GIUV2013-130
One of the main themes of our project is the analytical and numerical study of the so-called Relativistic Positioning Systems (RPS). A collaborator of our group (B. Coll) proposed this research line a decade ago. We will study in depth topics such as bifurcation and minimisation of positioning errors, and in the longer term gravimetry. We will also try to study ¿ in its relativistic aspects¿ satellite navigation based on pulsar observation. The European Space Agency has repeatedly shown its interest in relativistic positioning by setting up working groups and organising conferences. We are also conducting the following studies within the framework of the theory of General Relativity (GR): (1) intrinsic characterisation of some physically significant solutions of Einstein¿s equations (spherically symmetric solutions, cosmological models, etc.) and of the gravitational radiation states (Bel-Robinson tensor), and (2) study of the concepts of total intrinsic linear 4-momentum and angular 4-momentum of the universe, and application to the characterisation of universes that could be created by quantum vacuum fluctuations. In addition, part of our team is working on the study of...One of the main themes of our project is the analytical and numerical study of the so-called Relativistic Positioning Systems (RPS). A collaborator of our group (B. Coll) proposed this research line a decade ago. We will study in depth topics such as bifurcation and minimisation of positioning errors, and in the longer term gravimetry. We will also try to study ¿ in its relativistic aspects¿ satellite navigation based on pulsar observation. The European Space Agency has repeatedly shown its interest in relativistic positioning by setting up working groups and organising conferences. We are also conducting the following studies within the framework of the theory of General Relativity (GR): (1) intrinsic characterisation of some physically significant solutions of Einstein¿s equations (spherically symmetric solutions, cosmological models, etc.) and of the gravitational radiation states (Bel-Robinson tensor), and (2) study of the concepts of total intrinsic linear 4-momentum and angular 4-momentum of the universe, and application to the characterisation of universes that could be created by quantum vacuum fluctuations. In addition, part of our team is working on the study of non-linear anisotropies of the cosmic microwave background using numerical simulations. Following this line, we intend to study the secondary Rees-Sciama, Sunyaev-Zel´dovich and lensing anisotropies and, above all, we are interested in the non-linear superposition of these effects to compare it with recent observational data obtained within the framework of the SPT (South Pole Telescope) and ACT (Atacama Cosmology Telescope) projects at very small angular scales. This topic requires complicated simulations that are being carried out in collaboration with the main researcher (H.M.P Couchman) and other members (R. Thacker) of the International Hydra Consortium for the development of numerical simulations of structure formation. In-house equipment and equipment from the UV Computing Centre are being used. Finally, the nature of dark energy is a current topic of debate in which we want to participate by trying to study different alternatives to vacuum energy or of a certain dynamical scalar field (quintessence). Among others, we intend to analyse possible explanations based on: (a) the energy associated with certain vector fields (vector-tensor theories), (b) inhomogeneous universes within the framework of GR, and (c) negative pressure associated with the gravitational interaction between certain structures populating the universe. We have always considered that theoretical developments and simulations complement each other when it comes to explaining observations and that, therefore, when working on gravitation, direct collaboration between theoretical researchers with a solid geometrical background and those with extensive experience in developing simulations is highly desirable. The composition of our group guarantees this collaboration, which has already yielded good results and which we are confident will continue to do so. Not all our work will be carried out within the framework of General Relativity, since some cosmological observations, such as anomalies in the angular spectrum of the microwave background and the luminosity-redshift relation of type Ia supernovae, suggest the existence of new fields in the framework of certain generalisations of Einstein's theory of gravitation (scalar-tensor, vector-tensor, tensor-tensor theories, etc.). These alternative theories are currently being seriously investigated and we join this trend with moderation. We also join the opposite trend, which tries to explain the so-called dark sector through application models of Einstein's theory, without additional fields. Until 2015, we were funded by the FIS2012-33582 project of MINECO.
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- Estudio teorico y numerico (simulaciones) de los Sistemas de Posicionamiento Relativista. Bifurcacion y errores de posicionamiento
- Caracterizacion intrinseca de familias de soluciones de las ecuaciones de Einstein que sean significativas desde el punto de vista fisico
- Definicion de 4-momento lineal y angular propios de un espacio-tiempo. Universos creables como fluctuaciones cuanticas del vacio
- Aplicacion de codigos HYDRA modificados al estudio de anisotropias no lineales del fondo de microondas (lente, Rees-Sciama y Sunyaev-Zel'dovich)
- Origen de la energia oscura: teorias vector-tensor, modelos inhomogeneos de universo y explicaciones basadas en la teoria estandar de la gravedad
- Vector-tensor theories of gravitation, dark energy and cosmological models.Study of cosmological models based on vector-tensor theories of gravitation with acceptable PPN parameters. Use of numerical codes CMBFAST, CAMB and COSMOMC, adapted to the new cosmologies, in order to estimate cosmological parameters and their compatibility with observational data.
- Dynamic interpretation of dark matter and dark energy.Study of the relation between the self-gravitating N-particle issue in general relativity and the dark matter and dark energy phenomena on galactic and cosmological scales.
- Relativistic positioning systems: theory and simulations.Analytical and numerical study of single and dual (bifurcation) positioning. Selection of the true position in the case of bifurcation, and choice of the four satellites in the constellation that lead to minimum positioning errors. Pulsar navigation within the solar system.
- Exact solutions of the Einstein equations: intrinsic characterization.Study of the symmetries and parameters that characterise different solutions of Einstein's equations from concomitants of the curvature tensor. Analysis of the concept of the intrinsic state of gravitational radiation from the invariant properties of the Bel-Robinson tensor.
- Intrinsic energy and intrinsic moments of a space-time. Universes which could be creatable.Search for the most general definition of linear and angular 4-momentum proper to the universe. Use of this definition to determine whether the different models of the universe used in technical literature to explain the observations can be created (as quantum vacuum fluctuations).
- Cosmic microwave background anisotropies: simulations and statistical analysis.Adaptation of parallel codes of the HYDRA Consortium, cosmological structure simulations, to apply them to the study of the Rees-Sciama, lensing and Sunyaev-Zel´dovich effects. Statistical analysis of the resulting maps and comparison of the results with observational data.
| Name | Nature of participation | Entity | Description |
|---|---|---|---|
| JOAN JOSEP FERRANDO BARGUES | Director | Universitat de València | |
| Research team | |||
| JUAN ANTONIO MORALES LLADOSA | Member | Universitat de València | |
| JUAN ANTONIO SAEZ MORENO | Member | Universitat de València | |
| BARTOLOME COLL DURAN | Collaborator | Universitat de València - Estudi General | UVEG honorary professor |
| MARIUS FULLANA ALFONSO | Collaborator | Universitat Politècnica de València | full university school professor |
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- Teorias alternativas de la gravitación; energía oscura; modelo concordante; parámetros cosmológicos; CMBFAST; CAMB; COSMOMC
- Relatividad general; materia oscura; energía oscura
- Sistemas de satélites para la navegación (GPS, GALILEO); posicionamiento relativista; navegación con púlsares; simulaciones numéricas
- Soluciones exactas; caracterización intrínseca; campos de radiación gravitatoria; tensor de Bel-Robinson
- Pseudotensores de energía impulso; coordenadas de Gauss; energía y momentos intrínsecos del universo; fluctuaciones cuánticas y creación del universo
- Fondo cósmico de microondas; anisotropías no lineales; simulaciones numéricas; mapas de temperatura y polarización; espectro angular y correlaciones
