Photon-mediated qubit interactions in one-dimensional discrete and continuous models

In this work we study numerically and analytically the interaction of two qubits in a one-dimensionalwaveguide, as mediated by the photons that propagate through the guide. We develop strategies to assert the Markovianity of the problem, the effective qubit-qubit interactions, and their individual and collective spontaneous emission. We prove the existence of collective Lamb shifts that affect the qubit-qubit interactions and the dependency of coherent and incoherent interactions on the qubit separation. We also develop the scattering theory associated with these models and prove single-photon spectroscopy does probe the renormalized resonances of the singleand multiqubit models, in sharp contrast to earlier toy models in which individual and collective Lamb shifts cancel

Dynamics of a suspension of interacting yolk-shell particles

In this work we study the self-diffusion properties of a liquid of hollow spherical particles (shells)bearing a smaller solid sphere in their interior (yolks). We model this system using purely repulsive hard-body interactions between all (shell and yolk) particles, but assume the presence of a background ideal solvent such that all the particles execute free Brownian motion between collisions,characterized by short-time self-diffusion coefficients D0s for the shells and D0y for the yolks. Using a softened version of these interparticle potentials we perform Brownian dynamics simulations to determine the mean squared displacement and intermediate scattering function of the yolk-shell complex. These results can be understood in terms of a set of effective Langevin equations for the N interacting shell particles, pre-averaged over the yolks' degrees of freedom, from which an approximate self-consistent description of the simulated self-diffusion properties can be derived. Here we compare the theoretical and simulated results between them, and with the results for the same system in the absence of yolks. We find that the yolks, which have no effect on the shell-shell static structure, influence the dynamic properties in a predictable manner, fully captured by the theory.Comment: 5 pages, 1 figur

A Rational Expectations Model for Simulation and Policy Evaluation of the Spanish Economy

This paper describes a Rational Expectations Model of the Spanish economy, REMS, which is in the tradition of small open economy dynamic general equilibrium models, with a strongly microfounded system of equations. The model is built on standard elements, but incorporates some distinctive features to provide an accurate description of the Spanish economy. We contribute to the existing models of the Spanish economy by adding search and matching rigidities to a small open economy framework. Our model also incorporates habits in consumption and rule-of-thumb households. As Spain is a member of EMU, we model the interaction between a small open economy and monetary policy in a monetary union. The model is primarily constructed to serve as a simulation tool at the Spanish Ministry of Economic Affairs and Finance. As such, it provides a great deal of information regarding the transmission of policy shocks to economic outcomes. The paper describes the structure of the model in detail, as well as the estimation and calibration technique and some examples of simulations.general equilibrium, rigidities, policy simulations

The REMSDB Macroeconomic Database of The Spanish Economy

This paper presents a new macroeconomic database for the Spanish economy, REMSDB. The construction of this database has been oriented to conducting medium-term simulations for policy evaluation with the REMS model, a large Rational Expectations macroeconomic Model for Spain. The paper provides a detailed description of the data and documents its main statistical properties. The database is thought to be of major interest to related applications,whether strictly associated with the REMS model or, rather, with empirical macroeconomic studies.Spanish Data, Growth Data, Business Cycle Data, REMS