FRONTIERS OF FUNDAMENTAL AND COMPUTATIONAL PHYSICS: 10th International Symposium

How Advancements in Science are Made
View Description Hide DescriptionHow advances in science are made, and how they may come to benefit mankind at large are complex issues. The discoveries that most influence the way we think about nature seldom can be anticipated, and frequently the applications for new technologies developed to probe a specific characteristic of nature are also seldom clear, even to the inventors of these technologies. One thing is most clear: Seldom are such advances made by individuals alone. Rather, they result from the progress of the scientific community; asking questions, developing new technologies to answer those questions, and sharing their results and their ideas with others. However, there are indeed research strategies that can substantially increase the probability of oneŠs making a discovery. Professor Osheroff will illustrate some of these strategies in the context of a number of well known discoveries, including the work he did as a graduate student, for which he shared the Nobel Prize for Physics in 1996.

Gravity and the Quantum: the World may not be what it seems
View Description Hide DescriptionWhenever one attempts to include the gravitational force in models of quantized elementary particles, a spooky kind of non‐locality appears to emerge, either because attempts to renormalize the theory tend to violate unitarity, or because attempts to understand quantum mechanics in terms of some deterministic underlying theory also appear to require some spooky non‐locality. In contrast, the only tested particle theory, the Standard Model, is perfectly local. Different from the Standard Model, Quantum Gravity suggests that physically independent degrees of freedom are denumerable. To get a different intuitive picture of what is going in, we take a new look at the role of black holes. It is suggested to reduce the local scale parameters to be locally unobservable, which would make it easier to understand the back reaction of Hawking radiation on the space‐time metric. New approaches to Quantum Mechanics appear to allow for an interpretation in terms of a local, deterministic model, to be combined with General Relativity.

What happens to linear properties as we move from the Klein‐Gordon equation to the sine‐Gordon equation
View Description Hide DescriptionIn this article the sets of solutions of the sine‐Gordon equation and its linearization the Klein‐Gordon equation are discussed and compared. It is shown that the set of solutions of the sine‐Gordon equation possesses a richer structure which partly disappears during linearization. Just like the solutions of the Klein‐Gordon equation satisfy the linear superposition principle, the solutions of the sine‐Gordon equation satisfy a nonlinear superposition principle.

Electromagnetic energy dispersion in a 5D universe
View Description Hide DescriptionElectromagnetism is analyzed in a 5D expanding universe. Compared to the usual 4D description of electrodynamics it can be viewed as adding effective charge and current densities to the universe that are static in time. These lead to effective polarization and magnetization of the vacuum, which is most significant at high redshift. Electromagnetic waves propagate but group and phase velocities are dispersive. This introduces a new energy scale to the cosmos. And as a result electromagnetic waves propagate with superluminal speeds but no energy is transmitted faster than the canonical speed of light c.

Physics of Ultra‐cold and Rydberg Plasmas
View Description Hide DescriptionHere we discuss collective processes and plasma effects that can be found in ultra‐cold matter. First, we consider the ultra‐cold atomic gas that can be produced in a magneto‐optical trap. Due to the existence of long‐range repulsive forces, new collective oscillation can take place, resembling sound waves but with a cut‐off frequency. We also examine new phenomena in Rydberg plasmas, resulting from laser ionization of the ultra‐cold gas. In these very low temperature plasmas a large amount of excited Rydberg states can exist, leading to a new dispersion relation for the electromagnetic waves. Enhanced magnetic field generation will also be considered. Finally, we discuss the collective properties of Bose Einstein condensates, showing a strong analogy with collective plasma processes. Two related examples are given as an illustration: Bogoliubov oscillations in the condensate, and two‐stream instabilities of counter‐streaming BECs.

Scattering of photons in a two fixed extreme Reissner‐Nordstrom black hole system
View Description Hide DescriptionWe study the scattering of light by two fixed extreme Reissner‐Nordstrom black holes. We identify the set of unstable periodic orbits of the fractal repeller that describes the chaotic escape dynamics of photons. The main quantities of chaos associated with the repeller are obtained from the analysis of the linear stability of these orbits. The escape rate obtained from the periodic orbit theory is compared with the one obtained from the evolution of statistical ensembles of photons. An analytic estimate of the escape rate in the proximity of a perturbed black hole is also provided.

First‐principles many‐body theory for ultra‐cold atoms
View Description Hide DescriptionRecent breakthroughs in the creation of ultra‐cold atoms in the laboratory have ushered in unprecedented changes in physical science. These enormous changes in the coldest temperatures available in the laboratory mean that many novel experiments are possible. There is unprecedented control and simplicity in these novel systems, meaning that quantum many‐body theory is now facing severe challenges in quantitatively understanding these new results. We discuss some of the new experiments and recently developed theoretical techniques required to predict the results obtained.

Alternative Routes to Gravitation
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Effectively model dynamics, deterministic and stochastic, across multiple space and time scales
View Description Hide DescriptionA persistent feature of complex systems in engineering and science is the emergence of macroscopic, large scale, coherent behaviour from the interactions between microscopic agents (molecules, cells, grains) and also with their environment. In current modelling the underlying microscopic mechanisms are often known, but the closures to translate microscale knowledge to a system level macroscopic description are rarely available in closed form. I overview a systematic dynamical approach to extract analytically compact, accurate, system level models of complex systems in physics and engineering. The methodology also supports transforming fine scale, microscopic, detailed descriptions of discrete dynamical systems across a multiscale hierarchy to a coarse system level discrete model. This approach illuminates the appearance of emergent dynamics in both deterministic and stochastic dynamics.

Dynamics of time correlation functions and stochastic quantum trajectories methods in Non‐Markovian systems
View Description Hide DescriptionOpen quantum systems are often encountered in many different physical situations. From quantum optics to statistical mechanics, they are fundamental in the understanding of a great variety of different phenomena. Some of the most common examples are the relaxation to equilibrium, the existence of nonequilibrium stationary states, and the dynamics of atoms in interaction with electromagnetic fields. A crucial step in the analysis is to consider the quantum open system and its environment as the two mutually interacting components of a larger isolated system. Thereafter, the so‐called Markov approximation is often considered, which consists on assuming that the time scales associated to the dynamics of the quantum open system are larger than those of the environment. It is the interplay of the different time scales associated with the system and the environment what determines the validity of the different approximations made. In this paper we will discuss the dynamics of a open quantum system in contact with a reservoir when the Markov approximation is not valid, and we have to include some non‐Markovian or memory effects.

Binocular Rivalry in Vision: Nucleation and Dynamics of Domain Walls
View Description Hide DescriptionThis work addresses percept switches in binocular rivalry caused by visual stimuli. We discuss binocular rivalry in 1D in the framework of the Wilson‐Blake‐Lee model. We show that the onset of oscillations shows critical behavior with a second order phase transition. We also address binocular rivalry in 2D, discuss some recent experimental results and ask the question, what can be learnt from comparison of such experiments with modeling predictions.

Dark Energy: fiction or reality?
View Description Hide DescriptionIs Dark Energy justified as an alternative to the cosmological constant Λ in order to explain the acceleration of the cosmic expansion? It turns out that a straightforward dimensional analysis of Einstein equation provides us with clear evidences that the geometrical nature of Λ is the only viable source to this phenomenon, in addition of the application of Ockham’s razor principle. This contribution is primarily a review of the main stream in the interpretation of Λ because it is at the origin of such a research program.

Categories and Physics
View Description Hide DescriptionAfter a very short introduction to categories and tensor categories, as well as some of their applications to physics, I present some contemporary approaches on quantum gravity, with corresponding categorical interpretations.

Causal structure of general relativistic spacetimes
View Description Hide DescriptionWe present some of the recent results and open questions on the causality problem in General Relativity. The concept of singularity is intimately connected with future trapped surface and inner event horizon formation. We offer a brief overview of the Hawking‐Penrose singularity theorems [1] and discuss a few open problems concerning the future Cauchy development (domain of dependence) [11], break‐down criteria and energy conditions for the horizon stability. A key question is whether causality violating regions, generating a Cauchy horizon are allowed.
We raise several questions concerning the invisibility and stability of closed trapped surfaces from future null infinity and derive the imprisonment conditions. We provide an up‐to‐date perspective of the causal boundaries and spacelike conformal boundary extensions for time oriented Lorentzian manifolds and more exotic settings.

Analyses of the 2dF Deep Field
View Description Hide DescriptionWe briefly discuss the observational motivation for and then present statistical analyses performed by a computer algorithm on the 2dF deep field. The results show that high redshift extragalactic objects can be and in many cases are physically associated with low redshift extragalactic objects and that consequently these high redshifts are at least partly intrinsic and therefore not entirely due to Doppler shift.

Predicted behaviour of a universe with a low photon‐baryon ratio
View Description Hide DescriptionA fundamental assumption inherent in the standard ΛCDM Hot Big Bang (HBB) model is that matter‐antimatter annihilations shortly after the birth of the universe give rise to a vast excess of photons over baryons. Alternative cosmological models imply a much lower photon‐baryon ratio, We examine some of the consequences of for a number of cosmological processes, within the framework of Machian General Relativity, in which photon energy is an invariant in the cosmological reference frame.

Does Electromagnetic Radiation Generate Entropy? The Carnot Cycle Revisited
View Description Hide DescriptionThe Thermodynamics of radiation is to be found in some textbooks which portray the entropy of radiation as where T and V, respectively are the temperature and volume of a cavity at equilibrium with the radiation. Poynting and Thomson (1911) go through the exercise of putting a “photon gas” through a Carnot Cycle,—the only book I have found to do so, but there is an error in their calculation. One purpose of this paper is to correct that mistake, and in extension, rigorously work through the Carnot Cycle because present day students and scientists wanting to study the Carnot Cycle are unlikely to find that textbook. Feynman also dealt with the Thermodynamics of radiation, but his approach is different from that of other authors. Although the Thermodynamics of radiation superficially appears to be self‐consistent, there are some queries, which need to be exposed. Firstly, the unit of entropy of radiation is Joule/K which is different from the usual unit of entropy, namely Joule/mole‐K. Secondly, entropy in matter relates to atoms and molecules exchanging energy endlessly and randomly, but this is not true for photons. Thirdly, it is possible to do practical experiments in order to estimate numerically the entropy of substances or entropy changes in reactions, but for radiation, are there any experiments which can produce numerical values for the entropy? The importance of this study is that some cosmologists state that, according to the Hot Big Bang Theory, the Universe expanded isentropically and that radiation went through this isentropic process. Objections are raised against this part of the theory.

Dynamic Phase Transitions In The Spin‐1/2 Metamagnetic Ising System Within The Effective‐Field Theory
View Description Hide DescriptionThe dynamic behavior of a spin‐1/2 metamagnetic Ising model on a honeycomb lattice under a time‐varying magnetic field is studied by using the effective‐field theory with correlations. The set of effective‐field dynamic equations is derived by employing the Glauber transition rates. The phases in the system are obtained by solving these dynamic equations. The thermal behavior of the dynamic staggered magnetization is investigated in order to characterize the nature (continuous or discontinuous) of the dynamic transitions and to obtain dynamic phase transition temperatures. The dynamic phase diagram are constructed in the plane. The phase diagram exhibits a dynamic tricritical behavior.

Microwave cavity search for paraphotons
View Description Hide DescriptionIn this proceeding we report the first results of a microwave cavity search for hidden sector photons. Using a pair of isolated resonant cavities we look for ‘light shining through a wall’ from photon—hidden sector photon oscillations. Our prototype experiment consists of two cylindrical, copper cavities stacked axially inside a single vacuum chamber. At a hidden sector photon mass of 39.58 μeV we place an upper limit on the kinetic mixing parameter χ at Whilst this result is inside already established limits our experiment has great scope for improvement.