Concept

Brisure spontanée de symétrie

Publications associées (406)

The study of incommensurate structures as a probe to reveal atomic interactions in crystals

The structure of aperiodic crystals which includes incommensurate, quasi- and composite crystals is usually described in spaces of higher dimension, the so called superspace. The main advantage of the superspace formalism is that an aperiodic structure in ...

2004

Manifestation of the magnetic resonance mode in the nodal quasiparticle lifetime of the superconducting cuprates

Giorgio Margaritondo, Helmuth Berger

Studying the nodal quasiparticles in superconducting cuprates by photoemission with highly improved momentum resolution, we show that a new "kink" feature in the scattering rate is a key to uncover the nature of electron correlations in these compounds. Ou ...

2004

Polaron formation and symmetry breaking

Libero Zuppiroli, Marie-Noëlle Bussac, François Gygi, Giulia Galli Gygi

In a molecular semiconductor, a charged molecule experiences a lattice relaxation which reorganizes it into a cation or an anion-radical. This species is not, in general, a polaron. By using calculations of the geometry and the electronic structure both ab ...

Elsevier2003

Electroweak symmetry breaking and fermion masses from extra dimensions

Claudio Scrucca

We study higher-dimensional non-supersymmetric orbifold models where the Higgs field is identified with some internal component of a gauge field. We address two important and related issues that constitute severe obstacles towards model building within thi ...

2003

Global regularity of wave maps from $R^{3+1}$ to surfaces

Joachim Krieger

We consider Wave Maps with smooth compactly supported initial data of small (H) over dot (3/2)-norm from R3+1 to certain 2-dimensional Riemannian manifolds and show that they stay smooth globally in time. Our methods are based on the introduction of a glob ...

Springer Verlag2003

Open string models with Scherk-Schwarz SUSY breaking and localized anomalies

Claudio Scrucca

We study examples of chiral four-dimensional IIB orientifolds with Scherk-Schwarz supersymmetry breaking, based on freely acting orbifolds. We construct a new Z(3) x Z(3)' model, containing only D9-branes, and rederive from a more geometric perspective the ...

2002

Anomalies, Fayet-Iliopoulos terms, and the consistency of orbifold field theories

Riccardo Rattazzi, Claudio Scrucca, Roberto Contino

We study the consistency of orbifold field theories and clarify to what extent the condition of having an anomaly-free spectrum of zero modes is sufficient to guarantee it. Preservation of gauge invariance at the quantum level is possible, although at the ...

2002

Band features and strong correlations in 1D Peierls systems

Marco Grioni, Helmuth Berger, Luca Perfetti

High-resolution angle-resolved (ARPES) photoemission in the quasi-one dimensional (1D) Peierls systems (TaSe4)(2)I and K0.3MoO3 reveals spectral features with clear 1D character. Their dispersion and polarization dependence is consistent with open Fermi su ...

2002

Mobile small polarons and the Peierls transition in the quasi-one-dimensional conductor K0.3MoO3

Giorgio Margaritondo, László Forró, Marco Grioni, Luca Perfetti

High-resolution angle-resolved photoemission spectroscopy (ARPES) on the quasi-one-dimensional Peierls system K0.3MoO3 reveals a "hidden" open Fermi surface and band features displaying the symmetry properties of the underlying lattice. However, the ARPES ...

2002

Anderson localization of ballooning modes, quantum chaos and the stability of compact quasiaxially symmetric stellarators

Wilfred Anthony Cooper

The radially local magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), is examined just above the ballooning beta limit with a method that can lead to estimates of global stability. Here MHD stability is a ...

2002

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