Study of transport of laser-driven relativistic electrons in solid materials

With the ultra intense lasers available today, it is possible to generate very hot electron beams in solid density materials. These intense laser-matter interactions result in many applications which include the generation of ultrashort secondary sources of particles and radiation such as ions, neutrons, positrons, x-rays, or even laser-driven hadron therapy. For these applications to become reality, a comprehensive understanding of laser-driven energy transport including hot electron generation through the various mechanisms of ionization, and their subsequent transport in solid density media is required. This study will focus on the characterization of electron transport effects in solid density targets using the state-of- the-art particle-in-cell code PICLS. A number of simulation results will be presented on the topics of ionization propagation in insulator glass targets, non-equilibrium ionization mod- eling featuring electron impact ionization, and electron beam guiding by the self-generated resistive magnetic field. An empirically derived scaling relation for the resistive magnetic in terms of the laser parameters and material properties is presented and used to derive a guiding condition. This condition may prove useful for the design of future laser-matter interaction experiments

Emergent gravity: the analogue models perspective

This thesis is devoted to the study of some aspects of emergent gravity scenarios, i.e. of non-gravitational systems which exhibit, under suitable conditions, the emergence of effective spacetime metrics and the associated gravitational dynamics. While this area of research is rather broad, we will assume a particular perspective: the starting point is the discussion of analogue models for gravity, which have so far provided precious insights on aspects of physics on curved spacetimes, on extensions of Riemannian geometry and on the possible role of high energy Lorentz symmetry violations in low energy physics....

Like Thermodynamics before Boltzmann. On the Emergence of Einstein’s Distinction between Constructive and Principle Theories

In a 1919 article for the Times of London, Einstein declared the relativity theory to be a ‘principle theory,’ like thermodynamics, rather than a ‘constructive theory,’ like the kinetic theory of gases. The present paper attempts to trace back the prehistory of this famous distinction through a systematic overview of Einstein’s repeated use of the relativity theory/thermodynamics analysis after 1905. Einstein initially used the comparison to address a specific objection. In his 1905 relativity paper he had determined the velocity-dependence of the electron’s mass by adapting Newton’s particle dynamics to the relativity principle. However, according to many, this result was not admissible without making some assumption about the structure of the electron. Einstein replied that the relativity theory is similar to thermodynamics. Unlike the usual physical theories, it does not directly try to construct models of specific physical systems; it provides empirically motivated and mathematically formulated criteria for the acceptability of such theories. New theories can be obtained by modifying existing theories valid in limiting case so that they comply with such criteria. Einstein progressively transformed this line of the defense into a positive heuristics. Instead of directly searching for new theories, it is often more effective to search for conditions which constraint the number of possible theories. The paper argues that the latter was the strategy that led Einstein to most of his major successes. The constructive/principle theories opposition should be considered not only as abstract classification of theories, but also as Einstein’s attempt to formulate a sort of ‘logic of discovery.’ The paper argues that most of Einstein’s scientific successes were obtained by following the principle strategy. Most of his failures happened when he was forced to fall back to the constructive strategy

Like Thermodynamics before Boltzmann. On the Emergence of Einstein’s Distinction between Constructive and Principle Theories

In a 1919 article for the Times of London, Einstein declared the relativity theory to be a ‘principle theory,’ like thermodynamics, rather than a ‘constructive theory,’ like the kinetic theory of gases. The present paper attempts to trace back the prehistory of this famous distinction through a systematic overview of Einstein’s repeated use of the relativity theory/thermodynamics analysis after 1905. Einstein initially used the comparison to address a specific objection. In his 1905 relativity paper he had determined the velocity-dependence of the electron’s mass by adapting Newton’s particle dynamics to the relativity principle. However, according to many, this result was not admissible without making some assumption about the structure of the electron. Einstein replied that the relativity theory is similar to thermodynamics. Unlike the usual physical theories, it does not directly try to construct models of specific physical systems; it provides empirically motivated and mathematically formulated criteria for the acceptability of such theories. New theories can be obtained by modifying existing theories valid in limiting case so that they comply with such criteria. Einstein progressively transformed this line of the defense into a positive heuristics. Instead of directly searching for new theories, it is often more effective to search for conditions which constraint the number of possible theories. The paper argues that the latter was the strategy that led Einstein to most of his major successes. The constructive/principle theories opposition should be considered not only as abstract classification of theories, but also as Einstein’s attempt to formulate a sort of ‘logic of discovery.’ The paper argues that most of Einstein’s scientific successes were obtained by following the principle strategy. Most of his failures happened when he was forced to fall back to the constructive strategy

Like Thermodynamics before Boltzmann. On the Emergence of Einstein’s Distinction between Constructive and Principle Theories

In a 1919 article for the Times of London, Einstein declared the relativity theory to be a ‘principle theory,’ like thermodynamics, rather than a ‘constructive theory,’ like the kinetic theory of gases. The present paper attempts to trace back the prehistory of this famous distinction through a systematic overview of Einstein’s repeated use of the relativity theory/thermodynamics analysis after 1905. Einstein initially used the comparison to address a specific objection. In his 1905 relativity paper he had determined the velocity-dependence of the electron’s mass by adapting Newton’s particle dynamics to the relativity principle. However, according to many, this result was not admissible without making some assumption about the structure of the electron. Einstein replied that the relativity theory is similar to thermodynamics. Unlike the usual physical theories, it does not directly try to construct models of specific physical systems; it provides empirically motivated and mathematically formulated criteria for the acceptability of such theories. New theories can be obtained by modifying existing theories valid in limiting case so that they comply with such criteria. Einstein progressively transformed this line of the defense into a positive heuristics. Instead of directly searching for new theories, it is often more effective to search for conditions which constraint the number of possible theories. The paper argues that the latter was the strategy that led Einstein to most of his major successes. The constructive/principle theories opposition should be considered not only as abstract classification of theories, but also as Einstein’s attempt to formulate a sort of ‘logic of discovery.’ The paper argues that most of Einstein’s scientific successes were obtained by following the principle strategy. Most of his failures happened when he was forced to fall back to the constructive strategy