En
  • دکتری (1375)

    فیزیک

    دانشگاه صنعتی شریف،

  • کارشناسی‌ارشد (1371)

    فیزیک

    دانشگاه تهران، ایران

  • کارشناسی (1369)

    مهندسی مکانیک - طراحی جامدات

    دانشگاه شیراز،

  • دوگانی گرانش- نظریه میدان
  • نظریه ریسمان

    صفحه من را در سایت زیر ببینید: shahrokhparvizi.github.io

    ارتباط

    رزومه

    On Maximum Complexity in Holography

    Shahrokh Parvizi, Mojtaba Shahbazi
    Journal PapersarXiv preprint arXiv:2103.05367 , 2021 March 9, {Pages }

    Abstract

    In the quantum circuit, it is believed that complexity itself reaches a maximum of order exponential in the number of q-bits or equivalently exponential in entropy of the black hole. However, the current holographic proposals do not meet this criterion. The holographic proposals find the complexity of the very late times to be infinite, which makes it to be considered a non-physical quantity, while in the quantum circuit, it is expected that complexity meets within a finite time its maximum value. These points are required to be altered in holographic proposals of complexity. This letter introduces a new holographic proposal that meets all these criteria and consolidates the Lloyd bound.

    Circuit complexity in U(1) gauge theory

    A Moghimnejad, S Parvizi
    Journal Papers , , {Pages }

    Abstract

    Constraints on anisotropic RG flows from the holographic entanglement entropy

    M Ghasemi, S Parvizi
    Journal Papers , , {Pages }

    Abstract

    Einstein-Yang-Mills black brane in ads space and dc color conductivity

    SH PARVIZI, M SADEGHI
    Journal Papers , Volume 20 , Issue 100898, 2020 January 1, {Pages 139-145 }

    Abstract

    Considering the SU (2) Yang-Mills theory in a 4-dimensional Einstein Gravity, we find a black brane solution in the AdS space. For this setup, by using the AdS/CFT holography, we find non-Abelian color conductivity of the gauge theory on the boundary of the AdS space. Color conductivity is defined by the generalized Ohm’s law and computed by applying holography to the linear response theory.

    Relevant perturbation of entanglement entropy of singular surfaces

    Mostafa Ghasemi, Shahrokh Parvizi
    Journal PapersarXiv preprint arXiv:1902.05058 , 2019 February 13, {Pages }

    Abstract

    We study the entanglement entropy of theories that are derived from relevant perturbation of given CFTs for regions with a singular boundary by using the AdS/CFT correspondence. In the smooth case, it is well known that a relevant deformation of the boundary theory by the relevant operator with scaling dimension generates a logarithmic universal term to the entanglement entropy. As the smooth case, when the boundary CFT deformed by a relevant operator, we find that the entanglement entropy of singular surface also contains a new logarithmic term which is due to relevant perturbation of the conformal field theory, and depends on the scaling dimension of relevant operator. We also find for extended singular surfaces, , as well as logarithmic

    Curved Corner Contribution to the Entanglement Entropy in an Anisotropic Spacetime

    Mostafa Ghasemi, Shahrokh Parvizi
    Journal PapersarXiv preprint arXiv:1905.01675 , 2019 May 5, {Pages }

    Abstract

    We study the holographic entanglement entropy of anisotropic and nonconformal theories that are holographically dual to geometries with hyperscaling violation, parameterized by two parameters and . In the vacuum state of a conformal field theory, it is known that the entanglement entropy of a kink region contains a logarithmic universal term which is only due to the singularity of the entangling surface. But, we show that the effects of the singularity as well as anisotropy of spacetime on the entanglement entropy exhibit themselves in various forms depending on and ranges. We identify the structure of various divergences may appear in the entanglement entropy, specially those which are universal and appear in the logarithmic or double l

    Effect of massive potentials and the Gauss–Bonnet gravity on the holographic thermalization

    Ali Nemati, Shahrokh Parvizi
    Journal PapersInternational Journal of Modern Physics A , Volume 34 , Issue 22, 2019 August 10, {Pages 1950124 }

    Abstract

    We perform a numerical study to recognize the difference between various massive potentials in the massive gravity on the holographic thermalization in the AdS and AdS–Gauss–Bonnet gravities in 4+1 dimensions. In this space–time, three different massive potentials contribute to the graviton mass. We analyze the effects of these terms on the time evolution of entanglement entropy and the corresponding thermalization time. We also trace the effect of Gauss–Bonnet coupling on the thermalization process. The behavior of the holographic mutual information and size of the kinks, appearing in a large interval, are also studied.

    Constraints on anisotropic RG flows from holographic entanglement entropy

    Mostafa Ghasemi, Shahrokh Parvizi
    Journal PapersarXiv preprint arXiv:1907.01546 , 2019 July 2, {Pages }

    Abstract

    In the context of the gauge/gravity duality, we propose a candidate -function which is derived from the entanglement entropy of a strip-shaped region for -dimensional quantum field theories with broken Lorentz and rotational symmetries. We examine conditions of monotonicity of the -function for holographic anisotropic theories dual to the Einstein gravity via the constraints imposed by the null energy conditions. We consider near UV and IR behaviors of these theories with a dynamical exponent and hyperscaling violation parameter. We identify the sufficient conditions that guarantee the function decrease monotonically along the RG flows.

    Entanglement entropy of singular surfaces under relevant deformations in holography

    Mostafa Ghasemi, Shahrokh Parvizi
    Journal PapersJournal of High Energy Physics , Volume 2018 , Issue 2, 2018 February 1, {Pages 9 }

    Abstract

    A bstract In the vacuum state of a CFT, the entanglement entropy of singular surfaces contains a logarithmic universal term which is only due to the singularity of the entangling surface. We consider the relevant perturbation of a three dimensional CFT for singular entangling surface. We observe that in addition to the universal term due to the entangling surface, there is a new logarithmic term which corresponds to a relevant perturbation of the conformal field theory with a coefficient depending on the scaling dimension of the relevant operator. We also find a new power law divergence in the holographic entanglement entropy. In addition, we study the effect of a relevant perturbation in the Gauss-Bonnet gravity for a singular entangling s

    Holographic Aspects of a Higher Curvature Massive Gravity

    Shahrokh Parvizi, Mehdi Sadeghi
    Journal PapersarXiv preprint arXiv:1704.00441 , 2017 April 3, {Pages }

    Abstract

    We study the holographic dual of a massive gravity with Gauss-Bonnet and cubic quasi-topological higher curvature terms. Firstly, we find the energy-momentum two point function and central charges of the 4-dimensional boundary theory, albeit the massive term acts as a relevant perturbation to the conformal field theory. Then we focus on a black hole solution in this background and derive the ratio of shear viscosity to entropy density for the dual theory. Results smoothly cover the massless limit.

    Effect of massive potentials on the holographic thermalization

    Ali Nemati, Shahrokh Parvizi
    Journal PapersarXiv preprint arXiv:1710.05712 , 2017 October 16, {Pages }

    Abstract

    We perform a numerical study to recognize the difference between various massive potentials in the dRGT massive gravity on the holographic thermalization in the AdS and AdS Gauss-Bonnet gravities. The massive potential in dimensions includes three symmetric polynomial terms which we denote them as , and terms. We observe, in the case of time evolution of entanglement entropy that there is a critical size of the entangling surface on the boundary below which both signs of and above the critical size are able to reduce the thermal value of entanglement entropy. Our numerical computations show the more positive 's are, the faster system reaches to its thermal value. The order of saturation time of positive potentials when supplemented to

    Hydrodynamics of a black brane in Gauss–Bonnet massive gravity

    Mehdi Sadeghi, Shahrokh Parvizi
    Journal PapersClassical and Quantum Gravity , Volume 33 , Issue 3, 2016 January 11, {Pages 035005 }

    Abstract

    A black brane solution to Gauss–Bonnet massive gravity is introduced. In the context of AdS/CFT correspondence, the viscosity to entropy ratio is found by the Green–Kubo formula. The result indicates a violation of the well-known KSS bound, as expected in a higher derivative theory. Setting mass zero gives back the known viscosity to entropy ratio dependent on the Gauss–Bonnet coupling, while without the Gauss–Bonnet term, a nonzero mass parameter does not contribute to the ratio which saturates the bound of

    The stability and gravitational Newtonian limit of a modified Randall–Sundrum model

    Shahrokh Parvizi, Mojtaba Shahbazi
    Journal PapersThe European Physical Journal C , Volume 76 , Issue 1, 2016 January 1, {Pages 21 }

    Abstract

    For a modified Randall–Sundrum model (Jones et al. in Phys. Rev. D 88:025048, 2013), the graviton equations are derived and the mass spectrum found. The latter includes a massless graviton and a continuum mass with a gap. There is no negative mass-squared in the spectrum, so the model is stable. The gravitational Newtonian limit is obtained with an exponentially suppressed modification from the extra dimension.

    Shear Viscosity to Entropy Density for a Black Brane in 5-dimensional Einstein-Yang-Mills Gravity

    Mehdi Sadeghi, Shahrokh Parvizi
    Journal PapersarXiv preprint arXiv:1411.2358 , 2014 November 10, {Pages }

    Abstract

    We calculate the ratio of shear viscosity to entropy density for a black brane of -dimensional Einstein-Yang-Mills Gravity by Kubo and membrane paradigm methods. The former gives exactly which is an expected result in the context of the Einstein-Hilbert gravity. In contrast, the membrane paradigm reaches only in large horizon radius limit. We comment on this discrepancy.

    Graviton propagation in an asymmetric warped background: Lorentz violation and the null energy condition

    Shahrokh Parvizi, Hossein Rezaee
    Journal PapersJournal of High Energy Physics , Volume 2014 , Issue 8, 2014 August 1, {Pages 76 }

    Abstract

    A bstract The graviton propagation in an asymmetric background is studied. The background is a configuration in the six-dimensional Salam-Sezgin model, in which a 3-form H-field turned on [JHEP 0910 (2009) 086]. The compact dimensions form a cylindrical space with branes as boundaries. The background gets asymmetry due to the H-field and violates the Lorentz symmetry. We derive the graviton equation in this background and show that it gets massless mode traveling with superluminal speed. A tower of KK modes exists with a mass gap. On the other hand, it is known that breaking the Lorentz symmetry on an asymmetric background is constrained by the null energy condition. This no-go theorem doesn’t work well in six-dimensional space-times and

    dS solutions with co-dimension 2 branes in six dimensions

    Hamid R Afshar, Hassan Firouzjahi, Shahrokh Parvizi
    Journal PapersClassical and Quantum Gravity , Volume 30 , Issue 23, 2013 November 8, {Pages 235030 }

    Abstract

    We investigate phenomenological four-dimensional (4D) dS solutions with co-dimension 2 branes and finite 4D Planck mass in six dimensions. We present the conditions under which six-dimensional compactifications with holomorphic axion–dilaton field or models with pure gravity with local sources can yield 4D dS solutions. Different classes of solutions are specified by a holomorphic function describing different embeddings of multiple conical branes. Depending on the local singularities of this holomorphic function and the topology of the compact dimension, one has to introduce 3-branes creating a deficit angle equal to π and/or 4-branes with positive tensions.

    3-form flux compactification of Salam-Sezgin supergravity

    Hamid Reza Afshar, Shahrokh Parvizi
    Journal PapersJournal of High Energy Physics , Volume 2009 , Issue 10, 2009 October 28, {Pages 086 }

    Abstract

    The compactification of 6 dimensional Salam-Sezgin model in the presence of 3-form flux H is investigated. We find a torus topology for this compactification with two cusps which are the places of branes, while at the limit of large size L of the compact direction we also obtain sphere topology. This resembles the Randall-Sundrum I, II model. This compactification also provides an example for the so-calledtime warp'solution,[0812.5107 [hep-th]]. According to a no-go theorem in d≠ 6, the time warp compactification violates the null energy condition. While the theorem is quiet for d= 6, our model gives a time warp compactification which satisfies the null energy condition. We also derive the four dimensional effective Planck mass which is n

    Partition function of non-supersymmetric black holes in the supergravity limit

    Shahrokh Parvizi, Alireza Tavanfar
    Journal PapersModern Physics Letters A , Volume 23 , Issue 22, 2008 July 20, {Pages 1869-1883 }

    Abstract

    In this paper, we propose a free energy for general non-supersymmetric black hole attractors (with vanishing D0-brane charge) arising in type IIA(B) superstrings on 3-fold Calabi–Yau, in the supergravity limit. This, by definition, differs from its counterpart BPS free energy by a factor of 4. Correspondingly, a mixed ensemble for these black holes is proposed.

    AdS/CFT correspondence via R-current correlation functions revisited

    Shahin Mamedov, Shahrokh Parvizi
    Journal PapersInternational Journal of Modern Physics A , Volume 23 , Issue 22, 2008 September 10, {Pages 3721-3745 }

    Abstract

    Motivated by realizing open/closed string duality in the work by Gopakumar [Phys. Rev. D70, 025009 (2004)], we study two- and three-point correlation functions of R-current vector fields in super-Yang–Mills theory. These correlation functions in free field limit can be derived from the worldline formalism and are written as heat kernel integrals in the position space. We show that reparametrizing these integrals converts them to the expected AdS supergravity results which are known in terms of bulk to boundary propagators. We expect that this reparametrization corresponds to transforming open string moduli parametrization to the closed string ones.

    Non-supersymmetric attractors in R2 gravities

    Bhamidipati Chandrasekhar, Shahrokh Parvizi, Alireza Tavanfar, Hossein Yavartanoo
    Journal PapersJournal of High Energy Physics , Volume 2006 , Issue 08, 2006 August 1, {Pages 004 }

    Abstract

    We investigate the attractor mechanism for spherically symmetric extremal black holes in a theory of general R 2 gravity in 4-dimensions, coupled to gauge fields and moduli fields. For the general R 2 theory, we look for solutions which are analytic near the horizon, show that they exist and enjoy the attractor behavior. The attractor point is determined by extremization of an effective potential at the horizon. This analysis includes the backreaction and supports the validity of non-supersymmetric attractors in the presence of higher derivative interactions. To include a wider class of solutions, we continue our analysis for the specific case of a Gauss-Bonnet theory which is non-topological, due to the coupling of Gauss-Bonnet terms to th

    /pro/academic_staff/parvizi/publication

    دروس نیمسال جاری

    • كارشناسي ارشد
      نظريه ميدان هاي كوانتومي 1 ( واحد)
      دانشکده علوم پایه، گروه ذرات بنيادي و نظريه ميدان ها

    دروس نیمسال قبل

    • كارشناسي ارشد
      مكانيك آماري پيشرفته 1 ( واحد)
      دانشکده علوم پایه، گروه ذرات بنيادي و نظريه ميدان ها
    • 1399
      مقصودي شورابي, داود
      قضيه هاي جريان مقطع و درهمتنيدگي هولوگرافيك
    • 1397
      شهبازي برليان, مجتبي
      پيچيدگي محاسباتي از طريق هولوگرافي
    • مدیر گروه فیزیک ذرات بنیادی
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