DSpace Community:
http://hdl.handle.net/10261/14181
2016-04-29T21:53:20ZQuantum features of anionic species He*− and He2*− in small HeN clusters
http://hdl.handle.net/10261/130497
Title: Quantum features of anionic species He*− and He2*− in small HeN clusters
Authors: Villarreal, Pablo; Rodríguez-Cantano, Rocío; González-Lezana, Tomás; Prosmiti, Rita; Delgado Barrio, Gerardo; Gianturco, Franco A.
Abstract: We present variational calculations on systems containing a few boson helium atoms attached to electronically excited atomic and molecular helium anions He*– and He2*– and characterize their structures and energetics. Previously reported high-level ab initio results [Huber, S. E.; Mauracher, A. Mol. Phys. 2014, 112, 794] to describe the interactions between excited (metastable) anions and a neutral He atom have been employed. For the case of the atomic species He*–, the corresponding interaction with He suggests large anharmonicity effects due to the presence of a deep well of ∼17 500 cm–1 at short distances, together with a more external shallow secondary well of ∼4 cm–1, both supporting bound levels. Moreover, when a sum of pairwise interactions is assumed to describe the full PES corresponding to the presence of several neutral He atoms, geometrical constraints already predict the complete solvation of the anionic impurity by six helium atoms, giving rise to a bipyramidal structure. In turn, for the anisotropic weak interaction He–He2*–, where the anionic dimer is considered as a rigid rotor, the obtained structures show the tendency of the helium atoms to pack themselves together and largely far away from the dopant, thereby confirming the heliophobic character of He2*–.2016-03-29T09:24:07ZDriven spin-boson Luttinger liquids
http://hdl.handle.net/10261/128778
Title: Driven spin-boson Luttinger liquids
Authors: Kurcz, Andreas; García Ripoll, Juan José; Bermúdez, Alejandro
Abstract: We introduce a lattice model of interacting spins and bosons that leads to Luttinger-liquid physics, and allows for quantitative tests of the theory of bosonization by means of trapped-ion or superconducting-circuit experiments. By using a variational bosonization ansatz, we calculate the power-law decay of spin and boson correlation functions, and study their dependence on a single tunable parameter, namely a bosonic driving. For small drivings, matrix-product-states (MPSs) numerical methods are shown to be efficient and validate our ansatz. Conversely, even static MPS become inefficient for large-driving regimes, such that the experiment can potentially outperform classical numerics, achieving one of the goals of quantum simulations.2016-02-05T11:20:50ZLight-matter decoupling and A2 term detection in superconducting circuits
http://hdl.handle.net/10261/128773
Title: Light-matter decoupling and A2 term detection in superconducting circuits
Authors: García Ripoll, Juan José; Peropadre, Borja; Liberato, S. de
Abstract: The spontaneous and stimulated emission of a superconducting qubit in the presence of propagating microwaves originates from an effective light-matter interaction that, similarly to the case of the atomic case, can contain a diamagnetic term proportional to the square vector potential A2. In the present work we prove that an increase in the strength of the diamagnetic term leads to an effective decoupling of the qubit from the electromagnetic field, and that this effect is observable at any range of qubit-photon coupling. To measure this effect we propose to use a transmon suspended over a transmission line, where the relative strength of the A2 term is controlled by the qubit-line separation. We show that the spontaneous emission rate of the suspended transmon onto the line can, at short distances, increase with such a separation, instead of decreasing.2016-02-05T10:50:24ZOn the explicit expressions of the canonical 8-form on riemannian manifolds with spin(9) holonomy
http://hdl.handle.net/10261/127950
Title: On the explicit expressions of the canonical 8-form on riemannian manifolds with spin(9) holonomy
Authors: Castrillón López, M.; Gadea, Pedro M.; Mykytyuk, I.V.
Abstract: Two explicit expressions of the canonical 8-form on a Riemannian
manifold with holonomy group Spin(9) have been given: One by the present
authors and another by Parton and Piccinni. The relation between these two
expressions is obtained. Moreover, it is shown that they are different only from
a combinatorial viewpoint.
Description: 6 pags. 1991 Mathematics Subject Classification. Primary 53C29, Secondary 53C27.2016-01-22T10:26:24Z