arXiv subjects

E. Spallucci

Publications and source records attributed to E. Spallucci.

At least 19 recordsLinked to original sources

arXiv2004

Conformally Invariant Gauge Theory of 3-Branes in 6D and the Cosmological Constant

It is shown that the gauge theory of relativistic 3-Branes can be formulated in a conformally invariant way if the embedding space is six-dimensional. The implementation of conformal invariance requires the use of a modified measure, independent of the metric in the action. Brane-world scenarios without the need of a cosmological constant in 6D are constructed. Thus, no ``old'' cosmological constant problem appears at this level.

hep-th↗

arXiv2004

Quantum effects of a massive 3-form coupled to a Dirac field

We consider the coupling of A_{μνρ} to the generic current of matter field, later identified with the spin density current of a Dirac field. In fact, one of the objectives of this paper is to investigate the impact of the quantum fluctuations of A_{μνρ} on the effective dynamics of the spinor field. The consistency of the field equations, even at the classical level, requires the introduction of a mass term for A_{μνρ}. In this case, the Casimir vacuum pressure includes a contribution that is explicitly dependent on the mass of A_{μνρ} and leads us to conclude that the mass term plays the same role as the infrared cutoff needed to regularize the finite volume partition functional previously calculated in the massless case. Remarkably, even in the presence of a mass term, A_{μνρ} contains a mixture of massless and massive spin-0 fields so that the resulting equation is still gauge invariant. This is yet another peculiar, but physically relevant property of A_{μνρ} since it is reflected in the effective dynamics of the spinor fields and confirms the confining property of A_{μνρ} already expected from the earlier calculation of the Wilson loop.

hep-th↗

arXiv2004

Conformally Invariant Brane-universe and the Cosmological Constant

A relativistic 3-brane can be given a conformally invariant, gauge-type, formulation provided the embedding space is six-dimensional. The implementation of conformal invariance requires the use of a modified measure, independent of the metric in the action. A brane-world scenario without the need of a cosmological constant in 6D can be constructed. Thus, no ``old'' cosmological constant problem appears at this level.

gr-qc↗

arXiv2004

Quantum fluctuations of a "constant" gauge field

It is argued here that the quantum computation of the vacuum pressure must take into account the contribution of zero-point oscillations of a rank-three gauge field. The field A_{μνρ} possesses no radiative degrees of freedom, its sole function being that of polarizing the vacuum through the formation of \textit{finite} domains characterized by a non-vanishing, constant, but otherwise arbitrary pressure. This extraordinary feature, rather unique among quantum fields, is exploited to associate the A_{μνρ} field with the ``bag constant'' of the hadronic vacuum, or with the cosmological term in the cosmic case. We find that the quantum fluctuations of A_{μνρ} are inversely proportional to the confinement volume and interpret the result as a Casimir effect for the hadronic vacuum. With these results in hands and by analogy with the electromagnetic and string case, we proceed to calculate the Wilson loop of the three-index potential coupled to a ``test'' relativistic bubble. From this calculation we extract the static potential between two opposite points on the surface of a spherical bag and find it to be proportional to the enclosed volume.

hep-th↗

arXiv2003

String theory T-duality and the zero point length of spacetime

It has been often conjectured that the correct theory of quantum gravity will act as a UV regulator in the low energy limit of quantum field theory. Earlier work has shown that if the path integral defining the quantum field theory propagator is modified, so that the amplitude is invariant under the duality transformation l--> 1/l where l is the length of the path, then the propagator is UV-finite and exhibits a ``zero-point length'' of the spacetime. Since string theory uses extended structures and has a T-duality, these results should also emerge directly from string theory. We show, by explicit path integral computation, that this is indeed the case. The lowest order string theory correction to the propagator is the same as that obtained by the hypothesis of path integral duality.

hep-th↗

arXiv2002

Noncommutative 3D harmonic oscillator

We find transformation matrices allowing to express non-commutative three dimensional harmonic oscillator in terms of an isotropic commutative oscillator, following ``philosophy of simplicity'' approach. Non-commutative parameters have physical interpretation in terms of an external magnetic field. Furthermore, we show that for a particular choice of noncommutative parameters there is an equivalent anisotropic representation, whose transformation matrices are far more complicated. We indicate a way to obtain the more complex solutions from the simple ones.

hep-th↗

arXiv2002

Nambu-Goto Strings from SU(N) Born-Infeld model

The spectrum of quenched Yang-Mills theory in the large-N limit displays strings and higher dimensional extended objects. The effective dynamics of string-like excitations is encoded into area preserving Schild action. In this letter, we bridge the gap between SU(N) gauge models and fully reparametrization invariant Nambu-Goto string models by introducing an extra matrix degree of freedom in the Yang-Mills action. In the large-N limit this matrix variable becomes the world-sheet auxiliary field allowing a smooth transition between the Schild and Nambu-Goto strings. The new improved matrix model we propose here can be extended to p-branes provided we enlarge the dimensionality of the target spacetime.

hep-th↗

arXiv2001

Isotropic representation of noncommutative 2D harmonic oscillator

We show that 2D noncommutative harmonic oscillator has an isotropic representation in terms of commutative coordinates. The noncommutativity in the new mode, induces energy level splitting, and is equivalent to an external magnetic field effect. The equivalence of the spectra of the isotropic and anisotropic representation is traced back to the existence of SU(2) invariance of the noncommutative model.

hep-th↗

arXiv2001

The Dual Phases of Massless/Massive Kalb-Ramond Fields

We have developed dualization of ordinary and ``Stueckelberg compensated'' massive phase for the Kalb-Ramond theory. The compensated phase allows to study the interplay between spin jumping and duality. We show that spin jumping is caused by mass, while gauge symmetry is not necessary for this effect to take place.

hep-th↗

arXiv2001

The QCD Membrane

In this paper we study spatially quenched, SU(N) Yang-Mills theory in the large-N limit. The resulting reduced action shows the same formal look as the Banks-Fischler-Shenker-Susskind M-theory action. The Weyl-Wigner-Moyal symbol of this matrix model is the Moyal deformation of a p(=2)-brane action. Thus, the large-N limit of the spatially quenched SU(N) Yang-Mills is seen to describe a dynamical membrane. By assuming spherical symmetry we compute the mass spectrum of this object in the WKB approximation.

hep-th↗

arXiv2001

Quenched, Minisuperspace, Bosonic p-brane Propagator

We borrow the minisuperspace approximation from Quantum Cosmology and the quenching approximation from QCD in order to derive a new form of the bosonic p-brane propagator. In this new approximation we obtain an exact description of both the collective mode deformation of the brane and the center of mass dynamics in the target spacetime. The collective mode dynamics is a generalization of string dynamics in terms of area variables. The final result is that the evolution of a p-brane in the quenched-minisuperspace approximation is formally equivalent to the effective motion of a particle in a spacetime where points as well as hypersurfaces are considered on the same footing as fundamental geometrical objects. This geometric equivalence leads us to define a new tension-shell condition that is a direct extension of the Klein-Gordon condition for material particles to the case of a physical p-brane.

hep-th↗

arXiv2001

Vacuum Bubbles Nucleation and Dark Matter Production through Gauge Symmetry Rearrangement

Modern particle physics and cosmology support the idea that a background of invisible material pervades the whole universe, and identify in the cosmic vacuum the ultimate source of matter-energy, both seen and unseen. Within the framework of the theory of fundamental relativistic membranes, we suggest a self-consistent, vacuum energy-driven mechanism for dark matter creation through gauge symmetry rearrangement.

hep-ph↗

arXiv2001

p-Branes from Generalized Yang-Mills Theory

We consider the reduced, quenched version of a generalized Yang-Mills action in 4k-dimensional spacetime. This is a new kind of matrix theory which is mapped through the Weyl-Wigner-Moyal correspondence into a field theory over a non-commutative phase space. We show that the ``classical'' limit of this field theory is encoded into the effective action of an open, (4k-1)-dimensional, bulk brane enclosed by a dynamical, Chern-Simons type, (4k-2)-dimensional, boundary brane. The bulk action is a pure volume term, while the boundary action carries all the dynamical degrees of freedom.

hep-th↗

arXiv2000

Chern-Simons Hadronic Bag from Quenched Large-N QCD

SU(N) reduced, quenched, gauge theories have been shown to be related to string theories. We extend this result and show how a 4-dimensional, reduced, quenched, Yang-Mills theory, supplemented by the topological term, can be related through the Wigner-Weyl-Moyal correspondence to an open 3-brane model. The boundary of the 3-brane is described by a Chern-Simons 2-brane. We identify the bulk of the 3-brane with the interior of a hadronic bag and the world-volume of the Chern-Simons 2-brane with the dynamical boundary of the bag. We estimate the value of the induced bag constant to be a little less than 200MeV.

hep-th↗

arXiv2000

The Dual Higgs Mechanism and the Origin of Mass in the Universe

The idea that a background of invisible material pervades the whole universe is as old as the history of natural philosophy. Modern particle physics and cosmology support that idea and identify in the cosmic vacuum the ultimate source of matter-energy, both seen and unseen, in the universe. In the framework of the inflation-axion scenario, we suggest an unusual realization of the Higgs mechanism which converts the latent energy of the vacuum into observable mass. The existence of a new spontaneously broken symmetry is pointed out which has the same effect of the Peccei-Quinn symmetry in creating axions as pseudo-Goldstone bosons. However such particles are eliminated from the physical spectrum in favor of massive pseudoscalar particles.

hep-ph↗

arXiv2000

Dualization of non-Abelian BF model

We show that dualization of BF models to Stueckelberg-like massive gauge theories allows a non-Abelian extension. We obtain local Lagrangians which are straightforward extensions of the Abelian results.

hep-th↗

arXiv2000

Wess--Zumino terms and Duality

We show the equivalence between Stuckelberg and Wess-Zumino methods of restoration of gauge symmetries of the anomalous, Abelian, effective action, in arbitrary even dimensions D=2k. We present dual version of Wess-Zumino terms with the compensating field described by a Kalb-Ramond like p=2k-2 form.

hep-th↗

arXiv2000

On the WKB quantum equivalence between diverse p-brane actions

We consider an action for a closed, bosonic, p-brane, where the brane tension is not an assigned parameter but rather it is induced by a maximal rank gauge p-form. This model is classically equivalent to the Nambu--Goto/Howe-Tucker model. We investigate how this classical equivalence can be implemented in the path integral framework. For this purpose we adopt a ``first order'' integration procedure over gauge p-forms and a ``shortened'' Fadeev-Popov procedure.

hep-th↗