Waves, analytical signals, and some postulates of quantum theory

In this paper we apply the formalism of the analytical signal theory to the Schrödinger wavefunction. Making use exclusively of the wave-particle duality and the rinciple of relativistic covariance, we actually derive the form of the quantum energy and momentum operators for a single nonrelativistic particle. Without using any more quantum postulates, and employing the formalism of the characteristic function, we also derive the quantum-mechanical prescription for the measurement probability in such cases.

A Fluctuation-Dissipation Model for Electrical Noise

This paper shows that today’s modelling of electrical noise as coming from noisy resistances is a non sense one contradicting their nature as systems bearing an electrical noise. We present a new model for electrical noise that including Johnson and Nyquist work also agrees with the Quantum Mechanical description of noisy systems done by Callen and Welton, where electrical energy fluctuates and is dissipated with time. By the two currents the Admittance function links in frequency domain with their common voltage, this new model shows the connection Cause-Effect that exists between Fluctuation and Dissipation of energy in time domain. In spite of its radical departure from today’s belief on electrical noise in resistors, this Complex model for electrical noise is obtained from Nyquist result by basic concepts of Circuit Theory and Thermo- dynamics that also apply to capacitors and inductors.

Cálculo y diseño de los principales equipos eléctricos de la isla de potencia de una central de ciclo combinado

El objetivo de este proyecto se centra en la definición, diseño y cálculo de las principales instalaciones eléctricas de la isla de generación, típicas de una central de ciclo combinado en configuración mono-eje. Se procederá a la definición de la arquitectura del sistema de distribución eléctrica de la planta definiendo los equipos eléctricos necesarios para la alimentación y protección de los servicios auxiliares de la isla de potencia y estableciendo una filosofía basada en la optimización del dimensionamiento de los distintos componentes del sistema. El diseño de los componentes eléctricos de la planta se hará en base a los más estrictos estándares internacionales con los que se garantiza el cumplimiento de las condiciones de seguridad, tanto de las personas como la de los propios equipos, fiabilidad y funcionalidad. El siguiente paso consistirá en adaptar los equipos definidos a los existentes en el mercado y así, evitar los sobrecostes que conlleva la adquisición de equipos no estandarizados en el mercado. Abstract The main objective of the project is the definition, analysis and sizing of the main components of the electrical system of a combined cycle power plant. This includes generation, auxiliary services and emergency systems. The design is intended to meet the International Electrotechnical Commission´s standards. These will ensure the adequate and safe operation, taking into account all operation conditions of the plant and the mechanical calculation of the thermal balance by the sizing of main mechanical equipment. An acceptable level of safety and health of workers and equipment is a mandatory requirement. The final results obtained are equipment that are able to achieve the highest level of protection for workers, assets and environment.

Calculation Methodology and Fabrication Procedures for Particle Accelerator Strip-Line Kickers: Application to the CTF3 Combiner Ring Extraction Kicker and TL2 Tail Clippers

A particle accelerator is any device that, using electromagnetic fields, is able to communicate energy to charged particles (typically electrons or ionized atoms), accelerating and/or energizing them up to the required level for its purpose. The applications of particle accelerators are countless, beginning in a common TV CRT, passing through medical X-ray devices, and ending in large ion colliders utilized to find the smallest details of the matter. Among the other engineering applications, the ion implantation devices to obtain better semiconductors and materials of amazing properties are included. Materials supporting irradiation for future nuclear fusion plants are also benefited from particle accelerators. There are many devices in a particle accelerator required for its correct operation. The most important are the particle sources, the guiding, focalizing and correcting magnets, the radiofrequency accelerating cavities, the fast deflection devices, the beam diagnostic mechanisms and the particle detectors. Most of the fast particle deflection devices have been built historically by using copper coils and ferrite cores which could effectuate a relatively fast magnetic deflection, but needed large voltages and currents to counteract the high coil inductance in a response in the microseconds range. Various beam stability considerations and the new range of energies and sizes of present time accelerators and their rings require new devices featuring an improved wakefield behaviour and faster response (in the nanoseconds range). This can only be achieved by an electromagnetic deflection device based on a transmission line. The electromagnetic deflection device (strip-line kicker) produces a transverse displacement on the particle beam travelling close to the speed of light, in order to extract the particles to another experiment or to inject them into a different accelerator. The deflection is carried out by the means of two short, opposite phase pulses. The diversion of the particles is exerted by the integrated Lorentz force of the electromagnetic field travelling along the kicker. This Thesis deals with a detailed calculation, manufacturing and test methodology for strip-line kicker devices. The methodology is then applied to two real cases which are fully designed, built, tested and finally installed in the CTF3 accelerator facility at CERN (Geneva). Analytical and numerical calculations, both in 2D and 3D, are detailed starting from the basic specifications in order to obtain a conceptual design. Time domain and frequency domain calculations are developed in the process using different FDM and FEM codes. The following concepts among others are analyzed: scattering parameters, resonating high order modes, the wakefields, etc. Several contributions are presented in the calculation process dealing specifically with strip-line kicker devices fed by electromagnetic pulses. Materials and components typically used for the fabrication of these devices are analyzed in the manufacturing section. Mechanical supports and connexions of electrodes are also detailed, presenting some interesting contributions on these concepts. The electromagnetic and vacuum tests are then analyzed. These tests are required to ensure that the manufactured devices fulfil the specifications. Finally, and only from the analytical point of view, the strip-line kickers are studied together with a pulsed power supply based on solid state power switches (MOSFETs). The solid state technology applied to pulsed power supplies is introduced and several circuit topologies are modelled and simulated to obtain fast and good flat-top pulses.

Rotation-Induced Breakdown of Torsional Quantum Control

Control of the torsional angles of nonrigid molecules is key for the development of emerging areas like molecular electronics and nanotechnology. Based on a rigorous calculation of the rotation-torsion-Stark energy levels of nonrigid biphenyl-like molecules, we show that, unlike previously believed, instantaneous rotation-torsion-Stark eigenstates of such molecules, interacting with a strong laser field, present a large degree of delocalization in the torsional coordinate even for the lowest energy states. This is due to a strong coupling between overall rotation and torsion leading to a breakdown of the torsional alignment. Thus, adiabatic control of changes on the planarity of this kind of molecule is essentially impossible unless the temperature is on the order of a few Kelvin.

Teaching and evaluating mechanical vibrations with Matlab®

The study of the response of mechanical systems to external excitations, even in the simplest cases, involves solving second-order ordinary differential equations or systems thereof. Finding the natural frequencies of a system and understanding the effect of variations of the excitation frequencies on the response of the system are essential when designing mechanisms [1] and structures [2]. However, faced with the mathematical complexity of the problem, students tend to focus on the mathematical resolution rather than on the interpretation of the results. To overcome this difficulty, once the general theoretical problem and its solution through the state space [3] have been presented, Matlab®[4] and Simulink®[5] are used to simulate specific situations. Without them, the discussion of the effect of slight variations in input variables on the outcome of the model becomes burdensome due to the excessive calculation time required. Conversely, with the help of those simulation tools, students can easily reach practical conclusions and their evaluation can be based on their interpretation of results and not on their mathematical skills

Comparing the Luttinger–Kohn–Pikus–Bir and the Empiric K·P Hamiltonians in quantum dot intermediate band solar cells manufactured in zincblende semiconductors

The calculation of the energy spectrum and absorption coefficients of quantum dot nanostructured intermediate band solar cells using the Empiric K·P Hamiltonian method and its agreement with experimental data are summarized. The well established Luttinger Kohn Hamiltonian modified by Pikus and Bir for strained material, such as quantum dot arrays, is presented using a simplified strain field that allows for square band offsets. The energy spectrum and absorption coefficients are calculated with this new Hamiltonian. With the approximations made the energy spectrum results to be exactly the same but the absorption coefficient fits experiments less accurately. The computer time using the latter Hamiltonian is much longer than the former one.