Modelos bidimensionales en gravedad cuántica de lazos (original) (raw)

Quantum Gravity popular science text.pdf

Any theory of quantum gravity must be able to explain simultaneously the behaviour of the particles giving rise to gravity in the grand unification epoch of our universe as well as the state of the universe during and following a period of spontaneous symmetry-breaking. i.e. to ask the question as to whether or not our universe will end up in a period of heat death or whether there will be another Big Crunch leading ultimately to another Big Bang. Other than this we know very little about the size and extent of our own universe; but this may be possible to predict in the future. This is a book all about the state of our understanding of the connections between and limitations of our best current theories of matter, energy and space and time. It details my own personal journey to find a newer and more sophisticated model of gravitation and so how, and if, it may be possible to unify gravity with the three other, fundamental forces of nature; electromagnetism and the strong and weak nuclear forces. I am a citizen scientist and, as such, a lot of what I say – far from being scrutinized and commented-upon by the scientific community – will in fact be passed over. But the model I propose is something I'm sure we've all though about once or twice in physics class, that it really is the same force keeping electrons in orbit around the nucleus of the atom they belong to as it is keeping the earth in orbit around the sun. In the course of the ensuing first chapters I will give you a brief summary of quantum mechanics as it's currently understood, as well as general relativity and a survey of quantum field theory. I will then attempt to establish the basis for my model within a context which allows for gravity to be incorporated into a classical field theory exhibiting both particle and wave-like characteristics in objects at different points of their trajectories through space, based exclusively on the transmission of gauge bosons (or, just 'bosons') between particles appearing and disappearing within the same, underlying field; the descriptions of these processes will occupy the majority of the rest of the book. I should like to point out at this point that all of the ideas herein are my own and that I'm currently not affiliated with any institution of higher education, a research council or private sector organisation whose focus is research in physics. This is a personal theory of mine that I've developed over the .past two and a half years; or seven or eight possibly if you count reading about physics in my spare time. This is something I've always wanted to know the answer to and I feel as though I've figured it out. Naturally there are some details which still need to be worked out, such as the problem of explaining gravitational waves within the context this theory, but I hope in the future they will be. In any case, it forms a more complete explanation of gravity than the current theories competing at the moment; it also challenges preconceived notion about electrons and their behaviour which is, I feel, from a conceptual standpoint, a valuable contribution to our understanding of nature and the laws governing it. In spite of having no graduate, or even undergraduate, qualifications in physics I felt that this exercise has merit and is worth defending, I've hence decided to use this idea as my doctoral thesis in the philosophy of physics.

Departamento de Física, Universidade Federal da Paraíba

2003

Abstract. Corrections to Newton’s gravitational law inspired by extra dimensional physics and by the exchange of light and massless elementary particles between the atoms of two macrobodies are considered. These corrections can be described by the potentials of Yukawa-type and by the power-type potentials with different powers. The strongest up to date constraints on the corrections to Newton’s gravitational law are reviewed following from the Eötvos- and Cavendish-type experiments and from the measurements of the Casimir and van der Waals force. We show that the recent measurements of the Casimir force gave the possibility to strengthen the previously known constraints on the constants of hypothetical interactions up to several thousand times in a wide interaction range. Further strengthening is expected in near future that makes Casimir force measurements a prospective test for the predictions of fundamental physical theories. 1.