Efficient excitation of a two level atom by a single photon in a propagating mode

State mapping between atoms and photons, and photon-photon interactions play an important role in scalable quantum information processing. We consider the interaction of a two-level atom with a quantized \textit{propagating} pulse in free space and study the probability $P_e(t)$ of finding the atom in the excited state at any time $t$. This probability is expected to depend on (i) the quantum state of the pulse field and (ii) the overlap between the pulse and the dipole pattern of the atomic spontaneous emission. We show that the second effect is captured by a single parameter $\Lambda\in[0,8\pi/3]$, obtained by weighting the dipole pattern with the numerical aperture. Then $P_e(t)$ can be obtained by solving time-dependent Heisenberg-Langevin equations. We provide detailed solutions for both single photon Fock state and coherent states and for various temporal shapes of the pulses.Comment: 6 pages, 5 figures, 2 table

Analyses of shocked quartz at the global K-P boundary indicate an origin from a single, high-angle, oblique impact at Chicxulub

Accepted versio

The Power of Information and Communities of Color

In this age of the Information Superhighway, access to information has become a human rights issue for communities of color. Access to information is the backbone for economic growth in the world marketplace. Information literacy, the ability to find, evaluate, analyze, and use information effectively is the currency of infinite power and control of one\u27s economic, social, and political destiny. For communities of color to gain access to this phenomenal communications/technological revolution, there is a need to become information literate

Security Proof for Quantum Key Distribution Using Qudit Systems

We provide security bounds against coherent attacks for two families of quantum key distribution protocols that use $d$-dimensional quantum systems. In the asymptotic regime, both the secret key rate for fixed noise and the robustness to noise increase with $d$. The finite-key corrections are found to be almost insensitive to $d\lesssim 20$.Comment: 5 pages, 1 figure, version 3 corrects equations (9) and (11), and slightly modifies the figure to reflect the change to equation (11

Relación entre el uso de Internet y el rendimiento académico en una muestra de adolescentes canarios

El incremento en el número de ordenadores y conexiones a internet en los hogares canarios plantea la necesidad de analizar el tiempo y uso que se hace de internet en la adolescencia y su relación con el rendimiento escolar. 578 adolescentes respondieron a una entrevista semiestructurada sobre hábitos de consumo. Es frecuente es pasar 2 horas diarias “conectado” con diferencias significativas entre varones y mujeres. El tiempo de consumo se relaciona con el número de faltas a clase y el número de suspensos, pero no con el rendimiento en asignaturas como Lengua y Matemáticas.The increase in the number of computers and access to Internet in Canarian households suggests the necessity of studying the use that adolescents make of it, as well as its influence in their academic performance. 578 adolescents took part in a semi-structured interview on Internet use habits. The results showed that adolescents spend an average of two hours a day connected to Internet, with significant differences between males and females. The time invested in Internet is linked to the number of absences from school and subjects failed. However, there is no influence in the performance in subjects such as Linguistics and Maths