Introduction to Phenomenology

Aspects of Quantum Field Theory in Curved Space-Time: Quantization of a static, scalar field theory

The microscopic quantum field theory origins of warm inflation dynamics are reviewed. The warm inflation scenario is first described along with its results, predictions and comparison with the standard cold inflation scenario. The basics of thermal field theory required in the study of warm inflation are discussed. Quantum field theory real time calculations at finite temperature are then presented and the derivation of dissipation and stochastic fluctuations are shown from a general perspective. Specific results are given of dissipation coefficients for a variety of quantum field theory interaction structures relevant to warm inflation, in a form that can be readily used by model builders. Different particle physics models realizing warm inflation are presented along with their observational predictions.

https://iopscience.iop.org/article/10.1088/0034-4885/72/2/026901/pdf

Warm Inflation and its Microphysical Basis

Warm inflation in the adiabatic regime — a model, an existence proof for inflationary dynamics in quantum field theory

The microscopic quantum field theory origins of warm inflation dynamics are reviewed. The warm inflation scenario is first described along with its results, predictions and comparison with the standard cold inflation scenario. The basics of thermal field theory required in the study of warm inflation are discussed. Quantum field theory real time calculations at finite temperature are then presented and the derivation of dissipation and stochastic fluctuations are shown from a general perspective. Specific results are given of dissipation coefficients for a variety of quantum field theory interaction structures relevant to warm inflation, in a form that can readily be used by model builders. Different particle physics models realising warm inflation are presented along with their observational predictions.

We present a simple and thermodynamically consistent cosmology with a phenomenological model of quantum creation of radiation due to vacuum decay. Thermodynamics and Einstein's equations lead to an equation in which H is determined by the particle number N. The model is completed by specifying the particle creation rate , which leads to a second-order evolution equation for H. We propose a simple that is naturally defined and that conforms to the thermodynamical conditions: (i) the entropy production rate starts at a maximum; (ii) the initial vacuum (for radiation) is a non-singular regular vacuum and (iii) the creation rate is initially higher than the expansion rate H, but then falls below H. The evolution equation for H then has a remarkably simple exact solution, in which a non-adiabatic inflationary era exits smoothly to the radiation era, without a reheating transition. For this solution, we give exact expressions for the cosmic scale factor, energy density of radiation and vacuum, temperature, entropy and super-horizon scalar perturbations.

https://iopscience.iop.org/article/10.1088/0264-9381/15/4/014/pdf

Inflationary cosmology and thermodynamics

The Klein-Gordon equation is interpreted in the de Broglie-Bohm manner as a single-particle relativistic quantum mechanical equation that defines unique time-like particle trajectories The particle trajectories are determined by the conserved flow of the intrinsic energy density, which can be derived from the specification of the Klein-Gordon energy-momentum tensor in an Einstein-Riemann space The approach is illustrated by application to the simple single-particle phenomena associated with square potentials

https://iopscience.iop.org/article/10.1088/0305-4470/33/41/306/pdf

Time-like flows of energy momentum and particle trajectories for the Klein-Gordon equation

Light from the East: Theology, science and Eastern Orthodox Tradition

In this book a new and distinctive approach to the science-religion debate emerges from a synthesis of the Eastern Orthodox Christian tradition with phenomenological thought. Developing ideas of Greek Patristics the author treats faith, with its sense of the Divine presence, and knowledge of the universe, as two modes of communion which constitute the human condition. The modern opposition between science and theology (which is historically paralleled with the Church's split between East and West, and monasticism and Christianity in the world), is treated as the split between two intentionalities of the overall human subjectivity. The human person, as a centre of their reconciliation, becomes the major theme of the dialogue between science and theology. It is argued that the reconciliation of science and theology is not simply an academic exercise; it requires an existential change, a change of mind (metanoia), which cannot be effected without ecclesial involvement. Then the person who effectuates the mediation between science and theology is raised to the level of ""cosmic priesthood"" while the mediation acquires the features of a ""cosmic Eucharist"" in which all divisions and tensions in creation and humanity are removed. It is through this existential change accompanied by phenomenological analysis that scientific theories can be subjected to a certain ""vision"" through which the hidden ultimate goal (telos) of scientific research (as the explication of the human condition) shows its kinship to the saving telos advocated by Christian faith. The opposition between theology and science is thus being para-eucharistically overcome.

The Universe as Communion: Towards a Neo-Patristic Synthesis of Theology and Science

The paper discusses the problem of demarcation between the dimensions of natural and the human sciences in contemporary cosmology. In spite of a common presumption that cosmology is a natural science, the specificity of its alleged subject matter, that is the universe as a whole, makes cosmology fundamentally different from other natural sciences. The reason is that in cosmology the subject of cosmological research and its "object" are in a certain sense inseparable. Any study of the universe involves two opposite perspectives which can be described as "a-cosmic" and "cosmic", egocentric and non-egocentric. Cosmology involves two languages, namely that of physical causality (pertaining to the natural sciences) and that of intentionality (pertaining to the human sciences). On the one hand the universe can be seen as a product of discursive reason, that is as an abstract "physical" entity unfolding in space and time. On the other hand the universe can be experienced through our participation in, or communion with the world understood as the natural context of living beings. This dichotomy between reason and experience, abstract construction and concrete participation, originates in the essence of human persons understood as unities of the corporeal and spiritual. On account of this dichotomy it is hard to set up a strict line of demarcation between the elements of the human and the natural sciences in cosmology. This confirms the intuition that any realistic world view is incomplete without a knowledge of what it means to exist as a human being. Conversely it is likewise impossible to understand human existence without considering its natural setting, that is the universe. We conclude that anthropology is incomplete without cosmology and vice versa.

Alexei V. Nesteruk

Papers

Inflationary cosmology and thermodynamics

Time-like flows of energy momentum and particle trajectories for the Klein-Gordon equation

Light from the East: Theology, science and Eastern Orthodox Tradition

The Universe as Communion: Towards a Neo-Patristic Synthesis of Theology and Science

Cosmology at the Crossroads of the Natural and Human Sciences: is demarcation possible?