12,563 research outputs found

    Two-photon detuning and decoherence in cavity electromagnetically induced transparency for quantized fields

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    The interaction of a quantized field with three-level atoms in Λ\Lambda configuration inside a two-mode cavity is analyzed in the small noise approximation. The atoms are in a two-photon detuning with respect to the carriers of the field. We calculate the stationary quadrature noise spectrum of the field outside the cavity in the case where the input probe field is a squeezed state and the input pump field is a coherent state. The mean value of the field is unaltered in all the analysis: the atoms shows electromagnetically induced transparency (EIT). The effect of the atoms' base level decoherence in the cavity output field is also studied. It is found that the output field is very sensitive to two-photon detuning.Comment: 8 page

    The role of secondary Reggeons in central meson production

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    We estimate the contribution of f_2 trajectory exchange to the central \eta and \eta^\prime production. It is shown that secondary Reggeons may give a large contribution to processes of double diffractive meson production at high energy.Comment: 7 pages, Latex, 5 figure

    A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states

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    The production and decay properties of the f0(1370), f0(1500), f0(2000) and f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT, phi and |t| distributions of these resonances are presented. For the J = 0 states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These are different to the dPT and phi dependences of the f0(980), f0(1500) and f0(1710). For the J = 2 states the f2(1950) has different dependences to the f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not just J phenomena.Comment: 14 pages, Latex, 4 Figure

    Systematization of tensor mesons and the determination of the 2++2^{++} glueball

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    It is shown that new data on the (JPC=2++)(J^{PC}=2^{++})-resonances in the mass range M17002400M\sim1700-2400 MeV support the linearity of the (n,M2)(n,M^2)-trajectories, where nn is the radial quantum number of quark--antiquark state. In this way all vacancies for the isoscalar tensor qqˉq\bar q-mesons in the range up to 2450 MeV are filled in. This allows one to fix the broad f2f_2-state with M=2000±30M=2000\pm30 MeV and Γ=530±40\Gamma=530\pm40 MeV as the lowest tensor glueball. PACS numbers: 14.40.-n, 12.38.-t, 12.39.-MkComment: 10 pages, 1 figur

    Experimental evidence for a vector-like behaviour of Pomeron exchange

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    Evidence is presented that the Pomeron act as a non-conserved vector current. A study has been made of the azimuthal angle phi, which is defined as the angle between the pT vectors of the two outgoing protons, in the reaction pp -> pp(X0) for those resonances (X0) which are compatible with being produced by double Pomeron exchange. These distributions have been compared with a model which describes the Pomeron as a non-conserved vector current and a qualitative agreement is found. In addition, when one of the particles exchanged is known to have spin 0, namely pi-Pomeron exchange, the phi distribution is flat.Comment: 13 pages, Latex, 4 Figure

    Feedback in a cavity QED system for control of quantum beats

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    Conditional measurements on the undriven mode of a two-mode cavity QED system prepare a coherent superposition of ground states which generate quantum beats. The continuous system drive induces decoherence through the phase interruptions from Rayleigh scattering, which manifests as a decrease of the beat amplitude and an increase of the frequency of oscillation. We report recent experiments that implement a simple feedback mechanism to protect the quantum beat. We continuously drive the system until a photon is detected, heralding the presence of a coherent superposition. We then turn off the drive and let the superposition evolve in the dark, protecting it against decoherence. At a later time we reinstate the drive to measure the amplitude, phase, and frequency of the beats. The amplitude can increase by more than fifty percent, while the frequency is unchanged by the feedback.Comment: 13 pages, 5 figures, ICAP 2012 23rd International Conference on Atomic Physic