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We provide a thorough exposition of recent results on the quantum stabilization of cosmic strings. Stabilization occurs through the coupling to a heavy fermion doublet in a reduced version of the standard model. The study combines the…

High Energy Physics - Theory · Physics 2012-06-18 H. Weigel , M. Quandt , N. Graham

In this paper we analyse the vacuum polarization effects due to a magnetic flux on massless fermionic fields in a cosmic string background. Three distinct configurations of magnetic fields are considered. In all of them the magnetic fluxes…

High Energy Physics - Theory · Physics 2009-11-10 J. Spinelly , E. R. Bezerra de Mello

Some effects of vacuum polarization in QED due to the presence of field sources are investigated. We focus on effects with no counter-part in Maxwell electrodynamics. The the Uehling interaction energy between two stationary point-like…

High Energy Physics - Theory · Physics 2019-05-27 M. F. X. P. Medeiros , F. E. Barone , F. A. Barone

We study the effect of a background flux string on the vacuum energy of massive Dirac fermions in 3+1 dimensions confined to a finite spatial region through MIT boundary conditions. We treat two admissible self-adjoint extensions of the…

High Energy Physics - Theory · Physics 2009-11-07 Marcelo De Francia , Klaus Kirsten

A central problem in quantum condensed matter physics is the critical theory governing the zero temperature quantum phase transition between strongly renormalized Fermi-liquids as found in heavy fermion intermetallics and possibly high Tc…

High Energy Physics - Theory · Physics 2010-04-23 Mihailo Cubrovic , Jan Zaanen , Koenraad Schalm

We study the interaction of a massless quantized spinor field with the gravitational filed of N parallel static cosmic strings by using a perturbative approach. We show that the presence of more than one cosmic string gives rise to an…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. N. Aliev , M. Hortacsu , N. Ozdemir

Our aim is to study the electron-positron vacuum pressures in presence of a strong magnetic field $B$. To that end, we obtain a general energy-momentum tensor, depending on external parameters, which in the zero temperature and zero density…

High Energy Physics - Phenomenology · Physics 2009-11-11 H. Perez Rojas , E. Rodriguez Querts

In the context of a microscopic model of string-inspired foam, in which foamy structures are provided by brany point-like defects (D-particles) in space-time, we discuss flavour mixing as a result of flavour non-preserving interactions of…

High Energy Physics - Theory · Physics 2009-11-05 Nick E. Mavromatos , Sarben Sarkar , Walter Tarantino

Here we analyze the finite temperature expectation values of the charge and current densities for a massive fermionic quantum field with nonzero chemical potential, $\mu$, induced by a magnetic flux running along the axis of an idealized…

High Energy Physics - Theory · Physics 2015-09-30 Eugênio R. Bezerra de Mello , Aram A. Saharian , Azadeh Mohammadi

The main goal of this work is to pursue an investigation of cosmic string configurations focusing on possible consequences of the Lorentz-symmetry breaking by a background vector. We analyze the possibility of cosmic strings as a viable…

High Energy Physics - Theory · Physics 2010-03-25 C. N. Ferreira , J. A. Helayel-Neto , C. E. C. Lima

We evaluate the Hadamard function and the vacuum expectation value of the current density for a massive complex scalar field in the generalized geometry of a straight cosmic string with a finite core enclosing an arbitrary distributed…

High Energy Physics - Theory · Physics 2015-03-18 E. R. Bezerra de Mello , V. B. Bezerra , A. A. Saharian , H. H. Harutyunyan

The quantum energy-momentum tensor ${\hat T}^{\mu\nu}(x)$ is computed for strings in Minkowski space-time. We compute its expectation value for different physical string states both for open and closed bosonic strings. The states considered…

High Energy Physics - Theory · Physics 2016-08-15 E. J. Copeland , H. J. de Vega , A. Vázquez

We introduce a regularized free energy $\mathcal{F}_{\text{AdS}}$ for massive quantum field theories (QFTs) on Anti-de Sitter space (AdS). We conjecture this quantity to be monotonic under the renormalization group (RG) flow induced by…

High Energy Physics - Theory · Physics 2025-12-23 Davide Bason , Christian Copetti , Lorenzo Di Pietro , Ziming Ji , Shota Komatsu

We investigate the Wightman function, the vacuum expectation values of the field square and the energy-momentum tensor for a scalar field with general curvature coupling parameter in $(D+1)$-dimensional de Sitter spacetime with an arbitrary…

High Energy Physics - Theory · Physics 2008-11-26 S. Bellucci , A. A. Saharian

We extend the work done for cosmic strings on the perturbative calculation of vacuum polarization of a massless field in the space-time of multiple cosmic strings and show that for a more general class of locally flat metrics the one loop…

General Relativity and Quantum Cosmology · Physics 2009-10-30 M. Hortacsu , N. Ozdemir

One of J. Stuart Dowker's most significant achievements has been to observe that the theory of diffraction by wedges developed a century ago by Sommerfeld and others provided the key to solving two problems of great interest in…

Mathematical Physics · Physics 2015-06-05 S. A. Fulling , C. S. Trendafilova , P. N. Truong , J. Wagner

By considering Hadamard vacuum states, we first construct the two-point functions associated with Stueckelberg massive electromagnetism in de Sitter and anti-de Sitter spacetimes. Then, from the general formalism developed in [A. Belokogne…

General Relativity and Quantum Cosmology · Physics 2016-12-07 Andrei Belokogne , Antoine Folacci , Julien Queva

Realizing dark energy and the observed de Sitter spacetime in quantum gravity has proven to be obstructed in most every usual approach. We argue that additional degrees of freedom of the left- and right-movers in string theory and a…

General Relativity and Quantum Cosmology · Physics 2019-12-04 Per Berglund , Tristan Hubsch , Djordje Minic

In this paper we study the problem of neutral electro-weak interactions in a de Sitter geometry. We develop the formalism of reduction for the Proca field with the help of the solutions for the interacting fields and by using perturbative…

High Energy Physics - Theory · Physics 2023-11-27 Diana Dumitrele , Mihaela-Andreea Băloi , Cosmin Crucean

We investigate the geodesic motion of test particles around a charged Euler-Heisenberg Anti-de Sitter black hole (CEH-AdS-BH) with a cloud of strings (CoS) and surrounded by perfect fluid dark matter (PFDM). Our analysis examines how the…

General Relativity and Quantum Cosmology · Physics 2025-09-17 Faizuddin Ahmed , Ahmad Al-Badawi , İzzet Sakallı