Dynamical generation of Lorentz symmetry for a Lifshitz-type Yukawa model (2009)
Alexandre, J., Farakos, K., Pasipoularides, P., Tsapalis, A.
We study a Lifshitz-type model in 3+1 dimensions, for a dynamical critical exponent z=3, with a scalar and a fermion field coupled via a Yukawa interaction. Using the non-perturbative Schwinger-Dyson...
Farakos, K., Kouretsis, A. P., Pasipoularides, P.
We construct asymptotically AdS black hole solutions, with a self-interacting bulk scalar field, in the context of 5D general relativity. As the observable universe is characterized by spatial...
Lorentz violation effects in asymmetric two brane models: a nonperturbative analysis (2009)
We consider the case of bulk photons in a Lorentz violating brane background, with an asymmetric warping between space and time warp factors. A perturbative analysis, in a previous work, gave an...
Neutrino oscillations in a Robertson-Walker Universe with space time foam (2009)
Alexandre, J., Farakos, K., Mavromatos, N. E., Pasipoularides, P.
In Phys. Rev. D77 (2008) 105001, we have studied decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discussed briefly the sensitivity of...
Asymmetrically Warped Brane Models, Bulk Photons and Lorentz Invariance (2009)
Farakos, K., Mavromatos, N. E., Pasipoularides, P.
We present a brief review of our recent work [1] on asymmetrically warped brane models, where the background metric is characterized by different time and space warp factors. In particular we examine...
In this paper we study the properties of the phase diagram of a simple extra dimensional model on the lattice at finite temperature. We consider the five-dimensional pure gauge abelian model with...
Bulk photons in Asymmetrically Warped Space-times and Non-trivial Vacuum Refractive Index (2008)
Farakos, K., Mavromatos, N. E., Pasipoularides, P.
We consider asymmetrically warped brane models, or equivalently brane models where the background metric is characterized by different time and space warp factors. The main feature of these models is...
Establishment of the Coulomb law in the layer phase of a pure U(1) lattice gauge theory (2008)
In this article we examine the Layer phase of the five dimensional, anisotropic, Abelian gauge model. Our results are to be compared with the ones of the 4D U(1) gauge model in an attempt to verify...
Neutrino oscillations in a stochastic model for space-time foam (2007)
Alexandre, J., Farakos, K., Mavromatos, N. E., Pasipoularides, P.
We study decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discuss briefly the sensitivity of current neutrino experiments to such models. We...
Farakos, K., Koutsoumbas, G., Pasipoularides, P.
Brane world models with a non-minimally coupled bulk scalar field have been studied recently. In this paper we consider metric fluctuations around an arbitrary gravity-scalar background solution, and...
Gauss-Bonnet gravity, brane world models, and non-minimal coupling (2006)
Farakos, K., Pasipoularides, P.
We study the case of brane world models with an additional Gauss-Bonnet term in the presence of a bulk scalar field which interacts non-minimally with gravity, via a possible interaction term of the...
Brane world scenario in the presence of a non-minimally coupled bulk scalar field (2006)
Farakos, K., Pasipoularides, P.
We present our recent work on brane world models with a non-minimally coupled scalar field. In [9] we examined the stability of these models against scalar field perturbations and we discussed...
Dimopoulos, P., Farakos, K., Vrentzos, S.
We study a 4+1 dimensional pure Abelian Gauge model on the lattice with two anisotropic couplings independent of each other and of the coordinates. A first exploration of the phase diagram using mean...
Second Randall-Sundrum brane world scenario with a nonminimally coupled bulk scalar field (2006)
Farakos, K., Pasipoularides, P.
In our previous work of Ref. [5] we studied the stability of the RS2-model with a nonminimally coupled bulk scalar field $\phi$, and we found that in appropriate regions of $\xi$ the standard...
Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields (2005)
Farakos, K., De Forcrand, P., Altes, C. P. Korthals, Laine, M., Vettorazzo, M.
If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such...
Gravity-induced instability and gauge field localization (2005)
Farakos, K., Pasipoularides, P.
The spectrum of a massless bulk scalar field \Phi, with a possible interaction term of the form -\xi R \Phi^{2}, is investigated in the case of RS-geometry [1]. We show that the zero mode for \xi=0,...
Farakos, K., Pasipoularides, P.
We consider a U(1) gauge field theory with fermion fields (or with scalar fields) that live in a space with $\delta$ extra compact dimensions, and we compute the fermion-induced quantum energy in the...
Anomalous magnetic moment in parity-conserving QED3 (2004)
Alexandre, Jean, Farakos, K., Mavromatos, N. E.
In this article we derive the anomalous magnetic moment of fermions in (2+1)-dimensional parity-conserving QED3, in the presence of an externally applied constant magnetic field. We use a spectral...
Effective potential analysis for 5D SU(2) gauge theories at finite temperature and radius (2004)
Farakos, K., Pasipoularides, P.
We calculate the one loop effective potential for a 5D SU(2) gauge field theory at finite temperature $T=1/\beta$ and radius R=1/M. This calculation is performed, for the first time, in the case of...
Layered Higgs Phase as a Possible Field Localisation on a Brane (2004)
So far it has been found by using lattice techniques that in the anisotropic five--dimensional Abelian Higgs model, a layered Higgs phase exists in addition to the expected five--dimensional one. The...
Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields (2003)
Farakos, K., De Forcrand, P., Altes, C. P. Korthals, Laine, M., Vettorazzo, M.
If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such...
Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields (2003)
Farakos, K., De Forcrand, P., Altes, C. P. Korthals, Laine, M., Vettorazzo, M.
If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such...
Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields (2002)
Farakos, K, De Forcrand, Philippe, Altes, C P K, Laine, Mikko, Vettorazzo, M
If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such...
Finite temperature Z(N) phase transition with Kaluza-Klein gauge fields (2002)
Farakos, K., De Forcrand, P., Altes, C. P. Korthals, Laine, M., Vettorazzo, M.
If SU(N) gauge fields live in a world with a circular extra dimension, coupling there only to adjointly charged matter, the system possesses a global Z(N) symmetry. If the radius is small enough such...
Dimopoulos, P., Farakos, K., Koutsoumbas, G.
We explore, by Monte Carlo and Mean Field methods, the five--dimensional SU(2) adjoint Higgs model. We allow for the possibility of different couplings along one direction, describing the so--called...
Multi-Layer Structure in the Strongly Five Dimensional Abelian Higgs Model (2001)
Dimopoulos, P., Farakos, K., Nicolis, S.
We explore the phase diagram of the 5--D anisotropic Abelian Higgs model by Monte Carlo simulations. In particular, we study the transition between the confining phase and the four dimensional...
Branes in the 5D Abelian Higgs Model (2001)
Dimopoulos, P., Farakos, K., Korthals-Altes, C. P., Koutsoumbas, G., Nicolis, S.
We find 3-brane Higgs and Coulomb phases in the 5D Abelian Higgs Model and determine the transition surfaces that separate them from the usual bulk phases.
Alexandre, J, Farakos, K, Koutsoumbas, G, Mavromatos, Nikolaos E
We consider magnetic catalysis in a field-theoretic system of (3+1)-dimensional Dirac fermions with anisotropic kinetic term. By placing the system in a strong external magnetic field, we examine...
Alexandre, J., Farakos, K., Koutsoumbas, G., Mavromatos, N. E.
We consider magnetic catalysis in a field-theoretic system of (3+1)-dimensional Dirac fermions with anisotropic kinetic term. By placing the system in a strong external magnetic field, we examine...
Multi--Layer Structure in the Strongly Coupled 5D Abelian Higgs Model (2001)
Dimopoulos, P., Farakos, K., Nicolis, S.
We explore the phase diagram of the five-dimensional anisotropic Abelian Higgs model by Monte Carlo simulations. In particular, we study the transition between the confining phase and the four...
QED$_3$ with Dynamical Fermions in an External Magnetic Field (2001)
Alexandre, J., Farakos, K., Hands, S. J., Koutsoumbas, G., Morrison, S. E.
In this paper, we present results of numerical lattice simulations of two-flavor QED in three space-time dimensions. First, we provide evidence that chiral symmetry is spontaneously broken in the...
Phase Structure of the 5D Abelian Higgs Model with Anisotropic Couplings (2000)
Dimopoulos, P., Farakos, K., Korthals-Altes, C. P., Koutsoumbas, G., Nicolis, S.
We establish the phase diagram of the five-dimensional anisotropic Abelian Higgs model by mean field techniques and Monte Carlo simulations. The anisotropy is encoded in the gauge couplings as well...
Magnetic catalysis in QED_3 at finite temperature: beyond the constant mass approximation (2000)
Alexandre, J., Farakos, K., Koutsoumbas, G.
We solve the Schwinger-Dyson equations for (2+1)-dimensional QED in the presence of a strong external magnetic field. The calculation is done at finite temperature and the fermionic self energy is...
Lattice Evidence for Gauge Field Localization on a Brane (2000)
Dimopoulos, P., Farakos, K., Kehagias, A., Koutsoumbas, G.
We examine the problem of gauge-field localization in higher-dimensional gauge theories. In particular, we study a five-dimensional U(1) by lattice techniques and we find that gauge fields can indeed...
Decoupling of Layers in the Three-dimensional Abelian Higgs Model (2000)
Dimopoulos, P., Farakos, K., Koutsoumbas, G.
The Abelian Higgs model with anisotropic couplings in 2+1 dimensions is studied in both the compact and non-compact formulations. Decoupling of the space-like planes takes place in the extreme...
QED in a Strong External Magnetic Field: Beyond the Constant Mass Approximation (2000)
Alexandre, J., Farakos, K., Koutsoumbas, G.
We solve the Schwinger-Dyson equations for QED in 2+1 or 3+1 dimensions in the presence of a strong homogeneous external magnetic field. The magnetic field is assumed strong enough, so that the...
The Abelian Higgs Model in Three Dimensions with Improved Action (1999)
Dimopoulos, P., Farakos, K., Koutsoumbas, G.
We study the Abelian Higgs Model using an improved form of the action in the scalar sector. The subleading corrections are carefully analysed and the connection between lattice and continuous...
Even flavor QED3 in an external magnetic field (1999)
Farakos, K., Koutsoumbas, G., Mavromatos, N., Momen, A.
The magnetically induced fermionic condensate is studied at zero and finite temperatures. The effects of a non-homogeneous external magnetic fields is briefly considered.
Astrophysical Probes of the Constancy of the Velocity of Light (1999)
Ellis, Jonathan Richard, Farakos, K, Mavromatos, Nikolaos E, Mitsou, V A, Nanopoulos, Dimitri V
We discuss possible tests of the constancy of the velocity of light using distant astrophysical sources such as gamma-ray bursters (GRBs), Active Galactic Nuclei (AGNs) and pulsars. This speculative...
Astrophysical Probes of the Constancy of the Velocity of Light (1999)
Ellis, J., Farakos, K., Mavromatos, N. E., Mitsou, V., Nanopoulos, D. V.
We discuss possible tests of the constancy of the velocity of light using distant astrophysical sources such as gamma-ray bursters (GRBs), Active Galactic Nuclei (AGNs) and pulsars. This speculative...
Magnetic catalysis in even-flavor three-dimensional QED (1999)
Farakos, K, Koutsoumbas, G, Mavromatos, Nikolaos E, Momen, A
In this paper, we discuss the role of an external magnetic field on the dynamically generated fermion mass in even-flavor QED in three space-time dimensions. We show that for weak fields this mass...
On magnetic catalysis in even-flavor QED3 (1999)
Farakos, K., Koutsoumbas, G., Mavromatos, N. E., Momen, Arshad
In this paper, we discuss the role of an external magnetic field on the dynamically generated fermion mass in even-flavor QED in three space-time dimensions. Based on some reasonable approximations,...
Vacuum structure of gauge theory on lattice with two parallel plaquette action (1999)
We perform Monte Carlo simulations of a lattice gauge system with an action which contains two parallel plaquettes. The action is defined as a product of gauge group variables over two parallel...
Farakos, K., Koutsoumbas, G., Mavromatos, N., Momen, A.
The enhancement of the fermionic condensate due to the presence of both homogeneous and non-homogeneous external magnetic fields is studied for three-dimensional QED.
Phase Structure of lattice SU(2)xU_S(1) three-dimensional Gauge Theory (1998)
Farakos, K., Mavromatos, N. E., McNeill, D.
We discuss a phase diagram for a relativistic SU(2) x U_{S}(1) lattice gauge theory, with emphasis on the formation of a parity-invariant chiral condensate, in the case when the $U_{S}(1)$ field is...
Probing the Gauge Structure of high-temperature superconductors (1998)
Farakos, K., Koutsoumbas, G., Mavromatos, N. E.
We suggest that a spin-charge separating ansatz, leading to non-Abelian $SU(2) \otimes U_S(1)$ gauge symmetries in doped antiferromagnets, proposed earlier as a way of describing Kosterlitz-Thouless...
Dynamical Flavour Symmetry Breaking by a Magnetic Field in Lattice QED_3 (1998)
Farakos, K., Koutsoumbas, G., Mavromatos, N. E.
We perform a lattice study, in the quenched approximation, of dynamical mass generation in a system of relativistic (Dirac) fermions, coupled to an Abelian gauge field in (2+1)-dimensions, in the...
Gauge-theory approach to planar doped antiferromagnets and external magnetic fields (1997)
Farakos, K., Mavromatos, N. E.
A review is given of a relativistic non-Abelian gauge theory approach to the physics of spin-charge separation in doped quantum antiferromagnetic planar systems, proposed recently by the authors....
Wilson line in high temperature particle physics (1997)
Bronoff, S., Dvali, G., Farakos, K., Altes, C. P. Korthals
The physics of the Wilson line leads to new developments in high temperature particle physics. The main tool is the effective action for a given fixed value of the phase of the Wilson line. It...
Dynamical Gauge Symmetry Breaking and Superconductivity in three-dimensional systems (1997)
Farakos, K., Mavromatos, N. E.
We discuss dynamical breaking of non-abelian gauge groups in three dimensional (lattice) gauge systems via the formation of fermion condensates. A physically relevant example, motivated by...
Three-dimensional lattice U(1) gauge-Higgs model at low $m_H$ (1997)
Dimopoulos, P., Farakos, K., Koutsoumbas, G.
We study the non-compact version of the U(1) gauge-Higgs model in three dimensions for $m_H = 30 GeV.$ We found that, using this formulation, rather modest lattices approach quite well the infinite...
Hidden Non-Abelian Gauge Symmetries in Doped Planar Antiferromagnets (1996)
Farakos, K., Mavromatos, N. E.
We investigate the possibility of hidden non-Abelian Local Phase symmetries in large-U doped planar Hubbard antiferromagnets, believed to simulate the physics of two-dimensional (magnetic)...
Results from 3D electroweak phase transition simulations (1995)
Farakos, K, Kajantie, Keijo, Laine, Mikko, Rummukainen, K, Shaposhnikov, Mikhail E
We study the phase transition in SU(2)-Higgs model on the lattice using the 3D dimensionally reduced formalism. The 3D formalism enables us to obtain highly accurate Monte Carlo results, which we...
Results from 3D Electroweak Phase Transition Simulations (1995)
Farakos, K., Kajantie, K., Laine, M., Rummukainen, K., Shaposhnikov, M.
We study the phase transition in SU(2)-Higgs model on the lattice using the 3D dimensionally reduced formalism. The 3D formalism enables us to obtain highly accurate Monte Carlo results, which we...
3D physics and the electroweak phase transition: a framework for lattice Monte Carlo analysis (1995)
Farakos, K, Kajantie, Keijo, Rummukainen, K, Shaposhnikov, Mikhail E
3D physics and the electroweak phase transition: a framework for lattice Monte Carlo analysis We discuss a framework relying on both perturbative and non-perturbative lattice computations which will...
3d physics and the electroweak phase transition: a framework for lattice Monte Carlo analysis (1994)
Farakos, K., Kajantie, K., Rummukainen, K., Shaposhnikov, M.
We discuss a framework relying on both perturbative and non-perturbative lattice computations which will be able to reliably determine the parameters of the EW phase transition. A motivation for the...
The electroweak phase transition at m$_{H}$ $\appprox$ m$_{W}$ (1994)
Farakos, K, Kajantie, Keijo, Rummukainen, K, Shaposhnikov, Mikhail E
We study the finite temperature electroweak transition with non-perturbative lattice Monte Carlo simulations. We find that it is of first order, at least for Higgs masses up to 80 GeV. The critical...
The Electroweak Phase Transition at $m_H \simeq m_W$ (1994)
Farakos, K., Kajantie, K., Rummukainen, K., Shaposhnikov, M.
We study the finite temperature electroweak transition with non-perturbative lattice Monte Carlo simulations. We find that it is of first order, at least for Higgs masses up to 80 GeV. The critical...
3D physics and the electroweak phase transition: perturbation theory (1994)
Farakos, K, Kajantie, Keijo, Rummukainen, K, Shaposhnikov, Mikhail E
We develop a method for the construction of the effective potential at high temperatures based on the effective field theory approach and renormalization group. It allows one to sum up the leading...
3D Physics and the Electroweak Phase Transition: Perturbation Theory (1994)
Farakos, K., Kajantie, K., Rummukainen, K., Shaposhnikov, M.
We develop a method for the construction of the effective potential at high temperatures based on the effective field theory approach and renormalization group. It allows one to sum up the leading...
Level Crossing for Hot Sphalerons (1994)
Ambjorn, J., Farakos, K., Hands, S., Koutsoumbas, G., Thorleifsson, G.
We study the spectrum of the Dirac Hamiltonian in the presence of high temperature sphaleron-like fluctuations of the electroweak gauge and Higgs fields, relevant for the conditions prevailing in the...
The finite temperature phase transition in the lattice SU(2)-Higgs model (1993)
Farakos, K, Kajantie, Keijo, Rummukainen, K, Shaposhnikov, Mikhail E
We study the finite temperature transition of SU(2)-Higgs model with lattice Monte Carlo techniques. We use dimensional reduction to transform the original 4-dimensional SU(2)-gauge + fundamental...
The Finite Temperature Phase Transition in the Lattice SU(2)-Higgs Model (1993)
Farakos, K., Kajantie, K., Rummukainen, K., Shaposhnikov, M.
We study the finite temperature transition of SU(2)-Higgs model with lattice Monte Carlo techniques. We use dimensional reduction to transform the original 4-dimensional SU(2)-gauge + fundamental...
Topography of the hot sphaleron Transitions (1992)
By numerical simulations in {\it real time} we provide evidence in favour of sphaleron like transitions in the hot, symmetric phase of the electroweak theory. Earlier performed observations of a...
Parity breaking at high temperature and density (1992)
Ambjørn, Jan, Farakos, K, Shaposhnikov, Mikhail E
We investigate the question of parity breaking in three-dimensional Euclidean $SU(2)$ gauge-Higgs theory by Monte Carlo simulations. We observe no sign of spontaneous parity breaking in the behaviour...
Parity breaking at high temperature and density (1992)
Ambjørn, J., Farakos, K., Shaposhnikov, M. E.
We investigate the question of parity breaking in three-dimensional Euclidean SU(2) gauge-Higgs theory by Monte Carlo simulations. We observe no sign of spontaneous parity breaking in the behaviour...