Equations of motion in Double Field Theory: from classical particles to quantum cosmology (original) (raw)

Equations of motion in double field theory: From particles to scale factors

Physical Review D, 2011

The equation of motion for a point particle in the background field of double field theory is considered. We find that the motion is described by a geodesic flow in the doubled geometry. Inspired by analysis on the particle motion, we propose a modified model of quantum string cosmology, which includes two scale factors. The report is based on Phys. Rev. D84 (2011D84 ( ) 124049 [arXiv:1108].

Point particle motion in double field theory and a singularity-free cosmological solution

Physical Review D

We generalize the action for point particle motion to a double field theory background. After deriving the general equations of motion for these particle geodesics, we specialize to the case of a cosmological background with vanishing antisymmetric tensor field. We then show that the geodesics can be extended to infinity in both time directions once we define the appropriate physical clock. Following this prescription, we also show the existence of a singularity-free cosmological solution.

A Brief Introduction to Double Field Theory

String theory proposes that elementary particles are string-like one-dimensional objects instead of point particles as in the Standard Model of particle physics. A distinct characteristic of such an object is that a string can wrap around in non-contractible cycles. This wrapping introduces winding state which has no counterpart in point particle field theories. The presence of winding state together with momentum leads to T-duality representing a physical equivalence of string theories of different formulations.

Canonical formulation and conserved charges of double field theory

Journal of High Energy Physics

We provide the canonical formulation of double field theory. It is shown that this dynamics is subject to primary and secondary constraints. The Poisson bracket algebra of secondary constraints is shown to close on-shell according to the C-bracket. A systematic way of writing boundary integrals in doubled geometry is given. By including appropriate boundary terms in the double field theory Hamiltonian, expressions for conserved energy and momentum of an asymptotically flat doubled space-time are obtained and applied to a number of solutions.

Quantum Field Theory II (Master of Physics Thesis)

This report is an attempt to develop and explore the principles underlying the venerable theory that is formulated through the amalgamation of special relativity and quantum theory known as quantum field theory, which is by far the most successful theory that provides the best description of the world as we know it. A thorough quantitative investigation of the canonical quantization approach has been taken into account, in particular with regard to scalar, Dirac and interacting field theories within a Minkowski space-time. The most profound consequences and subtleties upon quantization for the respective theories are delineated and discussed. In addition, we discuss an application for the machinery that is implemented by field theories, in the context of the early universe. We study the history and development of the inflationary paradigm. Furthermore, we attempt to understand the link between elementary particle theory and cosmology, through the phenomenon of particle production by understanding the behaviour of an oscillating inflaton field within a non-expanding background.

Classical field-particle dynamics in space-time geometries

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2004

With the aid of a Fermi-Walker chart associated with an orthonormal frame attached to a timelike curve in space-time, a discussion is given of relativistic balance laws that may be used to construct models of massive particles with spin, electric charge and a magnetic moment, interacting with background electromagnetic fields and gravitation described by non-Riemannian geometries. A natural generalization to relativistic Cosserat media is immediate.

Equations of motion in the theory of relativistic vector fields

International Letters of Chemistry, Physics and Astronomy, Vol. 83, pp. 12-30, 2019

Within the framework of the theory of relativistic vector fields, the covariant expressions are presented for the equations of motion of the matter and the field. These expressions can be written either in terms of the field tensors, that is, the fields' strengths and solenoidal vectors, or in terms the four-potentials, that is, the fields' scalar and vector potentials. This state of things is due to the fact that the Lagrange function initially implied the complementarity of description in terms of the strengths and the field potentials. It is shown that the equation for the fields, obtained by taking the covariant derivative in the equation for the metric, has a deeper meaning than the ordinary equation of motion of the matter, found with the help of the principle of least action. In particular, the above-mentioned equation for the fields leads to the generalized Poynting theorem, and after integration over the volume it allows us to introduce for consideration the integral vector as a measure of the energy and the fields' energy fluxes, associated with a system of particles and fields.

The General-Covariant and Gauge-Invariant Theory of Quantum Particles in Classical Backgrounds

International Journal of Modern Physics D, 2003

A new approach to the concept of particles and their production in quantum field theory is developed. A local operator describing the current of particle density is constructed for scalar and spinor fields in arbitrary gravitational and electromagnetic backgrounds. This enables one to describe particles in a local, general-covariant and gauge-invariant way. However, the current depends on the choice of a 2-point function. There is a choice that leads to the local non-conservation of the current in a gravitational or an electromagnetic background, which describes local particle production consistent with the usual global description based on the Bogoliubov transformation. The most natural choice based on the Green function calculated using the Schwinger–DeWitt method leads to the local conservation of the current, provided that interactions with quantum fields are absent. Interactions with quantum fields lead to the local non-conservation of the current which describes local particle...