FM - Artículos de revistaFM - Artículos de revistahttp://uvadoc.uva.es/handle/10324/221552021-04-17T17:36:23Z2021-04-17T17:36:23ZExact results for nonequilibrium dynamics in Wigner phase spaceBencheikh, K.Nieto Calzada, Luis Miguelhttp://uvadoc.uva.es/handle/10324/410082021-02-09T11:31:01Z2020-01-01T00:00:00ZWe study time evolution of Wigner function of an initially interacting one-dimensional quantum gas following the switch-off of the interactions. For the scenario where at t=0the interactions are suddenly suppressed, we derive a relationship between the dynamical Wigner function and its initial value. A two-particle system initially interacting through two different interactions of Dirac delta type is examined. For a system of particles that is suddenly let to move ballistically (without interactions) in a harmonic trap in d dimensions, and using time evolution of one-body density matrix, we derive a relationship between the time dependent Wigner function and its initial value. Using the inverse Wigner transform we obtain, for an initially harmonically trapped noninteracting particles in ddimensions, the scaling law satisfied by the density matrix at time tafter a sudden change of the trapping frequency. Finally, the effects of interactions are analyzed in the dynamical Wigner function.
2020-01-01T00:00:00ZApproximate solutions of one dimensional systems with fractional derivativeFerrari, A.Gadella Urquiza, ManuelLara, L. P.Santillan Marcus, E.http://uvadoc.uva.es/handle/10324/410022020-06-08T16:58:17Z2020-01-01T00:00:00ZVer preprint.
2020-01-01T00:00:00ZCayley-Klein Poisson Homogeneous SpacesHerranz Zorrilla, Francisco JoséBallesteros Castañeda, ÁngelGutiérrez Sagredo, IvánSantander Navarro, Marianohttp://uvadoc.uva.es/handle/10324/408832020-05-19T12:12:33Z2019-01-01T00:00:00ZThe nine two-dimensional Cayley–Klein geometries are firstly reviewed by following a graded
contraction approach. Each geometry is considered as a set of three symmetrical homogeneous spaces (of points and two kinds of lines), in such a manner that the graded contraction
parameters determine their curvature and signature. Secondly, new Poisson homogeneous
spaces are constructed by making use of certain Poisson–Lie structures on the corresponding motion groups. Therefore, the quantization of these spaces provides noncommutative
analogues of the Cayley–Klein geometries. The kinematical interpretation for the semiRiemannian and pseudo-Riemannian Cayley–Klein geometries is emphasized, since they are
just Newtonian and Lorentzian spacetimes of constant curvature.
2019-01-01T00:00:00ZA Logical Approach to the Quantum-to-Classical TransitionFortin, SebastianGadella Urquiza, ManuelHolik, FedericoLosada, Marcelohttp://uvadoc.uva.es/handle/10324/408822020-06-08T17:00:50Z2019-01-01T00:00:00ZVer abstract
2019-01-01T00:00:00ZPartial coherent states in grapheneDíaz Bautista, E.Negro Vadillo, Francisco JavierNieto Calzada, Luis Miguelhttp://uvadoc.uva.es/handle/10324/408812020-05-21T11:12:00Z2019-01-01T00:00:00ZWe employ a symmetric gauge to describe the interaction of electrons in graphene
with a magnetic field which is orthogonal to the layer surface and to build the so-called partial
and bidimensional coherent states for this system in the Barut-Girardello sense. We also evaluate
the corresponding probability and current densities as well as the mean energy value.
2019-01-01T00:00:00ZIntegrability, Supersymmetry and Coherent States. A volume in honour of Professor Véronique HussinKuru, S.Negro, J.Nieto Calzada, Luis Miguelhttp://uvadoc.uva.es/handle/10324/408802020-06-08T17:02:19Z2019-01-01T00:00:00ZISBN 978-3-030-20087-9
2019-01-01T00:00:00ZThe Lippmann–Schwinger Formula and One Dimensional Models with Dirac Delta InteractionsErman, FatihGadella, ManuelUncu, Haydarhttp://uvadoc.uva.es/handle/10324/408792020-05-21T11:22:50Z2019-01-01T00:00:00ZWe show how a proper use of the Lippmann–Schwinger equation simplifies the calculations to obtain scattering states for one dimensional systems perturbed by N Dirac delta equations. Here, we consider two situations. In the former, attractive Dirac deltas perturbed the free one dimensional Schrödinger Hamiltonian. We obtain explicit expressions for scattering and Gamow states. For completeness, we show that the method to obtain bound states use comparable formulas, although not based on the Lippmann–Schwinger equation. Then, the attractive N deltas perturbed the one dimensional Salpeter equation. We also obtain explicit expressions for the scattering wave functions. Here, we need regularisation techniques that we implement via heat kernel regularisation.
2019-01-01T00:00:00ZJacobi Polynomials as su(2, 2) Unitary Irreducible RepresentationCeleghini, Enricodel Olmo, Mariano A.Velasco, Miguel A.http://uvadoc.uva.es/handle/10324/408782020-05-17T18:34:42Z2019-01-01T00:00:00ZVer abstract
2019-01-01T00:00:00ZTrends in Supersymmetric Quantum MechanicsC., David J. Fernándezhttp://uvadoc.uva.es/handle/10324/408772020-05-17T18:34:41Z2019-01-01T00:00:00ZVer abstract
2019-01-01T00:00:00ZCoherent States in Quantum Optics: An Oriented OverviewGazeau, Jean-Pierrehttp://uvadoc.uva.es/handle/10324/408762020-05-17T18:34:40Z2019-01-01T00:00:00ZVer abstract
2019-01-01T00:00:00ZNonlinear Supersymmetry as a Hidden SymmetryPlyushchay, Mikhail S.http://uvadoc.uva.es/handle/10324/408752020-05-17T18:34:39Z2019-01-01T00:00:00ZVer abstract
2019-01-01T00:00:00ZSecond harmonic Hamiltonian: Algebraic and Schrödinger approachesMohamadian, T.Panahi, H.Negro Vadillo, Francisco Javierhttp://uvadoc.uva.es/handle/10324/408732021-02-15T13:38:43Z2020-01-01T00:00:00ZWe study in detail the behavior of the energy spectrum for the second harmonic generation (SHG) and a family of corresponding quasi-exactly solvable Schrödinger potentials labeled by a real parameter b. The eigenvalues of this system are obtained by the polynomial deformation of the Lie algebra representation space. We have found the bi-confluent Heun equation (BHE) corresponding to this system in a differential realization approach, by making use of the symmetries. By means of a b-transformation from this second-order equation to a Schrödinger one, we have found a family of quasi-exactly solvable potentials. For each invariant n-dimensional subspace of the second harmonic generation, there are either n potentials, each with one known solution, or one potential with n-known solutions. Well-known potentials like a sextic oscillator or that of a quantum dot appear among them.
2020-01-01T00:00:00ZA note on the Moll-Arias de Reyna integralGlasser, M. Lawrencehttp://uvadoc.uva.es/handle/10324/408722020-06-16T08:51:03Z2020-01-01T00:00:00ZThe Moll-Arias de Reyna integral is generalized and several values are given.
2020-01-01T00:00:00ZCovariant integral quantization of the unit diskOlmo Martínez, Mariano Antonio delGazeau, Jean-Pierrehttp://uvadoc.uva.es/handle/10324/408712020-05-28T20:46:33Z2020-01-01T00:00:00ZWe implement a SU(1, 1) covariant integral quantization of functions on the unit disk. The latter can be viewed as the phase space for
the motion of a “massive” test particle on (1+1)-anti-de Sitter space-time, and the relevant unitary irreducible representations of SU(1, 1)
corresponding to the quantum version of such motions are found in the discrete series and its lower limit. Our quantization method depends
on the choice of a weight function on the phase space in such a way that different weight functions yield different quantizations. For instance,
the Perelomov coherent states quantization is derived from a particular choice. Semi-classical portraits or lower symbols of main physically
relevant operators are determined, and the statistical meaning of the weight function is discussed.
2020-01-01T00:00:00ZA complex storm system in Saturn’s north polar atmosphere in 2018Sánchez Lavega, A.García Melendo, E.Legarreta, J.Hueso, R.Río Gaztelurrutia, T. delSanz Requena, J. F.Pérez Hoyos, S.Simon, A. A.Wong, M. H.Soria, M.Gómez Forrellad, J. M.Barry, T.Delcroix, M.Sayanagi, K. M.Blalock, J. J.Gunnarson, J. L.Dyudina, U.Ewald, S.http://uvadoc.uva.es/handle/10324/408702020-05-26T11:31:26Z2020-01-01T00:00:00ZSaturn’s convective storms usually fall in two categories. One consists of mid-sized storms ∼2,000 km wide, appearing as irregular bright cloud systems that evolve rapidly, on scales of a few days. The other includes the Great White Spots, planetary-scale giant storms ten times larger than the mid-sized ones, which disturb a full latitude band, enduring several months, and have been observed only seven times since 1876. Here we report a new intermediate type, observed in 2018 in the north polar region. Four large storms with east–west lengths ∼4,000–8,000 km (the first one lasting longer than 200 days) formed sequentially in close latitudes, experiencing mutual encounters and leading to zonal disturbances affecting a full latitude band ∼8,000 km wide, during at least eight months. Dynamical simulations indicate that each storm required energies around ten times larger than mid-sized storms but ∼100 times smaller than those necessary for a Great White Spot. This event occurred at about the same latitude and season as the Great White Spot in 1960, in close correspondence with the cycle of approximately 60 years hypothesized for equatorial Great White Spots.
2020-01-01T00:00:00ZTesting the equation of state for viscous dark energyOdintsov, Sergei D.Sáez Gómez, DiegoSharov, German S.http://uvadoc.uva.es/handle/10324/408692021-02-16T08:50:00Z2020-01-01T00:00:00ZSome cosmological scenarios with bulk viscosity for the dark energy fluid are considered. Based on
some considerations related to hydrodynamics, two different equations of state for dark energy are
assumed, leading to power-law and logarithmic effective corrections to the pressure. The models are tested
with the latest astronomical data from type Ia supernovae (Pantheon sample), measurements of the Hubble
parameter HðzÞ, baryon acoustic oscillations and cosmic microwave background radiation. In comparison
with the ΛCDM model, some different results are obtained and their viability is discussed. The power-law
model shows some modest results, achieved under negative values of bulk viscosity, while the logarithmic
scenario provide good fits in comparison to the ΛCDM model.
2020-01-01T00:00:00Z