1,721,081 research outputs found
Dynamics of the central-depleted-well regime in the open Bose-Hubbard trimer
No full textWe study the quantum dynamics of the central-depleted-well (CDW) regime in a three-mode Bose Hubbard model subject to a confining parabolic potential. By introducing a suitable set of momentum-like modes we identify the microscopic variables involved in the quantization process and the dynamical algebra of the model. We describe the diagonalization procedure showing that the model reduces to a double oscillator. Interestingly, we find that the parameter-space domain where this scheme entails a discrete spectrum well reproduces the two regions where the classical trimer excludes unstable oscillations. Spectral properties are examined in different limiting cases together with various delocalization effects. These are shown to characterize quantum states of the CDW regime in the proximity of the borderline with classically unstable domain
Wave Function Representation for the Generalized Eigenstates of the SU(1,1) Noncompact Generators
No full text
Quantum dynamics of two-dimensional vortex pairs with arbitrary total vorticity
No full textPHYSICAL REIEW
Dynamical properties of two coupled quantum cavities with single-mode amplification
Full text linkCoupled optical cavities provide one of the simplest possible schemes to engineer the interaction of bosonic modes. This paper investigates a two-mode model where, in addition to the usual mode coupling, the presence of an amplification term associated to one of the modes triggers an unexpectedly rich dynamical scenario. The resulting nontrivial model is diagonalized by implementing the dynamical-algebra method, a group-theoretic approach which allows one to determine the stability diagram of the model Hamiltonian in terms of the two mode frequencies for given values of the interaction and amplification parameters. The mode interaction significantly modifies the simple amplification effect of the noninteracting model causing the separation of the
unstable domain (where the amplification takes place) into two subdomains, one of which is stable, features no amplification effect, and exhibits an extension controlled by the interaction parameter. The analysis of stability properties is corroborated by the fully analytic study of the energy spectrum which exhibits the transition from a discrete to a continuous structure whenever the system undergoes the transition from a stable region to an unstable region where the amplification effect occurs. This scenario is further confirmed by the calculation of the time evolution of the mode populations
Dynamics of the Hubbard model: weakly excited pairing states
No full textAccording to a recent proposal, we describe the quantum dynamics of the Hubbard model at the semiclassical level by implementing the Time-Dependent Variational Principle (TDVP) approach on appropriate macroscopic wave-functions constructed in terms of su(2)-coherent states. Within the TDVP procedure, such states turn out to include a time-dependent quantum phase, part of which can be recognized as Berry's phase. In particular, here we investigate the dynamics of the weakly excited states with non-vanishing pairing, away from half-filling and for repulsive Coulomb interaction
Phonons in the quantum Hall effect: A nonlinear-dynamics picture
Full text linkA model describing a system in which Landau electronic modes are coupled with phonons is proposed and discussed. A simplified version of the model is further analyzed, with special attention to the dynamical symmetries that characterize it. In particular, the corresponding equations of motion are thoroughly examined: they provide a variety of behaviors, ranging from completely integrable (in both the classical and quantum case) to chaotic (in the semiclassical approximation). The chaotic regime is believed to be suitable to eventually represent the stochastic behavior of the longitudinal voltage versus time, recently observed in several quantum Hall effect experiments
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