Results for "Emil T. Akhmedov"

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Ultraviolet phenomena in AdS self-interacting quantum field theoryFeb 08 2018We study the one-loop corrections to the four-point function in the Anti de Sitter space-time for a $\phi^4$ field theory. Our calculation shows the existence of non-local counterterms which however respect the AdS isometry. Our arguments are quite general ... More
Lectures on General Theory of RelativityJan 19 2016Nov 19 2016These are lectures on General Theory of Relativity that were given to students of the Mathematical Faculty of the Higher School of Economics in Moscow.
Expansion in Feynman Graphs as Simplicial String TheoryJul 02 2004Aug 22 2004We show that the series expansion of quantum field theory in the Feynman diagrams can be explicitly mapped on the partition function of the simplicial string theory -- the theory describing embeddings of the two--dimensional simplicial complexes into ... More
Non-Abelian Structures in BSFT and RR couplingsSep 29 2001Oct 04 2001In this talk we show that the tachyon annihilation combined with an approximation, in which string theory non-commutativity structure is captured by the algebra of differential operators on space-time, gives a unified point of view on: non-Abelian structures ... More
Real or Imaginary? (On pair creation in de Sitter space)Sep 21 2009Jul 06 2010Using properly defined Feynman propagator we obtain non--zero imaginary contribution to the scalar field effective action in even dimensional de Sitter space. Such a propagator follows from the path integral in de Sitter space and obeys composition principle ... More
Towards the Theory of Non--Abelian Tensor Fields IIJun 03 2005We go on with the definition of the theory of the non--Abelian two--tensor fields and find the gauge transformation rules and curvature tensor for them. To define the theory we use the surface {\it exponent} proposed in hep--th/0503234. We derive the ... More
Simplicial vs. Continuum String Theory and Loop EquationsFeb 19 2005Apr 07 2005We derive loop equations in a scalar matrix field theory. We discuss their solutions in terms of simplicial string theory -- the theory describing embeddings of two--dimensional simplicial complexes into the space--time of the matrix field theory. This ... More
Classical radiation by free-falling charges in de Sitter spacetimeJun 16 2010Aug 06 2010We study the classical radiation emitted by free-falling charges in de Sitter spacetime coupled to different kinds of fields. Specifically we consider the cases of the electromagnetic field, linearized gravity and scalar fields with arbitrary mass and ... More
Comment on the Surface Exponential for Tensor FieldsApr 19 2005Starting from essentially commutative exponential map $E(B|I)$ for generic tensor-valued 2-forms $B$, introduced in \cite{Akh} as direct generalization of the ordinary non-commutative $P$-exponent for 1-forms with values in matrices (i.e. in tensors of ... More
On the physical meaning of the Unruh effectMay 17 2007Oct 19 2007We present simple arguments that detectors moving with constant acceleration (even acceleration for a finite time) should detect particles. The effect is seen to be universal. Moreover, detectors undergoing linear acceleration and uniform, circular motion ... More
A simple way to take into account back reaction on pair creationDec 17 2009Mar 08 2010We propose a simple and systematic way of accounting for the back reaction on the background field due to the pair creation in the four--dimensional scalar QED. This method is straightforwardly generalizable to the gravity backgrounds. In the case of ... More
On the relation between Unruh and Sokolov--Ternov effectsOct 29 2006May 13 2007We show that the Sokolov--Ternov effect -- the depolarization of particles in storage rings coming from synchrotron radiation due to spin flip transitions -- is physically equivalent to the Unruh effect for circular acceleration if one uses a spin 1/2 ... More
Infrared dynamics of the massive $φ^4$ theory on de Sitter spaceMar 05 2013Nov 15 2013We study massive real scalar $\phi^4$ theory in the expanding Poincare patch of de Sitter space. We calculate the leading two-loop infrared contribution to the two-point function in this theory. We do that for the massive fields both from the principal ... More
Interacting Field Theories in de Sitter Space are Non-UnitaryAug 29 2008Sep 27 2008It is well known that there should be a total cancellation of the IR divergences in unitary interacting field theories, such as QED and gravity. The cancellation should be at all orders between loop and tree level contributions to cross--sections. This ... More
Subtleties in the quasi-classical calculation of Hawking radiationMay 17 2008Oct 02 2008he quasi-classical method of deriving Hawking radiation is investigated. In order to recover the original Hawking temperature one must take into account a previously ignored contribution coming from the temporal part of the action. This contribution plus ... More
Hawking temperature in the tunneling pictureAug 15 2006Sep 24 2006We examine Hawking radiation from a Schwarzschild black hole in several reference frames using the quasi-classical tunneling picture. It is shown that when one uses, $\Gamma \propto \exp(Im [\oint p dr])$, rather than, $\Gamma \propto \exp(2 Im [\int ... More
Majorana neutrinos and other Majorana particles:Theory and experimentDec 10 2014This is a somewhat modified version of Chapter 15 of the book "The Physics of Ettore Majorana", by Salvatore Esposito with contributions by Evgeny Akhmedov (Ch. 15) and Frank Wilczek (Ch. 14), Cambridge University Press, 2014.
Thermal radiation of various gravitational backgroundsMay 14 2006Feb 17 2007We present a simple and general procedure for calculating the thermal radiation coming from any stationary metric. The physical picture is that the radiation arises as the quasi--classical tunneling of particles through a gravitational barrier. We show ... More
Running couplings and triviality of field theories on non-commutative spacesOct 01 2000Oct 07 2000We examine the issue of renormalizability of asymptotically free field theories on non-commutative spaces. As an example, we solve the non-commutative O(N) invariant Gross-Neveu model at large N. On commutative space this is a renormalizable model with ... More
De Sitter space and perpetuum mobileMay 17 2009Feb 14 2010We give general arguments that any interacting non--conformal {\it classical} field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile. The arguments are based on the observation that massive free falling particles can ... More
On Unification of RR CouplingsMay 22 2001May 30 2001We consider the couplings of RR fields with open string sector for $Dp$-${\overline{Dp}}$ backgrounds of various $p$. Proposed approach, based on the approximation of the open string algebra by the algebra of differential operators, provides the unified ... More
A way to distinguish very compact stellar objects from black holesJan 15 2016Feb 15 2016We propose a way to distinguish compact stellar object, whose size is very close to its Schwarzschild radius, from the collapsing stars. Namely, we show that {\it massive} fields in the vicinity of a very compact stellar object have discrete energy levels. ... More
Non-commutative Gross-Neveu model at large NMar 23 2001Apr 05 2001The non-commutative O(N) Gross-Neveu model is solved in the large N limit in two and three space-time dimensions. The commutative version of the two dimensional model is a renormalizable quantum field theory, both in a coupling constant expansion and ... More
Hawking radiation and secularly growing loop correctionsAug 29 2015Dec 20 2015We study the expectation value of the energy momentum tensor during thin shell collapse for a massive, real, scalar field theory. At tree-level, we find thermal, Hawking-type, behaviour for the energy flux. Using the Schwinger-Keldysh technique, we calculate ... More
Neutrino oscillations: Quantum mechanics vs. quantum field theoryJan 27 2010Nov 20 2012A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between ... More
Exotic Smooth Structures on Small 4-Manifolds with Odd SignaturesJan 29 2007Sep 10 2009Let $M$ be $\CP#2\CPb$, $3\CP#4\CPb$ or $(2n-1)\CP#2n\CPb$ for any integer $n\geq 3$. We construct an irreducible symplectic 4-manifold homeomorphic to $M$ and also an infinite family of pairwise non-diffeomorphic irreducible non-symplectic 4-manifolds ... More
Curvature based triangulation of metric measure spacesJan 29 2010We prove that a Ricci curvature based method of triangulation of compact Riemannian manifolds, due to Grove and Petersen, extends to the context of weighted Riemannian manifolds and more general metric measure spaces. In both cases the role of the lower ... More
Metric Ricci curvature for $PL$ manifoldsMar 07 2012We introduce a metric notion of Ricci curvature for $PL$ manifolds and study its convergence properties. We also prove a fitting version of the Bonnet-Myers Theorem, for surfaces as well as for a large class of higher dimensional manifolds.
A Computational Non-Commutative Geometry Program for Disordered Topological InsulatorsNov 29 2016A computational program based on the principles of non-commutative geometry is presented. This includes the general algebraic principles, the algorithms themselves, the error estimates and the applications. The latter are mainly on the integer quantum ... More
Vector orthogonal polynomials with Bochner's propertySep 20 2016Classical orthogonal polynomial systems of Jacobi, Hermite, Laguerre and Bessel have the property that the polynomials of each system are eigenfunctions of a second order ordinary differential operator. According to a classical theorem by Bochner they ... More
Note on a Theorem of MunkresMar 02 2004Mar 14 2004We prove that given a $\mathcal{C^\infty}$ Riemannian manifold with boundary, any fat triangulation of the boundary can be extended to the whole manifold. We also show that this result holds extends to $\mathcal{C}^1$ manifolds, and that in dimensions ... More
Scalar Gravitational Waves in the Effective Theory of GravityJun 29 2016As a low energy effective field theory, classical General Relativity receives an infrared relevant modification from the conformal trace anomaly of the energy-momentum tensor of massless, or nearly massless, quantum fields. The local form of the effective ... More
The Trace Anomaly and Dynamical Vacuum Energy in CosmologyJun 17 2010The trace anomaly of conformal matter implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. These poles may be described by a local effective action with massless scalar fields, which couple to classical ... More
Functional Integration Over GeometriesFeb 17 1995The geometric construction of the functional integral over coset spaces ${\cal M}/{\cal G}$ is reviewed. The inner product on the cotangent space of infinitesimal deformations of $\cal M$ defines an invariant distance and volume form, or functional integration ... More
New Horizons in Gravity: Dark Energy and Condensate StarsJul 25 2011Black holes are an apparently unavoidable prediction of classical General Relativity, at least if matter obeys the strong energy condition rho + 3p > 0. However quantum vacuum fluctuations generally violate this condition, as does the eq. of state of ... More
The complexity of admissible rules of Łukasiewicz logicAug 31 2011Feb 28 2012We investigate the computational complexity of admissibility of inference rules in infinite-valued {\L}ukasiewicz propositional logic (\L). It was shown in [13] that admissibility in {\L} is checkable in PSPACE. We establish that this result is optimal, ... More
The Existence of Quasimeromorphic MappingsApr 30 2004We prove that a Kleinian group $G$ acting upon $\mathbb{H}^{n}$ admits a non-constant $G$-automorphic function, even if it has torsion elements, provided that the orders of the elliptic (torsion) elements are uniformly bounded. This is accomplished by ... More
Existence of Weak Solutions for the Incompressible Euler EquationsFeb 17 2011Using a recent result of C. De Lellis and L. Sz\'{e}kelyhidi Jr. we show that, in the case of periodic boundary conditions and for dimension greater or equal 2, there exist infinitely many global weak solutions to the incompressible Euler equations with ... More
Generalized Gould-Hopper polynomialsSep 20 2016Classical orthogonal polynomial systems of Jacobi, Hermite, Laguerre and Bessel have the property that the polynomials of each system are eigenfunctions of a second order ordinary differential operator. According to a famous theorem by Bochner they are ... More
Conformal Invariance, Dynamical Dark Energy and the CMBMar 08 2011General Relativity receives quantum corrections relevant at cosmological distance scales from the conformal scalar degrees of freedom required by the trace anomaly of the quantum stress tensor in curved space. In the theory including the trace anomaly ... More
Gauge Invariance in 2PI Effective ActionsApr 29 2003The problem of maintaining gauge invariance in the 2PI formulation of QED is discussed. A modified form of the 2PI effective action is suggested in which Ward identities for external (background field) and internal (quantum field) gauge transformations ... More
New Horizons in Gravity: The Trace Anomaly, Dark Energy and Condensate StarsAug 30 2010General Relativity receives quantum corrections relevant at macroscopic distance scales and near event horizons. These arise from the conformal scalar degrees of freedom in the extended effective field theory of gravity generated by the trace anomaly ... More
A Simple Sampling Method for Metric Measure SpacesMar 20 2011We introduce a new, simple metric method of sampling metric measure spaces, based on a well-known "snowflakeing operator" and we show that, as a consequence of a classical result of Assouad, the sampling of doubling metric spaces is bilipschitz equivalent ... More
Free limits of Thompson's group $F$Aug 10 2009Sep 17 2010We produce a sequence of markings $S_k$ of Thompson's group $F$ within the space ${\mathcal G}_n$ of all marked $n$-generator groups so that the sequence $(F,S_k)$ converges to the free group on $n$ generators, for $n \geq 3$. In addition, we give presentations ... More
The existence of thick triangulations -- an "elementary" proofDec 02 2008We provide an alternative, simpler proof of the existence of thick triangulations for noncompact $\mathcal{C}^1$ manifolds. Moreover, this proof is simpler than the original one given in \cite{pe}, since it mainly uses tools of elementary differential ... More
Gluing of Surfaces with Polygonal BoundariesDec 17 2007Aug 24 2008By pairwise gluing of edges of a polygon, one produces two-dimensional surfaces with handles and boundaries. In this paper, we count the number ${\cal N}_{g,L}(n_1, n_2, ..., n_L)$ of different ways to produce a surface of given genus $g$ with $L$ polygonal ... More
On the Entropy of Matrix Black HolesApr 17 1997May 07 1997We compute the entropy of 5d black holes carrying up to three charges using matrix theory.
Matrix Black HolesMar 28 1997Apr 17 1997Four and five dimensional extremal black holes with nonzero entropy have simple presentations in M-theory as gravitational waves bound to configurations of intersecting M-branes. We discuss realizations of these objects in matrix models of M-theory, investigate ... More
Density Functional Model for Nondynamic and Strong CorrelationOct 24 2014Dec 18 2015A single-term density functional model for nondynamic and strong correlation is presented, based on single-determinant Kohn-Sham density functional theory. It is derived from modeling the adiabatic connection and contains only two nonlinear empirical ... More
Systematics of High Temperature Perturbation Theory: The Two-Loop Electron Self-Energy in QEDJul 23 2009Feb 09 2010In order to investigate the systematics of the loop expansion in high temperature gauge theories beyond the leading order hard thermal loop (HTL) approximation, we calculate the two-loop electron proper self-energy in high temperature QED. The two-loop ... More
Integrable time-dependent Hamiltonians, solvable Landau-Zener models and Gaudin magnetsFeb 03 2018We solve the non-stationary Schrodinger equation for several time-dependent Hamiltonians, such as the BCS Hamiltonian with an interaction strength inversely proportional to time, periodically driven BCS and linearly driven inhomogeneous Dicke models as ... More
The Trace Anomaly and Massless Scalar Degrees of Freedom in GravityDec 01 2008The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, ... More
Macroscopic Effects of the Quantum Trace AnomalyApr 11 2006The low energy effective action of gravity in any even dimension generally acquires non-local terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action ... More
Classification of Sol latticesJun 23 2011$\SOL$ geometry is one of the eight homogeneous Thurston 3-geomet-ri-es $$\EUC, \SPH, \HYP, \SXR, \HXR, \SLR, \NIL, \SOL.$$ In \cite{Sz10} the {\it densest lattice-like translation ball packings} to a type (type {\bf I/1} in this paper) of $\SOL$ lattices ... More
Darboux Transformations of Bispectral Quantum Integrable SystemsJun 05 1998We present an approach to higher dimensional Darboux transformations suitable for application to quantum integrable systems and based on the bispectral property of partial differential operators. Specifically, working with the algebro-geometric definition ... More
Constructing infinitely many smooth structures on small 4-manifoldsMar 16 2007Apr 18 2007The purpose of this article is twofold. First we outline a general construction scheme for producing simply-connected minimal symplectic 4-manifolds with small Euler characteristics. Using this scheme, we illustrate how to obtain irreducible symplectic ... More
Comments on QED with background electric fieldsJan 05 2009Feb 23 2009It is well known that there is a total cancellation of the \emph{factorizable} IR divergences in unitary interacting field theories, such as QED and quantum gravity. In this note we show that such a cancellation does not happen in QED with background ... More
An exact statement for Wilsonian and Holographic renormalization groupJan 22 2010Mar 03 2010We show that Polchinski equations in the D--dimensional matrix scalar field theory can be reduced at large $N$ to the Hamiltonian equations in a (D+1)-dimensional theory. In the subsector of the $\Tr \phi^l$ (for all $l$) operators we find the exact form ... More
Non-linear evolution in CCFM: The interplay between coherence and saturationMay 27 2010We solve the CCFM equation numerically in the presence of a boundary condition which effectively incorporates the non-linear dynamics. We retain the full dependence of the unintegrated gluon distribution on the coherence scale, and extract the saturation ... More
Dark Energy and Condensate Stars: Casimir Energy in the LargeMay 19 2004Vacuum fluctuations and the Casimir effect are considered in a cosmological setting. It is suggested that the dark energy, which recent observations suggest make up 73% of our universe, is vacuum energy due to a causal boundary effect at the cosmological ... More
On the Instability of Global de Sitter Space to Particle CreationSep 30 2013We show that global de Sitter space is unstable to particle creation, even for a massive free field theory with no self-interactions. The O(4,1) de Sitter invariant state is a definite phase coherent superposition of particle and anti-particle solutions ... More
Gravitational Condensate Stars: An Alternative to Black HolesSep 11 2001Feb 27 2002A new solution for the endpoint of gravitational collapse is proposed. By extending the concept of Bose-Einstein condensation to gravitational systems, a cold, compact object with an interior de Sitter condensate phase and an exterior Schwarzschild geometry ... More
A few more comments on secularly growing loop corrections in strong electric fieldsDec 04 2014Aug 25 2015We extend the observations of our previous paper JHEP 1409, 071 (2014) [arXiv:1405.5285]. In particular, we show that the secular growth of the loop corrections to the two--point correlation functions is gauge independent: we observe the same growth in ... More
Weyl Cohomology and the Effective Action for Conformal AnomaliesJun 18 2001We present a general method of deriving the effective action for conformal anomalies in any even dimension, which satisfies the Wess-Zumino consistency condition by construction. The method relies on defining the coboundary operator of the local Weyl ... More
Compactness of the d-bar-Neumann problem on convex domainsNov 30 1997The d-bar-Neumann operator on (0,q)-forms ($1\le q \le n$) on a bounded convex domain Omega in C^n is compact if and only if the boundary of Omega contains no complex analytic (equivalently: affine) variety of dimension greater than or equal to q.
Young Measures Generated by Ideal Incompressible Fluid FlowsJan 18 2011May 19 2012In their seminal paper "Oscillations and concentrations in weak solutions of the incompressible fluid equations", R. DiPerna and A. Majda introduced the notion of measure-valued solution for the incompressible Euler equations in order to capture complex ... More
On the relation between effective supersymmetric actions in different dimensionsFeb 05 2002We make two remarks: (i) Renormalization of the effective charge in a 4--dimensional (supersymmetric) gauge theory is determined by the same graphs and is rigidly connected to the renormalization of the metric on the moduli space of the classical vacua ... More
The Quantum Vlasov Equation and its Markov LimitMar 18 1998Mar 19 1998The adiabatic particle number in mean field theory obeys a quantum Vlasov equation which is nonlocal in time. For weak, slowly varying electric fields this particle number can be identified with the single particle distribution function in phase space, ... More
Physical States of the Quantum Conformal FactorSep 28 1995The conformal factor of the spacetime metric becomes dynamical due to the trace anomaly of matter fields. Its dynamics is described by an effective action which we quantize by canonical methods on the Einstein universe $R\times S^3$. We find an infinite ... More
Pseudo-Newtonian Potential for Charged Particle in Kerr-Newman GeometryApr 06 2005We consider the equatorial circular motion of a test particle of specific charge q/m << 1 in the Kerr-Newman geometry of a rotating charged black hole. We find the particle's conserved energy and conserved projection of the angular momentum on the black ... More
On the Field Equations of Kaluza's TheoryJan 26 2004Jul 14 2005The field equations of the original Kaluza's theory are analyzed and it is shown that they lead to modification of Einstein's equations. The appearing extra energy-momentum tensor is studied and an example is given where this extra energy-momentum tensor ... More
Energy-Momentum Tensor of Particles Created in an Expanding UniverseJun 30 1999We present a general formulation of the time-dependent initial value problem for a quantum scalar field of arbitrary mass and curvature coupling in a FRW cosmological model. We introduce an adiabatic number basis which has the virtue that the divergent ... More
Comment on "Nongaussian Isocurvature Perturbations from Inflation"May 24 1997In a recent paper of Linde and Mukhanov, a hybrid inflationary model with nongaussian density perturbations and a ``blue'' spectral index n > 1 was presented. In this comment we point out that this model can be considered as a particular realization of ... More
Quantum Diffeomorphisms and Conformal SymmetrySep 28 1995We analyze the constraints of general coordinate invariance for quantum theories possessing conformal symmetry in four dimensions. The character of these constraints simplifies enormously on the Einstein universe $R \times S^3$. The $SO(4,2)$ global conformal ... More
Cosmological Dark Energy: Prospects for a Dynamical TheoryDec 12 2006We present an approach to the problem of vacuum energy in cosmology, based on dynamical screening of Lambda on the horizon scale. We review first the physical basis of vacuum energy as a phenomenon connected with macroscopic boundary conditions, and the ... More
Weak-strong uniqueness for measure-valued solutions of some compressible fluid modelsMar 17 2015We prove weak-strong uniqueness in the class of admissible measure-valued solutions for the isentropic Euler equations in any space dimension and for the Savage-Hutter model of granular flows in one and two space dimensions. For the latter system, we ... More
Vanishing viscosity as a selection principle for the Euler equations: The case of 3D shear flowAug 11 2012We show that for a certain family of initial data, there exist non-unique weak solutions to the 3D incompressible Euler equations satisfying the weak energy inequality, whereas the weak limit of every sequence of Leray-Hopf weak solutions for the Navier-Stokes ... More
T violation in neutrino oscillations in matterMay 03 2001May 29 2001We consider the interplay of fundamental and matter-induced T violation effects in neutrino oscillations in matter. After discussing the general features of these effects we derive a simple approximate analytic expression for the T-violating probability ... More
Neutrinos with Mixing in Twisting Magnetic FieldsJan 06 1993Transitions in a system of neutrinos with vacuum mixing and magnetic moments, propagating in matter and transverse magnetic field, are considered. It is shown that in the realistic case of magnetic field direction varying along the neutrino path qualitatively ... More
Observation of a Dislocation Related Interfacial Friction Mechanism in Mobile Solid $^4$HeJun 05 2012Jul 16 2015We report a study of the temperature and stress dependence of the friction associated with a relative motion of two masses of solid $^4$He in contact. The situation where "two masses" coupled only by friction exists emerges spontaneously during a disordering ... More
Influence of Point Defects on the Shear Elastic Coefficients and on the Melting Temperature of CopperMay 02 2001We present molecular dynamics simulations of the influence of point defects on the shear elastic coefficients of copper. We find that vacancies do not influence these coefficients at all, while the introduction of interstitials causes a large reduction ... More
Observation of quantum friction in solid 4HeApr 04 2016Classical sliding friction is dominated by the slip-stick mechanism, where contacts between two bodies are alternately formed and sheared as the bodies move past each other. When the interface between two bodies is perfectly smooth, classical friction ... More
Vacuum Structure and Gravitational Bags Produced by Metric-Independent Spacetime Volume-Form DynamicsApr 04 2015May 29 2015We propose a new class of gravity-matter-gauge theories in terms of two different non-Riemannian volume-forms independent of the Riemannian metric. The nonlinear gauge field system contains a square-root $\sqrt{-F^2}$ of the standard Maxwell Lagrangian ... More
Quintessential Inflation, Unified Dark Energy and Dark Matter, and Higgs MechanismSep 22 2016We describe a new type of gravity-matter models where gravity couples in a non-conventional way to two distinct scalar fields providing a unified Lagrangian action principle description of: (a) the evolution of both "early" and "late" Universe - by the ... More
Cosmology via Metric-Independent Volume-Form DynamicsSep 04 2015The method of non-Riemannian volume-forms (metric-independent covariant integration measure densities on the spacetime manifold) is applied to construct a unified model of dynamical dark energy plus dark matter as a dust fluid resulting from a hidden ... More
Entanglement Scaling of Fractional Quantum Hall states through Geometric DeformationsMar 29 2010Aug 08 2010We present a new approach to obtaining the scaling behavior of the entanglement entropy in fractional quantum Hall states from finite-size wavefunctions. By employing the torus geometry and the fact that the torus aspect ratio can be readily varied, we ... More
Winding Transitions at Finite Energy and Temperature: An O(3) ModelAug 14 1996Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at ... More
Minijet Initial Conditions For Non-Equilibrium Parton Evolution at RHIC and LHCOct 28 2002Jan 24 2003An important ingredient for the non-equilibrium evolution of partons at RHIC and LHC is to have some physically reasonable initial conditions for the single particle phase space distribution functions for the partons. We consider several plausible parametrizations ... More
Finite Energy Instantons in the O(3) Non-Linear Sigma ModelNov 09 1994We consider winding number transitions in the two dimensional O(3) non-linear sigma model, modified by a suitable conformal symmetry breaking term. We discuss the general properties of the relevant instanton solutions which dominate the transition amplitudes ... More
Wheeler-DeWitt Quantization of Gravity Models of Unified Dark Energy and Dark MatterDec 28 2017First, we describe the construction of a new type of gravity-matter models based on the formalism of non-Riemannian space-time volume forms - alternative generally covariant integration measure densities (volume elements) defined in terms of auxiliary ... More
Hints on integrability in the Wilsonian/holographic renormalization groupJun 10 2010Sep 20 2011The Polchinski equations for the Wilsonian renormalization group in the $D$--dimensional matrix scalar field theory can be written at large $N$ in a Hamiltonian form. The Hamiltonian defines evolution along one extra holographic dimension (energy scale) ... More
Modularity prevents tailsSep 30 1996We establish a direct correspondence between two congruence poroperties for finite algebras. The first property is that minimal sets of type i omit tails. The second property is that congruence lattices omit pentagons of type i.
Optimal Detection in Training Assisted SIMO Systems with Phase Noise ImpairmentsApr 09 2015In this paper, the problem of optimal maximum likelihood detection in a single user single-input multiple-output (SIMO) channel with phase noise at the receiver is considered. The optimal detection rules under training are derived for two operation modes, ... More
Massive MIMO for Maximal Spectral Efficiency: How Many Users and Pilots Should Be Allocated?Dec 22 2014Oct 20 2015Massive MIMO is a promising technique to increase the spectral efficiency (SE) of cellular networks, by deploying antenna arrays with hundreds or thousands of active elements at the base stations and performing coherent transceiver processing. A common ... More
ML Detection in Phase Noise Impaired SIMO Channels with Uplink TrainingMay 25 2015Oct 30 2015The problem of maximum likelihood (ML) detection in training-assisted single-input multiple-output (SIMO) systems with phase noise impairments is studied for two different scenarios, i.e. the case when the channel is deterministic and known (constant ... More
Toward the End of TimeMar 14 2006Apr 27 2006The null-brane space-time provides a simple model of a big crunch/big bang singularity. A non-perturbative definition of M-theory on this space-time was recently provided using matrix theory. We derive the fermion couplings for this matrix model and study ... More
Secularly growing loop corrections in strong electric fieldsMay 21 2014Nov 25 2014We calculate one--loop corrections to the vertexes and propagators of photons and charged particles in the strong electric field backgrounds. We use the Schwinger--Keldysh diagrammatic technique. We observe that photon's Keldysh propagator receives growing ... More
Implications of Gallium Solar Neutrino Data for the Resonant Spin-Flavor Precession ScenarioJan 14 1993We consider the implications of the recent results of SAGE and GALLEX experiments for the solution of the solar neutrino problem in the framework of the resonant neutrino spin-flavor precession scenario. It is shown that this scenario is consistent with ... More
Solar Neutrino Data, Neutrino Magnetic Moments and Flavor MixingNov 15 1994The results of all currently operating solar neutrino experiments are analyzed in the framework of the resonant neutrino spin--flavor precession scenario including the effects of neutrino mixing. Nine different profiles of the solar magnetic field are ... More