Browsing by Subject "Quantum theory"

Now showing items 21-40 of 98

    • Exploring NbTiN superconducting single photon detectors with quantum detector tomography 

      Rivera Hernández, Juan Carlos (Universitat Politècnica de Catalunya, 2019-09-09)
      Master thesis
      Open Access
      The optical response of NbTiN superconducting single photon detectors is studied using quantum detector tomography which separates the detector response in single and multiple photon contributions. Three different NbTiN ...

    • Exploring nonlocal correlations in many-body systems 

      López Pastor, Víctor José (Universitat Politècnica de Catalunya, 2018-07-19)
      Master thesis
      Open Access
      We address the question of how to evaluate the Bell correlations depth, i.e. the number of parties sharing genuinely nonlocal correlations in a multipartite system. Previous work has shown that it is possible to construct ...

    • External fluctuations in front propagation 

      Armero Rovira, J.; Sancho, Jose Maria; Casademunt, Jaume; Lacasta Palacio, Ana María; Ramírez de la Piscina Millán, Laureano; Sagués Mestre, Francesc (American Physical Society, 1996-04-01)
      Article
      Open Access
      We study the effects of external noise in a one-dimensional model of front propagation. Noise is introduced through the fluctuations of a control parameter leading to a multiplicative stochastic partial differential equation. ...

    • First-passage times for a marginal state driven by colored noise 

      Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (The American Physical Society, 1991-01-18)
      Article
      Open Access
      The dynamical process through a marginal state (saddle point) driven by colored noise is studied. For small correlation time of the noise, the mean first-passage time and its variance are calculated using standard methods. ...

    • Física cuántica : interferencias, correlaciones y realidad 

      Scarani, Valerio (Iniciativa Digital Politècnica, 2015)
      Book
      Restricted access to the UPC academic community
      La física cuántica se ha erigido como uno de los pilares fundamentales sobre los cuales se asienta la física moderna. Es una puerta a un mundo fascinante, de características sorprendentes; un microcosmos regido por la ...

    • Física e informática 

      Barceló Garcia, Miquel (2005-09)
      Article
      Open Access

    • From poly(3,4-ethylenedioxythiophene) to poly(3,4-phenylenedioxythiophene) : impact of the ethylene bridge by the phenyl ring in the molecular propierties 

      Carrión Fajardo, Sergio (Universitat Politècnica de Catalunya, 2010-09)
      Master thesis
      Restricted access - author's decision
      The structural and electronic properties of poly(3,4-phenylenedioxythiophene) and poly(3,4- ethylenedioxythiophene) have been studied using quantum mechanical methods. Calculations have been performed considering a series ...

    • Ground-state wave-function optimization for a quantum system of N bosons 

      Sala Juárez, Jordi (Universitat Politècnica de Catalunya, 2020-06-29)
      Bachelor thesis
      Open Access
      Aquest treball s'emmarca en el camp de l'estudi i simulació del comportament de sistemes quàntics complexos, les propietats dels quals vénen dictades per les lleis de la física quàntica. Aquestes juguen un paper fonamental ...

    • Highly efficient noise-assisted energy transport in classical oscillator systems 

      Leon Montiel, R de J.; Pérez Torres, Juan (2013-05)
      Article
      Open Access
      Photosynthesis is a biological process that involves the highly-efficient transport of energy captured from the sun to a reaction center, where conversion into useful biochemical energy takes place. Even though one can ...

    • Holographic imaging of nanometer-scale phase-separation during a phase transition 

      Valls Conesa, Jordi (Universitat Politècnica de Catalunya, 2019-09-09)
      Master thesis
      Open Access
      Quantum materials is a broad term used in condensed matter physics to define materials whose collective properties are governed by quantum behavior, which are challenging to understand. These materials are sensitive to ...

    • Klein's paradox and the relativistic d-shell interaction in R3 

      Mas Blesa, Albert (Mathematical Sciences Publishers, 2017-12-20)
      Article
      Open Access
      Under certain hypotheses of smallness on the regular potential V, we prove that the Dirac operator in Unexpected text node: 'R', coupled with a suitable rescaling of V, converges in the strong resolvent sense to the ...

    • Large-scale cuantum computing simulation using tensor networks 

      Sánchez Ramírez, Sergio (Universitat Politècnica de Catalunya, 2021-06-29)
      Master thesis
      Open Access
      Resource usage of traditional quantum computing simulation techniques scale exponentially fast either with the number of qubits or the depth of the circuit. Simulations of medium-sized circuits are then intractable but ...

    • Llenguatges de Programació Quàntica 

      Marcos Pitarch, Eric (Universitat Politècnica de Catalunya, 2009-06)
      Master thesis (pre-Bologna period)
      Open Access
      Aprofundir en els coneixements de computació quàntica, tant des del vessant de la física com des del vessant de la teoria de la computació, que em situïn en un punt de "pre-recerca". Tenir un mapa de les diferents ...

    • Local discrimination of rotationally invariant states 

      Ronco Bonvehi, Elio (Universitat Politècnica de Catalunya / Universitat Autònoma de Barcelona, 2010)
      Master thesis
      Open Access
      We provide lower bounds for the minimum error discrimination probability of multipartite rotationally invariant states using separable measurements. The separability of the measurement operators has been investigated, ...

    • Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres 

      Hensen, B.; Bernien, H.; Dréau, A. E.; Reiserer, A.; Kalb, N.; Blok, M. S.; Ruitenberg, J.; Vermeulen, R. F. L.; Schouten, R. N.; Abellán, Carlos, 1990-; Amaya, W.; Pruneri, P.; Mitchell, Morgan W.; Markham, M.; Twitchen, D. J.; Elkouss, D.; Wehner, S.; Taminiau, Tim Hugo; Hanson, R. (Nature Publishing Group, 2015-10-21)
      Article
      Restricted access - publisher's policy
      More than 50 years ago1, John Bell proved that no theory of nature that obeys locality and realism2 can reproduce all the predictions of quantum theory: in any local-realist theory, the correlations between outcomes of ...

    • Macroscopic Quantum State Analyzed Particle by Particle 

      Beduini, Federica A.; Zielińska, Joanna Ada; Lucivero, Vito G.; Icaza Astiz, Yannick A. de; Mitchell, Morgan W. (ACS Publications, 2015-03-27)
      Article
      Open Access
      Macroscopic quantum phenomena, e.g., superconductivity and squeezing, are believed to result from entanglement of macroscopic numbers of particles. We report the first direct study of this kind of entanglement: we use ...

    • Matter Bounce Scenario in F(T) gravity 

      Haro Cases, Jaume; Amorós Torrent, Jaume (2016)
      Article
      Open Access
      It is shown that teleparallel F(T) theories of gravity combined with holonomy corrected Loop Quantum Cosmology (LQC) support a Matter Bounce Scenario (MBS) which is a potential alternative to the inflationary paradigm. The ...

    • Maximally Nonlocal Theories Cannot Be Maximally Random 

      Torre, Gonzalo de la; Hoban, Matty J.; Dhara, Chirag; Prettico, Giuseppe; Acín dal Maschio, Antonio (APS, 2015-04-22)
      Article
      Open Access
      Correlations that violate a Bell inequality are said to be nonlocal; i.e., they do not admit a local and deterministic explanation. Great effort has been devoted to study how the amount of nonlocality (as measured by a ...

    • Methods for solving 1D Stefan problems with application to contact melting 

      De Decker, Michelle (Universitat Politècnica de Catalunya, 2011-05)
      Master thesis
      Open Access
      Contact melting is the process during which a phase change material is placed in contact with a substrate that is at a temperature above the phase change temperature. This leads to melting of the phase change material and ...

    • Monte Carlo simulation of recent experiments with ultracold dipolar atoms in one dimension 

      Santos Plana, David (Universitat Politècnica de Catalunya, 2021-06-28)
      Bachelor thesis
      Open Access
      In a recent experiment (https://arxiv.org/abs/2002.10475) with ultracold dysprosium atoms, it was possible to realize a dipolar gas in one-dimensional geometry at low temperature. The goal of the project is to provide ...