909 research outputs found
Projective Group Algebras
In this paper we apply a recently proposed algebraic theory of integration to
projective group algebras. These structures have received some attention in
connection with the compactification of the theory on noncommutative tori.
This turns out to be an interesting field of applications, since the space
of the equivalence classes of the vector unitary irreducible
representations of the group under examination becomes, in the projective case,
a prototype of noncommuting spaces. For vector representations the algebraic
integration is equivalent to integrate over . However, its very
definition is related only at the structural properties of the group algebra,
therefore it is well defined also in the projective case, where the space has no classical meaning. This allows a generalization of the usual group
harmonic analysis. A particular attention is given to abelian groups, which are
the relevant ones in the compactification problem, since it is possible, from
the previous results, to establish a simple generalization of the ordinary
calculus to the associated noncommutative spaces.Comment: 24 pages, Late
Color superconductivity in high density QCD
In this contributed paper the gapless phases of QCD are discussed.Comment: Contributed paper to the Conference "Quark confinement ant the Hadron
Spectrum VI 2004". Latex, 3 page
Inhomogeneous Color Superconductivity
We discuss the possibility that in finite density QCD an anisotropic phase is
realized. This case might arise for quarks with different chemical potential
and/or different masses. In this phase crystalline structures may be formed. We
consider this possibility and we describe, in the context of an effective
lagrangian, the corresponding phonons as the Nambu-Goldstone bosons associated
to the breaking of the space symmetries.Comment: LaTex,20 pages, 6 figures. Talk at the International Workshop on QCD:
QCD@Work 2003 - Conversano (Italy) 14-18 June 2003 (eConf C030614). Change in
the CERN preprint numbe
Integration over a generic algebra
In this paper we consider the problem of quantizing theories defined over
configuration spaces described by non-commuting parameters. If one tries to do
that by generalizing the path-integral formalism, the first problem one has to
deal with is the definition of integral over these generalized configuration
spaces. This is the problem we state and solve in the present work, by
constructing an explicit algorithm for the integration over a general algebra.
Many examples are discussed in order to illustrate our construction.Comment: 31 pages, Latex. A few typos have been corrected. Some comments about
algebras with identity and about inner derivations have been inserted,
together with a further example: the q-bosonic oscillato
Pseudo Goldstones at Future Colliders from the Extended Bess Model
We consider the production of the lightest pseudo-Goldstone bosons at future
colliders through the vector resonances predicted by the extended BESS model,
which consists of an effective lagrangian parametrization with dynamical
symmetry breaking, describing scalar, vector and axial-vector bound states in a
rather general framework. We find that the detection of pseudo-Goldstone pairs
at LHC requires a careful evaluation of backgrounds. For e+e- collisions in the
TeV range the backgrounds can be easily reduced and the detection of
pseudo-Goldstone pairs is generally easier.Comment: 17 pages and 12 figures (included as a uuencoded tar file), LaTeX
(style article), UGVA-DPT 1994/03-84
Algebraic treatment of compactification on noncommutative tori
In this paper we study the compactification conditions of the M theory on
D-dimensional noncommutative tori. The main tool used for this analysis is the
algebra A(Z^D) of the projective representations of the abelian group Z^D. We
exhibit the explicit solutions in the space of the multiplication algebra of
A(Z^D), that is the algebra generated by right and left multiplications.Comment: 8 pages, Latex, shortened version as accepted for publication in
Physics Letter
Effective description of QCD at high density
After an introduction to the phases of QCD at high density and zero
temperature, we introduce the effective lagrangian for the CFL phase and
discuss the perturbative evaluation of its parametersComment: Invited talk at the Conference on Compact Stars in the QCD Phase
Diagram, Copenhagen, August 15-18, 2001. LateX file, pages 16, no figure
New vector bosons in the electroweak sector: a renormalizable model with decoupling
A linear realization of a model of dynamical electroweak symmetry breaking
describing additional heavy vector bosons is proposed. The model is a SU(2)_L x
U(1) x SU(2)_L' x SU(2)_R' gauge theory, breaking at some high scale u to
SU(2)_weak x U(1)_Y and breaking again in the standard way at the electroweak
scale v to U(1)_(em). The model is renormalizable and reproduces the Standard
Model in the limit u\to infinity. This decoupling property is shown to hold
also at the level of radiative corrections by computing, in particular, the
epsilon parameters.Comment: 39 pages, 16 Figures, Late
- …