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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 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 (up) WOS:000585761000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1257
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Author Comisso, L.; Asenjo, F.A.
Title Magnetic reconnection as a mechanism for energy extraction from rotating black holes Type
Year 2021 Publication Physical Review D Abbreviated Journal Phys. Rev. D.
Volume 103 Issue 2 Pages 023014
Keywords BLANDFORD-ZNAJEK MECHANISM; NEAR-INFRARED FLARES; SIMULATIONS; JETS; DRIVEN
Abstract Spinning black holes store rotational energy that can be extracted. When a black hole is immersed in an externally supplied magnetic field, reconnection of magnetic field lines within the ergosphere can generate negative energy (relative to infinity) particles that fall into the black hole event horizon while the other accelerated particles escape stealing energy from the black hole. We show analytically that energy extraction via magnetic reconnection is possible when the black hole spin is high (dimensionless spin a similar to 1) and the plasma is strongly magnetized (plasma magnetization sigma(0) > 1/3). The parameter space region where energy extraction is allowed depends on the plasma magnetization and the orientation of the reconnecting magnetic field lines. For sigma(0) >> 1, the asymptotic negative energy at infinity per enthalpy of the decelerated plasma that is swallowed by a maximally rotating black hole is found to be epsilon(infinity)(-) similar or equal to – root sigma(0)/3. The accelerated plasma that escapes to infinity and takes away black hole energy asymptotes the energy at infinity per enthalpy epsilon(infinity)(+) similar or equal to root 3 sigma(0).. We show that the maximum power extracted from the black hole by the escaping plasma is P-extr(max) similar to 0.1M(2) root sigma(0)w(0) (here, M is the black hole mass and w(0) is the plasma enthalpy density) for the collisionless plasma regime and one order of magnitude lower for the collisional regime. Energy extraction causes a significant spindown of the black hole when a similar to 1. The maximum efficiency of the plasma energization process via magnetic reconnection in the ergosphere is found to be eta(max) similar or equal to 3/2. Since fast magnetic reconnection in the ergosphere should occur intermittently in the scenario proposed here, the associated emission within a few gravitational radii from the black hole is expected to display a bursty nature.
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 2470-0010 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000607513600001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1323
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Author Asenjo, F.A.; Hojman, S.A.
Title Nondiffracting gravitational waves Type
Year 2021 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 81 Issue 1 Pages 98
Keywords
Abstract It is proved that accelerating nondiffracting gravitational Airy wave-packets are solutions of linearized gravity. It is also showed that Airy functions are exact solutions to Einstein equations for non-accelerating nondiffracting gravitational wave-packets.
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 1434-6044 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000616135600003 Approved
Call Number UAI @ alexi.delcanto @ Serial 1336
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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 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 (up) WOS:000636139700002 Approved
Call Number UAI @ alexi.delcanto @ Serial 1366
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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 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 (up) WOS:000664659600001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1433
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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 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 (up) 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 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 (up) WOS:000698808000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1467
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Author Asenjo, F.A.; Hojman, S.A.
Title Reply to Comment on 'Do electromagnetic waves always propagate along null geodesics?' Reply Type
Year 2021 Publication Classical And Quantum Gravity Abbreviated Journal Class. Quantum Gravity
Volume 38 Issue 23 Pages 238002
Keywords couplings; electromagnetic wave; propagation; consistency; geometrical; eikonal limit
Abstract A reply to the previous article commenting on non-geodesical propagation of electromagnetic fields on gravitational backgrounds and the eikonal limit 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 0264-9381 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000728942300001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1512
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Author Asenjo, F.A.; Hojman, S.A.
Title Light-like propagation of self-interacting Klein-Gordon fields in cosmology Type
Year 2022 Publication European Physical Journal Plus Abbreviated Journal Eur. Phys. J. Plus.
Volume 137 Issue 1 Pages 20
Keywords
Abstract It is showed that complex scalar fields with a self-interaction potential may propagate along null geodesics on isotropic flat Friedmann-Lemaitre-Robertson-Walker universes with different time-dependent scale factors. This effect appears for certain kinds of self-interactions only, for different forms of potentials, and even for the massive case.
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 (up) WOS:000730210100003 Approved
Call Number UAI @ alexi.delcanto @ Serial 1501
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Author Soto-Eguibar, F.; Asenjo, F.A.; Hojman, S.A.; Moya-Cessa, H.M.
Title Bohm potential for the time dependent harmonic oscillator Type
Year 2021 Publication Journal of Mathematical Physics Abbreviated Journal J. Math. Phys.
Volume 62 Issue 12 Pages 122103
Keywords SCHRODINGER-EQUATION; QUANTUM-THEORY; MASS; PROPAGATION; INVARIANTS; SYSTEMS; STATES
Abstract In the Madelung-Bohm approach to quantum mechanics, we consider a time dependent phase that depends quadratically on position, and we show that it leads to a Bohm potential that corresponds to a time dependent harmonic oscillator, provided the time dependent term in the phase obeys an Ermakov equation.
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 0022-2488 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000731943600003 Approved
Call Number UAI @ alexi.delcanto @ Serial 1504
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Author Moya-Cessa, H.M.; Hojman, S.A.; Asenjo, F.A.; Soto-Eguibar, F.
Title Bohm approach to the Gouy phase shift Type
Year 2022 Publication Optik Abbreviated Journal Optik
Volume 252 Issue Pages 168468
Keywords Gouy phase; Bohm potential; Lewis-Ermakov invariant
Abstract By adapting the Madelung-Bohm formalism to paraxial wave propagation we show, by using Ermakov-Lewis techniques, that the Gouy phase is related to the form of the phase chosen in order to produce a Gaussian function as a propagated field. For this, we introduce a quantum mechanical invariant, that it is explicitly time dependent. We finally show that the effective Bohm index of refraction generates a GRIN medium that produces the focusing needed for the Gouy phase.
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 (up) WOS:000756682400010 Approved
Call Number UAI @ alexi.delcanto @ Serial 1543
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Author Caerols, H.; Carrasco, R.A.; Asenjo, F.A.
Title Using smartphone photographs of the Moon to acquaint students with non-Euclidean geometry Type
Year 2021 Publication American Journal of Physics Abbreviated Journal Am. J. Phys.
Volume 89 Issue 12 Pages 1079-1085
Keywords
Abstract Non-Euclidean geometry can be taught to students using astronomical images. By using photographs o the Moon taken with a smartphone through a simple telescope, we were able to introduce these concepts to high-school students and lower-level college students. We teach students how to calculate lengths of mountain ranges or areas of craters on the Moon's surface and introduce ideas of geodesics and spherical triangles. Students can see that accurate measurements cannot be

obtained using at geometry. Instead, by using three{dimensional curved geometry, estimates of lengths and areas can be computed with less than 4% error.
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 0002-9505 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000757066700003 Approved
Call Number UAI @ alexi.delcanto @ Serial 1447
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Author Mahajan, S.M.; Asenjo, F.A.
Title Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave Type
Year 2022 Publication Physics Of Plasmas Abbreviated Journal Phys. Plasmas
Volume 29 Issue 2 Pages 022107
Keywords KLEIN-GORDON; DIRAC EQUATIONS; FIELD; PARTICLE; ACCELERATION
Abstract Dynamics of electrons subjected to a constant amplitude classical electromagnetic (EM) wave is investigated as a fundamental, representative problem in the physics of interacting quantum and classical waves. In the nonrelativistic regime (electrons as Schrodinger waves), the electron energy acquires a constant and a time dependent part. Driven by EM waves, both parts scale strongly with the amplitude, but we expect no resonant enhancement since the parallel electron “speed ” of nonrelativistic electrons could never match the wave phase velocity. In the relativistic regime (electron as a Klein-Gordon wave), however, a class of electron waves (with parallel speed matching the EM phase speed) are resonantly excited to extremely high energies. Such a direct resonant energy transfer from intense electromagnetic waves constitutes a mechanism that could, in principle, power the most energetic of cosmic rays (this mechanism will work on protons just as well). Some predictions of the theory will, hopefully, be tested in laboratory laser experiments. The nonrelativistic calculations will also be examined in the context of recent experiments using photon-induced near-field electron microscopy in detail.
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 1070-664X ISBN Medium
Area Expedition Conference
Notes (up) WOS:000760744200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1540
Permanent link to this record
 

 
Author Hojman, S.A.; Asenjo, F.A.
Title Unification of massless field equations solutions for any spin Type
Year 2022 Publication Epl Abbreviated Journal Epl
Volume 137 Issue 2 Pages 24001
Keywords QUANTIZATION
Abstract A unification in terms of exact solutions for massless Klein-Gordon, Dirac, Maxwell, Rarita-Schwinger, Einstein, and bosonic and fermionic fields of any spin is presented. The method is based on writing all of the relevant dynamical fields in terms of products and derivatives of pre-potential functions, which satisfy the d'Alembert equation. The coupled equations satisfied by the pre-potentials are non-linear. Remarkably, there are particular solutions of (gradient) orthogonal pre-potentials that satisfy the usual wave equation which may be used to construct exact non-trivial solutions to Klein-Gordon, Dirac, Maxwell, Rarita-Schwinger, (linearized and full) Einstein and any spin bosonic and fermionic field equations, thus giving rise to a unification of the solutions of all massless field equations for any spin. Some solutions written in terms of orthogonal prepotentials are presented. Relations of this method to previously developed ones, as well as to other subjects in physics are pointed out.
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 0295-5075 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000780902300001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1555
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Author Moya-Cessa, H.M.; Asenjo, F.A.; Hojman, S.A.; Soto-Eguibar, F.
Title Two-mode squeezed state generation using the Bohm potential Type
Year 2022 Publication Modern Physics Letters B Abbreviated Journal Mod. Phys. Lett. B
Volume 36 Issue 09 Pages 2250025
Keywords Time-dependent coupled harmonic oscillator; Bohm potential; entangled states; two-mode squeezed states
Abstract We show that two-mode squeezed vacuum-like states may be engineered in the Bohm-Madelung formalism by adequately choosing the phase of the wave function. The difference between our wave function and the one of the squeezed vacuum states is given precisely by the phase we selected. We would like to stress that the engineering of two-mode vacuum states is possible due to the existence of the Bohm potential, and it is relevant because of its potential use in the propagation of optical fields, where it may render a variety of applications in optics. The approach to generate non-classical states, namely, two-mode squeezed states of a quantum mechanical system is one of the first applications of the Madelung-Bohm formalism.
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 0217-9849 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000782958100001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1572
Permanent link to this record
 

 
Author Asenjo, F.A.; Hojman, S.A.; Moya-Cessa, H.M.; Soto-Eguibar, F.
Title Supersymmetric relativistic quantum mechanics in time-domain Type
Year 2022 Publication Physics Letters A Abbreviated Journal Phys. Lett. A
Volume 450 Issue Pages 128371
Keywords Supersymmetry; Time-domain; Neutrino oscillation
Abstract A supersymmetric relativistic quantum theory in the temporal domain is developed for bi-spinor fields satisfying the Dirac equation. The simplest time-domain supersymmetric theory can be postulated for fields with time-dependent mass, showing an equivalence with the bosonic supersymmetric theory in time-domain. Solutions are presented and they are used to produce probability oscillations between mass states. As an application of this idea, we study the two-neutrino oscillation problem, showing that flavour state oscillations may emerge from the supersymmetry originated by the time-dependence of the unique mass of the neutrino.(c) 2022 Elsevier B.V. All rights reserved.
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 0375-9601 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000860777300004 Approved
Call Number UAI @ alexi.delcanto @ Serial 1643
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