Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"superradiance"”.
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Far-infrared superradiance in methyl fluoride
Dicke superradiance, that is, cooperative spontaneous emission, has been observed in methyl fluoride, which is optically pumped by a pulsed carbon dioxide TEA laser operated on the P(20) line at 9.55 ~m. The far-infrared (FIR) super-radiant pulses, at a wavelength of 496 microns, were identified by …
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Stability of charged rotating black holes for linear scalar perturbations
… main obstacles to the proof of these results are superradiance, trapping and their interaction. These difficulties are surmounted by localising solutions of the wave equation in phase space and applying the vector field method. Miraculously, as in the Kerr case, superradiance and trapping occur in …
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Forward Light Scattering in an Extended Sample of Cold Atoms
… of 87Rb. Specifically,we study single-photon superradiance which is characterized by a rapid decay faster than the single atom lifetime with the light preferentially emitted in the forward direction. Additionally, we report measurements on its counterpart, the cooperative Lamb shift. The …
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Coherent Processes in Rare-Earth-Ion-Doped Solids
… such as quantum information processing, superradiance and electromagnetically induced transparency, which have been experimentally implemented using rare-earth-ion-doped crystals. The rare-earths are a class of elements that have in common, an atomic structure that allows for very long …
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Millimeter-wave dynamics and control of Rydberg-Rydberg transitions
… describe the detection of single-shot free space superradiance in a buffer gas cooled beam of barium atoms. The frequency of this emission is shifted and broadened by a factor of ~ 10⁶ x greater than the natural lifetime, indicating the presence of quantum many-body dipole-dipole effects in the …
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Direct observation of Rydberg-Rydberg transitions via CPmmW spectroscopy
… In addition, strong collective effects (superradiance) have also been observed.
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Simulation of curved-space quantum field theories with two-component Bose-Einstein condensates: from black-hole physics to cosmology
… phenomena (Hawking radiation and rotational superradiance) that have already been analysed with single-component systems, generalising the results to mixtures; we then proceed to tackle a problem (the decay from the false vacuum) which instead requires the additional degrees of freedom that …
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Manipulating Bose-Einstein condensates with laser light
… is shown to be directly analogous to Dicke superradiance, where the electronic coherence is replaced by the coherent center-of-mass motion of the atoms in the condensate. Superradiant Rayleigh scattering was used to amplify atomic matter waves. The active medium was a Bose-Einstein …
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Superradiant Emission from Delocalized Frenkel Excitons in Molecular J-Aggregates
… which confirm J-type excitonic coupling and superradiance, both necessary for obtaining fast radiative rates. Even though non-radiative rates are significantly reduced in the rigidified dye J-aggregates, competing non-radiative processes originating from imperfections in the J-aggregate …
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Exploring fundamental physics and astrophysics with gravitational-wave sources
… This search relies on the process called superradiance, in which boson clouds form around fast spinning black holes (BHs), reduce the BH spins to characteristic values, and lead to an exclusion region in the parameter space of BH mass and spin. Based on the second GW catalog released by …
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Measurements of FEL dynamics
… Further evidence for the recent observation of superradiance in an FEL oscillator has been provided by an investigation which shows that the efficiency and intracavity power of the radiation scale respectively as the inverse square root and the inverse square of the cavity losses, verifying the …
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Numerical Construction of Gravitational Solutions in Asymptotically Anti-de Sitter Spacetimes
… phenomena in general relativity. In particular, superradiance has been important in the context of the weak cosmic censorship hypothesis. In order to study this relationship, we constructed novel four-dimensional asymptotically global AdS solutions by turning on a dipolar differential rotation at …
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Motion in a scalar field
… and grow exponentially through a process akin to superradiance. Although these effects turn out to be highly suppressed in the regime amenable to analytic methods, the novel techniques developed herein lay the groundwork for future studies of these complex gravitational systems.
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Light-Induced Collective Interactions in Arrays of Quantum Emitters
… dissipation channels suppresses steady-state superradiance in extended arrays.
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The imprint of scalar clouds around Kerr black holes: hairy solutions and weak cosmic censorship
… from the Kerr solution at the onset of scalar superradiance, when the scalar cloud starts forming. Since their discovery a number of studies have been carried out, trying to relate their properties to astrophysics. However, prior to our work, no stability analysis was performed. This is …
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Gravitational Radiation from Superradiant Instabilities of Rotating Black Holes
We use the Teukolsky formalism to calculate the gravitational radiation from a non-axi\-symmetric cloud formed due to superradiant amplification of a spin-0 bosonic field. We focus on the prospects of the future space-based gravitational wave detector, Laser Interferometer Space Antenna (LISA), and …