Andronikashvili Institute of Physics

Tbilisi, Georgia

Andronikashvili Institute of Physics

Tbilisi, Georgia

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Gogoladze I.,University of Delaware | Gogoladze I.,Andronikashvili Institute of Physics | Nasir F.,University of Delaware | Shafi Q.,University of Delaware
International Journal of Modern Physics A | Year: 2013

We demonstrate that natural supersymmetry is readily realized in the framework of SU(4)c ×SU(2)L ×SU(2)R with nonuniversal gaugino masses. Focusing on ameliorating the little hierarchy problem, we explore the parameter space of this model which yields small fine-tuning measuring parameters (natural supersymmetry) at the electroweak scale (ΔEW) as well as at high scale (ΔHS). It is possible to have both ΔEW and ΔHS less than 100 in these models, (2% or better fine-tuning), while keeping the light CP-even (Standard Model-like) Higgs mass in the 123-127 GeV range. The light stop quark mass lies in the range 700 GeV < mt̄1 < 1500 GeV, and the range for the light stau lepton mass is 900 GeV m t̄1 < 1300 GeV. The first two family squarks are in the mass range 3000 GeV < mt̄1 < 4500 GeV, and for the gluino we find 2500 GeV < mt̄1 < 3500 GeV. We do not find any solution with natural supersymmetry which yields significant enhancement for Higgs production and decay in the diphoton channel. © 2013 World Scientific Publishing Company.


Strom A.,Gothenburg University | Johannesson H.,Gothenburg University | Japaridze G.I.,Andronikashvili Institute of Physics | Japaridze G.I.,Ilia State University
Physical Review Letters | Year: 2010

We analyze the dynamics of the helical edge modes of a quantum spin Hall state in the presence of a spatially nonuniform Rashba spin-orbit (SO) interaction. A randomly fluctuating Rashba SO coupling is found to open a scattering channel which causes localization of the edge modes for a weakly screened electron-electron (e-e) interaction. A periodic modulation of the SO coupling, with a wave number commensurate with the Fermi momentum, makes the edge insulating already at intermediate strengths of the e-e interaction. We discuss implications for experiments on edge state transport in a HgTe quantum well. © 2010 The American Physical Society.


Gogberashvili M.,Andronikashvili Institute of Physics | Gogberashvili M.,Tbilisi State University | Midodashvili P.,Ilia State University | Midodashvili L.,Gori University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

We investigate the problem of localization of gauge fields within the 5D standing wave braneworld model and show that in the case of increasing warp factor there exist normalizable vector field zero modes on the brane. © 2011 Elsevier B.V.


Tavartkiladze Z.,Andronikashvili Institute of Physics | Tavartkiladze Z.,Ilia State University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Within supersymmetric SU(5) Grand Unified Theory, we present several new scenarios with anomaly free flavor symmetry U(1)F. Within each scenario, a variety of cases offer many possibilities for phenomenologically interesting model building. We present three concrete and economical models with anomaly free U(1)F leading to natural understanding of observed hierarchies between charged fermion masses and CKM mixing angles. © 2011 Elsevier B.V.


Gogberashvili M.,Andronikashvili Institute of Physics | Gogberashvili M.,Tbilisi State University
Journal of High Energy Physics | Year: 2012

We investigate the localization problem of matter fields within the 5D standing wave braneworld. In this model the brane emits anisotropic waves into the bulk with different amplitudes along different spatial dimensions. We show that in the case of increasing warp factor there exist the pure gravitational localization of all kinds of quantum and classical particles on the brane. For classical particles the anisotropy of the background metric is hidden, brane fields exhibit standard Lorentz symmetry in spite of anisotropic nature of the primordial 5D metric. © SISSA 2012.


Tskhakaya D.,University of Innsbruck | Tskhakaya D.,Andronikashvili Institute of Physics
Contributions to Plasma Physics | Year: 2012

Recent results of massively parallel kinetic (PIC/MC) simulations of the tokamak scrape-off layer are discussed. It is demonstrated that a number of well studied properties of the low-recycling divertor plasma, such as the sound speed and the average energy of plasma particles impinging on the divertors, cannot be generalized to the high recycling case. A new analytical model for plasma boundary condition has been derived. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chaloupka J.,Masaryk University | Chaloupka J.,Max Planck Institute for Solid State Research | Jackeli G.,Max Planck Institute for Solid State Research | Jackeli G.,Andronikashvili Institute of Physics | Khaliullin G.,Max Planck Institute for Solid State Research
Physical Review Letters | Year: 2010

We derive and study a spin one-half Hamiltonian on a honeycomb lattice describing the exchange interactions between Ir4+ ions in a family of layered iridates A2IrO3 (A=Li,Na). Depending on the microscopic parameters, the Hamiltonian interpolates between the Heisenberg and exactly solvable Kitaev models. Exact diagonalization and a complementary spin-wave analysis reveal the presence of an extended spin-liquid phase near the Kitaev limit and a conventional Néel state close to the Heisenberg limit. The two phases are separated by an unusual stripy antiferromagnetic state, which is the exact ground state of the model at the midpoint between two limits. © 2010 The American Physical Society.


Tagviashvili M.,Andronikashvili Institute of Physics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

The classical Mie theory for electromagnetic radiation scattering by homogeneous spherical particles is considered in the dielectric constant (ε) →0 limit separately for the materials of the particles and the surrounding medium. The maxima of a scattered transverse electrical (TE) field for the surrounding medium materials with ε→0 limits are investigated. The effective multipole polarizabilities of the corresponding scattering particles are investigated. The possibility of achieving magnetic dipole resonance and accordingly of constructing metamaterials with negative refractive index for aggregates of spherical particles in the surrounding medium with the dielectric constant near zero is demonstrated. © 2010 The American Physical Society.


Berger M.S.,Indiana University Bloomington | Maziashvili M.,Andronikashvili Institute of Physics | Maziashvili M.,Ilia State University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

At a fundamental level the notion of particle (quantum) comes from quantum field theory. From this point of view we estimate corrections to the free particle wave function due to minimum-length deformed quantum mechanics to the first order in the deformation parameter. Namely, in the matrix element that in the standard case sets the free particle wave function there appear three kinds of corrections when the field operator is calculated by using the minimum-length deformed quantum mechanics. Starting from the standard (not modified at the classical level) Lagrangian, after the field quantization we get a modified dispersion relation, and besides that we find that the particle's wave function contains a small fraction of an antiparticle wave function and the backscattered wave. The result leads to interesting implications for black hole physics. © 2011 American Physical Society.


Gogberashvili M.,Andronikashvili Institute of Physics | Gogberashvili M.,Tbilisi State University | Midodashvili P.,Ilia State University | Midodashvili L.,Gori University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We investigate scalar and tensor fields in the brane model solution for the 5D space-time with standing gravitational waves in the bulk and show that even in the case of increasing warp factor there exist normalizable zero modes localized on the brane. © 2011 Elsevier B.V.

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