Showing papers by "Jürg Fröhlich published in 2000"
TL;DR: In this article, the structures in target space geometry that correspond to conformally invariant boundary conditions in WZW theories are determined both by studying the scattering of closed string states and by investigating the algebra of open string vertex operators.
240 citations
TL;DR: In this article, an atom with finitely many energy levels in contact with a heat bath consisting of photons (blackbody radiation) at a temperature T > 0 was studied, and it was shown that an arbitrary initial state that is normal with respect to the equilibrium state of the uncoupled system at temperature T converges to an equilibrium state at the same temperature, as time tends to +∞ (return to equilibrium).
Abstract: We study an atom with finitely many energy levels in contact with a heat bath consisting of photons (blackbody radiation) at a temperature T>0. The dynamics of this system is described by a Liouville operator, or thermal Hamiltonian, which is the sum of an atomic Liouville operator, of a Liouville operator describing the dynamics of a free, massless Bose field, and a local operator describing the interactions between the atom and the heat bath. We show that an arbitrary initial state that is normal with respect to the equilibrium state of the uncoupled system at temperature T converges to an equilibrium state of the coupled system at the same temperature, as time tends to +∞ (return to equilibrium).
202 citations
TL;DR: A general construction of all correlation functions of a two-dimensional rational conformal field theory, for an arbitrary number of bulk and boundary fields and arbitrary topologies, is presented.
Abstract: We present a general construction of all correlation functions of a two-dimensional rational conformal field theory, for an arbitrary number of bulk and boundary fields and arbitrary topologies. Th ...
83 citations
TL;DR: In this paper, the Mourre theory of positive commutators is applied to prove absolute continuity of the energy spectrum well in between Landau levels, corresponding to edge states, for a two-dimensional electron gas confined to a half-plane, or to a domain in the plane satisfying a certain geometric condition.
Abstract: Properties of eigenstates of one-particle Quantum Hall Hamiltonians localized near the boundary of a two-dimensional electron gas – so-called edge states – are studied. For finite samples it is shown that edge states with energy in an appropriate range between Landau levels remain extended along the boundary in the presence of a small amount of disorder, in the sense that they carry a non-zero chiral edge current. For a two-dimensional electron gas confined to a half-plane, or to a domain in the plane satisfying a certain geometric condition, the Mourre theory of positive commutators is applied to prove absolute continuity of the energy spectrum well in between Landau levels, corresponding to edge states.
72 citations
TL;DR: In this article, the power law decay of SU(2)×Spin(d) invariant wavefunctions satisfying Qβψ=0 for all sd=2(d−1) supercharges of reduced (d+1)-dimensional supersymmetric SU (2) Yang-Mills theory was derived.
50 citations
TL;DR: In this paper, a Knizhnik-Zamolodchikov-like differential equation for correlators of boundary twist fields and ordinary string vertex operators is derived, and explicit integral formulas for its solutions are provided.
44 citations
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TL;DR: In this paper, the authors describe consequences of the chiral anomaly in the theory of quantum wires, the (quantum) Hall effect, and of a four-dimensional cousin of the Hall effect.
Abstract: We describe consequences of the chiral anomaly in the theory of quantum wires, the (quantum) Hall effect, and of a four-dimensional cousin of the Hall effect. We explain which aspects of conductance quantization are related to the chiral anomaly. The four-dimensional analogue of the Hall effect involves the axion field, whose time derivative can be interpreted as a (space-time dependent) difference of chemical potentials of left-handed and right-handed charged fermions. Our four-dimensional analogue of the Hall effect may play a significant role in explaining the origin of large magnetic fields in the (early) universe.
41 citations