Research Jan Naudts

Abstract

This is research about fundamental problems in the statistical physics of small systems. Can one define temperature for isolated clusters existing of a few atoms? Are they stable? Should one not replace the classical treatment by a quantum mechanical one? What are the consequences of the (anti-)symmetrisation of the wavefunctions? Starting from a microcanonical description of model systems we try to answer these questions and to give a fundamental explanation of certain experimental results.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Verhulst Tobias

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• Research Project

Abstract

The generalised exponential family is studied and new examples are searched for in the domain of statistical physics. Special attention is paid to the configurational probability distribution in th emicrocanonical ensemble. The question is studied whether this new point of view can lead to a more satisfactory definition of the quantum microcanonical ensemble.

Researcher(s)

• Promoter: Naudts Jan

Research team(s)

Project type(s)

• Research Project

Abstract

This is research about fundamental problems in the statistical physics of small systems. Can one define temperature for isolated clusters existing of a few atoms? Are they stable? Should one not replace the classical treatment by a quantum mechanical one? What are the consequences of the (anti-)symmetrisation of the wavefunctions? Starting from a microcanonical description of model systems we try to answer these questions and to give a fundamental explanation of certain experimental results.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Verhulst Tobias

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• Research Project

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: Van der Straeten Erik

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• Research Project

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: Verhulst Tobias

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• Research Project

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: Van der Straeten Erik

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• Research Project

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: De Roeck Wojciech

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This project is a continuation of an ongoing collaboration between a research group at the Politechnika Gdanska and one at the University of Antwerp. These groups have worked in the past years in the areas of integrable systems and of quantum mechanics and quantum field theory. These topics are coming together in the present project, which focuses on those aspects of integrable systems that are directly connected with issues of field quantization.Aim of the project is to apply soliton techniques in the context of quantum field theory. Three different approaches will be developed simultaneously. The first approach starts from the experimental observation of acoustic solitons in crystals. Quantum lattice models will be used to model the experimental situation. A second approach starts from available expertise with Darboux techniques and explores their generalization in a systematic manner. Finally, a correlation function approach will be used in an attempt to transform the nonlinear operator equations of quantum electrodynamics into ordinary nonlinear equations. The three approaches hopefully converge into a better understanding of the concept of quantum soliton.

Researcher(s)

• Promoter: Naudts Jan

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: Czachor Marek

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Researcher(s)

• Promoter: Naudts Jan
• Co-promoter: Malfliet Willy

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Researcher(s)

• Promoter: Naudts Jan
• Fellow: De Roeck Wojciech

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Researcher(s)

• Promoter: Naudts Jan

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The aim is to arrive at a physically correct description of space-time in the context of the C*-algebraic formalism of quantum mechanics. The existing construction of the CCR algebra has been generalized with the intention to extend the model of Doplicher et al. The study of this generalized CCR-algebra will be continued.

Researcher(s)

• Promoter: Naudts Jan

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Abstract

The link between the nonlinear von Neumann equation and nonextensive thermodynamics is studied. We try to show that small perturbations of the equilibrium state are stable for this non-linear dynamics. For small perturbations of the dynamics a linear response theory is developed.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Kuna Maciej

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• Research Project

Abstract

New techniques, relevant for the development of medical work stations, are studied. A first technique concerns multi-modal user interfaces, with emphasis on the development of a generic architecture for simultaneous and combined use of multiple modes, including speech generation and recognition. Also, developments concerning the semantic web are evaluated. One expects that document oriented architectures using XML will have a big impact on the way of building medical work stations.

Researcher(s)

• Promoter: Naudts Jan

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• Research Project

Abstract

In a clinical workstation several applications are executed simultaneously. The present project studies the techniques used to integrate these applications into a cooperating entity. A weak form of integration of open applications is mixed at. A suitable architecture is presented. Several recent component technologies (Java Beans, DCOM, ...) are evaluated in this context. The project includes also the implementation of an experimental prototype which can be used to test alternatives under operational conditions.

Researcher(s)

• Promoter: Naudts Jan

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• Research Project

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The patient medical record will consist of multimedia documents. It is a virtual object with data storage distributed over hospitals and physician's cabinets. Images and reports about images form an essential part of the patient record. In this context the project aims at research in new technologies and paradigms. Experimental setups are realised in the hospitals AZ Middelheim and UZ Leuven, and a prototype system for medical diagnostics is developped by the company AGFA nv. The contribution of the UIA in this project concerns research in new technologies and the architecture of complex systems.

Researcher(s)

• Promoter: Naudts Jan

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The project studies and develops advanced planning and traffic engineering algorithms for broadband ISDN networks, both for the access network and the core ATM network. These algorithms are used to design the topology of the network, to define routing strategies and to dimension network resources. The traffic engineering part deals with buffer dimensioning,traffic management, routing and billing in ATM networks. Simple but accurate traffic engineering rules are used to plan the network.

Researcher(s)

• Promoter: Blondia Chris
• Co-promoter: Naudts Jan

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• Research Project

Abstract

The underlying idea behind this project is to use techniques and develop methods from stochastic and from mathematical analysis to model physical processes. In particular the following topics will be considered : completeness of scattering systems, the use of loop spaces, properties of stationary states, non-equilibrium states and long-range correlations in many particle systems. Among others the theory of Markov processes, Malliavin calculus and random walks will be used. The construction of Gibbs states and potential functions will play an important role.

Researcher(s)

• Promoter: Van Casteren Jan
• Co-promoter: Naudts Jan

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• Research Project

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Techniques of theoretical physics are applied in solid state physics. Methods to solve non-linear wave equations are developped. Systems of interacting particles are studied using stochastic techniques.

Researcher(s)

• Promoter: Naudts Jan

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• Research Project

Abstract

A system for tele-diagnose will be implemented. It will allow medical experts via video-conferencing to reach a common opinion based on images present at all participating sites. The experimental setup will be used to try out new algorithms in an operational context.

Researcher(s)

• Promoter: Naudts Jan
• Co-promoter: Van Dyck Dirk

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• Research Project

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Object of this project is the study of collective behaviour in communication networks of the ATM-B-ISDN type by means of stochastic analysis. New techniques are proposed for calculating distribution functions which are not of the product form. In a second phase of the project algorithms for adaptive routing will be studied in the above context.

Researcher(s)

• Promoter: Naudts Jan

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• Research Project

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The project has two parts a) orientational disorder in crystals, theory of molecular glasses, molecular crystals and fullerenes; b) random walk problems and anomalous transport properties in classical lattice gas models, theory of percolation and of nucleation phenomena.

Researcher(s)

• Promoter: Michel Karl
• Co-promoter: Naudts Jan

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• Research Project

Abstract

In systems with spontaneous symmetry breaking one observes after quenching from a disordered high-temperature phase to an ordered low-temperature phase that the spatial ordering scales in time. Starting from microscopic models and using techniques of statistical physics one derives Langevin equations describing the kinetics of the phase separation.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Van Gulck Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

The underlying idea behind this project is to use techniques and develop methods from stochastic and from mathematical analysis to model physical processes. In particular the following topics will be considered : completeness of scattering systems, the use of loop spaces, properties of stationary states, non-equilibrium states and long-range correlations in many particle systems. Among others the theory of Markov processes, Malliavin calculus and random walks will be used. The construction of Gibbs states and potential functions will play an important role.

Researcher(s)

• Promoter: Van Casteren Jan
• Co-promoter: Naudts Jan

Research team(s)

Project type(s)

• Research Project

Abstract

In systems with spontaneous symmetry breaking one observes after quenching from a disordered high-temperature phase to an ordered low-temperature phase that the spatial ordering scales in time. Starting from microscopic models and using techniques of statistical physics one derives Langevin equations describing the kinetics of the phase separation.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Van Gulck Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

The project has two parts a) orientational disorder in crystals, theory of molecular glasses, molecular crystals and fullerenes; b) random walk problems and anomalous transport properties in classical lattice gas models, theory of percolation and of nucleation phenomena.

Researcher(s)

• Promoter: Michel Karl
• Co-promoter: Naudts Jan

Research team(s)

Project type(s)

• Research Project

Abstract

In systems with spontaneous symmetry breaking one observes after quenching from a disordered high-temperature phase to an ordered low-temperature phase that the spatial ordering scales in time. Starting from microscopic models and using techniques of statistical physics one derives Langevin equations describing the kinetics of the phase separation.

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Van Gulck Stefan

Research team(s)

Project type(s)

• Research Project

Abstract

The behaviour of microscopic model systems after quench from a high temperature phase into an ordered phase is studied by means of numerical simulation.

Researcher(s)

• Promoter: Naudts Jan

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• Research Project

Abstract

The derivation of hydrodynamic and macroscopic kinetic equations starting from the microscopic laws is the fundamental goal of statistical physics. The subject is studied on simple models like the stochastic Lorentz lattice gas using rigorous techniques

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Redig Frank H J

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Abstract

These systems are ideal to study the transformation kinetics of first order phase transitions with non-conserved order parameter. The evolution of spatial correlations is followed in real time by means of X-ray scattering. The relation between domain growth and the formation of an orientational glass is investigated.

Researcher(s)

• Promoter: Naudts Jan

Research team(s)

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• Research Project

Abstract

Researcher(s)

• Promoter: Naudts Jan
• Fellow: Redig Frank H J

Research team(s)

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• Research Project