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H. C. Rosu

Publications and source records attributed to H. C. Rosu.

At least 127 records · Page 7Linked to original sources
arXiv2001

Ermakov-Lewis angles for one-parameter supersymmetric families of Newtonian free damping modes

We apply the Ermakov-Lewis procedure to the one-parameter damped modes \tilde{y} recently introduced by Rosu and Reyes, which are related to the common Newtonian free damping modes y by the general Riccati solution [H.C. Rosu and M. Reyes, Phys. Rev. E 57, 4850 (1998), physics/9707019]. In particular, we calculate and plot the angle quantities of this approach that can help to distinguish these modes from the common y modes

physics.class-ph↗
arXiv2001

On first-order scaling intertwining in quantum mechanics

We generalize the standard first-order intertwining relationship of supersymmetric quantum mechanics in order to include simultaneous scaling transformations in both the original Hamiltonian and the intertwining operator. It is argued that in this way one can generate potentials with more interesting spectra than those obtained by means of the standard first-order intertwining technique and, as an outcome, a simple engineering procedure is presented. The harmonic oscillator potential is used in order to illustrate the previous statements. Moreover, a matrix representation of the scaled intertwining relationship is sketched up allowing for higher-dimensional generalizations in the case of separable potentials

quant-ph↗
arXiv2000

Strictly isospectral potentials from excited quantum states

The strictly nonrelativistic isospectral scheme based on the general Riccati solution and Darboux transformation function corresponding to excited states is presented on the following examples: the harmonic oscillator, the square well, and the hydrogen atom

quant-ph↗
arXiv2000

Darboux cosmological fluids in comoving time

The barotropic indices and the corresponding FRW scale factors of the so-called Darboux cosmological fluids are presented in the comoving time axis, which is the natural one for the phenomenology related to the cosmological data. Some useful comments on the features of the plots are included

gr-qc↗
arXiv2000

Classical Electrodynamics

Excerpts are presented from a graduate course on Classical Electrodynamics held during the spring semester of 2000 at the Institute of Physics, Guanajuato State University, Mexico

physics.ed-ph↗
arXiv2000

Elementary Quantum Mechanics

This is the first graduate course on elementary quantum mechanics in Internet written in Romanian for the benefit of Romanian speaking students (Romania and Moldova). It is a translation (with corrections) of the Spanish version of the course (physics/9808031, English translation physics/0004072), which I did at the request of students of physics in Bucharest. The topics included refer to the postulates of quantum mechanics, one-dimensional barriers and wells, angular momentum and spin, WKB method, harmonic oscillator, hydrogen atom, quantum scattering, and partial waves

physics.ed-ph↗
arXiv2000

Elementary Nonrelativistic Quantum Mechanics

This is a graduate course on elementary quantum mechanics written for the benefit of undergraduate and graduate students. It is the English version of physics/0003106, which I did at the suggestion of several students from different countries. The topics included refer to the postulates of quantum mechanics, one-dimensional barriers and wells, angular momentum and spin, WKB method, harmonic oscillator, hydrogen atom, quantum scattering, and partial waves

physics.ed-ph↗
arXiv2000

Multiple parameter structure of Mielnik's isospectrality in unbroken SUSYQM

Within unbroken SUSYQM and for zero factorization energy, I present an iterative generalization of Mielnik's isospectral method by employing a Schroedinger true zero mode in the first-step general Riccati solution and imposing the physical condition of normalization at each iterative step. This procedure leads to a well-defined multiple-parameter structure within Mielnik's construction for both zero modes and potentials

quant-ph↗
arXiv2000

Ermakov approach for Q=0 empty FRW minisuperspace oscillators

The Wheeler-DeWitt equation for empty FRW minisuperspace universes of Hartle-Hawking factor ordering parameter Q=0 is mapped onto the dynamics of a unit mass classical oscillator. The latter is studied by the classical Ermakov invariant method. Angle quantities are presented in the same context

gr-qc↗
arXiv2000

Relativistic quantum field inertia and vacuum field noise spectra

The main theme of this survey is the equivalence statements for quantum scalar field vacuum states that have been recognized over the last couple of decades as a powerful line of reasoning when discussing the highly academic thermal-like Hawking effect and Unruh effect. An important ingredient in this framework is the concept of vacuum field noise spectrum by which one can obtain information about the curvature invariants of classical worldlines (relativistic classical trajectories). It is argued, in the spirit of the free fall type universality, that the preferred quantum field vacua with respect to accelerated worldlines should be chosen in the class of all those possessing stationary spectra for their quantum fluctuations. For scalar quantum field vacua there are six stationary cases as shown by Letaw some time ago, these are reviewed here. However, the non-stationary vacuum noises are not out of reach and can be processed by a few mathematical methods that are mentioned as well. Since the information about the kinematical curvature invariants of the worldlines is of radiometric origin, hints are given on a more useful application of such an academic formalism to radiation and beam radiometric standards at high energy accelerators and in astrophysics. The survey ends up with a quick look to related axiomatic quantum field topics and a few other recent works

gr-qc↗
arXiv1999

Stationary and nonstationary scalar vacuum field noises

If stationary, the spectrum of vacuum field noise (VFN) is an important ingredient to get information about the curvature invariants of classical worldlines (relativistic classical trajectories). For scalar quantum field vacua there are six stationary cases as shown by Letaw some time ago, these are reviewed here. However, the non-stationary vacuum noises are not out of reach and can be processed by a few mathematical methods which I briefly comment on. Since the information about the kinematical curvature invariants of the worldlines is of radiometric origin, hints are given on a more useful application to radiation and beam radiometric standards at relativistic energies

gr-qc↗
arXiv1999

Hydrogen atom as an eigenvalue problem in 3D spaces of constant curvature and minimal length

An old result of A.F. Stevenson [Phys. Rev.} 59, 842 (1941)] concerning the Kepler-Coulomb quantum problem on the three-dimensional (3D) hypersphere is considered from the perspective of the radial Schrödinger equations on 3D spaces of any (either positive, zero or negative) constant curvature. Further to Stevenson, we show in detail how to get the hypergeometric wavefunction for the hydrogen atom case. Finally, we make a comparison between the ``space curvature" effects and minimal length effects for the hydrogen spectrum

quant-ph↗
arXiv1999

q deformation by intertwining with application to the singular oscillator

We present a version of q-deformed calculus based on deformed counterparts of Darboux intertwining operators. The case in which the deformed transformation function is of the vacuum type is detailed, but the extension to counterparts of excited states used as Darboux transformation functions is also formally discussed. The method leads to second-order Fokker-Planck-like deformed operators which may be considered as supersymmetric partners, though for a sort of q-deformed open systems, i.e., those possessing q nonlocal drift terms, potential part, as well as q-spreaded vacuum fluctuations. The undeformed limit corresponds to the conservative case, since all q nonlocalities wash out. The procedure is applied to the x^{-2} singular oscillator, for which we also present a formal q generalization of the Bagrov-Samsonov coherent states

quant-ph↗
arXiv1999

Ermakov approach for minisuperspace oscillators

The WDW equation of arbitrary Hartle-Hawking factor ordering for several minisuperspace universe models, such as the pure gravity FRW and Taub ones, is mapped onto the dynamics of corresponding classical oscillators. The latter ones are studied by the classical Ermakov invariant method, which is a natural aproach in this context. For the more realistic case of a minimally coupled massive scalar field, one can study, within the same type of approach, the corresponding squeezing features as a possible means of describing cosmological evolution. Finally, we comment on the analogy with the accelerator physics

gr-qc↗
arXiv1999

Blind spot may reveal vacuum radiation

This is a Physics World features paper on Chen-Tajima proposal to detect Unruh radiation by means of high-intensity lasers (PRL 83, 256 (1999)).

physics.pop-ph↗