392 research outputs found
Vergleichende Zeitstand- und Kriechversuche an drei titanstabilisierten 15/15CrNi-Staehlen mit unterschiedlichen Gehalten an W-Mn-Mo und Bor
Robust Entanglement in Atomic Systems via Lambda-Type Processes
It is shown that the system of two three-level atoms in
configuration in a cavity can evolve to a long-lived maximum entangled state if
the Stokes photons vanish from the cavity by means of either leakage or
damping. The difference in evolution picture corresponding to the general model
and effective model with two-photon process in two-level system is discussed.Comment: 10 pages, 3 figure
Zeitstandfestigkeits- und Kriechversuche am Stahl X6CrNi 1811 (1.4948) im Rahmen des Extrapolationsprogrammes (Teil III)
Zeitstandfestigkeits- und Kriechversuche am Stahl X6CrNi 1811(1.4948) im Rahmen des Extrapolationsprogrammes. (Teil II)
Untersuchungen zum Einfluss des Stickstoff- und Niobgehaltes auf die Zugfestigkeitseigenschaften und das Zeitstandverhalten des Stahles X2CrNiMo 1814. Abschlussbericht
Zeitstandversuche am Grundwerkstoff und an Schweissverbindungen des Stahles X6CrNi 1811 (DIN 1.4948) im Rahmen des Programmes AUSOL. 1.Zwischenbericht (Sept. 1986)
Zeitstandversuche am Grundwerkstoff und Schweissverbindungen des Stahles X6CrNi 1811 (DIN 1.4948) im Rahmen des Programmes AUSOL (Abschlussbericht)
Zeitstand- und Strukturuntersuchungen am SNR-Strukturwerkstoff X6CrNi 18 11 (1.4948) im Rahmen des Extrapolationsprogrammes. Abschlussbericht
Generation of entangled coherent states via cross phase modulation in a double electromagnetically induced transparency regime
The generation of an entangled coherent state is one of the most important
ingredients of quantum information processing using coherent states. Recently,
numerous schemes to achieve this task have been proposed. In order to generate
travelling-wave entangled coherent states, cross phase modulation, optimized by
optical Kerr effect enhancement in a dense medium in an electromagnetically
induced transparency (EIT) regime, seems to be very promising. In this
scenario, we propose a fully quantized model of a double-EIT scheme recently
proposed [D. Petrosyan and G. Kurizki, {\sl Phys. Rev. A} {\bf 65}, 33833
(2002)]: the quantization step is performed adopting a fully Hamiltonian
approach. This allows us to write effective equations of motion for two
interacting quantum fields of light that show how the dynamics of one field
depends on the photon-number operator of the other. The preparation of a
Schr\"odinger cat state, which is a superposition of two distinct coherent
states, is briefly exposed. This is based on non-linear interaction via
double-EIT of two light fields (initially prepared in coherent states) and on a
detection step performed using a beam splitter and two photodetectors.
In order to show the entanglement of a generated entangled coherent state, we
suggest to measure the joint quadrature variance of the field. We show that the
entangled coherent states satisfy the sufficient condition for entanglement
based on quadrature variance measurement. We also show how robust our scheme is
against a low detection efficiency of homodyne detectors.Comment: 15 pages, 9 figures; extensively revised version; added Section
Observation of hard scattering in photoproduction events with a large rapidity gap at HERA
Events with a large rapidity gap and total transverse energy greater than 5
GeV have been observed in quasi-real photoproduction at HERA with the ZEUS
detector. The distribution of these events as a function of the
centre of mass energy is consistent with diffractive scattering. For total
transverse energies above 12 GeV, the hadronic final states show predominantly
a two-jet structure with each jet having a transverse energy greater than 4
GeV. For the two-jet events, little energy flow is found outside the jets. This
observation is consistent with the hard scattering of a quasi-real photon with
a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
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