Andreas Honecker

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We construct several quantum coset W-algebras, e.g. sl(2, IR)/ U (1) and sl(2, IR)⊕ sl(2, IR)/ sl(2, IR), and argue that they are finitely nonfreely generated. Furthermore, we discuss in detail their rôle as unifying W-algebras of Casimir W-algebras. We show that it is possible to give coset realizations of various types of unifying W-algebras, e.g. the(More)
We show that quantum Casimir W-algebras truncate at degenerate values of the central charge c to a smaller algebra if the rank is high enough: Choosing a suitable parametriza-tion of the central charge in terms of the rank of the underlying simple Lie algebra, the field content does not change with the rank of the Casimir algebra any more. This leads to(More)
In conformal field theory we investigate the representations of recently discovered W-algebras with a single generator in addition to the Virasoro field. We show that many of these W-algebras have only a finite number of highest weight representations. We describe methods for the classification and give complete lists. In a sporadic case we determine(More)
The hopping motion of classical particles on a chain coupled to reservoirs at both ends is studied for parallel dynamics with arbitrary probabilities. The stationary state is obtained in the form of an alternating matrix product. The properties of one-and two-dimensional representations are studied in detail and a general relation of the matrix algebra to(More)
Fermionic and bosonic ghost systems are defined each in terms of a single vertex algebra which admits a one-parameter family of conformal structures. The observation that these structures are related to each other provides a simple way to obtain character formulae for a general twisted module of a ghost system. The U (1) symmetry and its subgroups that(More)
We comment on a program designed for the study of local chiral algebras and their representations in 2D conformal field theory. Based on the algebraic approach described by W. Nahm, this program efficiently calculates arbitrary n-point functions of these algebras. The program is designed such that calculations involving e.g. current algebras, W-algebras and(More)
An external magnetic field induces large relative changes in the entropy of one-dimensional quantum spin systems at finite temperatures. This leads to a magnetocaloric effect, i.e. a change in temperature during an adiabatic (de)magne-tization process. Several examples of one-dimensional spin-1/2 models are studied by employing the Jordan-Wigner(More)