Browsing DFA  Artículos by Author "García Ramos, José Enrique"
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An extended Agassi model: algebraic structure, phase diagram, and large size limit
García Ramos, José Enrique; Dukelsky, J.; Pérez Fernández, Pedro (IOP Publishing, 2019)The Agassi model (Agassi 1968 Nucl. Phys. A 116 49) is a schematic twolevel model that involves pairing and monopole–monopole interactions. It is, therefore, an extension of the well known Lipkin–Meshkov–Glick model (Lipkin ... 
Continuous unitary transformations in twolevel boson systems
Dusuel, Sébastien; Vidal, Julien; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique (American Physical Society, 20051230)Twolevel boson systems displaying a quantum phase transition from a spherical (symmetric) to a deformed (broken) phase are studied. A formalism to diagonalize Hamiltonians with O(2L + 1) symmetry for large number of ... 
Decoherence as a signature of an excited state quantum phase transition
Relaño Pérez, Armando; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique; Pérez Fernández, Pedro (American Physical Society, 20081216)We analyze the decoherence induced on a single qubit by the interaction with a twolevel boson system with critical internal dynamics. We explore how the decoherence process is affected by the presence of quantum phase ... 
Decoherence due to an excited state quantum phase transition in a twolevel boson model
Pérez Fernández, Pedro; Relaño Pérez, Armando; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique (American Physical Society, 20090917)The decoherence induced on a single qubit by its interaction with the environment is studied. The environment is modeled as a scalar twolevel boson system that can go through either firstorder or continuousexcitedstate ... 
Deformation and mixing of coexisting shapes in neutrondeficient polonium isotopes
Kesteloot, N.; García Ramos, José Enrique; Zielińska, M. (American Physical Society, 2015)Coulombexcitation experiments are performed with postaccelerated beams of neutrondeficient Po196,198,200,202 isotopes at the REXISOLDE facility. A set of matrix elements, coupling the lowlying states in these isotopes, ... 
Disentangling phase transitions and critical points in the proton–neutron interacting boson model by catastrophe theory
García Ramos, José Enrique; Arias Carrasco, José Miguel; Dukelsky, J. (Elsevier, 2014)We introduce the basic concepts of catastrophe theory needed to derive analytically the phase diagram of the protonneutron interacting boson model (IBM2). Previous studies [1,2,3] were based on numerical solutions. We ... 
Disentangling the nuclear shape coexistence in eveneven Hg isotopes using the interacting boson model
García Ramos, José Enrique; Heyde, K. (EDP Sciences, 2015)We intend to provide a consistent description of the eveneven Hg isotopes, 172−200Hg, using the interacting boson model including configuration mixing. We pay special attention to the description of the shape of the ... 
Excitedstate phase transition and onset of chaos in quantum optical models
Pérez Fernández, Pedro; Relaño Pérez, Armando; Arias Carrasco, José Miguel; Cejnar, P.; Dukelsky, J.; García Ramos, José Enrique (American Physical Society, 20110415)We study critical behavior of excited states and its relation to order and chaos in the Jaynes Cummings and Dicke models of quantum optics. We show that both models exhibit a chain of excitedstate quantum phase transitions ... 
Excitedstate quantum phase transitions in a twofluid Lipkin model
García Ramos, José Enrique; Pérez Fernández, Pedro; Arias Carrasco, José Miguel (American Physical Society, 2017)[Background:] Composed systems have became of great interest in the framework of the ground state quantum phase transitions (QPTs) and many of their properties have been studied in detail. However, in these systems ... 
Finitesize corrections in the bosonic algebraic approach to twodimensional systems
Pérez Fernández, Pedro; Arias Carrasco, José Miguel; García Ramos, José Enrique; Pérez Bernal, Francisco (American Physical Society, 20110630)Analytical results beyond the meanfieldlimit approximation for several observables of the twodimensional limit of the vibron model are presented. Finitesize scaling exponent values are also analytically derived. The ... 
The interacting boson model with SU(3) charge symmetry and its application to even–even N≈Z nuclei
García Ramos, José Enrique; Van Isacker, P. (Elsevier, 1999)The isospininvariant interacting boson model IBM3 is analyzed in situations where SUT (3) charge symmetry [or, equivalently, UL(6) sd symmetry] is conserved. Analytic expressions for energies, electromagnetic ... 
MATS and LaSpec: Highprecision experiments using ion traps and lasers at FAIR
Rodríguez Rubiales, Daniel; Blaum, K.; Nörtershäuser, W.; García Ramos, José Enrique (Springer, 201005)Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penningtrap based mass spectrometry and laser spectroscopy. The MATS and ... 
Mean field study of structural changes in Pt isotopes with the Gogny interaction
Rodríguez Guzmán, R.; Sarriguren, P.; Robledo, L. M.; García Ramos, José Enrique (American Physical Society, 201002)The evolution of the nuclear shapes along the triaxial landscape is studied in the Pt isotopic chain using the selfconsistent HartreeFockBogoliubov approximation based on the Gogny interaction. In addition to the ... 
New states in 18Na and 19Mg observed in the twoproton decay of 19Mg
Mukha, I.; Grigorenko, L.; Acosta Sánchez, Luis Armando; Álvarez, M. A. G.; Casarejos, E.; Chatillón, A.; Cortina Gil, D.; Espino, José Manuel; Fomichev, A.; García Ramos, José Enrique; Geissel, H.; Gómez Camacho, Joaquín; Hofmann, J.; Kiselev, O.; Korsheninnikov, A.; Kurz, N.; Litvinov, Yu. A.; Martel Bravo, Ismael; Nociforo, C.; Ott, W.; Pfützner, M.; Rodríguez Tajes, C.; Roeckl, E.; Scheidenberger, C.; Stanoiu, M.; Sümmerer, K.; Weick, H.; Woods, P. J. (American Physical Society, 201206)Previously unknown states in 18Na and 19Mg have been studied by measuring the trajectories of their decay products with microstrip detectors. Analyzing angular correlations of the fragments provided information on decay ... 
Novel results from an algebraic approach to molecular bending dynamics
Pérez Bernal, Francisco; Álvarez Bajo, Osiris; Arias Carrasco, José Miguel; Carvajal Zaera, Miguel; García Ramos, José Enrique; Larese, Danielle; Pérez Fernández, Pedro (Institute of Physics, 2011)We present a brief review of research topics of current interest that depend on an algebraic approach to molecular bending dynamics. This approach is based on a u(3) spectrum generating algebra. In particular, we briefly ... 
Nuclear binding energies : global collective structure and local shellmodel correlations
Fossion, R.; De Coster, C.; García Ramos, José Enrique; Werner, T.; Heyde, K. (Elsevier, 20080128)Nuclear binding energies and twoneutron separation energies are analysed starting from the liquiddrop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently ... 
Nuclear shape coexistence : a study of the eveneven Hg isotopes using the interacting boson model with configuration mixing
García Ramos, José Enrique; Heyde, K. (American Institute of Physics, 2011)Background: The Po, Pb, Hg, and Pt region is known for the presence of coexisting structures that correspond to different particlehole configurations in the Shell Model language or equivalently to nuclear shapes with ... 
Nuclear shape coexistence in Po isotopes : an interacting boson model study
García Ramos, José Enrique; Heyde, K. (2015)Background: The lead region, Po, Pb, Hg, and Pt, shows up the presence of coexisting structures having different deformation and corresponding to different particlehole configurations in the Shell Model language. ... 
Observation of narrow states in nuclei beyond the proton drip line: (15)F and (16)Ne
Mukha, I.; Timofeyuk, N.K.; Sümmerer, K.; Acosta Sánchez, Luis Armando; Álvarez, M. A. G.; García Ramos, José Enrique (American Physical Society, 200906)Two highlying states in 15F and 16Ne, unbound with respect to oneproton (1p) and twoproton (2p) emissions, have been observed in fragmentation of 17Ne at intermediate energies. They undergo mainly sequential emissions ... 
Observation of twoproton radioactivity of (19)Mg by tracking the decay products
Mukha, I.; Sümmerer, K.; Acosta Sánchez, Luis Armando; Álvarez, M. A. G.; García Ramos, José Enrique (American Physical Society, 20071102)We have observed the twoproton radioactivity of the previously unknown 19Mg groundstate by tracking the decay products in°ight. For the ¯rst time, the trajectories of the 2pdecay products, 17Ne+p+p, have been measured ...