We present a new mechanism of fluctuation-induced Nambu-Goldstone bosons in a scalar field theory of Higgs-Josephson systems. We consider a simple scalar field model with U(1) rotational symmetry. When there is an interaction which violates the rotational symmetry, the Nambu-Goldstone bosons become massive and massless bosons are concealed. We present a model where the massive boson becomes a m...

In this work we compute the effective action describing the low-energy brane Goldstone-boson dynamics. The Goldstone bosons or branons appear because the brane spontaneously breaks the translational invariance along the extra dimensions. We discuss the Higgs-like mechanism in which the KaluzaKlein gauge fields absorb the Goldstone bosons and acquire mass. We also present the explicit form of th...

The AdS/CFT correspondence allows to relate 4D strongly coupled theories to weakly coupled theories in 5D AdS. We use this correspondence to study a scenario in which the Higgs appears as a composite pseudo-Goldstone boson (PGB) of a strongly coupled theory. We show how a non-linearly realized global symmetry protects the Higgs mass and guarantees the absence of quadratic divergences at any loo...

In natural inflation models, the inflaton is a pseudo Nambu-Goldstone boson and the flatness of the potential is protected by shift symmetries. In this framework, a successful inflation requires the global symmetry to be spontaneously broken at a scale close to the Planck mass. Such a high value of the spontaneous breaking scale may not be legitimate in an effective field theory. On the other h...

We present "twin Higgs models," simple realizations of the Higgs boson as a pseudo Goldstone boson that protect the weak scale from radiative corrections up to scales of order 5-10 TeV. In the ultraviolet these theories have a discrete symmetry which interchanges each standard model particle with a corresponding particle which transforms under a twin or a mirror standard model gauge group. In a...

By coupling axions strongly to a hidden sector, the energy density in coherent axions may be converted to radiative degrees of freedom, alleviating the “axion energy crisis”. The strong coupling is achieved by mixing the axion and some other Goldstone boson through their kinetic energy terms, in a manner reminiscent of paraphoton models. Even with the strong coupling it proves difficult to rela...

CONTENTS I. Introduction: Short and long range interactions 843 II. Spontaneous Symmetry Breaking 844 A. Spontaneous symmetry breaking in phase transitions 844 B. Spontaneous symmetry breaking in field theory 845 III. The BEH Mechanism 846 A. The fate of the Nambu-Goldstone boson and vector boson masses 846 B. The fate of the massive scalar boson 847 C. Fermion masses 848 D. Why is the mechanis...

A pseudo-Goldstone boson for quintessence is known to require the decay constant Fq ∼ MP and the height of the potential (0.003 eV) 4, and hence the pseudo-Goldstone boson mass of order 10−33 eV. The modeldependent axion in some superstring models is suggested as a good candidate for the quintessence. We realize this idea with a hidden-sector gauge group SU(3)H × U(1)H . The hidden-sector insta...

We present a unified description of the spontaneous symmetry breaking and its associated bosons in fermion field theory. There is no Goldstone boson in the fermion field theory models of Nambu-Jona-Lasinio, Thirring and QCD2 after the chiral symmetry is spontaneously broken in the new vacuum. The defect of the Goldstone theorem is clarified, and the ”massless boson” predicted by the theorem is ...

The 5D Scherk-Schwarz breaking with orbifold S/Z2 in SU(6) symmetry under special condition leads to a dimensional deconstruction without gauge symmetry breaking where SU(6) Little Higgs-like scalars show up either as weakly-coupled or strongly-coupled. The latest, together with the broken fifth component of 5D gauge boson, composes Coleman-Weinberg potential which can be generalized by substit...