arXiv subjects

Antonio Filippi

Publications and source records attributed to Antonio Filippi.

7 recordsLinked to original sources

arXiv2001

New physics in the charged relativistic Bose gas using zeta-function regularization?

The multiplicative anomaly, recently introduced in QFT, plays a fundamental role in solving some mathematical inconsistencies of the widely used zeta-function regularization method. Its physical relevance is still an open question and is here analyzed in the light of a non-perturbative method. Even in this approach the ``different physics'' seems to hold and not to be easily removable by renormalization.

hep-th↗

arXiv1998

Chemical potential and multiplicative anomaly

The relativistic complex scalar field at finite temperature and in presence of a net conserved charge is studied in reference to recent developments on the multiplicative anomaly. This quantity, overlooked until now, is computed and it is shown how it could play a role for this system. Other possible applications are also mentioned.

hep-th↗

arXiv1998

Multiplicative anomaly and finite charge density

When dealing with zeta-function regularized functional determinants of matrix valued differential operators, an additional term, overlooked until now and due to the multiplicative anomaly, may arise. The presence and physical relevance of this term is discussed in the case of a charged bosonic field at finite charge density and other possible applications are mentioned.

hep-th↗

arXiv1998

Is the multiplicative anomaly dependent on the regularization ?

In a recent work, T.S. Evans has claimed that the multiplicative anomaly associated with the zeta-function regularization of functional determinants is regularization dependent. We show that, if one makes use of consistent definitions, this is not the case and clarify some points in Evans' argument.

hep-th↗

arXiv1998

Is the multiplicative anomaly relevant ?

In a recent work, S. Dowker has shed doubt on a recipe used in computing the partition function for a matrix valued operator. This recipe, advocated by Benson, Bernstein and Dodelson, leads naturally to the so called multiplicative anomaly for the zeta-function regularized functional determinants. In this letter we present arguments in favour of the mentioned prescription, showing that it is the valid one in calculations involving the relativistic charged bosonic ideal gas in the framework of functional analysis.

hep-th↗

arXiv1998

One-loop Effective Potential for a Fixed Charged Self-interacting Bosonic Model at Finite Temperature with its Related Multiplicative Anomaly

The one-loop partition function for a charged self-interacting Bose gas at finite temperature in D-dimensional spacetime is evaluated within a path integral approach making use of zeta-function regularization. For D even, a new additional vacuum term ---overlooked in all previous treatments and coming from the multiplicative anomaly related to functional determinants-- is found and its dependence on the mass and chemical potential is obtained. The presence of the new term is shown to be crucial for having the factorization invariance of the regularized partition function. In the non interacting case, the relativistic Bose-Einstein condensation is revisited. By means of a suitable charge renormalization, for D=4 the symmetry breaking phase is shown to be unaffected by the new term, which, however, gives actually rise to a non vanishing new contribution in the unbroken phase.

hep-th↗

arXiv1997

Inclusion of Chemical Potential for Scalar Fields

There are two possible methods for the inclusion of the chemical potential in a relativistic bosonic field theory. The most popular method has recently been criticised by some authors, so much so as to require a re-analysis of the entire problem. I here present a new approach to the inclusion of the chemical potential that uses the second method and zeta-function regularisation techniques. I first apply it to the non-interacting field, obtaining an expression for the effective potential which is formally coincident with the well-known one from the first method. My approach, however, seems here mathematically more rigorous since it excludes the presence of the multiplicative anomaly. I then obtain a new expression for the one loop effective potential for the interacting field. This is regularised, presents less cryptic excitation energies, shows Goldstone excitations, and in the non-interacting limit gives the expected expression. The high-temperature expansion is calculated easily and with clarity, and confirms the results of the first method for the critical temperature.

hep-ph↗