Now showing items 1-20 of 78

    • A super frequency-shifter: enhancing the capabilities of acousto-optic modulators 

      Salazar Serrano, Luis José (Universitat Politècnica de Catalunya, 2012-09-06)
      Master thesis
      Open Access
      [ANGLÈS] We put forward a new scheme to enhance the capabilities of currently available acousto-optic frequency shifters (AOFS) by making use of the idea of weak value amplification. The key result of our approach is that ...
    • Applications of a quantum random number generator to simulations in condense matter physics 

      Guigó Corominas, Guillem (Universitat Politècnica de Catalunya, 2018-10-15)
      Master thesis
      Open Access
      Covenantee:   Institut de Ciències Fotòniques (ICFO)
      We study the importance of the quality of random numbers in Monte Carlo simulations of 2D Ising systems. Simulations are carried out at critical temperature to find the dynamic scaling law of the linear relaxation time. ...
    • Automatic compensation of polarisation drifts in an optical fibre 

      Cichy Cusi, Simon (Universitat Politècnica de Catalunya, 2020-06)
      Bachelor thesis
      Open Access
      In days where Science Fiction uses the word ?Quantum? to justify any weird phenomena, we are actually on the edge of the Second Quantum Revolution. The ability to harness the potential of the quantum state of single particles ...
    • Characterization of a quantum frequency converter for quantum repeater applications 

      Fernandez Gonzalvo, Xavier (Universitat Politècnica de Catalunya, 2012-09-03)
      Master thesis
      Open Access
      [ANGLÈS] Quantum frequency conversion of quantum memory compatible photons to telecom wavelength is a requirement for the implementation of scalable quantum repeaters, a key ingredient for long distance quantum communications ...
    • Classical simulation of restricted quantum computations 

      Nebhwani, Mrityunjaya (Universitat Politècnica de Catalunya, 2013-09-09)
      Master thesis
      Open Access
      [ANGLÈS] We study restricted models of measurement-based quantum computation; and we investigate whether their output probability distributions can be sampled from efficiently on a classical computer. We find that even for ...
    • Coherence-based quantum random number generator 

      Álvarez Velásquez, Juan Rafael (Universitat Politècnica de Catalunya, 2018-08-27)
      Master thesis
      Open Access
      We consider the random change of the phase of a laser as the physical source of randomness that allows the implementation a new type of quantum random number generator (QRNG) . We analyze the phase noise model of a laser ...
    • Correlations and coherence: an experimental proposal 

      Sendra Molins, Lluc (Universitat Politècnica de Catalunya, 2017-10-24)
      Bachelor thesis
      Open Access
      We propose and realize a variation of Mandel's experiment where the Englert's inequality can be demonstrated. This is a relation of the coherence and the which-way information, which is one of the most fundamental results ...
    • Delta kick cooling for cold atom interferometry and its application in space missions 

      Augst, Nadja (Universitat Politècnica de Catalunya, 2020-09-08)
      Master thesis
      Open Access
      Delta kick cooling (DKC) gives control over the free expansion of Bose-Einstein-Condensates for the purpose of atom interferometry. Recent projects and future proposals on how to apply DKC for cold atom interferometry in ...
    • Demonstration of a highly-sensitive tunable beam displacer with no use of beam deflection based on the concept of weak value amplification 

      Salazar Serrano, Luis Jose; Guzman, David A; Valencia, Alejandra; Pérez Torres, Juan (2015-04-10)
      Article
      Restricted access - publisher's policy
      We report the implementation of a highly sensitive tunable beam displacer based on the concept of weak value amplification, that allows to displace the centroid of a Gaussian beam a distance much smaller than its beam width ...
    • Design and construction of optical superlattices for a quantum gas experiment 

      Sastre Pellicer, Jordi (Universitat Politècnica de Catalunya, 2015-10)
      Bachelor thesis
      Open Access
      In recent years ultracold atomic gases have emerged as a new and promising platform for exploring the physics of quantum many-body systems, allowing researchers to revisit fundamental problems of condensed-matter physics ...
    • Detection loophole attacks on semi-device-independent quantum and classical protocols 

      Dall’Arno, Michele; Passaro, Elsa; Gallego, Rodrigo; Pawlowski, Marcin; Acín, Antonio (Rinton Press, 2015-01-01)
      Article
      Open Access
      Semi-device-independent quantum protocols realize information tasks – e.g. secure key distribution, random access coding, and randomness generation – in a scenario where no assumption on the internal working of the devices ...
    • Detection of entanglement in asymmetric quantum networks and multipartite quantum steering 

      Cavalcanti, D.; Skrzypczyk, P.; Aguilar, G. H.; Souto Ribeiro, P. H.; Walborn, S. P. (Nature Publishing Group, 2015-08-03)
      Article
      Open Access
      The future of quantum communication relies on quantum networks composed by observers sharing multipartite quantum states. The certification of multipartite entanglement will be crucial to the usefulness of these networks. ...
    • Detection of graphene motion through light-matter interactions 

      Schädler, Kevin Gerd (Universitat Politècnica de Catalunya, 2012-09-06)
      Master thesis
      Open Access
      [ANGLÈS] In this thesis, we study both experimentally and theoretically the optical detection of the motion of graphene membranes based on fluorescence quenching of the emitters close to graphene. Fluorescence quenching ...
    • Detection of quantum phase transitions via machine learning algorithms 

      Pérez Díaz, Joel (Universitat Politècnica de Catalunya, 2019-08-31)
      Master thesis
      Open Access
      A Neural Network is trained to classify Mott Insulator and Superfluid phases in an optical lattice using data generated with Diffusion Monte Carlo algorithms (DMC). The trained model is used to predict the phase transition ...
    • Detection of Zak phases and topological invariants in a chiral quantum walk of twisted photons 

      Cardano, Filippo; D'Errico, Alessio; dauphin, Alexandre; Maffei, Maria; Piccirillo, Bruno; de Lisio, Corrado; de Filippis, Guido; Cataudella, Vittorio; Santamato, Enrico; Marrucci, Lorenzo; Lewenstein, Maciej; Massignan, Pietro Alberto (2017)
      Article
      Open Access
      Topological insulators are fascinating states of matter exhibiting protected edge states and robust quantized features in their bulk. Here we propose and validate experimentally a method to detect topological properties ...
    • Development of a fluorescence imaging system for a quantum gas experiment 

      Sanz Sánchez, Julio (Universitat Politècnica de Catalunya, 2015-09-10)
      Master thesis
      Open Access
      Covenantee:   Universitat Autònoma de Barcelona / Institut de Ciències Fotòniques (ICFO) / Universitat de Barcelona
      In this report we present a technique for imaging the momentum distribution of an ultracold atomic gas in 3D and with single atom resolution. We describe the first experimental steps taken to implement it in a quantum gas ...
    • Diagrammatic expansions of Hubbard models 

      Losada Sosnovsky, Juan Manuel (Universitat Politècnica de Catalunya, 2016-06-19)
      Bachelor thesis
      Open Access
      Optical lattice are periodic structures made of light, they are formed by the interference of laser beams producing standing waves. The depth and the periodicity of the optical lattice can be highly controlled, therefore, ...
    • Digital coherent receiver for orbital angular momentum demultiplexing 

      Belmonte Molina, Aniceto; Pérez Torres, Juan (2013-01-15)
      Article
      Open Access
      We put forward a type of receiver for coherent detection of the photon orbital angular momentum (OAM). A coherent array receiver, consisting of multiple subapertures, with each subaperture coupled to a single-mode fiber, ...
    • Dynamics of a Bose Einstein condensate in a ring potential 

      Pino Quintana, Hernán (Universitat Politècnica de Catalunya / Universitat Autònoma de Barcelona, 2012-09-04)
      Master thesis
      Open Access
      [ANGLÈS] We have addressed the dynamics of a repulsive interacting 87 Rb Bose Einstein condensate (BEC) in a ring potential trap. Our study has been focused in the analysis of the interference pattern that arises by the ...
    • Dynamics of matter wave solitons 

      Polo Gómez, Juan (Universitat Politècnica de Catalunya / Universitat Autònoma de Barcelona, 2012-09-04)
      Master thesis
      Open Access
      [ANGLÈS] We study the implementation of a matter wave bright soliton interferometer formed by a Gaussian potential barrier placed at the center of a harmonic trap potential. After numerically evaluating the transmission ...