D. V. Vassilevich

Universidade Federal do ABC (UFABC), Santo André, São Paulo, Brazil

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Publications (141)396.48 Total impact

  • Daniel Grumiller · Jakob Salzer · Dmitri Vassilevich
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    ABSTRACT: We study generic two-dimensional dilaton gravity with a Maxwell field and prove its triviality for constant dilaton boundary conditions, despite of the appearance of a Virasoro algebra with non-zero central charge. We do this by calculating the canonical boundary charges, which turn out to be trivial, and by calculating the quantum gravity partition function, which turns out to be unity. We show that none of the following modifications changes our conclusions: looser boundary conditions, non-linear interactions of the Maxwell field with the dilaton, inclusion of higher spin fields, inclusion of generic gauge fields. Finally, we consider specifically the charged Jackiw--Teitelboim model, whose holographic study was pioneered by Hartman and Strominger, and show that it is non-trivial for certain linear dilaton boundary conditions. We calculate the entropy from the Euclidean path integral, using Wald's method and exploiting the chiral Cardy formula. The macroscopic and microscopic results for entropy agree with each other.
    No preview · Article · Sep 2015 · Journal of High Energy Physics
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    M. Bordag · I. Fialkovsky · D. Vassilevich
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    ABSTRACT: We analyze the Casimir interaction of doped graphene. To this end we derive a simple expression for the finite temperature polarization tensor with a chemical potential. It is found that doping leads to a strong enhancement of the Casimir force reaching almost $60\%$ in quite realistic situations. This result should be important for planning and interpreting the Casimir measurements, especially taking into account that the Casimir interaction of undoped graphene is rather weak.
    Full-text · Article · Jul 2015
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    V. G. Kupriyanov · D. V. Vassilevich
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    ABSTRACT: Deformation quantization is a formal deformation of the algebra of smooth functions on some manifold. In the classical setting, the Poisson bracket serves as an initial conditions, while the associativity allows to proceed to higher orders. Some applications to string theory require deformation in the direction of a quasi-Poisson bracket (that does not satisfy the Jacobi identity). This initial conditions is incompatible with associativity, it is quite unclear which restrictions can be imposed on the deformation. We show that for any quasi-Poisson bracket the deformation quantization exists and is essentially unique if one requires (weak) hermiticity and the Weyl condition. We also propose an iterative procedure that allows to compute the star product up to any desired order.
    Full-text · Article · Jun 2015 · Journal of High Energy Physics
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    ABSTRACT: We investigate whether inclusion of dimension six terms in the Standard Model lagrangean may cause the unification of the coupling constants at a scale comprised between 10^14 and 10^17 GeV. Particular choice of the dimension 6 couplings is motivated by the spectral action. Given the theoretical and phenomenological constraints, as well as recent data on the Higgs mass, we find that the unification is indeed possible, with a lower unification scale slightly favoured.
    Preview · Article · Oct 2014 · International Journal of Modern Physics A
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    M. A. Kurkov · Fedele Lizzi · Dmitri Vassilevich
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    ABSTRACT: We discuss the propagation of bosons (scalars, gauge fields and gravitons) at high energy in the context of the spectral action. Using heat kernel techniques, we find that in the high-momentum limit the quadratic part of the action does not contain positive powers of the derivatives. We interpret this as the fact that the two-point Green functions vanish for nearby points, where the proximity scale is given by the inverse of the cutoff. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license
    Preview · Article · Dec 2013 · Physics Letters B
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    Daniel Grumiller · Mauricio Leston · Dmitri Vassilevich
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    ABSTRACT: We provide a holographic description of two-dimensional dilaton gravity with Anti-de Sitter boundary conditions. We find that the asymptotic symmetry algebra consists of a single copy of the Virasoro algebra with non-vanishing central charge and point out difficulties with the standard canonical treatment. We generalize our results to higher spin theories and thus provide the first examples of two-dimensional higher spin gravity with holographic description. For spin-3 gravity we find that the asymptotic symmetry algebra is a single copy of the W_3-algebra.
    Preview · Article · Nov 2013 · Physical Review D
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    ABSTRACT: We consider gated graphene nanoribbons subject to Berry-Mondragon boundary conditions in the presence of weak impurities. Using field--theoretical methods, we calculate the density of charge carriers (and, thus, the quantum capacitance) as well as the optical and DC conductivities at zero temperature. We discuss in detail their dependence on the gate (chemical) potential, and reveal a non-linear behaviour induced by the quantization of the transversal momentum.
    Full-text · Article · Nov 2013 · Physics of Condensed Matter
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    D. V. Vassilevich
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    ABSTRACT: Poisson sigma models are a very rich class of two-dimensional theories that includes, in particular, all 2D dilaton gravities. By using the Hamiltonian reduction method, we show that a Poisson sigma model (with a sufficiently well-behaving Poisson tensor) on a finite cylinder is equivalent to a noncommutative quantum mechanics for the boundary data.
    Preview · Article · Jan 2013 · Physical review D: Particles and fields
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    ABSTRACT: We propose Lobachevsky boundary conditions that lead to asymptotically H^2xR solutions. As an example we check their consistency in conformal Chern-Simons gravity. The canonical charges are quadratic in the fields, but nonetheless integrable, conserved and finite. The asymptotic symmetry algebra consists of one copy of the Virasoro algebra with central charge c=24k, where k is the Chern-Simons level, and an affine u(1). We find also regular non-perturbative states and show that none of them corresponds to black hole solutions. We attempt to calculate the one-loop partition function, find a remarkable separation between bulk and boundary modes, but conclude that the one-loop partition function is ill-defined due to an infinite degeneracy. We comment on the most likely resolution of this degeneracy.
    Full-text · Article · Dec 2012 · Journal of High Energy Physics
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    N.shtykov · D. V.vassilevich
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    ABSTRACT: We compute the Casimir energy for a free scalar field on the spaces where is two-dimensional deformed two-sphere.
    Preview · Article · May 2012 · Modern Physics Letters A
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    I. V. Fialkovsky · D. V. Vassilevich
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    ABSTRACT: We study magneto--optical properties of monolayer graphene by means of quantum field theory methods in the framework of the Dirac model. We reveal a good agreement between the Dirac model and a recent experiment on giant Faraday rotation in cyclotron resonance. We also predict other regimes when the effects are well pronounced. The general dependence of the Faraday rotation and absorption on various parameters of samples is revealed both for suspended and epitaxial graphene.
    Full-text · Article · Mar 2012 · Physics of Condensed Matter
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    Bruno Iochum · Cyril Levy · Dmitri Vassilevich
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    ABSTRACT: The principal object in noncommutatve geometry is the spectral triple consisting of an algebra A, a Hilbert space H, and a Dirac operator D. Field theories are incorporated in this approach by the spectral action principle, that sets the field theory action to Tr f(D^2/\Lambda^2), where f is a real function such that the trace exists, and \Lambda is a cutoff scale. In the low-energy (weak-field) limit the spectral action reproduces reasonably well the known physics including the standard model. However, not much is known about the spectral action beyond the low-energy approximation. In this paper, after an extensive introduction to spectral triples and spectral actions, we study various expansions of the spectral actions (exemplified by the heat kernel). We derive the convergence criteria. For a commutative spectral triple, we compute the heat kernel on the torus up the second order in gauge connection and consider limiting cases.
    Preview · Article · Jan 2012 · Journal of Physics A Mathematical and Theoretical
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    D. V.vassilevich
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    ABSTRACT: We compute a Chern–Simons term induced by the fermions on noncommutative torus interacting with two U(1) gauge fields. For rational noncommutativity θ∝P/Q we find a new mixed term in the action which involves only those fields which are (2π)/Q periodic, like the fields in a crystal with Q2 nodes.
    Preview · Article · Nov 2011 · Modern Physics Letters A
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    D. V.vassilevich
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    ABSTRACT: It has been proposed that the Poincaré and some other symmetries of noncommutative field theories should be twisted. Here we extend this idea to gauge transformations and find that twisted gauge symmetries close for arbitrary gauge group. We also analyse twisted-invariant actions in noncommutative theories.
    Preview · Article · Nov 2011 · Modern Physics Letters A
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    I. V. Fialkovsky · D. V. Vassilevich
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    ABSTRACT: This is a short non-technical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.
    Full-text · Article · Nov 2011 · International Journal of Modern Physics A
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    B. Iochum · C. Levy · D. Vassilevich
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    ABSTRACT: The spectral action for a non-compact commutative spectral triple is computed covariantly in a gauge perturbation up to order 2 in full generality. In the ultraviolet regime, $p\to\infty$, the action decays as $1/p^4$ in any even dimension.
    Preview · Article · Aug 2011 · Communications in Mathematical Physics
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    T. C. Adorno · D. M. Gitman · A. E. Shabad · D. V. Vassilevich
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    ABSTRACT: In a $U(1)_{\star}$-noncommutative (NC) gauge field theory we extend the Seiberg-Witten (SW) map to include the (gauge-invariance-violating) external current and formulate - to the first order in the NC parameter - gauge-covariant classical field equations. We find solutions to these equations in the vacuum and in an external magnetic field, when the 4-current is a static electric charge of a finite size $a$, restricted from below by the elementary length. We impose extra boundary conditions, which we use to rule out all singularities, $1/r$ included, from the solutions. The static charge proves to be a magnetic dipole, with its magnetic moment being inversely proportional to its size $a$. The external magnetic field modifies the long-range Coulomb field and some electromagnetic form-factors. We also analyze the ambiguity in the SW map and show that at least to the order studied here it is equivalent to the ambiguity of adding a homogeneous solution to the current-conservation equation.
    Full-text · Article · Jun 2011 · Physical review D: Particles and fields
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    T. C. Adorno · D. M. Gitman · A. E. Shabad · D. V. Vassilevich
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    ABSTRACT: It has been argued, that in noncommutative field theories sizes of physical objects cannot be taken smaller than an elementary length related to noncommutativity parameters. By gauge-covariantly extending field equations of noncommutative U(1)_*-theory to the presence of external sources, we find electric and magnetic fields produces by an extended charge. We find that such a charge, apart from being an ordinary electric monopole, is also a magnetic dipole. By writing off the existing experimental clearance in the value of the lepton magnetic moments for the present effect, we get the bound on noncommutativity at the level of 10^4 TeV.
    Full-text · Article · Apr 2011 · Physical review D: Particles and fields
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    Mario Bertin · Daniel Grumiller · Dmitri Vassilevich · Thomas Zojer
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    ABSTRACT: The graviton 1-loop partition function is calculated for Euclidean generalised massive gravity (GMG) using AdS heat kernel techniques. We find that the results fit perfectly into the AdS/(L)CFT picture. Conformal Chern-Simons gravity, a singular limit of GMG, leads to an additional contribution in the 1-loop determinant from the conformal ghost. We show that this contribution has a nice interpretation on the conformal field theory side in terms of a semi-classical null vector at level two descending from a primary with conformal weights (3/2,-1/2).
    Full-text · Article · Mar 2011 · Journal of High Energy Physics
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    Ignat V. Fialkovsky · Valery N. Marachevsky · Dmitri V. Vassilevich
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    ABSTRACT: We adopt the Dirac model for quasiparticles in graphene and calculate the finite temperature Casimir interaction between a suspended graphene layer and a parallel conducting surface. We find that at high temperature the Casimir interaction in such system is just one half of that for two ideal conductors separated by the same distance. In this limit single graphene layer behaves exactly as a Drude metal. In particular, the contribution of the TE mode is suppressed, while one of the TM mode saturates the ideal metal value. Behaviour of the Casimir interaction for intermediate temperatures and separations accessible for an experiment is studied in some detail. We also find an interesting interplay between two fundamental constants of graphene physics: the fine structure constant and the Fermi velocity.
    Full-text · Article · Feb 2011 · Physical review. B, Condensed matter

Publication Stats

3k Citations
396.48 Total Impact Points

Institutions

  • 2009-2014
    • Universidade Federal do ABC (UFABC)
      Santo André, São Paulo, Brazil
  • 2013
    • Universidade Federal de São Paulo
      San Paulo, São Paulo, Brazil
  • 2007-2011
    • University of São Paulo
      • São Carlos Institute of Physics
      San Paulo, São Paulo, Brazil
    • Dnepropetrovsk National University
      Yekaterinoslav, Dnipropetrovs'ka Oblast', Ukraine
  • 1992-2011
    • Saint Petersburg State University
      Sankt-Peterburg, St.-Petersburg, Russia
  • 1998-2007
    • University of Leipzig
      • Institute of Theoretical Physics
      Leipzig, Saxony, Germany
  • 2002-2003
    • Max Planck Institute for Mathematics in the Sciences
      Leipzig, Saxony, Germany
    • Max Planck Institute for Mathematics
      Bonn, North Rhine-Westphalia, Germany
  • 1996-1998
    • Vienna University of Technology
      • Institute of Theoretical Physics
      Wien, Vienna, Austria
  • 1994
    • Tokyo Institute of Technology
      • Department of Physics
      Edo, Tokyo, Japan
  • 1992-1994
    • Abdus Salam International Centre for Theoretical Physics
      Trst, Friuli Venezia Giulia, Italy
  • 1989-1991
    • Leningrad State University
      Sankt-Peterburg, St.-Petersburg, Russia