1,720,967 research outputs found
Ergodic states and symmetry breaking in phase transitions: a C*algebra approach
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mmubn000001_205230008.pdf (Publisher’s version ) (Open Access)Promotor : E. Verboven
cum laude121 p
Contributions to the theory of the ising model
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mmubn000001_027884902.pdf (Publisher’s version ) (Open Access)Promotor : G. Vertogen111 p
Roughening and preroughening in the six-vertex model with an extended range of interaction
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28127.pdf (Publisher’s version ) (Open Access
Modulated phases in Ising models with diluted frustration
No full textA particular class of periodic Ising models with diluted frustration is studied using a simple recursion relation for spinor correlation functions. A modulated phase is found at T = 0 which extends into a modulated paramagnetic phase for finite temperatures. The disorder line at which this latter phase changes into a paramagnetic phase is located. In a study of the ground state excitations of the model contact is made with results known for the ANNNI-model
Cross-over to classical behaviour for an Ising model with vacancies
No full textA real space renormalization is applied to the Ising model for d 3, allowing for the generation of vacancies. A fixed point structure is obtained that reflects the cross-over to classical behaviour as known from e-expansion. The exponents found are an improvement over those obtained by the same method applied to the Ising model without vacancies
Ground state and non-linear excitations of two strongly coupled Su-Schrieffer-Heeger chains
No full textA two-chain version of the original Su-Schrieffer-Heeger model with a strong interchain coupling is analysed for the case of a half-filled band, using a self-consistent iteration procedure and a continuum description in conjunction with bosonisation techniques. The problem of the stability of the iteration procedure is addressed and it is shown that the iteration converges to the (local) minima of the total ground state energy. The ground state of the present model is a trimerisation but also other homogeneous (metastable) phases are possible. The solitons in the model are of phason, amplitudon and intermediary type, but other more complicated solitons are also observed
Correlated percolation and the correlated resistor network
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28138___.PDF (Publisher’s version ) (Open Access
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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