Geometric Models of the Relativistic Harmonic Oscillator

A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1+1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.Comment: 8 pages, Late

Relativistic P\"oschl-Teller and Rosen-Morse problems

It is shown that the new family of geometric models of the relativistic oscillator, which generalize the anti-de Sitter model, leads to relativistic P\"oschl-Teller or Rosen-Morse problems.Comment: 7 pages, Late

Quasi-digital low-dropout voltage regulators uses controlled pass transistors

This article presents a low quiescent current output capacitorless quasi-digital CMOS LDO regulator with controlled pass transistors according to load demands. The pass transistor of the LDO is broken up to two smaller sizes based on a breakup criterion defined here, which considers the maximum output voltage variations to different load current steps to find the suitable current boundary for breaking up. This criterion shows that low load conditions will cause more output variations and settling time if the pass transistor is used in its maximum size. Therefore, using one smaller transistor for low load currents, and another one larger for higher currents, is the best trade-off between output variations, complexity, and power dissipation. The proposed LDO regulator has been designed and post-simulated in HSPICE in a 0.35 µm CMOS process to supply a load current between 0-100 mA while consumes 7.6 µA quiescent current. The results reveal 46% and 69% improvement on the output voltage variations and settling time, respectively.Postprint (published version

Geometric Models of the Quantum Relativistic Rotating Oscillator

A family of geometric models of quantum relativistic rotating oscillator is defined by using a set of one-parameter deformations of the static (3+1) de Sitter or anti-de Sitter metrics. It is shown that all these models lead to the usual isotropic harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is different. As in the case of the (1+1) models, these will have even countable energy spectra or mixed ones, with a finite discrete sequence and a continuous part. In addition, all these spectra, except that of the pure anti-de Sitter model, will have a fine-structure, given by a rotator-like term.Comment: 8 pages, Late

Recensions

Obra ressenyada: M. L. CASES; C. M. MARUGAN; M. I. RABASA, Descripció del marquesat de Pallars i del vescomtat de Vilamur per Onofre Timbau (1628). Lleida: Pagès, 200

Recensions

Index de l'obra ressenyada: Núria SALES, Tractà dels Pirineus, el Tractat dels Pirineus. Estudis d'Història Agrària, núm. 17 (2004