5,368 research outputs found
Spontaneous symmetry breaking in the gl(N)-NLS hierarchy on the half line
We describe an algebraic framework for studying the symmetry properties of
integrable quantum systems on the half line. The approach is based on the
introduction of boundary operators. It turns out that these operators both
encode the boundary conditions and generate integrals of motion. We use this
direct relationship between boundary conditions and symmetry content to
establish the spontaneous breakdown of some internal symmetries, due to the
boundary.Comment: LaTeX2e, 28 pages, no figur
Superspace evaluation of the two-loop effective potential for the O'Raifeartaigh model
All-order spurion-corrected superpropagators and superfield Feynman rules are
employed to systematically compute a two-loop corrected effective potential for
the O'Raifeartaigh model, that realizes spontaneous supersymmetry breaking.
Though the shifted superpropagators are rather nontrivial, superspace
techniques may be suitably extended and confirm their efficacy in computing
radiative corrections even when supersymmetry breakdown occurs.Comment: 24 pages, 2 figures, revtex4, 2 pages added, new appendix adde
Effective theory for deformed nuclei
Techniques from effective field theory are applied to nuclear rotation. This
approach exploits the spontaneous breaking of rotational symmetry and the
separation of scale between low-energy Nambu-Goldstone rotational modes and
high-energy vibrational and nucleonic degrees of freedom. A power counting is
established and the Hamiltonian is constructed at next-to-leading order
Laws, Symmetry, and Symmetry Breaking; Invariance, Conservation Principles, and Objectivity
Given its importance in modern physics, philosophers of science have paid surprisingly little attention to the subject of symmetries and invariances, and they have largely neglected the subtopic of symmetry breaking. I illustrate how the topic of laws and symmetries brings into fruitful interaction technical issues in physics and mathematics with both methodological issues in philosophy of science, such as the status of laws of physics, and metaphysical issues, such as the nature of objectivity
Linguistics and some aspects of its underlying dynamics
In recent years, central components of a new approach to linguistics, the
Minimalist Program (MP) have come closer to physics. Features of the Minimalist
Program, such as the unconstrained nature of recursive Merge, the operation of
the Labeling Algorithm that only operates at the interface of Narrow Syntax
with the Conceptual-Intentional and the Sensory-Motor interfaces, the
difference between pronounced and un-pronounced copies of elements in a
sentence and the build-up of the Fibonacci sequence in the syntactic derivation
of sentence structures, are directly accessible to representation in terms of
algebraic formalism. Although in our scheme linguistic structures are classical
ones, we find that an interesting and productive isomorphism can be established
between the MP structure, algebraic structures and many-body field theory
opening new avenues of inquiry on the dynamics underlying some central aspects
of linguistics.Comment: 17 page
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