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Author Hojman, S.A.; Asenjo, F.A.; Moya-Cessa, H.M.; Soto-Eguibar, F.
Title Bohm potential is real and its effects are measurable Type
Year 2021 Publication Optik Abbreviated Journal Optik
Volume 232 Issue Pages (down) 166341
Keywords Bohm potential; Non-vanishing; Accelerating solutions
Abstract We analyze Bohm potential effects both in the realms of Quantum Mechanics and Optics, as well as in the study of other physical phenomena described in terms of classical and quantum wave equations. We approach this subject by using theoretical arguments as well as experimental evidence. We find that the effects produced by Bohm potential are both theoretically responsible for the early success of Quantum Mechanics correctly describing atomic and nuclear phenomena and, more recently, by confirming surprising accelerating behavior of free waves and particles experimentally, for instance.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0030-4026 ISBN Medium
Area Expedition Conference
Notes WOS:000636139700002 Approved
Call Number UAI @ alexi.delcanto @ Serial 1366
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Author Asenjo, F.A.; Hojman, S.A.; Moya-Cessa, H.M.; Soto-Eguibar, F.
Title Propagation of light in linear and quadratic GRIN media: The Bohm potential Type
Year 2021 Publication Optics Communications Abbreviated Journal Opt. Commun.
Volume 490 Issue Pages (down) 126947
Keywords
Abstract It is shown that field propagation in linear and quadratic gradient-index (GRIN) media obeys the same rules of free propagation in the sense that a field propagating in free space has a (mathematical) form that may be exported to those particular GRIN media. The Bohm potential is introduced in order to explain the reason of such behavior: it changes the dynamics by modifying the original potential . The concrete cases of two different initials conditions for each potential are analyzed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0030-4018 ISBN Medium
Area Expedition Conference
Notes WOS:000664742700011 Approved
Call Number UAI @ alexi.delcanto @ Serial 1424
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Author Hojman, S.J.; Moya-Cessa, H.M.; Soto-Eguibar, F.; Asenjo, F.A.
Title Time-dependent harmonic oscillators and SUSY in time domain Type
Year 2021 Publication Physica Scripta Abbreviated Journal Phys. Scr.
Volume 96 Issue 12 Pages (down) 125218
Keywords time domain super-symmetry; time dependent harmonic oscillator; Bohm potential; Ermakov-lewis invariant
Abstract We show that the time-dependent harmonic oscillator has a repulsive or inverted oscillator as a time domain SUSY-like partner. Examples of several kinds of super-symmetrical time dependent frequency systems are presented.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-8949 ISBN Medium
Area Expedition Conference
Notes WOS:000698808000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1467
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Author Hojmann, S.A.; Asenjo, F.A.
Title Quantum particles that behave as free classical particles Type
Year 2020 Publication PHYSICAL REVIEW A Abbreviated Journal Phys. Rev. A
Volume 102 Issue 5 Pages (down) 052211
Keywords Wave; Generation
Abstract The existence of nonvanishing Bohm potentials, in the Madelung-Bohm version of the Schrödinger equation, allows for the construction of particular solutions for states of quantum particles interacting with nontrivial external potentials that propagate as free classical particles. Such solutions are constructed with phases which satisfy the classical Hamilton-Jacobi for free particles and whose probability densities propagate with constant velocity, as free classical particles do.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9926 ISBN Medium
Area Expedition Conference
Notes Approved
Call Number UAI @ alexi.delcanto @ Serial 1269
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Author Asenjo, F.A.; Erices, C.; Gomberoff, A.; Hojman, S.A.; Montecinos, A.
Title Differential geometry approach to asymmetric transmission of light Type
Year 2017 Publication Optics Express Abbreviated Journal Opt. Express
Volume 25 Issue 22 Pages (down) 26405-26416
Keywords
Abstract In the last ten years, the technology of differential geometry, ubiquitous in gravitational physics, has found its place in the field of optics. It has been successfully used in the design of optical metamaterials through a technique now known as “transformation optics.” This method, however, only applies for the particular class of metamaterials known as impedance matched, that is, materials whose electric permittivity is equal to their magnetic permeability. In that case, the material may be described by a spacetime metric. In the present work we will introduce a generalization of the geometric methods of transformation optics to situations in which the material is not impedance matched. In such situations, the material -or more precisely, its constitutive tensor-will not be described by a metric only. We bring in a second tensor, with the local symmetries of the Weyl tensor, the “W-tensor.” In the geometric optics approximation we show how the properties of the W-tensor are related to the asymmetric transmission of the material. We apply this feature to the design of a particularly interesting set of asymmetric materials. These materials are birefringent when light rays approach the material in a given direction, but behave just like vacuum when the rays have the opposite direction with the appropriate polarization (or, in some cases, independently of the polarization). (C) 2017 Optical Society of America
Address [Asenjo, Felipe A.; Gomberoff, Andres] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Av Diagonal Torres 2640, Santiago, Chile, Email: andres.gomberoff@uai.cl
Corporate Author Thesis
Publisher Optical Soc Amer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1094-4087 ISBN Medium
Area Expedition Conference
Notes WOS:000413995000004 Approved
Call Number UAI @ eduardo.moreno @ Serial 798
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Author Mahajan, S.M.; Asenjo, F.A.; Hazeltine, R.D.
Title Comparison of the electron-spin force and radiation reaction force Type
Year 2015 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 446 Issue 4 Pages (down) 4112-4115
Keywords magnetic fields; plasmas; radiation mechanisms: general
Abstract It is shown that the forces that originate from the electron-spin interacting with the electromagnetic field can play, along with the Lorentz force, a fundamentally important role in determining the electron motion in a high energy density plasma embedded in strong high-frequency radiation, a situation that pertains to both laser-produced and astrophysical systems. These forces, for instance, dominate the standard radiation reaction force as long as there is a 'sufficiently' strong ambient magnetic field for affecting spin alignment. The inclusion of spin forces in any advanced modelling of electron dynamics pertaining to high energy density systems (for instance in particle-in-cell codes), therefore, is a must.
Address [Mahajan, Swadesh M.; Hazeltine, Richard D.] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 USA, Email: felipe.asenjo@uai.cl
Corporate Author Thesis
Publisher Oxford Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000350272400066 Approved
Call Number UAI @ eduardo.moreno @ Serial 462
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Author Mahajan, S.M.; Asenjo, F.A.
Title Hot Fluids and Nonlinear Quantum Mechanics Type
Year 2015 Publication International Journal Of Theoretical Physics Abbreviated Journal Int. J. Theor. Phys.
Volume 54 Issue 5 Pages (down) 1435-1449
Keywords Nonlinear quantum mechanics; Fluids; Temperature; High energy density physics
Abstract A hot relativistic fluid is viewed as a collection of quantum objects that represent interacting elementary particles. We present a conceptual framework for deriving nonlinear equations of motion obeyed by these hypothesized objects. A uniform phenomenological prescription, to affect the quantum transition from a corresponding classical system, is invoked to derive the nonlinear Schrodinger, Klein-Gordon, and Pauli-Schrodinger and Feynman-GellMaan equations. It is expected that the emergent hypothetical nonlinear quantum mechanics would advance, in a fundamental way, both the conceptual understanding and computational abilities, particularly, in the field of extremely high energy-density physics.
Address [Mahajan, Swadesh M.] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 USA, Email: mahajan@mail.utexas.edu;
Corporate Author Thesis
Publisher Springer/Plenum Publishers Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-7748 ISBN Medium
Area Expedition Conference
Notes WOS:000352858600004 Approved
Call Number UAI @ eduardo.moreno @ Serial 485
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Author Asenjo, F.A.; Hojman, S.A.
Title Class of Exact Solutions for a Cosmological Model of Unified Gravitational and Quintessence Fields Type
Year 2017 Publication Foundations Of Physics Abbreviated Journal Found. Phys.
Volume 47 Issue 7 Pages (down) 887-896
Keywords Quintessence; Exact solution; Unification of geometry and dark matter
Abstract A new approach to tackle Einstein equations for an isotropic and homogeneous Friedmann-Robertson-Walker Universe in the presence of a quintessence scalar field is devised. It provides a way to get a simple exact solution to these equations. This solution determines the quintessence potential uniquely and it differs from solutions which have been used to study inflation previously. It relays on a unification of geometry and dark matter implemented through the definition of a functional relation between the scale factor of the Universe and the quintessence field. For a positive curvature Universe, this solution produces perpetual accelerated expansion rate of the Universe, while the Hubble parameter increases abruptly, attains a maximum value and decreases thereafter. The behavior of this cosmological solution is discussed and its main features are displayed. The formalism is extended to include matter and radiation.
Address [Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: felipe.asenjo@uai.cl;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0015-9018 ISBN Medium
Area Expedition Conference
Notes WOS:000404224500003 Approved
Call Number UAI @ eduardo.moreno @ Serial 741
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Author Asenjo, F.A.; Hojman, S.A.
Title Accelerating solutions to diffusion equation Type
Year 2021 Publication European Physical Journal Plus Abbreviated Journal Eur. Phys. J. Plus.
Volume 136 Issue 6 Pages (down) 677
Keywords NONLINEAR DIFFUSIONSIMILARITY SOLUTIONS
Abstract We report accelerating diffusive solutions to the diffusion equation with a constant diffusion tensor. The maximum values of the diffusion density evolve in an accelerating fashion described by Airy functions. We show the diffusive accelerating behavior for one-dimensional systems, as well as for a general three-dimensional case. We also construct a modulated modified form of the diffusion solution that retains the accelerating features.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2190-5444 ISBN Medium
Area Expedition Conference
Notes WOS:000664659600001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1433
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Author Caerols, H.; Asenjo, F.A.
Title Estimating the Moon-to-Earth Radius Ratio with a Smartphone, a Telescope, and an Eclipse Type
Year 2020 Publication Physics Teacher Abbreviated Journal Phys. Teach.
Volume 58 Issue 7 Pages (down) 497-501
Keywords
Abstract From ancient times, the different features of planets and moons have created a huge interest. Aristarchus was one of the first to study the relative relations among Earth, Moon, and Sun. This interest has remained until today, and therefore it is always relevant to make this knowledge more appealing to the younger generations. Nowadays, smartphone technology has become an important tool to teach physics, and this gives us a huge opportunity to bring science closer to students in a simpler manner. In this work, we show how simple photographs of a partial lunar eclipse are sufficiently good to estimate the ratio between the Moon and Earth radii. After taking the photographs, the procedure for the calculation is straightforward and it can be reproduced easily in a one–hour class
Address [Caerols, Hugo; Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: felipe.asenjo@uai.cl
Corporate Author Thesis
Publisher Amer Assn Physics Teachers Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-921x ISBN Medium
Area Expedition Conference
Notes WOS:000576343700015 Approved
Call Number UAI @ alexi.delcanto @ Serial 1234
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Author Munoz, V.; Asenjo, F.A.; Dominguez, M.; Lopez, R.A.; Valdivia, J.A.; Vinas, A.; Hada, T.
Title Large-amplitude electromagnetic waves in magnetized relativistic plasmas with temperature Type
Year 2014 Publication Nonlinear Processes In Geophysics Abbreviated Journal Nonlinear Process Geophys.
Volume 21 Issue 1 Pages (down) 217-236
Keywords
Abstract Propagation of large-amplitude waves in plasmas is subject to several sources of nonlinearity due to relativistic effects, either when particle quiver velocities in the wave field are large, or when thermal velocities are large due to relativistic temperatures. Wave propagation in these conditions has been studied for decades, due to its interest in several contexts such as pulsar emission models, laser-plasma interaction, and extragalactic jets. For large-amplitude circularly polarized waves propagating along a constant magnetic field, an exact solution of the fluid equations can be found for relativistic temperatures. Relativistic thermal effects produce: (a) a decrease in the effective plasma frequency (thus, waves in the electromagnetic branch can propagate for lower frequencies than in the cold case); and (b) a decrease in the upper frequency cutoff for the Alfven branch (thus, Alfven waves are confined to a frequency range that is narrower than in the cold case). It is also found that the Alfven speed decreases with temperature, being zero for infinite temperature. We have also studied the same system, but based on the relativistic Vlasov equation, to include thermal effects along the direction of propagation. It turns out that kinetic and fluid results are qualitatively consistent, with several quantitative differences. Regarding the electromagnetic branch, the effective plasma frequency is always larger in the kinetic model. Thus, kinetic effects reduce the transparency of the plasma. As to the Alfven branch, there is a critical, nonzero value of the temperature at which the Alfven speed is zero. For temperatures above this critical value, the Alfven branch is suppressed; however, if the background magnetic field increases, then Alfven waves can propagate for larger temperatures. There are at least two ways in which the above results can be improved. First, nonlinear decays of the electromagnetic wave have been neglected; second, the kinetic treatment considers thermal effects only along the direction of propagation. We have approached the first subject by studying the parametric decays of the exact wave solution found in the context of fluid theory. The dispersion relation of the decays has been solved, showing several resonant and nonresonant instabilities whose dependence on the wave amplitude and plasma temperature has been studied systematically. Regarding the second subject, we are currently performing numerical 1-D particle in cell simulations, a work that is still in progress, although preliminary results are consistent with the analytical ones.
Address [Munoz, V.; Dominguez, M.; Lopez, R. A.; Valdivia, J. A.] Univ Chile, Fac Ciencias, Dept Fis, Santiago, Chile, Email: vmunoz@fisica.ciencias.uchile.cl
Corporate Author Thesis
Publisher Copernicus Gesellschaft Mbh Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1023-5809 ISBN Medium
Area Expedition Conference
Notes WOS:000332337700017 Approved
Call Number UAI @ eduardo.moreno @ Serial 360
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Author Zalaquett, N.; Hojman, S.A.; Asenjo, F.A.
Title Spinning massive test particles in cosmological and general static spherically symmetric spacetimes Type
Year 2014 Publication Classical And Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 31 Issue 8 Pages (down) 21 pp
Keywords exact solution; conformally flat spacetimes; spinning massive particle; cosmological spacetimes
Abstract A Lagrangian formalism is used to study the motion of a spinning massive particle in Friedmann-Robertson-Walker and Godel spacetimes, as well as in a general Schwarzschild-like spacetime and in static spherically symmetric conformally flat spacetimes. Exact solutions for the motion of the particle and general exact expressions for the momenta and velocities are displayed for different cases. In particular, the solution for the motion in spherically symmetric metrics is presented in the equatorial plane. The exact solutions are found using constants of motion of the particle, namely its mass, its spin, its angular momentum, and a fourth constant, which is its energy when the metric is time-independent, and a different constant otherwise. These constants are associated to Killing vectors. In the case of the motion on the Friedmann-Robertson-Walker metric, a new constant of motion is found. This is the fourth constant which generalizes previously known results obtained for spinless particles. In the case of general Schwarzschild-like spacetimes, our results allow for the exploration of the case of the Reissner-Nordstrom-(Anti) de Sitter metric. Finally, for the case of the conformally flat spacetimes, the solution is explicitly evaluated for different metric tensors associated to a universe filled with static perfect fluids and electromagnetic radiation. For some combination of the values of the constants of motion the particle trajectories may exhibit spacelike velocity vectors in portions of the trajectories.
Address [Zalaquett, Nicolas] Pontificia Univ Catolica Chile, Fac Fis, Santiago 22, Chile, Email: nzalaque@puc.cl;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000334418900012 Approved
Call Number UAI @ eduardo.moreno @ Serial 373
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Author Mahajan, S.M.; Asenjo, F.A.
Title Explicitly covariant dispersion relations and self-induced transparency Type
Year 2017 Publication Journal Of Plasma Physics Abbreviated Journal J. Plasma Phys.
Volume 83 Issue Pages (down) 15 pp
Keywords magnetized plasmas; plasma waves
Abstract Explicitly covariant dispersion relations for a variety of plasma waves in unmagnetized and magnetized plasmas are derived in a systematic manner from a fully covariant plasma formulation. One needs to invoke relatively little known invariant combinations constructed from the ambient electromagnetic fields and the wave vector to accomplish the program. The implication of this work applied to the self- induced transparency effect is discussed. Some problems arising from the inconsistent use of relativity are pointed out.
Address [Mahajan, S. M.] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 USA, Email: mahajan@mail.utexas.edu;
Corporate Author Thesis
Publisher Cambridge Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3778 ISBN Medium
Area Expedition Conference
Notes WOS:000396123100018 Approved
Call Number UAI @ eduardo.moreno @ Serial 713
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Author Asenjo, F.A.; Moya, P.S.
Title The contribution of magnetic monopoles to the ponderomotive force Type
Year 2019 Publication Journal Of Physics A-Mathematical And Theoretical Abbreviated Journal J. Phys. A-Math. Theor.
Volume 52 Issue 25 Pages (down) 13 pp
Keywords plasma waves; magnetic monopoles; ponderomotive force
Abstract When magnetic monopoles are assumed to exist in plasma dynamics, the propagation of electromagnetic waves is modified as Maxwell equations acquire a symmetrical structure due to the existence of electric and magnetic charge and current densities. This work presents a theoretical exploration on how far we can push the limits of a plasma theory under the presence of magnetic monopoles. In particular, we study the modification of ponderomotive forces in a plasma composed by electric and magnetic charges. We show that the general ponderomotive force on this plasma depends non-trivially on the magnetic monopoles, through the slow temporal and spatial variations of the electromagnetic field amplitudes. The magnetic charges introduce corrections even if the plasma is unmagnetized. Also, it is shown that the magnetic monopoles also experience a ponderomotive force due to the electrons. This force is in the direction of propagation of the electromagnetic waves.
Address [Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago 7941169, Chile, Email: felipe.asenjo@uai.cl;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1751-8113 ISBN Medium
Area Expedition Conference
Notes WOS:000469448000001 Approved
Call Number UAI @ eduardo.moreno @ Serial 1029
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Author Mahajan, S.M.; Asenjo, F.A.
Title A statistical model for relativistic quantum fluids interacting with an intense electromagnetic wave Type
Year 2016 Publication Physics Of Plasmas Abbreviated Journal Phys. Plasmas
Volume 23 Issue 5 Pages (down) 12 pp
Keywords
Abstract A statistical model for relativistic quantum fluids interacting with an arbitrary amplitude circularly polarized electromagnetic wave is developed in two steps. First, the energy spectrum and the wave function for a quantum particle (Klein Gordon and Dirac) embedded in the electromagnetic wave are calculated by solving the appropriate eigenvalue problem. The energy spectrum is anisotropic in the momentum K and reflects the electromagnetic field through the renormalization of the rest mass m to M = root m(2) + q(2)Q(2). Based on this energy spectrum of this quantum particle plus field combination (QPF), a statistical mechanics model of the quantum fluid made up of these weakly interacting QPF is developed. Preliminary investigations of the formalism yield highly interesting results-a new scale for temperature, and fundamental modification of the dispersion relation of the electromagnetic wave. It is expected that this formulation could, inter alia, uniquely advance our understanding of laboratory as well as astrophysical systems where one encounters arbitrarily large electromagnetic fields. (C) 2016 AIP Publishing LLC.
Address [Mahajan, Swadesh M.] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 USA, Email: mahajan@mail.utexas.edu;
Corporate Author Thesis
Publisher Amer Inst Physics Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1070-664x ISBN Medium
Area Expedition Conference
Notes WOS:000378427900152 Approved
Call Number UAI @ eduardo.moreno @ Serial 638
Permanent link to this record
 

 
Author Asenjo, F.A.; Hojman, S.A.
Title Birefringent light propagation on anisotropic cosmological backgrounds Type
Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 96 Issue 4 Pages (down) 12 pp
Keywords
Abstract Exact electromagnetic wave solutions to Maxwell equations on anisotropic Bianchi I cosmological spacetime backgrounds are studied. The waves evolving on Bianchi I spacetimes exhibit birefringence (associated with linear polarization) and dispersion. The particular case of a vacuum-dominated anisotropic Universe, which reproduces a Friedmann-Robertson-Walker Universe (for late times)-while, for earlier times, it matches a Kasner Universe-is studied. The electromagnetic waves do not, in general, follow null geodesics. This produces a modification of the cosmological redshift, which is then dependent on light polarization, its dispersion, and its non-null geodesic behavior. New results presented here may help to tackle some issues related to the “horizon” problem.
Address [Asenjo, Felipe A.; Hojman, Sergio A.] Univ Adolfo Ibanez, UAI Phys Ctr, Santiago 7941169, Chile, Email: felipe.asenjo@uai.cl;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000407716200007 Approved
Call Number UAI @ eduardo.moreno @ Serial 756
Permanent link to this record
 

 
Author Asenjo, F.A.; Hojman, S.A.
Title Do electromagnetic waves always propagate along null geodesics? Type
Year 2017 Publication Classical And Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 34 Issue 20 Pages (down) 12 pp
Keywords electromagnetic waves; curved spacetime; non-null geodesics
Abstract We find exact solutions to Maxwell equations written in terms of fourvector potentials in non-rotating, as well as in Gdel and Kerr spacetimes. We show that Maxwell equations can be reduced to two uncoupled secondorder differential equations for combinations of the components of the four-vector potential. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non-rotating spherical symmetric spacetimes, electromagnetic waves travel along null geodesics. However, electromagnetic waves on Gdel and Kerr spacetimes do not exhibit that behavior.
Address [Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: felipe.asenjo@uai.cl;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000411741800008 Approved
Call Number UAI @ eduardo.moreno @ Serial 800
Permanent link to this record
 

 
Author Hojman, S.A.; Asenjo, F.A.
Title Phenomenological dynamics of COVID-19 pandemic: Meta-analysis for adjustment parameters Type
Year 2020 Publication Chaos Abbreviated Journal Chaos
Volume 30 Issue 10 Pages (down) 12 pp
Keywords
Abstract We present a phenomenological procedure of dealing with the COVID-19 (coronavirus disease 2019) data provided by government health agencies of 11 different countries. Usually, the exact or approximate solutions of susceptible-infected-recovered (or other) model(s) are obtained fitting the data by adjusting the time-independent parameters that are included in those models. Instead of that, in this work, we introduce dynamical parameters whose time-dependence may be phenomenologically obtained by adequately extrapolating a chosen subset of the daily provided data. This phenomenological approach works extremely well to properly adjust the number of infected (and removed) individuals in time for the countries we consider. Besides, it can handle the sub-epidemic events that some countries may experience. In this way, we obtain the evolution of the pandemic without using any a priori model based on differential equations.
Address [Hojman, Sergio A.] Univ Adolfo Ibanez, Fac Artes Lib, Dept Ciencias, Santiago 7491169, Chile, Email: sergio.hojman@uai.cl;
Corporate Author Thesis
Publisher Amer Inst Physics Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1054-1500 ISBN Medium
Area Expedition Conference
Notes WOS:000585761000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1257
Permanent link to this record
 

 
Author Hojman, S.A.; Asenjo, F.A.
Title Can gravitation accelerate neutrinos? Type
Year 2013 Publication Classical And Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 30 Issue 2 Pages (down) 10 pp
Keywords
Abstract The Lagrangian equations of motion for massive spinning test particles (tops) moving on a gravitational background using general relativity are presented. The paths followed by tops are nongeodesic. An exact solution for the motion of tops on a Schwarzschild background which allows for superluminal propagation of tops is studied. It is shown that the solution becomes relevant for particles with small masses, such as neutrinos. This general result is used to calculate the necessary condition to produce superluminal motion in part of the trajectory of a small mass particle in a weak gravitational field. The condition for superluminal motion establishes a relation between the mass, energy and total angular momentum of the particle.
Address [Hojman, Sergio A.] Univ Adolfo Ibanez, Dept Ciencias, Fac Artes Liberales, Fac Ingn & Ciencias, Santiago, Chile, Email: sergio.hojman@uai.cl;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0264-9381 ISBN Medium
Area Expedition Conference
Notes WOS:000313097300008 Approved
Call Number UAI @ eduardo.moreno @ Serial 257
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Author Comisso, L.; Asenjo, F.A.
Title Collisionless magnetic reconnection in curved spacetime and the effect of black hole rotation Type
Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 97 Issue 4 Pages (down) 9 pp
Keywords
Abstract Magnetic reconnection in curved spacetime is studied by adopting a general-relativistic magneto-hydrodynamic model that retains collisionless effects for both electron-ion and pair plasmas. A simple generalization of the standard Sweet-Parker model allows us to obtain the first-order effects of the gravitational field of a rotating black hole. It is shown that the black hole rotation acts to increase the length of azimuthal reconnection layers, thus leading to a decrease of the reconnection rate. However, when coupled to collisionless thermal-inertial effects, the net reconnection rate is enhanced with respect to what would happen in a purely collisional plasma due to a broadening of the reconnection layer. These findings identify an underlying interaction between gravity and collisionless magnetic reconnection in the vicinity of compact objects.
Address [Comisso, Luca] Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA, Email: lcomisso@princeton.edu;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000424748300002 Approved
Call Number UAI @ eduardo.moreno @ Serial 819
Permanent link to this record