Now showing items 1-20 of 119

    • A Combinatorial Approach to Nonlocality and Contextuality 

      Acín dal Maschio, Antonio; Fritz, Tobias; Leverrier, Anthony (Springer, 2015-03-01)
      Article
      Open Access
      So far, most of the literature on (quantum) contextuality and the Kochen– Specker theorem seems either to concern particular examples of contextuality, or be considered as quantum logic. Here, we develop a general formalism ...
    • A general framework for information-work interconvertibility in the quantum regime 

      Rodríguez Ramos, Constantino (Universitat Politècnica de Catalunya, 2016-09)
      Master thesis
      Open Access
      In this theoretical work we study three theorems that establish limitations to three basic processes in thermodynamics: an adiabatic process, an erasure process and a work extraction process. We propose a theoretical setting ...
    • Ag2ZnSnS4–ZnS core–shell colloidal quantum dots: a near-infrared luminescent material based on environmentally friendly elements 

      Saha, Avijit; Konstantatos, Gerasimos (RSC, 2021-05-07)
      Article
      Open Access
      Low cost, multinary colloidal quantum dots (QDs) based on environmentally friendly elements, with bright, narrow-width, tunable near-infrared (NIR) luminescence are promising alternatives to Cd and Pb chalcogenide QDs for ...
    • Almost quantum correlations 

      Navascués, Miguel; Guryanova, Yelena; Hoban, Matty J.; Acín dal Maschio, Antonio (Nature Publishing group, 2015-02-20)
      Article
      Open Access
      Quantum theory is not only successfully tested in laboratories every day but also constitutes a robust theoretical framework: small variations usually lead to implausible consequences, such as faster-than-light communication. ...
    • An experimental setup for gray molasses sub-Doppler cooling of potassium gases 

      Bosch Aguilera, Manel (Universitat Politècnica de Catalunya, 2014-09-09)
      Master thesis
      Open Access
      [ÀNGLÈS] An experimental setup for cooling a gas of potassium atoms below the Doppler limit is presented. This method is known as gray molasses cooling. It will be implemented using light blue light blue detuned with respect ...
    • Applications of machine learning to studies of quantum phase transitions 

      Malo Roset, Laura (Universitat Politècnica de Catalunya, 2019-09-06)
      Master thesis
      Open Access
      In the past years Machine Learning has shown to be a useful tool in quantum many-body physics to detect phase transitions. Being able to identify phases via machine learning introduces the question of how did the algorithm ...
    • Bloch oscillations in optical and Zeeman lattices in the presence of spin-orbit coupling 

      Kartashov, Yaroslav V.; Konotop, Vladimir V; Zezyulin, Dmitry A; Torner Sabata, Lluís (2016-11-18)
      Article
      Open Access
      We address Bloch oscillations of a spin-orbit coupled atom in periodic potentials of two types: optical and Zeeman lattices. We show that in optical lattices the spin-orbit coupling allows controlling the direction of ...
    • Bose polarons at finite temperature and strong coupling 

      Guenther, Nils Eric; Massignan, Pietro Alberto; Lewenstein, Maciej; Bruun, Georg (2018-02-01)
      Article
      Open Access
      A mobile impurity coupled to a weakly interacting Bose gas, a Bose polaron, displays several interesting effects. While a single attractive quasiparticle is known to exist at zero temperature, we show here that the spectrum ...
    • Bound states in the continuum in anisotropic structures 

      Gomis Bresco, Jordi; Artigas García, David; Pujol Closa, Maria del Pilar; Torner Sabata, Lluís (Institute of Electrical and Electronics Engineers (IEEE), 2017)
      Conference report
      Restricted access - publisher's policy
      We report theoretical and experimental observation of radiationless bound states in the continuum (BIC) in waveguiding anisotropic structures. BICs may have all possible polarizations and be the only possible boundstates ...
    • Bound states in the continuum in spin-orbit-coupled atomic systems 

      Kartashov, Yaroslav V.; Konotop, Vladimir V; Torner Sabata, Lluís (2017-09-14)
      Article
      Restricted access - publisher's policy
      We show that the interplay between spin-orbit coupling and Zeeman splitting in atomic systems can lead to the existence of bound states in the continuum (BICs) supported by trapping potentials. Such states have energies ...
    • Can quantum effects due to a massless conformally coupled field avoid gravitational singularities? 

      Haro Cases, Jaume (2012-04)
      Article
      Restricted access - publisher's policy
      Using quantum corrections from massless fields conformally coupled to gravity, we study the possibility of avoiding singularities that appear in the flat Friedmann–Robertson–Walker model. We assume that the universe ...
    • Characterizing and witnessing multipartite correlations : from nonlocality to contextuality 

      Sainz, Ana Belén (Universitat Politècnica de Catalunya, 2014-02-10)
      Doctoral thesis
      Open Access
      In the past century, experimental discoveries have witnessed phenomena in Nature which challenge our everyday classical intuition. In order to explain these facts, quantum theory was developed, which so far has been able ...
    • Characterizing entanglement and quantum correlations constrained by symmetry 

      Tura i Brugués, Jordi (Universitat Politècnica de Catalunya, 2015-07-20)
      Doctoral thesis
      Open Access
      Entanglement and nonlocal correlations constitute two fundamental resources for quantum information processing, as they allow for novel tasks that are otherwise impossible in a classical scenario. However, their elusive ...
    • Coherent control of a superconducting quantum bit 

      Luque Merino, Rafael (Universitat Politècnica de Catalunya, 2019-09-06)
      Master thesis
      Open Access
      Transmon qubits are at the forefront of solid state platforms for quantum computing. In this thesis, results obtained from the experimental study of a transmon qubit in a 3D cavity are presented. A complete view of the ...
    • Complex systems for quantum technologies 

      Braungardt, Sibylle (Universitat Politècnica de Catalunya, 2011-07-12)
      Doctoral thesis
      Open Access
    • Complexity Reduction in Large Quantum Systems: Fragment Identification and Population Analysis via a Local Optimized Minimal Basis 

      Mohr, Stephan; Masella, Michel; Ratcliff, Laura E.; Genovese, Luigi (American Chemical Society, 2017-07-21)
      Article
      Open Access
      We present, within Kohn–Sham density functional theory calculations, a quantitative method to identify and assess the partitioning of a large quantum-mechanical system into fragments. We then show how within this framework ...
    • Computación cuántica : nuevas perspectivas en el tratamiento de la información 

      Salas Peralta, Pedro J.; Sanz Sáenz, Ángel L. (Escola Tècnica Superior d'Enginyers de Telecomunicació de Barcelona, 2000)
      Article
      Open Access
    • Conformal data from finite entanglement scaling 

      Stojevic, Vid; Haegeman, Jutho; McCulloch, I. P.; Tagliacozzo, Luca; Verstraete, Frank (APS Physics, 2015-01-20)
      Article
      Open Access
      In this paper, we apply the formalism of translation invariant (continuous) matrix product states in the thermodynamic limit to (1 + 1)-dimensional critical models. Finite bond dimension bounds the entanglement entropy ...
    • Detection of nonlocality with two-body correlation functions 

      Aloy López, Albert (Universitat Politècnica de Catalunya, 2015-09-10)
      Master thesis
      Open Access
      Nonlocality detection in multipartite quantum systems is of great interest. The most popular tool to detect nonlocality in quantum systems are Bell inequalities. Most of the provided constructions of multipartite Bell ...
    • Development of hole selective contacts on p-type c-Ge substrates 

      Lladós Cos, Òscar (Universitat Politècnica de Catalunya, 2020-12)
      Master thesis
      Open Access
      Thermophotovoltaic devices convert heat to electricity by absorbing infra-red photons with low energies. In order to do so semiconductors materials with low band-gap are needed. The crystalline Germanium (cGe) is an ...