191 research outputs found
Generating a Schr\"odinger-cat-like state via a coherent superposition of photonic operations
We propose an optical scheme to generate a superposition of coherent states
with enhanced size adopting an interferometric setting at the single-photon
level currently available in the laboratory. Our scheme employs a nondegenerate
optical parametric amplifier together with two beam splitters so that the
detection of single photons at the output conditionally implements the desired
superposition of second-order photonic operations. We analyze our proposed
scheme by considering realistic on-off photodetectors with nonideal efficiency
in heralding the success of conditional events. A high-quality performance of
our scheme is demonstrated in view of various criteria such as quantum
fidelity, mean output energy, and measure of quantum interference
Transition times in the Landau-Zener model
This paper presents analytic formulas for various transition times in the
Landau-Zener model. Considerable differences are found between the transition
times in the diabatic and adiabatic bases, and between the jump time (the time
for which the transition probability rises to the region of its asymptotic
value) and the relaxation time (the characteristic damping time of the
oscillations which appear in the transition probability after the crossing).
These transition times have been calculated by using the exact values of the
transition probabilities and their derivatives at the crossing point and
approximations to the time evolutions of the transition probabilities in the
diabatic basis, derived earlier \protect{[}N. V. Vitanov and B. M. Garraway,
Phys. Rev. A {\bf 53}, 4288 (1996)\protect{]}, and similar results in the
adiabatic basis, derived in the present paper.Comment: 7 pages, two-column revtex style, 5 figures, to appear in Phys. Rev.
A (Feb 1999
Heteroskedasticity of Unknown Form in Spatial Autoregressive Models with Moving Average Disturbance Term
Exchange Rate Linkages between the ASEAN Currencies, the US Dollar and the Chinese RMB
Prolonged Holiday Effects on Romanian Capital Market before and After the Adhesion to EU
Off-pump occlusion of trans-thoracic minimal invasive surgery (OPOTTMIS) on simple congenital heart diseases (ASD, VSD and PDA) attached consecutive 210 cases report: A single institute experience
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