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Browsing by Author "Pérez Fernández, Pedro"
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A digital quantum simulation of the Agassi model
Pérez Fernández, Pedro; Arias Carrasco, José Miguel; García Ramos, José Enrique
; Lamata, Lucas (2022)
A digital quantum simulation of the Agassi model from nuclear physics is proposed and analyzed. The proposal is worked out for the case with four different sites. Numerical simulations and analytical estimations are presented ... -
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 two-level model that involves pairing and monopole–monopole interactions. It is, therefore, an extension of the well known Lipkin–Meshkov–Glick model (Lipkin ... -
Decoherence and quantum quench: their relationship with excited state quantum phase transitions
García Ramos, José Enrique; Arias Carrasco, José Miguel; Cejnar, P.; Dukelsky, J.; Pérez Fernández, Pedro; Relaño Pérez, Armando (American Institute of Physics, 2012-05)
We study the similarities and differences between the phenomena of Quantum Decoherence and Quantum Quench in presence of an Excited State Quantum Phase Transition (ESQPT).We analyze, on one hand, the decoherence induced ... -
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, 2008-12-16)
We analyze the decoherence induced on a single qubit by the interaction with a two-level 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 two-level boson model
Pérez Fernández, Pedro; Relaño Pérez, Armando; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique (American Physical Society, 2009-09-17)
The decoherence induced on a single qubit by its interaction with the environment is studied. The environment is modeled as a scalar two-level boson system that can go through either first-order or continuous-excited-state ... -
Digital quantum simulation of an extended Agassi model: Using machine learning to disentangle its phase-diagram
Sáiz, Álvaro; García Ramos, José Enrique; Arias Carrasco, José Miguel; Lamata, Lucas; Pérez Fernández, Pedro (American Physical Society, 2022)
A digital quantum simulation for the extended Agassi model is proposed using a quantum platform with eight trapped ions. The extended Agassi model is an analytically solvable model including both short range pairing and ... -
Excited state quantum phase transitions and chaos in the Dicke model
Pérez Fernández, Pedro; Relaño Pérez, Armando; Cejnar, P.; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique (American Institute of Physics, 2012)
In this contribution, the critical behavior of excited state quantum phase transitions (ESQPT’s) and its relation to order and chaos in the Dicke model are studied. This model is nonintegrable. For comparison, the same ... -
Excited-state 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, 2011-04-15)
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 excited-state quantum phase transitions ... -
Excited-state quantum phase transitions in a two-fluid 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 ... -
Excited-state quantum phase transitions in the anharmonic Lipkin-Meshkov-Glick model: Static aspects
Gamito, J.; Khalouf-Rivera, Jamil; Arias Carrasco, José Miguel; Pérez Fernández, Pedro; Pérez Bernal, Francisco (American Physical Society, 2022)
The basic Lipkin-Meshkov-Glick model displays a second-order ground-state quantum phase transition and an excited-state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the Hamiltonian implies a ... -
Finite-size corrections in the bosonic algebraic approach to two-dimensional systems
Pérez Fernández, Pedro; Arias Carrasco, José Miguel; García Ramos, José Enrique; Pérez Bernal, Francisco (American Physical Society, 2011-06-30)
Analytical results beyond the mean-field-limit approximation for several observables of the two-dimensional limit of the vibron model are presented. Finite-size scaling exponent values are also analytically derived. The ... -
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 ... -
Number conserving particle-hole RPA for superfluid nuclei
Dukelsky, J.; García Ramos, José Enrique; Arias, J.M.; Pérez Fernández, Pedro; Schuck, P. (Elsevier, 2019-07)
We present a number conserving particle-hole RPA theory for collective excitations in the transition from normal to superfluid nuclei. The method derives from an RPA theory developed long ago in quantum chemistry using ... -
Phase diagram of an extended Agassi model
García Ramos, José Enrique; Dukelsky, J.; Pérez Fernández, Pedro; Arias Carrasco, José Miguel (American Physical Society, 2018)
Background: The Agassi model [D. Agassi, Nucl. Phys. A 116, 49 (1968)] is an extension of the Lipkin-Meshkov-Glick (LMG) model [H. J. Lipkin, N. Meshkov, and A. J. Glick, Nucl. Phys. 62, 188 (1965)] that incorporates the ... -
Phase diagram of the two-fluid Lipkin model : a "butterfly" catastrophe
García Ramos, José Enrique; Pérez Fernández, Pedro; Arias Carrasco, José Miguel; Freire, Emilio (American Physical Society, 2016)
Background: In the last few decades quantum phase transitions have been of great interest in Nuclear Physics. In this context, two-fluid algebraic models are ideal systems to study how the concept of quantum phase transition ... -
Quantum quench influenced by an excited-state phase transition
Pérez Fernández, Pedro; Cejnar, P.; Arias Carrasco, José Miguel; Dukelsky, J.; García Ramos, José Enrique; Relaño Pérez, Armando (American Physical Society, 2011-03-03)
We analyze excited-state quantum phase transitions (ESQPTs) in three schematic (integrable and nonintegrable) models describing a single-mode bosonic field coupled to a collection of atoms. It is shown that the presence ...
