Strong coupling expansion Monte Carlo

We give an overview on recently accomplished successful generalizations of `worm' or loop gas simulation methods to O(N) and CP(N-1) sigma models and to simple fermion models. Beside the advantage of (practically) eliminated critical slowing down we also explain additional opportunities to estimate some observables with extremely improved signal to noise levels.Comment: Contribution to the proceedings of Lattice 2010, Sardinia, 14 pages, 7 figure

MC simulations of O(2)ϕ4O(2)\phi^4 theory in three dimensions with worm algorithm

We study the critical region of the $O(2)\,\phi^4$ theory by means of Monte Carlo simulations on the lattice. In particular we determine the ratio $\Delta\langle\phi^2\rangle_c/g$ in order to estimate the first correction to the critical temperature of a weak interacting Bose gas

Quantum dynamics and universality far from equilibrium

The aim of the present thesis is to contribute to a better understanding of the nonequilibrium dynamics of isolated many-body quantum systems, and to develop new theoretical methods for their description. Important questions that will be addressed here concern the emergence of universal behavior far from equilibrium as well as the role of genuine quantum effects on the dynamics. In the first part, we study the far-from-equilibrium universal dynamics of relativistic and nonrelativistic quantum field theories close to a nonthermal fixed point. In this regime, the dynamics is characterized by self-similar scaling and transport of conserved quantities. Using classical-statistical simulations we compute the scaling functions and scaling exponents of different equal-time and unequal-time correlation functions, including statistical as well as spectral components. This analysis is complemented by analytical estimates using a resummed kinetic theory based on a nonperturbative 1/N expansion of the two-particle irreducible (2PI) effective action. Our results shed light on the process of condensate formation, the transport of particles at low momenta, as well as the spectrum of excitations. In the second part, we theoretically and experimentally investigate the relaxation dynamics of an XY dipolar-interacting quantum spin model in an external field, which is realized with ultracold Rydberg atoms. Starting from a fully magnetized initial state, we suddenly switch on the external field and study the subsequent demagnetization dynamics. To disentangle the processes responsible for the relaxation in a closed system, we employ a well-defined hierarchy of theoretical approximations. Our analysis reveals the role of disorder and quantum fluctuations in the dynamics. In the last part, we investigate possible extensions of the classical-statistical or truncated Wigner approximation (TWA) to include quantum effects. Corrections to TWA are added by applying the sampling over initial conditions to a larger set of variables and equations of motion to solve. We consider two different approaches. In the first one, we benchmark a scheme based on BBGKY-type equations by comparing to exact solutions of a spin-boson model relevant for trapped-ion experiments. In the second one, we use 2PI equations instead and compare to exact numerical results of an anharmonic oscillator. Furthermore, we test the potential of the method to capture essential aspects needed for quantum thermalization in a relativistic scalar field theory. Our findings indicate that these methods may be capable of describing thermalization in quantum systems in which both classical fluctuations and genuine quantum effects are important

Advances in Optimization and Nonlinear Analysis

The present book focuses on that part of calculus of variations, optimization, nonlinear analysis and related applications which combines tools and methods from partial differential equations with geometrical techniques. More precisely, this work is devoted to nonlinear problems coming from different areas, with particular reference to those introducing new techniques capable of solving a wide range of problems. The book is a valuable guide for researchers, engineers and students in the field of mathematics, operations research, optimal control science, artificial intelligence, management science and economics

The Fifteenth Marcel Grossmann Meeting

The three volumes of the proceedings of MG15 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 40 morning plenary talks over 6 days, 5 evening popular talks and nearly 100 parallel sessions on 71 topics spread over 4 afternoons. These proceedings are a representative sample of the very many oral and poster presentations made at the meeting.Part A contains plenary and review articles and the contributions from some parallel sessions, while Parts B and C consist of those from the remaining parallel sessions. The contents range from the mathematical foundations of classical and quantum gravitational theories including recent developments in string theory, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics, including topics such as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star, pulsar and white dwarf astrophysics. Parallel sessions touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, white dwarfs, binary systems, radiative transfer, accretion disks, quasars, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, cosmic rays and the history of general relativity

The contemporary visualization and modelling technologies and the techniques for the design of the green roofs

The contemporary design solutions are merging the boundaries between real and virtual world. The Landscape architecture like the other interdisciplinary field stepped in a contemporary technologies area focused on that, beside the good execution of works, designer solutions has to be more realistic and “touchable”. The opportunities provided by Virtual Reality are certainly not negligible, it is common knowledge that the designs in the world are already presented in this way so the Virtual Reality increasingly used. Following the example of the application of virtual reality in landscape architecture, this paper deals with proposals for the use of virtual reality in landscape architecture so that designers, clients and users would have a virtual sense of scope e.g. rooftop garden, urban areas, parks, roads, etc. It is a programming language that creates a series of images creating a whole, so certain parts can be controlled or even modified in VR. Virtual reality today requires a specific gadget, such as Occulus, HTC Vive, Samsung Gear VR and similar. The aim of this paper is to acquire new theoretical and practical knowledge in the interdisciplinary field of virtual reality, the ability to display using virtual reality methods, and to present through a brief overview the plant species used in the design and construction of an intensive roof garden in a Mediterranean climate, the basic characteristics of roofing gardens as well as the benefits they carry. Virtual and augmented reality as technology is a very powerful tool for landscape architects, when modeling roof gardens, parks, and urban areas. One of the most popular technologies used by landscape architects is Google Tilt Brush, which enables fast modeling. The Google Tilt Brush VR app allows modeling in three-dimensional virtual space using a palette to work with the use of a three dimensional brush. The terms of two "programmed" realities - virtual reality and augmented reality - are often confused. One thing they have in common, though, is VRML - Virtual Reality Modeling Language. In this paper are shown the ways on which this issue can be solved and by the way, get closer the term of Virtual Reality (VR), also all the opportunities which the Virtual reality offered us. As well, in this paper are shown the conditions of Mediterranean climate, the conceptual solution and the plant species which will be used by execution of intensive green roof on the motel “Marković”