Soliton-radiation trapping in gas-filled photonic crystal fibers

We propose an optical trapping technique in which a fundamental soliton traps an ultrashort small amplitude radiation in a symmetric hollow-core photonic crystal fiber filled with a noble gas, preventing its dispersion. The system is Raman- and plasma-free. Trapping is due to the cross phase modulation effect between the two pulses. The trapped radiation inside the soliton-induced potential will oscillate periodically due to the shock effect, similar to the motion of a mechanical pendulum. DOI: 10.1103/PhysRevA.87.04380

Trapped Bose-Einstein condensates in the presence of a current nonlinearity

We investigate the effect of a current nonlinearity on the evolution of a trapped atomic Bose-Einstein condensate. We have implemented techniques from the field of nonlinear optics to provide new insights into the irregular dynamics associated with chiral superfluids. We have found that the current nonlinearity can be treated as a Kerr-like nonlinearity modulated by a spatiotemporal function that can lead to a number of processes such as broadening and compression of the wave function. In the long time scale limit, the wave function is drastically deformed and delocalised compared to its initial state. However, localised modes which oscillate with the period of the inverse trap frequency can still be observed.Comment: A short note on the links between nonlinear gauge potentials and nonlinear optics. Comments are welcom

Soliton dynamics in gas-filled hollow-core photonic crystal fibers

Gas-filled hollow-core photonic crystal fibers offer unprecedented opportunities to observe novel nonlinear phenomena. The various properties of gases that can be used to fill these fibers give additional degrees of freedom for investigating nonlinear pulse propagation in a wide range of different media. In this review, we will consider some of the the new nonlinear interactions that have been discovered in recent years, in particular those which are based on soliton dynamics

Photonic circuits for generating modal, spectral, and polarization entanglement

We consider the design of photonic circuits that make use of Ti:LiNbO$_{3}$ diffused channel waveguides for generating photons with various combinations of modal, spectral, and polarization entanglement. Down-converted photon pairs are generated via spontaneous optical parametric down-conversion (SPDC) in a two-mode waveguide. We study a class of photonic circuits comprising: 1) a nonlinear periodically poled two-mode waveguide structure, 2) a set of single-mode and two-mode waveguide-based couplers arranged in such a way that they suitably separate the three photons comprising the SPDC process, and, for some applications, 3) a holographic Bragg grating that acts as a dichroic reflector. The first circuit produces frequency-degenerate down-converted photons, each with even spatial parity, in two separate single-mode waveguides. Changing the parameters of the elements allows this same circuit to produce two nondegenerate down-converted photons that are entangled in frequency or simultaneously entangled in frequency and polarization. The second photonic circuit is designed to produce modal entanglement by distinguishing the photons on the basis of their frequencies. A modified version of this circuit can be used to generate photons that are doubly entangled in mode number and polarization. The third photonic circuit is designed to manage dispersion by converting modal, spectral, and polarization entanglement into path entanglement

Strong Raman-induced non-instantaneous soliton interactions in gas-filled photonic crystal fibers

We have developed an analytical model based on the perturbation theory in order to study the optical propagation of two successive intense solitons in hollow-core photonic crystal fibers filled with Raman-active gases. Based on the time delay between the two solitons, we have found that the trailing soliton dynamics can experience unusual nonlinear phenomena such as spectral and temporal soliton oscillations and transport towards the leading soliton. The overall dynamics can lead to a spatiotemporal modulation of the refractive index with a uniform temporal period and a uniform or chirped spatial period

Whither Corruption? A Quantitative Survey of the Literature on Corruption and Growth

Does corruption grease or sand the wheels of economic growth? This paper uses meta-analysis techniques to systematically evaluate the evidence addressing this question. It uses a data set comprising 460 estimates of the effect of corruption on growth from 41 empirical studies. The main factors explaining the variation in these estimates are whether the model accounts for institutions and trade openness (both are found to deflate the negative effect of corruption), authors' affiliation (academics systematically report less negative impacts), and use of fixed-effects. We also find that publication bias, albeit somewhat acute, does not eliminate the genuine negative effect of corruption on economic growth.corruption, economic growth, meta-regression analysis

Dynamic Ethnic Fractionalization and Economic Growth in the Transition Economies from 1989 to 2007

In their survey of the literature on ethnic fractionalization and economic performance, Alesina and La Ferrara (JEL 2005) identify two main directions for future research. One is to improve the measurement of diversity and the other to treat diversity as an endogenous variable. This paper tries to address these two issues: it investigates the effects of ethnic fractionalization on economic growth across countries using unique time-varying measures. We first replicate the finding of a weak effect of exogenous diversity on growth and then we show that accounting for how diversity changes over time and treating it as an endogenous variable makes a difference. Once diversity is instrumented (with lagged diversity and latitude), it shows a significant negative impact on economic growth which is robust to different specifications, polarization measures, econometric estimators, as well as to the use of an index of ethnic-religious-linguistic fractionalization.ethnic diversity, fractionalization, polarization, growth

Dynamic Ethnic Fractionalization and Economic Growth

In their survey of the literature on ethnic fractionalization and economic performance, Alesina and La Ferrara (JEL 2005) identify two main directions for future research. One is to improve the measurement of diversity and the other to treat diversity as an endogenous variable. This paper tries to address these two issues. We study the effects of ethnic fractionalization on economic growth using unique time-varying measures across countries, for 26 transition economies from 1989 to 2007. Our main conclusion is that we can replicate the most recent results from the literature and show that static (exogenous) diversity is not robustly related to growth. However, when we account empirically for how ethnic diversity changes over time and treat it as an endogenous variable, our estimates show that it is negatively related to growth an effect which is robust to different estimators, specifications, and fractionalization measures. --ethnic diversity,fractionalization,polarization,growth

The School of Ahl Al-sunnah Wa Al-jama`ah and the Attachment of Indonesian Muslims to Its Doctrines

The doctrine of Ahl al-Sunnah wa al-Jama`ah has been exploited by two major Muslim organizations in Indonesia, NU and Muhammadiyah, as the theological basis in determining their religious identity and rituals. Although these organizations claim that all Muslims should adhere to the doctrines of Ahl al-Sunnah, they have never clearly defined that term. This paper discusses in detail the meaning of the term followed by an examination of the ways in which those two Muslim organizations attach themselves to this doctrine. This paper argues that, although the NU links itself to this doctrine, it is still necessary to critically examine to what extent its members apply the doctrines of Ahl al-Sunnah in their daily life. Muhammadiyah, on the other hand, is not obsessed with the claim of being faithful to the doctrines of Ahl al-Sunnah, although its constitution mentions that they advocate theological creeds which are evidently in line with the precepts of Ahl al-Sunnah

Quantum Holography

We propose to make use of quantum entanglement for extracting holographic information about a remote 3-D object in a confined space which light enters, but from which it cannot escape. Light scattered from the object is detected in this confined space entirely without the benefit of spatial resolution. Quantum holography offers this possibility by virtue of the fourth-order quantum coherence inherent in entangled beams.Comment: 7 pages, submitted to Optics Expres