31,969 research outputs found
Travelling to exotic places with cavity QED systems
Recent theoretical schemes for utilizing cavity QED models as quantum
simulators are reviewed. By considering a quadrature representation for the
fields, it is shown how Jahn-Teller models, effective Abelian or non-Abelian
gauge potentials, transverse Hall currents, and relativistic effects naturally
arise in these systems. Some of the analytical predictions are verified
numerically using realistic experimental parameters taking into account for
system losses. Thereby demonstrating their feasibility with current
experimental setups.Comment: 5 pages, 3 figure
Kolmogorov-Burgers Model for Star Forming Turbulence
The process of star formation in interstellar molecular clouds is believed to
be controlled by driven supersonic magnetohydrodynamic turbulence. We suggest
that in the inertial range such turbulence obeys the Kolmogorov law, while in
the dissipative range it behaves as Burgers turbulence developing shock
singularities. On the base of the She-Leveque analytical model we then predict
the velocity power spectrum in the inertial range to be E_k ~ k^{-1.74}. This
result reproduces the observational Larson law, ~ l^{0.74...0.76},
[Larson, MNRAS 194 (1981) 809] and agrees well with recent numerical findings
by Padoan and Nordlund [astro-ph/0011465]. The application of the model to more
general dissipative structures, with higher fractal dimensionality, leads to
better agreement with recent observational results.Comment: revised, new material added, 8 page
Time-temperature characteristics of thin- skinned models as affected by thermocouple variables Semiannual report
Time-temperature characteristics of thin skinned models as affected by thermocouple variable
Time-temperature characteristics of thin- skinned models as affected by thermocouple variables First semiannual report
Time temperature characteristics of thin skinned models as affected by thermocouple variables - Laplace transfor
Cometary spectroscopy and imaging
The objective is to investigate the spectroscopic and morphological characteristics of comets and selected minor planets over a wide range of heliocentric distances as they may suggest or constrain models of cometary processes, their formation environments and evolution. Direct images of all observable comets and 300-800 nm spectra of the brighter ones are obtained on a monthly basis with a charge coupled device spectrograph-camera. The direct images may be used for astrometry, photometry, and studies of coma and tail morphology. In some cases, anisotropic dust emission can provide information on the nucleus spin vector. Spectra may provide data on strengths of the principle emission for comparison of gas/dust ratios of a large sample of comets. Long integrations of minor planets in comet-like and nearby orbits are made to search for faint comae
Dynamics of a Raman coupled model: entanglement and quantum computation
The evolution of a Raman coupled three-level lambda atom with two quantized
cavity modes is studied in the large detuning case; i.e. when the upper atomic
level can be adiabatically eliminated. Particularly the situation when the two
modes are prepared in initial coherent or squeezed states, with a large average
number of photons, is investigated. It is found that the atom, after specific
interaction times, disentangles from the two modes, leaving them, in certain
cases, in entangled Schrodinger cat states. These disentanglement times can be
controlled by adjusting the ratio between average numbers of photons in the two
modes. It is also shown how this effective model may be used for implementing
quantum information processing. Especially it is demonstrated how to generate
various entangled states, such as EPR- and GHZ-states, and quantum logic
operations, such as the control-not and the phase-gate.Comment: 8 pages, 6 figure
Terrorism on Trial: The President’s Constitutional Authority to Order the Prosecution of Suspected Terrorists by Military Commission
Sverige har sedan 1960-talet varit ett invandringsland. Av befolkningen är idag cirka 15 % födda i annat land. Andelen av befolkningen som är utlands-födda är i nivå med länder som USA och Tyskland. Andelen är inte bara betydligt högre än i övriga Nordiska länder, utan också högre än länder som Nederländerna, Frankrike och Storbritannien (RiR 2008:13).1 Utrikes födda beräknas utgöra en dryg fjärdedel av arbetskraftsreserven i Sverige. Under senare år har olika insatser genomförts med avsikt att öka arbetskraftsdelta-gandet
Storm on Saturn
In September 1990, a white spot appeared on Saturn's atmosphere, which later spread over the entire equatorial region. The accompanying images were obtained as part of an effort to refine techniques for obtaining high resolution groundbased charge coupled device (CCD) images of the planets, and show the turbulent disturbance in Saturn's atmosphere. These broad red-band CCD images were obtained in November 1990 with the Catalina 1.5 m telescope. The planet was low in the sky at sunset, but the viewing was good enough to show detail in the equatorial region over all longitudes. Visibility of the features is enhanced by digital spatial filtering techniques. A storm of this magnitude has not been seen on Saturn since 1933
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