406 research outputs found

    Dynamical and Steady State Properties of a Bose-Hubbard Chain with Bond-Dissipation: A Study based on Matrix Product Operators

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    We study a dissipative Bose-Hubbard chain subject to an engineered bath using a superoperator approach based on matrix product operators. The dissipation is engineered to stabilize a BEC condensate wave function in its steady state. We then characterize the steady state emerging from the interplay between incompatible Hamiltonian and dissipative dynamics. While it is expected that interactions lead to this competition, even the kinetic energy in an open boundary condition setup competes with the dissipation, leading to a non-trivial steady state. We also present results for the transient dynamics and probe the relaxation time revealing the closing of the dissipative gap in the thermodynamic limit.Comment: 9 pages, 13 figure

    Thermal vs. Entanglement Entropy: A Measurement Protocol for Fermionic Atoms with a Quantum Gas Microscope

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    We show how to measure the order-two Renyi entropy of many-body states of spinful fermionic atoms in an optical lattice in equilibrium and non-equilibrium situations. The proposed scheme relies on the possibility to produce and couple two copies of the state under investigation, and to measure the occupation number in a site- and spin-resolved manner, e.g. with a quantum gas microscope. Such a protocol opens the possibility to measure entanglement and test a number of theoretical predictions, such as area laws and their corrections. As an illustration we discuss the interplay between thermal and entanglement entropy for a one dimensional Fermi-Hubbard model at finite temperature, and its possible measurement in an experiment using the present scheme

    La convivencia en el Multilugar

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    En el cap√≠tulo se desarrollan algunos conceptos con los que se espera contribuir a dise√Īar mejores ambientes para la convivencia en el multilugar urbano, con el fin de explicar y comprender las din√°micas de la vida y promover la prosocialidad. Como eje central, en el cap√≠tulo se presentan los resultados de una investigaci√≥n, que busc√≥ identificar algunos elementos que constituyen la experiencia del lugar residencial de los habitantes de conjuntos de propiedad horizontal, junto con los aspectos normativos que pretenden reglamentar la interdependencia entre vecinos, e interpretar dicha experiencia desde conceptos tales como: pedagog√≠a urbana, ciudad educadora, calidad de vida urbana, multilugar, comportamientos urbano responsables, macro y metacontingencias.1a edici√≥

    Empirical agent-based modelling of everyday pro-environmental behaviours at work

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    We report on agent-based modelling work in the LOCAW project (Low Carbon at Work: Modelling Agents and Organisations to Achieve Transition to a Low Carbon Europe). The project explored the effectiveness of various backcasting scenarios conducted with case study organisations in bringing about pro-environmental change in the workforce in the domains of transport, energy use and waste. The model used qualitative representations of workspaces in formalising each scenario, and decision trees learned from questionnaire responses to represent decision-making. We describe the process by which the decision trees were constructed, noting that the use of decision trees in agent-based models requires particular considerations owing to the potential use of explanatory variables in model dynamics. The results of the modelling in various scenarios emphasise the importance of structural environmental changes in facilitating everyday pro-environmental behaviour, but also show there is a role for psychological variables such as norms, values and efficacy. As such, the topology of social interactions is a potentially important driver, raising the interesting prospect that both workplace geography and organisational hierarchy have a role to play in influencing workplace pro-environmental behaviours
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