Publications (31)
Functional Callan-Symanzik equation for QED
J. Alexandre, J. Polonyi, K. Sailer
An exact evolution equation, the functional generalization of the Callan-Symanzik method, is given for the effective action of QED where the electron mass is used to turn the quant…
Emergent relativistic-like Kinematics and Dynamical Mass Generation for a Lifshitz-type Yukawa model
J. Alexandre, N. E. Mavromatos, D. Yawitch
We study the Infra Red (IR) limit of dispersion relations for scalar and fermion fields in a Lifshitz-type Yukawa model, after dressing by quantum fluctuations. Relativistic-like d…
QED in a Strong External Magnetic Field: Beyond the Constant Mass Approximation
J. Alexandre, K. Farakos, G. Koutsoumbas
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…
Maxwell Construction for Scalar Field Theories with Spontaneous Symmetry Breaking
J. Alexandre, A. Tsapalis
Using a non-perturbative approximation for the partition function of a complex scalar model, which features spontaneous symmetry breaking, we explicitly derive the flattening of th…
Liouville-Lifshitz theory in 3+1 dimensions
J. Alexandre, K. Farakos, A. Tsapalis
We consider a four-dimensional theory in the z=3 Lifshitz context, with an exponential (Liouville) potential. We determine the exact renormalized potential of the theory and derive…
Dark Energy as an off-shell Tachyon Background in four-dimensional Strings
J. Alexandre, N. E. Mavromatos
We consider a time-dependent bosonic string in graviton, dilaton and tachyon backgrounds, for which it was already shown that conformal invariance is respected to all orders in alp…
The Physics Programme Of The MoEDAL Experiment At The LHC
B. Acharya, J. Alexandre, J. Bernabéu +59
The MoEDAL experiment at Point 8 of the LHC ring is the seventh and newest LHC experiment. It is dedicated to the search for highly ionizing particle avatars of physics beyond the…
Schwinger-Dyson approach for a Lifshitz-type Yukawa model
J. Alexandre, K. Farakos, P. Pasipoularides +1
We consider a 3+1 dimensional field theory at a Lifshitz point for a dynamical critical exponent z=3, with a scalar and a fermion field coupled via a Yukawa interaction. Using the…
Quantization leading to a natural flattening of the axion potential
J. Alexandre, D. Tanner
Starting from the general cosine form for the axion effective potential, we quantize the axion and show that the result is described by a naturally flat potential, if interactions…
Lorentz-symmetry violation and dynamical flavour oscillations
J. Alexandre
We show how a mass mixing matrix can be generated dynamically, for two massless fermion flavours coupled to a Lorentz invariance violating (LIV) gauge field. The LIV features play…
Spatially Anisotropic Four-Dimensional Gauge Interactions, Planar Fermions and Magnetic Catalysis
J. Alexandre, K. Farakos, G. Koutsoumbas +1
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 fi…
On higher-order corrections in a four-fermion Lifshitz model
J. Alexandre, J. Brister, N. Houston
We study a flavour-violating four-fermion interaction in the Lifshitz context, in 3+1 dimensions and with a critical exponent z=3. This model is renormalizable, and features dynami…
Wilsonian renormalization group properties of a novel non-critical cosmological string configuration
J. Alexandre, N. E. Mavromatos
We show that an exact, non-critical-string cosmological configuration of dilaton and graviton backgrounds, found in [1], constitutes an infrared stable fixed point of an exact Wils…
Towards Exact Results in Nodal Antiferromagnetic Planar Liquids
J. Alexandre, N. E. Mavromatos, Sarben Sarkar
It has been argued in previous works by the authors that nodal excitations in (2+1)-dimensional doped antiferromagnets might exhibit, in the spin-charge separation framework and at…
Neutrino oscillations in a stochastic model for space-time foam
J. Alexandre, K. Farakos, N. E. Mavromatos +1
We study decoherence models for flavour oscillations in four-dimensional stochastically fluctuating space times and discuss briefly the sensitivity of current neutrino experiments…
Neutrino oscillations in a Robertson-Walker Universe with space time foam
J. Alexandre, K. Farakos, N. E. Mavromatos +1
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 se…
Effective fermion kinematics from a modified quantum gravity
J. Alexandre, J. Leite
We consider a classical fermion and a classical scalar, propagating on two different kinds of 4-dimensional diffeomorphism breaking gravity backgrounds, and we derive the one-loop…
Magnetic catalysis in QED_3 at finite temperature: beyond the constant mass approximation
J. Alexandre, K. Farakos, G. Koutsoumbas
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 fermioni…
First search for dyons with the full MoEDAL trapping detector in 13 TeV pp collisions
B. Acharya, J. Alexandre, P. Benes +66
The MoEDAL trapping detector, consists of approximately 800 kg of aluminium volumes. It was exposed during Run-2 of the LHC program to 6.46 fb^-1 of 13 TeV proton-proton collisions…
Non-renormalization for the Liouville wave function
J. Alexandre, Anna Kostouki, N. E. Mavromatos
Using an exact functional method, within the framework of the gradient expansion for the Liouville effective action, we show that the kinetic term for the Liouville field is not re…
Renormalisation of non-differentiable potentials
J. Alexandre, N. Defenu, G. Grigolia +5
Non-differentiable potentials, such as the V-shaped (linear) potential, appear in various areas of physics. For example, the effective action for branons in the framework of the br…
First experimental search for production of magnetic monopoles via the Schwinger mechanism
B. Acharya, J. Alexandre, P. Benes +64
Schwinger showed that electrically-charged particles can be produced in a strong electric field by quantum tunnelling through the Coulomb barrier. By electromagnetic duality, if ma…
Induced N=2 composite supersymmetry in 2+1 dimensions
J. Alexandre, N. E. Mavromatos, Sarben Sarkar
Starting from N=1 scalar supermultiplets in 2+1 dimensions, we build explicitly the composite superpartners which define a N=2 superalgebra induced by the initial N=1 supersymmetry…
QED with Dynamical Fermions in an External Magnetic Field
J. Alexandre, K. Farakos, S. J. Hands +2
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 spontaneousl…
BUSSTEPP lecture notes: Exact Wilsonian Renormalisation
J. Alexandre
These lecture notes introduce exact Wilsonian renormalisation, and describe its technical approach, from an intuitive implementation to more advanced realisations. The methods and…
Search for magnetic monopoles with the MoEDAL forward trapping detector in 13 TeV proton-proton collisions at the LHC
MoEDAL Collaboration, B. Acharya, J. Alexandre +68
MoEDAL is designed to identify new physics in the form of long-lived highly-ionising particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors…
MoEDAL search in the CMS beam pipe for magnetic monopoles produced via the Schwinger effect
B. Acharya, J. Alexandre, S. C. Behera +64
We report on a search for magnetic monopoles (MMs) produced in ultraperipheral Pb--Pb collisions during Run-1 of the LHC. The beam pipe surrounding the interaction region of the CM…
Search for Highly-Ionizing Particles in pp Collisions at the LHC's Run-1 Using the Prototype MoEDAL Detector
B. Acharya, J. Alexandre, P. Benes +68
A search for highly electrically charged objects (HECOs) and magnetic monopoles is presented using 2.2 fb-1 of p - p collision data taken at a centre of mass energy (ECM) of 8 TeV…
Magnetic monopole search with the full MoEDAL trapping detector in 13 TeV collisions interpreted in photon-fusion and Drell-Yan production
MoEDAL Collaboration, B. Acharya, J. Alexandre +66
MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we u…
Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC
MoEDAL Collaboration, B. Acharya, J. Alexandre +66
The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL det…
Search for magnetic monopoles with the MoEDAL forward trapping detector in 2.11 fb of 13 TeV proton-proton collisions at the LHC
MoEDAL Collaboration, B. Acharya, J. Alexandre +68
We update our previous search for trapped magnetic monopoles in LHC Run 2 using nearly six times more integrated luminosity and including additional models for the interpretation o…