On the coupling of two quantum dots through a cavity mode

The effective coupling of two distant quantum dots through virtual photon exchange in a semiconductor microcavity is studied. The experimental conditions for strong coupling and its manifestation in the spectra of emission are analyzed.Comment: 2 pages, 1 figur

Open Heavy Flavor Production in p-p and Pb-Pb collisions as seen by ALICE at the LHC

Charm and beauty production are probed with the ALICE experiment at the LHC by studying the single lepton transverse momentum distribution (electrons at mid-rapidity, muons at large-rapidities) and D mesons reconstructed in their hadronic decays. The differential production cross sections in proton proton interactions show a good agreement with perturbative QCD calculations at both sqrt(s) = 2.76 and 7 TeV. The measurements in lead lead reactions at sqrt(s_{NN})= 2.76 TeV evidence a reduction (or suppression) of the production rate at intermediate and high pt in the most central collisions with respect to the rate in proton proton interactions.Comment: To appear in the Proceedings of the 19th Particles and Nuclei International Conference, PANIC 201

Correlator expansion approach to stationary states of weakly coupled cavity arrays

We introduce a method for calculating the stationary state of a translation invariant array of weakly coupled cavities in the presence of dissipation and coherent as well as incoherent drives. Instead of computing the full density matrix our method directly calculates the correlation functions which are relevant for obtaining all local quantities of interest. It considers an expansion of the correlation functions and their equations of motion in powers of the photon tunneling rate between adjacent cavities, leading to an exact second order solution for any number of cavities. Our method provides a controllable approximation for weak tunneling rates applicable to the strongly correlated regime that is dominated by nonlinearities in the cavities and thus of high interest.Comment: contribution to J. Phys. B special issue celebrating Jaynes-Cummings physic

Non-thermal emission from stellar bow shocks

Since the detection of non-thermal radio emission from the bow shock of the massive runaway star BD +43$^{\circ}$3654 simple models have predicted high-energy emission, at X and gamma-rays, from these Galactic sources. Observational searches for this emission so far give no conclusive evidence but a few candidates at gamma rays. In this work we aim at developing a more sophisticated model for the non-thermal emission from massive runaway star bow shocks. The main goal is to establish whether these systems are efficient non-thermal emitters, even if they are not strong enough to be yet detected. For modeling the collision between the stellar wind and the interstellar medium we use 2D hydrodynamic simulations. We then adopt the flow profile of the wind and the ambient medium obtained with the simulation as the plasma state for solving the transport of energetic particles injected in the system, and the non-thermal emission they produce. For this purpose we solve a 3D (2 spatial + energy) advection-diffusion equation in the test-particle approximation. We find that a massive runaway star with a powerful wind converts 0.16-0.4% of the power injected in electrons into non-thermal emission, mostly produced by inverse Compton scattering of dust-emitted photons by relativistic electrons, and secondly by synchrotron radiation. This represents a fraction of $\sim$ $10^{-5}-10^{-4}$ of the wind kinetic power. Given the better sensibility of current instruments at radio wavelengths theses systems are more prone to be detected at radio through the synchrotron emission they produce rather than at gamma energies.Comment: 18 pages, 12 figures. Accepted for publication in Ap

On Schr\"odinger's equation, 3-dimensional Bessel bridges, and passage time problems

In this work we relate the density of the first-passage time of a Wiener process to a moving boundary with the three dimensional Bessel bridge process and a solution of the heat equation with a moving boundary. We provide bounds