições de Enoque e na apocalíptica, do Mito dos Vigilantes.

Utjecaj toplinske obrade na fizička svojstva tankih slojeva antimon trisulfida

The influence of isochronal and isothermal annealing for 0 to 180 minutes and at 27 to 250°C, respectively, on the optical and electrical properties of thin films of Sb2S3 have been investigated. The films deposited on glass substrate by thermal vacuum evaporation have amorphous structure, but after annealing at temperatures above 200°C for 3 hours, they change to polycrystalline structure. The optical absorption coefficient becomes higher for subgap absorption at higher annealing temperatures. The value of the optical Tauc gap and direct band gap changed with the annealing temperature. The dark electrical resistivity showed a decrease by about an order of magnitude when increasing both the isochronal and isothermal annealing treatment.Ispitivao se je utjecaj izotermičkog toplinskog otpuštanja na optička i električna svojstva tankih slojeva Sb2S3 na temperaturama 27 do 250° C i u vremenima od 0 do 180 minuta. Tanki slojevi dobiveni vakuumskim naparavanjem na staklenu podlogu imaju amorfnu strukturu, ali nakon otpuštanja iznad 200° C kroz 3 sata oni mijenjaju strukturu u polikristaliničnu. Optički apsorpcijski koeficijent raste za podprocijepnu apsorpciju s povišenjem temperature otpuštanja. Vrijednost optičkog Taucovog procijepa i izravni procijep mijenjali su se s temperaturom otpuštanja. Tamna električna otpornost se je smanjila za red veličine kada se je povećalo vrijeme otpuštanja i temperatura

Measurement noise floor for a long-distance optical carrier transmission via fiber

We investigated the measurement floor and link stability for the transfer of an ultra-stable optical frequency via an optical fiber link. We achieved a near-delay-limited instability of 3x10^(-15)/(tau x Hz) for 147 km deployed fiber, and 10^(-20) (integrations time tau = 4000 s) for the noise floor.Comment: 5 pages, 3 figures, 7th Symposium on Frequency Standards and Metrology (Pacific Grove,USA, Oct 2008

Sedimentary Processes on Venus

The sedimentary cycle, including the processes of erosion, transport, and lithification, is a key part of how planets evolve over time. Early images of Venus’s vast volcanic plains, numerous volcanoes, and rugged tectonic regions led to the interpretation that Venus is a volcanic planet with little sediment cover and perhaps few processes for generating sedimentary rocks. However, in the years since the Magellan mission in the 1990s we have developed a better understanding of sedimentary process on Venus. Impact craters are the largest present-day source of sediments, with estimates from the current crater population suggesting an average sediment layer 8–63 cm in thickness if distributed globally. There is clear evidence of fine-grained material in volcanic summit regions that is likely produced through volcanism, and dune fields and yardangs indicate transport of sediments and erosion of rocks through wind. Landslides and fine-grained materials in highland tessera regions demonstrate erosive processes that move sediment downhill. It is clear that sediments are an important part of Venus’s geology, and it is especially important to realize that they mantle features that may be of interest to future landed or low-altitude imaging missions. The sinks of sediments are less well known, as it has been difficult to identify sedimentary rocks with current data. Layering observed in Venera images and in Magellan images of some tessera regions, as well as calculated rock densities, suggest that sedimentary rocks are present on Venus. New data is needed to fully understand and quantify the present-day sedimentary cycle and establish with certainty whether sedimentary rock packages do, in fact, exist on Venus. These data sets will need to include higher-resolution optical and radar imaging, experimental and geochemical measurements to determine how chemical weathering and lithification can occur, and topography to better model mesospheric winds. Sediments and sedimentary rocks are critical to understanding how Venus works today, but are also extremely important for determining how Venus’s climate has changed through time and whether it was once a habitable planet