Non-Markovian qubit dynamics in a circuit-QED setup

We consider a circuit-QED setup that allows the induction and control of non-Markovian dynamics of a qubit. Non-Markovianity is enforced over the qubit by means of its direct coupling to a bosonic mode which is controllably coupled to other qubit-mode system. We show that this configuration can be achieved in a circuit-QED setup consisting of two initially independent superconducting circuits, each formed by one charge qubit and one transmission-line resonator, which are put in interaction by coupling the resonators to a current-biased Josephson junction. We solve this problem exactly and then proceed with a thorough investigation of the emergent non-Markovianity in the dynamics of the qubits. Our study might serve the context for a first experimental assessment of non-Markovianity in a multi-element solid-state device.Comment: 8 pages, 7 figures, slightly changed titl

Percolation study for the capillary ascent of a liquid through a granular soil

Capillary rise plays a crucial role in the construction of road embankments in flood zones, where hydrophobic compounds are added to the soil to suppress the rising of water and avoid possible damage of the pavement. Water rises through liquid bridges, menisci and trimers, whose width and connectivity depends on the maximal half-length {\lambda} of the capillary bridges among grains. Low {\lambda} generate a disconnect structure, with small clusters everywhere. On the contrary, for high {\lambda}, create a percolating cluster of trimers and enclosed volumes that form a natural path for capillary rise. Hereby, we study the percolation transition of this geometric structure as a function of {\lambda} on a granular media of monodisperse spheres in a random close packing. We determine both the percolating threshold {\lambda}_{c} = (0.049 \pm 0.004)R (with R the radius of the granular spheres), and the critical exponent of the correlation length {\nu} = (0.830 \pm 0.051), suggesting that the percolation transition falls into the universality class of ordinary percolation

Atomic Effective Pseudopotentials for Semiconductors

We derive an analytic connection between the screened self-consistent effective potential from density functional theory (DFT) and atomic effective pseudopotentials (AEPs). The motivation to derive AEPs is to address structures with thousands to hundred thousand atoms, as given in most nanostructures. The use of AEPs allows to bypass a self-consistent procedure and to address eigenstates around a certain region of the spectrum (e.g., around the band gap). The bulk AEP construction requires two simple DFT calculations of slightly deformed elongated cells. The ensuing AEPs are given on a fine reciprocal space grid, including the small reciprocal vector components, are free of parameters, and involve no fitting procedure. We further show how to connect the AEPs of different bulk materials, which is necessary to obtain accurate band offsets. We derive a total of 20 AEPs for III-V, II-VI and group IV semiconductors and demonstrate their accuracy and transferability by comparison to DFT calculations of strained bulk structures, quantum wells with varying thickness, and semiconductor alloys.Comment: 10 pages, 5 figures, submitted to PR

Degree of Quantumness in Quantum Synchronization

We introduce the concept of degree of quantumness in quantum synchronization, a measure of the quantum nature of synchronization in quantum systems. Following techniques from quantum information, we propose the number of non-commuting observables that synchronize as a measure of quantumness. This figure of merit is compatible with already existing synchronization measurements, and it captures different physical properties. We illustrate it in a quantum system consisting of two weakly interacting cavity-qubit systems, which are coupled via the exchange of bosonic excitations between the cavities. Moreover, we study the synchronization of the expectation values of the Pauli operators and we propose a feasible superconducting circuit setup. Finally, we discuss the degree of quantumness in the synchronization between two quantum van der Pol oscillators

La Hipoteca Inversa: instrumento de previsión social

Treballs Finals del Grau de d'Administració i Direcció d'Empreses, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2015-2016 , Tutor: Antonio Alegre Escolano(spa) Las previsiones en cuanto a sostenimiento de las pensiones públicas, en especial la de jubilación, hacen prever un futuro incierto y pesimista de su viabilidad y mantenimiento. Por ello, se buscan alternativas privadas que la complementen ante una posible bajada en su cuantía económica. Como instrumentos complementarios se proponen los planes de pensiones, los seguros y los PPAS. No obstante, ante la baja propensión o incapacidad para ahorrar a futuro, surge la idea de utilizar el valor del inmueble para garantizar una renta complementaria a las personas mayores. La hipoteca inversa es un instrumento de conversión de activos inmobiliarios a tal fin, importada de los países anglosajones, permite que el prestatario perciba una pensión dejando como garantía su vivienda habitual. A pesar de las ventajas que ofrece, presenta ciertos problemas por los que actualmente no está siendo un producto atractivo.(eng) Probably the measures that contribute to the maintenance of the actual level of public pensions, especially retirement pensions, will be insufficient to guarantee their viability towards the future, because the forecast in that regard is really uncertain and pessimistic. Therefore, the financial and insurance sector is looking for privates alternatives to relieve a possible decline of the amount of retirement pensions. Currently, the main financial instrument used to complement the retirement pensions are Pension Plans, Insurances and Insured Retirement Plans (PPA). However, on account of the low propensity or the incapacity to save enough money, arose the idea of use the value of the property to ensure additional income to the elderly. The reverse mortgage is a financial instrument of real estate assets conversion, imported from Anglo-Saxons countries. This product allows the homeowner to receive a complementary pension leaving his residence as a guarantee. The main advantage of reverse mortgage is that the owner does not lose the property of his residence. The debt will accumulate until the end of the loan or the death of the borrower. When it happens, heirs will have the duty to pay the debt, if they do not have enough money they could sell the property or hire a mortgage. Spain being a country with a high culture of property and a large life expectancy could be the perfect market to commercialise this kind of product. Despite the advantages, it presents certain problems for the different agents that intervene in the operation. On the other hand, the recent crisis of 2008 has an important impact on financial and real estate sector, increasing the distrust. As a result, the reverse mortgage currently is not being an attractive product in Spain

Impacto de las nanopartículas de carbono en las técnicas analíticas de separación

II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

The pupal morphology of the Carabus (s. l.) (Coleoptera, Carabidae) in the southwestern Iberian peninsula

The pupae of Carabus (s. l.) of the south-west Iberian peninsula are described. The study was carried out with pupae of Macrothorax rugosus (Fabricius, 1792), Hadrocarabus dufouri (Dejean, 1831), H. lusitanicus (Fabricius, 1801) and Rhabdotocarabus melancholicus (Fabricius, 1798) reared in the laboratory from adults caught in the field. By determining and testing various morphological structures, all three genera were identified. These results indicate that the presence or absence of setae on the pronotum, the distribution of hairs on the abdominal tergi and the development of tergal expansions from urotergi are the most significant features for identification