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Fioresi, R., Lledo, M. A., & Razzaq, J. (2022). N=2 quantum chiral superfields and quantum super bundles. J. Phys. A, 55(38), 384012–19pp.
Abstract: We give the superalgebra of N = 2 chiral (and antichiral) quantum superfields realized as a subalgebra of the quantum supergroup SL q (4|2). The multiplication law in the quantum supergroup induces a coaction on the set of chiral superfields. We also realize the quantum deformation of the chiral Minkowski superspace as a quantum principal bundle.
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Faleiro, R., Pavao, R., Costa, H. A. S., Hiller, B., Blin, A. H., & Sampaio, M. (2020). Perturbative approach to entanglement generation in QFT using the S matrix. J. Phys. A, 53(36), 365301–19pp.
Abstract: We compute the variation of the von Neumann (VN) entropy Delta Sbetween the asymptoticinandoutmomenta modes of a real scalar field A, when elastically scattered against the modes of another scalar field B. This is done to see how the entanglement between the two fields' momenta changes under the scattering procedure. The calculation is separated into two case studies, one where the fields' asymptoticinstates are separable, and another where they are arbitrarily entangled. We perform a perturbative calculation to one loop order in the separable case, and verify that Delta Schanges in a non-trivial way when we vary the momentum of the incoming field modes and/or the coupling of the theory. Finally, also in the separable case, we show an explicit dependence between Delta Sand the cross-section of the collision, consistent with perturbation theory.
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Andrianopoli, L., Merino, N., Nadal, F., & Trigiante, M. (2013). General properties of the expansion methods of Lie algebras. J. Phys. A, 46(36), 365204–33pp.
Abstract: The study of the relation between Lie algebras and groups, and especially the derivation of new algebras from them, is a problem of great interest in mathematics and physics, because finding a new Lie group from an already known one also means that a new physical theory can be obtained from a known one. One of the procedures that allow us to do so is called expansion of Lie algebras, and has been recently used in different physical applications-particularly in gauge theories of gravity. Here we report on further developments of this method, required to understand in a deeper way their consequences in physical theories. We have found theorems related to the preservation of some properties of the algebras under expansions that can be used as criteria and, more specifically, as necessary conditions to know if two arbitrary Lie algebras can be related by some expansion mechanism. Formal aspects, such as the Cartan decomposition of the expanded algebras, are also discussed. Finally, an instructive example that allows us to check explicitly all our theoretical results is also provided.
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Hinarejos, M., Bañuls, M. C., Perez, A., & de Vega, I. (2017). Non-Markovianity and memory of the initial state. J. Phys. A, 50(32), 335301–17pp.
Abstract: We explore in a rigorous manner the intuitive connection between the non-Markovianity of the evolution of an open quantum system and the performance of the system as a quantum memory. Using the paradigmatic case of a two-level open quantum system coupled to a bosonic bath, we compute the recovery fidelity, which measures the best possible performance of the system to store a qubit of information. We deduce that this quantity is connected, but not uniquely determined, by the non-Markovianity, for which we adopt the Breuer-Laine-Piilo measure proposed in Breuer et al (2009 Phys. Rev. Lett. 103 210401). We illustrate our findings with explicit calculations for the case of a structured environment.
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Botella-Soler, V., Castelo, J. M., Oteo, J. A., & Ros, J. (2011). Bifurcations in the Lozi map. J. Phys. A, 44(30), 305101–14pp.
Abstract: We study the presence in the Lozi map of a type of abrupt order-to-order and order-to-chaos transitions which are mediated by an attractor made of a continuum of neutrally stable limit cycles, all with the same period.
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