K-quantum Nonlinear Jaynes-Cummings Model in Two Trapped Ions

A k-quantum nonlinear Jaynes-Cummings model for two trapped ions interacting with laser beams resonant to k-th red side-band of center-of-mass mode, far from Lamb-Dicke regime, has been obtained. The exact analytic solution showed the existence of quantum collapses and revivals of the occupation of two atoms.Comment: 8 pages, 3 figure

A Hidden Markov Model For Conversion Rate Dynamics In Online Retail

In this study, we use a proprietary data set from an online marketplace to study the conversion rate dynamics in online retail. We examine how seller-level covariates, such as online sellers’ pricing and product strategies, service responsiveness, and other attributes, affect conversion rates. Specifically, we address the following research questions: (i) How do sellers’ covariates affect their conversion rates? (ii) Is the relationship between the conversion rate and sellers’ covariates state dependent? (iii) If the relationship is state dependent, what are the factors that determine the states and the state transitions? The estimation results indicate that there are two states that affect conversion rate dynamics. The relationship between the conversion rate and the sellers’ covariates is state dependent, that is, given the different states of sellers, the effects of the sellers’ covariates on their conversion rates are different. We also estimate the thresholds between states

A Simple Model for Cavity Enhanced Slow Lights in Vertical Cavity Surface Emission Lasers

We develop a simple model for the slow lights in Vertical Cavity Surface Emission Lasers (VCSELs), with the combination of cavity and population pulsation effects. The dependences of probe signal power, injection bias current and wavelength detuning for the group delays are demonstrated numerically and experimentally. Up to 65 ps group delays and up to 10 GHz modulation frequency can be achieved in the room temperature at the wavelength of 1.3 $\mu$m. The most significant feature of our VCSEL device is that the length of active region is only several $\mu$m long. Based on the experimental parameters of quantum dot VCSEL structures, we show that the resonance effect of laser cavity plays a significant role to enhance the group delays