DSpace Community:
http://hdl.handle.net/2117/222
Mon, 30 Mar 2015 09:28:19 GMT2015-03-30T09:28:19Zwebmaster.bupc@upc.eduUniversitat Politècnica de Catalunya. Servei de Biblioteques i DocumentaciónoDiffraction control of reflected beam by chirped mirror
http://hdl.handle.net/2117/22805
Title: Diffraction control of reflected beam by chirped mirror
Authors: Cheng, Yu Chieh; Peckus, Martynas; Kicas, S.; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, R.; Staliunas, Kestutis
Abstract: We propose and demonstrate a novel functionality of chirped mirror for monochromatic light beams: a diffraction control in reflections resulting in focusing or imaging of beams. The chirped mirrors, commonly used for manipulating temporal profiles of pulses, here are applied for manipulating the spatial dispersion of a monochromatic beam. By penetrating into dielectric layers of chirped mirror, the monochromatic beam experiences the negative diffraction, therefore the beam diverge propagating in front and behind the structure in normal diffraction region can be compensated inside this structure with negative diffraction. The result is focusing or imaging of the reflected beam from a flat interface of chirped mirror without optical axis.http://hdl.handle.net/2117/22805Cheng, Yu Chieh; Peckus, Martynas; Kicas, S.; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, R.; Staliunas, Kestutisnochirped mirror, diffraction, focusing, imaging, photonic crystalsWe propose and demonstrate a novel functionality of chirped mirror for monochromatic light beams: a diffraction control in reflections resulting in focusing or imaging of beams. The chirped mirrors, commonly used for manipulating temporal profiles of pulses, here are applied for manipulating the spatial dispersion of a monochromatic beam. By penetrating into dielectric layers of chirped mirror, the monochromatic beam experiences the negative diffraction, therefore the beam diverge propagating in front and behind the structure in normal diffraction region can be compensated inside this structure with negative diffraction. The result is focusing or imaging of the reflected beam from a flat interface of chirped mirror without optical axis.Numerical bifurcation methods and their application to fluid dynamics: analysis beyond simulation
http://hdl.handle.net/2117/21331
Title: Numerical bifurcation methods and their application to fluid dynamics: analysis beyond simulation
Authors: Dijkstra, Hendrik; Wubs, Fred W.; Cliffe, Andrew K.; Doedel, Eusebius J.; Dragomirescu, Ioana Florica; Eckhardt, Bruno; Gelfgat, Alexander Yu; Hazel, Andrew L.; Lucarini, Valerio; Salinger, Andrew G.; Phipps, Erik T.; Sánchez Umbría, Juan; Schuttelaars, Henk M.; Tuckerman, Laurette S.; Thiele, Uwe
Abstract: We provide an overview of current techniques and typical applications of numerical bifurcation analysis in fluid dynamical problems. Many of these problems are characterized by high-dimensional dynamical systems which undergo transitions as parameters are changed. The computation of the critical conditions associated with these transitions, popularly referred to as 'tipping points', is important for understanding the transition mechanisms. We describe the two basic classes of methods of numerical bifurcation analysis, which differ in the explicit or implicit use of the Jacobian matrix of the dynamical system. The numerical challenges involved in both methods are mentioned and possible solutions to current bottlenecks are given. To demonstrate that numerical bifurcation techniques are not restricted to relatively low-dimensional dynamical systems, we provide several examples of the application of the modern techniques to a diverse set of fluid mechanical problems.http://hdl.handle.net/2117/21331Dijkstra, Hendrik; Wubs, Fred W.; Cliffe, Andrew K.; Doedel, Eusebius J.; Dragomirescu, Ioana Florica; Eckhardt, Bruno; Gelfgat, Alexander Yu; Hazel, Andrew L.; Lucarini, Valerio; Salinger, Andrew G.; Phipps, Erik T.; Sánchez Umbría, Juan; Schuttelaars, Henk M.; Tuckerman, Laurette S.; Thiele, UwenoHigh-dimensional dynamical systems, Numerical bifurcation analysis, Transitions in fluid flowsWe provide an overview of current techniques and typical applications of numerical bifurcation analysis in fluid dynamical problems. Many of these problems are characterized by high-dimensional dynamical systems which undergo transitions as parameters are changed. The computation of the critical conditions associated with these transitions, popularly referred to as 'tipping points', is important for understanding the transition mechanisms. We describe the two basic classes of methods of numerical bifurcation analysis, which differ in the explicit or implicit use of the Jacobian matrix of the dynamical system. The numerical challenges involved in both methods are mentioned and possible solutions to current bottlenecks are given. To demonstrate that numerical bifurcation techniques are not restricted to relatively low-dimensional dynamical systems, we provide several examples of the application of the modern techniques to a diverse set of fluid mechanical problems.Two computational approaches for the simulation of fluid problems in rotating spherical shells
http://hdl.handle.net/2117/27104
Title: Two computational approaches for the simulation of fluid problems in rotating spherical shells
Authors: García González, Fernando; Dormy, Emmanuel; Sánchez Umbría, Juan; Net Marcé, Marta
Abstract: Many geophysical and astrophysical phenomena such as magnetic fields generation, or the differential rotation observed in the atmospheres of the major planets are studied by means of numerical simulations of the Navier-Stokes equations in rotating spherical shells. Two different computational codes, spatially discretized using spherical harmonics in the angular variables, are presented. The first code, PARODY, solves the magneto-hydrodynamic anelastic convective equations with finite a difference discretization in the radial direction. This allows the parallelization on distributed memory computers to run massive numerical simulations of second order in time. It is mainly designed to perform direct numerical simulations. The second code, SPHO, solves the fully spectral Boussinesq convective equations, and its variationals, parallelized on shared memory architectures and it uses optimized linear algebra libraries. High-order time integration methods are implemented to allow the use of dynamical systems tools for the study of complex dynamics.Fri, 27 Mar 2015 17:27:29 GMThttp://hdl.handle.net/2117/271042015-03-27T17:27:29ZGarcía González, Fernando; Dormy, Emmanuel; Sánchez Umbría, Juan; Net Marcé, MartanoHydrodynamics, Spherical shells, Parallelism, Direct numerical simulation, Dynamical systemsMany geophysical and astrophysical phenomena such as magnetic fields generation, or the differential rotation observed in the atmospheres of the major planets are studied by means of numerical simulations of the Navier-Stokes equations in rotating spherical shells. Two different computational codes, spatially discretized using spherical harmonics in the angular variables, are presented. The first code, PARODY, solves the magneto-hydrodynamic anelastic convective equations with finite a difference discretization in the radial direction. This allows the parallelization on distributed memory computers to run massive numerical simulations of second order in time. It is mainly designed to perform direct numerical simulations. The second code, SPHO, solves the fully spectral Boussinesq convective equations, and its variationals, parallelized on shared memory architectures and it uses optimized linear algebra libraries. High-order time integration methods are implemented to allow the use of dynamical systems tools for the study of complex dynamics.Nanopatterned Graphene on a Polymer Substrate by a Direct Peel-off Technique
http://hdl.handle.net/2117/27103
Title: Nanopatterned Graphene on a Polymer Substrate by a Direct Peel-off Technique
Authors: Chen, T. L.; Ghosh, D. S.; Marchena, M.; Osmond, J.; Pruneri, Valerio
Abstract: : A graphene (Gr) on a polyimide (PI) polymer
film (Gr−PI film), obtained by a direct peel-off technique, is
proposed and investigated. Thanks to its high transparency,
electrical conductivity, mechanical strength, and chemical
durability, the Gr−PI film is an ideal substrate for flexible
electronic and optoelectronic devices, including transistors, lightemitting
diodes, and plasmonic antennas. It is obtained using a
straightforward method. After spin coating and curing a PI film
on Gr previously grown on Cu, one can separate the Gr−PI film
from the Cu foil thanks to the difference in the adhesive energy
between the Gr−Cu and Gr−PI interfaces. The resulting Gr−PI
film shows an average electrical sheet resistance ranging from 520 to 860 Ω/sq and a very high optical transmission (>90%),
which have allowed the demonstration of a transparent heater. The surface morphology of the Gr−PI film follows that of the Cu
foil, with the latter maintaining its surface properties and allowing in this way its reuse in subsequent chemical vapor deposition
growth. The meFri, 27 Mar 2015 16:05:50 GMThttp://hdl.handle.net/2117/271032015-03-27T16:05:50ZChen, T. L.; Ghosh, D. S.; Marchena, M.; Osmond, J.; Pruneri, Valerionographene: A graphene (Gr) on a polyimide (PI) polymer
film (Gr−PI film), obtained by a direct peel-off technique, is
proposed and investigated. Thanks to its high transparency,
electrical conductivity, mechanical strength, and chemical
durability, the Gr−PI film is an ideal substrate for flexible
electronic and optoelectronic devices, including transistors, lightemitting
diodes, and plasmonic antennas. It is obtained using a
straightforward method. After spin coating and curing a PI film
on Gr previously grown on Cu, one can separate the Gr−PI film
from the Cu foil thanks to the difference in the adhesive energy
between the Gr−Cu and Gr−PI interfaces. The resulting Gr−PI
film shows an average electrical sheet resistance ranging from 520 to 860 Ω/sq and a very high optical transmission (>90%),
which have allowed the demonstration of a transparent heater. The surface morphology of the Gr−PI film follows that of the Cu
foil, with the latter maintaining its surface properties and allowing in this way its reuse in subsequent chemical vapor deposition
growth. The meTunable beam displacer
http://hdl.handle.net/2117/27096
Title: Tunable beam displacer
Authors: Luis José, Salazar-Serrano; Valencia, Alejandra; Perez Torres, Juan
Abstract: We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.Fri, 27 Mar 2015 14:47:53 GMThttp://hdl.handle.net/2117/270962015-03-27T14:47:53ZLuis José, Salazar-Serrano; Valencia, Alejandra; Perez Torres, JuannoBeamsWe report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.Thermodynamics of creating correlations: Limitations and optimal protocols
http://hdl.handle.net/2117/27085
Title: Thermodynamics of creating correlations: Limitations and optimal protocols
Authors: Bruschi, David Edward; Perarnau-Llobet, Martí; Friis, Nicolai; Hovhannisyan, Karen V.; Huber, Marcus
Abstract: We establish a rigorous connection between fundamental resource theories at the quantum scale. Correlations
and entanglement constitute indispensable resources for numerous quantum information tasks. However, their
establishment comes at the cost of energy, the resource of thermodynamics, and is limited by the initial entropy.
Here, the optimal conversion of energy into correlations is investigated. Assuming the presence of a thermal
bath, we establish general bounds for arbitrary systems and construct a protocol saturating them. The amount
of correlations, quantified by the mutual information, can increase at most linearly with the available energy,
and we determine where the linear regime breaks down. We further consider the generation of genuine quantum
correlations, focusing on the fundamental constituents of our universe: fermions and bosons. For fermionic
modes, we find the optimal entangling protocol. For bosonic modes, we show that while GausFri, 27 Mar 2015 10:32:41 GMThttp://hdl.handle.net/2117/270852015-03-27T10:32:41ZBruschi, David Edward; Perarnau-Llobet, Martí; Friis, Nicolai; Hovhannisyan, Karen V.; Huber, MarcusnoThermodynamicsWe establish a rigorous connection between fundamental resource theories at the quantum scale. Correlations
and entanglement constitute indispensable resources for numerous quantum information tasks. However, their
establishment comes at the cost of energy, the resource of thermodynamics, and is limited by the initial entropy.
Here, the optimal conversion of energy into correlations is investigated. Assuming the presence of a thermal
bath, we establish general bounds for arbitrary systems and construct a protocol saturating them. The amount
of correlations, quantified by the mutual information, can increase at most linearly with the available energy,
and we determine where the linear regime breaks down. We further consider the generation of genuine quantum
correlations, focusing on the fundamental constituents of our universe: fermions and bosons. For fermionic
modes, we find the optimal entangling protocol. For bosonic modes, we show that while GausEffects of Fermion Exchange on the Polarization of Exciton Condensates
http://hdl.handle.net/2117/27084
Title: Effects of Fermion Exchange on the Polarization of Exciton Condensates
Authors: Combescot, Monique; Combescot, Roland; Alloing, Mathieu; Dubin, François
Abstract: Exchange interaction is responsible for the stability of elementary boson condensates with respect to
momentum fragmentation. This remains true for composite bosons when single fermion exchanges are
included but spin degrees of freedom are ignored. Here, we show that their inclusion can produce a spin
fragmentation of the dark exciton condensate, i.e., an unpolarized condensate with an equal amount of spin
ðþ2Þ and ð−2Þ excitons not coupled to light. The composite boson many-body formalism allows us to
predict that, for spatially indirect excitons, the condensate polarization switches from unpolarized to fully
polarized when the distance between the layers confining electrons and holes increases. Importantly, the
threshold distance for this switch lies in a regime fully accessible to experimentsFri, 27 Mar 2015 10:15:08 GMThttp://hdl.handle.net/2117/270842015-03-27T10:15:08ZCombescot, Monique; Combescot, Roland; Alloing, Mathieu; Dubin, FrançoisnobosonsExchange interaction is responsible for the stability of elementary boson condensates with respect to
momentum fragmentation. This remains true for composite bosons when single fermion exchanges are
included but spin degrees of freedom are ignored. Here, we show that their inclusion can produce a spin
fragmentation of the dark exciton condensate, i.e., an unpolarized condensate with an equal amount of spin
ðþ2Þ and ð−2Þ excitons not coupled to light. The composite boson many-body formalism allows us to
predict that, for spatially indirect excitons, the condensate polarization switches from unpolarized to fully
polarized when the distance between the layers confining electrons and holes increases. Importantly, the
threshold distance for this switch lies in a regime fully accessible to experimentsStructural and dynamical properties of Mg65Cu25Y10 metallic glasses studied by in situ high energy X-ray diffraction and time resolved xray photon correlation spectroscopy
http://hdl.handle.net/2117/27080
Title: Structural and dynamical properties of Mg65Cu25Y10 metallic glasses studied by in situ high energy X-ray diffraction and time resolved xray photon correlation spectroscopy
Authors: Ruta, Beatrice; Giordano, Valentina; Erra, Loredana; Liu, Chaoren; Pineda Soler, Eloi
Abstract: We present a temperature investigation of the structural and dynamical evolution of rapidly quenched metallic glasses of Mg65Cu25Y10 at the atomic length scale by means of in situ high energy x-ray diffraction and time resolved x-ray photon correlation spectroscopy. We find a flattening of the temperature evolution of the position of the first sharp diffraction peak on approaching the glass transition temperature from the glassy state, which reflects into a surprising slowing down of the relaxation ynamics
of even one order of magnitude with increasing temperature. The comparison between structural and dynamical properties strengthens the idea of a stress-induced, rather than pure diffusive, atomic motion in metallic glassesThu, 26 Mar 2015 17:14:00 GMThttp://hdl.handle.net/2117/270802015-03-26T17:14:00ZRuta, Beatrice; Giordano, Valentina; Erra, Loredana; Liu, Chaoren; Pineda Soler, EloinoWe present a temperature investigation of the structural and dynamical evolution of rapidly quenched metallic glasses of Mg65Cu25Y10 at the atomic length scale by means of in situ high energy x-ray diffraction and time resolved x-ray photon correlation spectroscopy. We find a flattening of the temperature evolution of the position of the first sharp diffraction peak on approaching the glass transition temperature from the glassy state, which reflects into a surprising slowing down of the relaxation ynamics
of even one order of magnitude with increasing temperature. The comparison between structural and dynamical properties strengthens the idea of a stress-induced, rather than pure diffusive, atomic motion in metallic glassesStabilization of spatiotemporal solitons in Kerr media by dispersive coupling
http://hdl.handle.net/2117/27078
Title: Stabilization of spatiotemporal solitons in Kerr media by dispersive coupling
Authors: Kartashov, Yaroslav V.; Malomed, Boris A.; Konotop, Vladimir V.; Lobanov, Valery E.; Torner Sabata, Lluis
Abstract: We introduce a mechanism to stabilize spatiotemporal solitons in Kerr nonlinear media, based on the dispersion of
linear coupling between the field components forming the soliton states. Specifically, we consider solitons in a
two-core guiding structure with inter-core coupling dispersion (CD). We show that CD profoundly affects properties
of the solitons, causing the complete stabilization of the otherwise highly unstable spatiotemporal solitons in Kerr
media with focusing nonlinearity. We also find that the presence of CD stimulates the formation of bound states,
which, however, are unstable.Thu, 26 Mar 2015 16:18:45 GMThttp://hdl.handle.net/2117/270782015-03-26T16:18:45ZKartashov, Yaroslav V.; Malomed, Boris A.; Konotop, Vladimir V.; Lobanov, Valery E.; Torner Sabata, LluisnoSpatial solitonsWe introduce a mechanism to stabilize spatiotemporal solitons in Kerr nonlinear media, based on the dispersion of
linear coupling between the field components forming the soliton states. Specifically, we consider solitons in a
two-core guiding structure with inter-core coupling dispersion (CD). We show that CD profoundly affects properties
of the solitons, causing the complete stabilization of the otherwise highly unstable spatiotemporal solitons in Kerr
media with focusing nonlinearity. We also find that the presence of CD stimulates the formation of bound states,
which, however, are unstable.An Indium Tin Oxide-Free Polymer Solar Cell on Flexible Glass
http://hdl.handle.net/2117/27073
Title: An Indium Tin Oxide-Free Polymer Solar Cell on Flexible Glass
Authors: Formica, Nadia; Mantilla-Perez, Paola; Ghosh, Dhriti S.; Janner, David; Chen, Tong Lai; Huang, Minghuang; Garner, Sean; Martorell, Jordi; Pruneri, Valerio
Abstract: : Future optoelectronic devices and their low-cost roll-to-roll production
require mechanically flexible transparent electrodes (TEs) and substrate materials.
Indium tin oxide (ITO) is the most widely used TE because of its high optical
transmission and low electrical sheet resistance. However, ITO, besides being expensive,
has very poor performance under mechanical stress because of its fragile oxide nature.
Alternative TE materials have thus been sought. Here we report the development of a
multilayer TiO2/Ag/Al-doped ZnO TE structure and an ITO-free polymer solar cell
(PSC) incorporating it. Electro-optical performances close to those of ITO can be
achieved for the proposed TE and corresponding PSC with an additional advantage in
their mechanical flexibility, as demonstrated by the fact that the cell efficiency maintains
94% of its initial value (6.6%) after 400 cycles of bending, with 6 and 3 cm maximum
and minimum radii, respectively. Instead of common plastic materials, our work uses a
very thin (0.14 mm) flexible glass substrate with several benefits, such as the possibility
of high-temperature processes, superior aThu, 26 Mar 2015 15:40:19 GMThttp://hdl.handle.net/2117/270732015-03-26T15:40:19ZFormica, Nadia; Mantilla-Perez, Paola; Ghosh, Dhriti S.; Janner, David; Chen, Tong Lai; Huang, Minghuang; Garner, Sean; Martorell, Jordi; Pruneri, Valerionoultrathin: Future optoelectronic devices and their low-cost roll-to-roll production
require mechanically flexible transparent electrodes (TEs) and substrate materials.
Indium tin oxide (ITO) is the most widely used TE because of its high optical
transmission and low electrical sheet resistance. However, ITO, besides being expensive,
has very poor performance under mechanical stress because of its fragile oxide nature.
Alternative TE materials have thus been sought. Here we report the development of a
multilayer TiO2/Ag/Al-doped ZnO TE structure and an ITO-free polymer solar cell
(PSC) incorporating it. Electro-optical performances close to those of ITO can be
achieved for the proposed TE and corresponding PSC with an additional advantage in
their mechanical flexibility, as demonstrated by the fact that the cell efficiency maintains
94% of its initial value (6.6%) after 400 cycles of bending, with 6 and 3 cm maximum
and minimum radii, respectively. Instead of common plastic materials, our work uses a
very thin (0.14 mm) flexible glass substrate with several benefits, such as the possibility
of high-temperature processes, superior aAvailability simulation software adaptation to the IFMIF accelerator facility RAMI analyses
http://hdl.handle.net/2117/27060
Title: Availability simulation software adaptation to the IFMIF accelerator facility RAMI analyses
Authors: Bargalló Font, Enric; Sureda, Pere Joan; Arroyo Macias, José Manuel; Abal López, Javier; Blas Del Hoyo, Alfredo de; Dies Llovera, Javier; Tapia Fernández, Carlos; Mollá Lorente, Joaquin; Ibarra Sanchez, Angel
Abstract: Several problems were found when using generic reliability tools to perform RAM! (Reliability Availability Maintainability Inspectability) studies for the IFMIF (International Fusion Materials Irradiation Facility) accelerator. A dedicated simulation tool was necessary to model properly the complexity of the accelerator facility.; AvailSim, the availability simulation software used for the International Linear Collider (ILC) became an excellent option to fulfill RAMI analyses needs. Nevertheless, this software needed to be adapted and modified to simulate the IFMIF accelerator facility in a useful way for the RAMI analyses in the current design phase. Furthermore, some improvements and new features have been added to the software. This software has become a great tool to simulate the peculiarities of the IFMIF accelerator facility allowing obtaining a realistic availability simulation. Degraded operation simulation and maintenance strategies are the main relevant features.; In this paper, the necessity of this software, main modifications to improve it and its adaptation to IFMIF RAMI analysis are described. Moreover, first results obtained with AvailSim 2.0 and a comparison with previous results is shown.Thu, 26 Mar 2015 13:18:25 GMThttp://hdl.handle.net/2117/270602015-03-26T13:18:25ZBargalló Font, Enric; Sureda, Pere Joan; Arroyo Macias, José Manuel; Abal López, Javier; Blas Del Hoyo, Alfredo de; Dies Llovera, Javier; Tapia Fernández, Carlos; Mollá Lorente, Joaquin; Ibarra Sanchez, AngelnoIFMIF, RAMI, Availability, Reliability, Accelerator, AvailSimSeveral problems were found when using generic reliability tools to perform RAM! (Reliability Availability Maintainability Inspectability) studies for the IFMIF (International Fusion Materials Irradiation Facility) accelerator. A dedicated simulation tool was necessary to model properly the complexity of the accelerator facility.; AvailSim, the availability simulation software used for the International Linear Collider (ILC) became an excellent option to fulfill RAMI analyses needs. Nevertheless, this software needed to be adapted and modified to simulate the IFMIF accelerator facility in a useful way for the RAMI analyses in the current design phase. Furthermore, some improvements and new features have been added to the software. This software has become a great tool to simulate the peculiarities of the IFMIF accelerator facility allowing obtaining a realistic availability simulation. Degraded operation simulation and maintenance strategies are the main relevant features.; In this paper, the necessity of this software, main modifications to improve it and its adaptation to IFMIF RAMI analysis are described. Moreover, first results obtained with AvailSim 2.0 and a comparison with previous results is shown.Almost quantum correlations
http://hdl.handle.net/2117/27048
Title: Almost quantum correlations
Authors: Navascués, Miguel; Guryanova, Yelena; Hoban, Matty J.; Acín, Antonio
Abstract: 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. It has even been argued that quantum theory may be special among possible theories. Here we report that, at the level of correlations among different systems, quantum theory is not so special. We define a set of correlations, dubbed ‘almost quantum’, and prove that it strictly contains the set of quantum correlations but satisfies all-but-one of the proposed principles to capture quantum correlations. We present numerical evidence that the remaining principle is satisfied too.Thu, 26 Mar 2015 11:31:26 GMThttp://hdl.handle.net/2117/270482015-03-26T11:31:26ZNavascués, Miguel; Guryanova, Yelena; Hoban, Matty J.; Acín, AntonionoQuantum correlationsQuantum 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. It has even been argued that quantum theory may be special among possible theories. Here we report that, at the level of correlations among different systems, quantum theory is not so special. We define a set of correlations, dubbed ‘almost quantum’, and prove that it strictly contains the set of quantum correlations but satisfies all-but-one of the proposed principles to capture quantum correlations. We present numerical evidence that the remaining principle is satisfied too.Self-deflecting plasmonic lattice solitons and surface modes in chirped plasmonic arrays
http://hdl.handle.net/2117/27046
Title: Self-deflecting plasmonic lattice solitons and surface modes in chirped plasmonic arrays
Authors: Li, Chunyan; Cui, Ran; Ye, Fangwei; Kartashov, Yaroslav V; Torner Sabata, Lluis; Chen, Xianfeng
Abstract: We show that chirped metal-dielectric waveguide arrays with focusing cubic nonlinearity can support plasmonic
lattice solitons that undergo self-deflection in the transverse plane. Such lattice solitons are deeply subwavelength
self-sustained excitations, although they cover several periods of the array. Upon propagation, the excitations accelerate
in the transverse plane and follow trajectories curved in the direction in which the separation between
neighboring metallic layers decreases, a phenomenon that yields considerable deflection angles. The deflection
angle can be controlled by varying the array chirp. We also reveal the existence of surface modes at the boundary
of truncated plasmonic chirped array that form even in the absence of nonlinearity.Thu, 26 Mar 2015 11:14:07 GMThttp://hdl.handle.net/2117/270462015-03-26T11:14:07ZLi, Chunyan; Cui, Ran; Ye, Fangwei; Kartashov, Yaroslav V; Torner Sabata, Lluis; Chen, XianfengnoSolitonsWe show that chirped metal-dielectric waveguide arrays with focusing cubic nonlinearity can support plasmonic
lattice solitons that undergo self-deflection in the transverse plane. Such lattice solitons are deeply subwavelength
self-sustained excitations, although they cover several periods of the array. Upon propagation, the excitations accelerate
in the transverse plane and follow trajectories curved in the direction in which the separation between
neighboring metallic layers decreases, a phenomenon that yields considerable deflection angles. The deflection
angle can be controlled by varying the array chirp. We also reveal the existence of surface modes at the boundary
of truncated plasmonic chirped array that form even in the absence of nonlinearity.Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons
http://hdl.handle.net/2117/27031
Title: Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons
Authors: Garcia March, Miguel Angel; Julia Diaz, Bruno; Astrakharchik, Grigori; Busch, T; Boronat Medico, Jordi; Rios Polls, Artur
Abstract: We show that a two-component mixture of a few repulsively interacting ultracold atoms in a one-dimensional trap possesses very diverse quantum regimes and that the crossover between them can be induced by tuning the interactions in one of the species. Starting from the composite fermionization regime, in which the interactions between both components are large and neither gas is phase coherent, our results show that a phase-separated state can be reached by increasing the interaction in one of the species. In this regime, the weakly interacting component stays at the center of the trap and becomes almost fully phase coherent, while the strongly interacting one is expelled to the edges of the trap. The crossover is sharp, as can be witnessed in the system's energy and in the occupation of the lowest natural orbital of the weakly interacting species. We show that such a transition is a few-atom effect which disappears for a large population imbalance.Wed, 25 Mar 2015 16:00:33 GMThttp://hdl.handle.net/2117/270312015-03-25T16:00:33ZGarcia March, Miguel Angel; Julia Diaz, Bruno; Astrakharchik, Grigori; Busch, T; Boronat Medico, Jordi; Rios Polls, ArturnoInteracting species, Large population, Natural orbitals, Phase coherent, Quantum regimes, Two-component mixtures, Ultracold atoms, Ultracold bosonsWe show that a two-component mixture of a few repulsively interacting ultracold atoms in a one-dimensional trap possesses very diverse quantum regimes and that the crossover between them can be induced by tuning the interactions in one of the species. Starting from the composite fermionization regime, in which the interactions between both components are large and neither gas is phase coherent, our results show that a phase-separated state can be reached by increasing the interaction in one of the species. In this regime, the weakly interacting component stays at the center of the trap and becomes almost fully phase coherent, while the strongly interacting one is expelled to the edges of the trap. The crossover is sharp, as can be witnessed in the system's energy and in the occupation of the lowest natural orbital of the weakly interacting species. We show that such a transition is a few-atom effect which disappears for a large population imbalance.Luminous recycling
http://hdl.handle.net/2117/27026
Title: Luminous recycling
Authors: Vásquez Paredes, Rodrigo Antonio; Franco González, Fidel; Roset Calzada, JaimeWed, 25 Mar 2015 09:50:30 GMThttp://hdl.handle.net/2117/270262015-03-25T09:50:30ZVásquez Paredes, Rodrigo Antonio; Franco González, Fidel; Roset Calzada, JaimenoLuminous recycling, Energetic compatibility, Energy savings