21,620 research outputs found

    Geomorphic and landform survey of northern Appennini

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    There are no author-identified significant results in this report

    Generation of 87^{87}Rb-resonant bright two-mode squeezed light with four-wave mixing

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    Squeezed states of light have found their way into a number of applications in quantum-enhanced metrology due to their reduced noise properties. In order to extend such an enhancement to metrology experiments based on atomic ensembles, an efficient light-atom interaction is required. Thus, there is a particular interest in generating narrow-band squeezed light that is on atomic resonance. This will make it possible not only to enhance the sensitivity of atomic based sensors, but also to deterministically entangle two distant atomic ensembles. We generate bright two-mode squeezed states of light, or twin beams, with a non-degenerate four-wave mixing (FWM) process in hot 85^{85}Rb in a double-lambda configuration. Given the proximity of the energy levels in the D1 line of 85^{85}Rb and 87^{87}Rb, we are able to operate the FWM in 85^{85}Rb in a regime that generates two-mode squeezed states in which both modes are simultaneously on resonance with transitions in the D1 line of 87^{87}Rb, one mode with the F=2F=2 to F′=2F'=2 transition and the other one with the F=1F=1 to F′=1F'=1 transition. For this configuration, we obtain an intensity difference squeezing level of −3.5-3.5 dB. Moreover, the intensity difference squeezing increases to −5.4-5.4 dB and −5.0-5.0 dB when only one of the modes of the squeezed state is resonant with the D1 F=2F=2 to F′=2F'=2 or F=1F=1 to F′=1F'=1 transition of 87^{87}Rb, respectively

    Quantization of classical integrable systems. Part IV: systems of resonant oscillators

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    By applying methods already discussed in a previous series of papers by the same authors, we construct here classes of integrable quantum systems which correspond to n fully resonant oscillators with nonlinear couplings. The same methods are also applied to a series of nontrivial integral sets of functions, which can be constructed when additional symmetries are present due to the equality of some of the frequencies. Besides, for n=3 and resonance 1:1:2, an exceptional integrable system is obtained, in which integrability is not explicitly connected with this type of symmetry. In this exceptional case, quantum integrability can be realized by means of a modification of the symmetrization procedure.Comment: 23 page

    More on softly broken N=2 QCD

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    We extend previous work on the soft breaking of N=2N=2 supersymmetric QCD. We present the formalism for the breaking due to a dilaton spurion for a general gauge group and obtain the exact effective potential. We obtain some general features of the vacuum structure in the pure SU(N)SU(N) Yang-Mills theory and we also derive a general mass formula for this class of theories, in particular we present explicit results for the mass spectrum in the SU(2)SU(2) case. Finally we analyze the vacuum structure of the SU(2)SU(2) theory with one massless hypermultiplet. This theory presents dyon condensation and a first order phase transition in the supersymmetry breaking parameter driven by non-mutually local BPS states. This could be a hint of Argyres-Douglas-like phases in non-supersymmetric gauge theories.Comment: 35 pages, 9 Postscript figure
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