Periodicity enclosed in boundaries: local density of states in photonic clusters\ud

We have studied the effect of the boundaries on the local density of states (LDOS) in one-, two-, and three-dimensional finite size photonic structures. The LDOS was calculated with the help of the local perturbation method (LPM) and a new LPM-Bloch method using periodicity of the system. The methods are applicable for the clusters made of small (relative to the incident wavelength) particles or for the clusters which can be considered as made of such particles. It was demonstrated that the LPM-Bloch method is an accurate numerical tool for calculation of the LDOS in the finite size photonic structures with weak interference. \ud \u

Interplay between multiple scattering, emission, and absorption of light in the phosphor of a white light-emitting diode

We study light transport in phosphor plates of white light-emitting diodes (LEDs). We measure the broadband diffuse transmission through phosphor plates of varying YAG:Ce$^{3+}$ density. We distinguish the spectral ranges where absorption, scattering, and re-emission dominate. Using diffusion theory, we derive the transport and absorption mean free paths from first principles. We find that both transport and absorption mean free paths are on the order of the plate thickness. This means that phosphors in commercial LEDs operate well within an intriguing albedo range around 0.7. We discuss how salient parameters that can be derived from first principles control the optical properties of a white LED.Comment: 14 pages, 9 figure

A new numerical approach to Anderson (de)localization

We develop a new approach for the Anderson localization problem. The implementation of this method yields strong numerical evidence leading to a (surprising to many) conjecture: The two dimensional discrete random Schroedinger operator with small disorder allows states that are dynamically delocalized with positive probability. This approach is based on a recent result by Abakumov-Liaw-Poltoratski which is rooted in the study of spectral behavior under rank-one perturbations, and states that every non-zero vector is almost surely cyclic for the singular part of the operator. The numerical work presented is rather simplistic compared to other numerical approaches in the field. Further, this method eliminates effects due to boundary conditions. While we carried out the numerical experiment almost exclusively in the case of the two dimensional discrete random Schroedinger operator, we include the setup for the general class of Anderson models called Anderson-type Hamiltonians. We track the location of the energy when a wave packet initially located at the origin is evolved according to the discrete random Schroedinger operator. This method does not provide new insight on the energy regimes for which diffusion occurs.Comment: 15 pages, 8 figure

Topic "little man" in the early works of Leonid Andreyev

В статье впервые осуществлен анализ наиболее репрезентативных образцов ранней прозы Л. Н. Андреева, новаторски продолжающих и развивающих традиции русской классической литературы в изображении "маленького человека".The article analyzes for the first time the most representative examples of early prose by L. N. Andreyev, innovatively continuing and developing the traditions of Russian classical literature in the image of a "little man"

Exact Quantum Monte Carlo Process for the Statistics of Discrete Systems

We introduce an exact Monte Carlo approach to the statistics of discrete quantum systems which does not rely on the standard fragmentation of the imaginary time, or any small parameter. The method deals with discrete objects, kinks, representing virtual transitions at different moments of time. The global statistics of kinks is reproduced by explicit local procedures, the key one being based on the exact solution for the biased two-level system.Comment: 4 pages, latex, no figures, English translation of the paper

Inequity in postpartum healthcare provision at home and its association with subsequent healthcare expenditure

BACKGROUND: Provision of postpartum care can support new families in adapting to a new situation. We aimed to determine whether various determinants of socioeconomic status (SES) were associated with utilization of postpartum care. In addition, to stress the relevance of increasing postpartum care uptake among low SES-groups, an assessment of the potential (cost-)effectiveness of postpartum care is required. METHODS: National retrospective cohort study using linked routinely collected healthcare data from all registered singleton deliveries (2010-13) in the Netherlands. Small-for-gestational age and preterm babies were excluded. The associations between SES and postpartum care uptake, and between uptake and health care expenditure were studied using multivariable regression analyses. RESULTS: Of all 569 921 deliveries included, 1.2% did not receive postpartum care. Among women who did receive care, care duration was below the recommended minimum of 24 h in 15.3%. All indicators of low SES were independently associated with a lack in care uptake. Extremes of maternal age, single parenthood and being of non-Dutch origin were associated with reduced uptake independent of SES determinants. No uptake of postpartum care was associated with maternal healthcare expenses in the highest quartile: aOR 1.34 (95% CI 1.10-1.67). Uptake below the recommended amount was associated with higher maternal and infant healthcare expenses: aOR 1.09 (95% CI 1.03-1.18) and aOR 1.20 (95% CI 1.13-1.27), respectively. CONCLUSION: Although uptake was generally high, low SES women less often received postpartum care, this being associated with higher subsequent healthcare expenses. Strategies to effectively reduce these substantial inequities in early life are urgently needed

Signatures of photon localization

Signatures of photon localization are observed in a constellation of transport phenomena which reflect the transition from diffusive to localized waves. The dimensionless conductance, g, and the ratio of the typical spectral width and spacing of quasimodes, \delta, are key indicators of electronic and classical wave localization when inelastic processes are absent. However, these can no longer serve as localization parameters in absorbing samples since the affect of absorption depends upon the length of the trajectories of partial waves traversing the sample, which are superposed to create the scattered field. A robust determination of localization in the presence of absorption is found, however, in steady-state measurements of the statistics of radiation transmitted through random samples. This is captured in a single parameter, the variance of the total transmission normalized to its ensemble average value, which is equal to the degree of intensity correlation of the transmitted wave, \kappa. The intertwined effects of localization and absorption can also be disentangled in the time domain since all waves emerging from the sample at a fixed time delay from an exciting pulse, t, are suppressed equally by absorption. As a result, the relative weights of partial waves emerging from the sample, and hence the statistics of intensity fluctuations and correlation, and the suppression of propagation by weak localization are not changed by absorption, and manifest the growing impact of weak localization with t.Comment: RevTex 16 pages, 12 figures; to appear in special issue of J. Phys. A on quantum chaotic scatterin

Localization in a random phase-conjugating medium

We theoretically study reflection and transmission of light in a one-dimensional disordered phase-conjugating medium. Using an invariant imbedding approach a Fokker-Planck equation for the distribution of the probe light reflectance and expressions for the average probabilities of reflection and transmission are derived. A new crossover length scale for localization of light is found, which depends on the competition between phase conjugation and disorder. For weak disorder, our analytical results are in good agreement with numerical simulations.Comment: RevTex, 4 pages, 4 figure