scholarly journals Understanding the holographic principle via RG flow

2016 ◽  
Vol 31 (34) ◽  
pp. 1630059 ◽  
Author(s):  
Ayan Mukhopadhyay
Keyword(s):  
Hydrodynamic Limit ◽  
Transport Coefficients ◽  
New Approach ◽  
Strongly Coupled ◽  
Naked Singularities ◽  
Large N ◽  
Gravity Equations ◽  
Local Operators ◽  
Classical Gravity ◽  
Single Trace

This is a review of some recent works which demonstrate how the classical equations of gravity in AdS themselves hold the key to understand their holographic origin in the form of a strongly coupled large N QFT whose algebra of local operators can be generated by a few (single-trace) elements. I discuss how this can be realized by reformulating Einstein’s equations in AdS in the form of a nonperturbative RG flow that further leads to a new approach toward constructing strongly interacting QFTs. In particular, the RG flow can self-determine the UV data that are otherwise obtained by solving classical gravity equations and demanding that the solutions do not have naked singularities. For a concrete demonstration, I focus on the hydrodynamic limit in which case this RG flow connects the AdS/CFT correspondence with the membrane paradigm, and also reproduces the known values of the dual QFT transport coefficients.

scholarly journals Quantum information probes of charge fractionalization in large-N gauge theories

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Brandon S. DiNunno ◽  
Niko Jokela ◽  
Juan F. Pedraza ◽  
Arttu Pönni
Keyword(s):  
Degrees Of Freedom ◽  
Gauge Theories ◽  
Entanglement Entropy ◽  
Coarse Grained ◽  
Strongly Coupled ◽  
Information Theoretic ◽  
Large N ◽  
Wide Range ◽  
Charge Fractionalization ◽  
Electric Flux

Abstract We study in detail various information theoretic quantities with the intent of distinguishing between different charged sectors in fractionalized states of large-N gauge theories. For concreteness, we focus on a simple holographic (2 + 1)-dimensional strongly coupled electron fluid whose charged states organize themselves into fractionalized and coherent patterns at sufficiently low temperatures. However, we expect that our results are quite generic and applicable to a wide range of systems, including non-holographic. The probes we consider include the entanglement entropy, mutual information, entanglement of purification and the butterfly velocity. The latter turns out to be particularly useful, given the universal connection between momentum and charge diffusion in the vicinity of a black hole horizon. The RT surfaces used to compute the above quantities, though, are largely insensitive to the electric flux in the bulk. To address this deficiency, we propose a generalized entanglement functional that is motivated through the Iyer-Wald formalism, applied to a gravity theory coupled to a U(1) gauge field. We argue that this functional gives rise to a coarse grained measure of entanglement in the boundary theory which is obtained by tracing over (part) of the fractionalized and cohesive charge degrees of freedom. Based on the above, we construct a candidate for an entropic c-function that accounts for the existence of bulk charges. We explore some of its general properties and their significance, and discuss how it can be used to efficiently account for charged degrees of freedom across different energy scales.

scholarly journals Critical behaviour of hydrodynamic series

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
M. Asadi ◽  
H. Soltanpanahi ◽  
F. Taghinavaz
Keyword(s):  
Chemical Potential ◽  
Transport Coefficients ◽  
Hydrodynamic Modes ◽  
Third Order ◽  
Hydrodynamic Mode ◽  
Strongly Coupled ◽  
Conformal Theory ◽  
Shear Dispersion ◽  
Type Iib String Theory ◽  
Hydrodynamic Transport

Abstract We investigate the time-dependent perturbations of strongly coupled $$ \mathcal{N} $$ N = 4 SYM theory at finite temperature and finite chemical potential with a second order phase transition. This theory is modelled by a top-down Einstein-Maxwell-dilaton description which is a consistent truncation of the dimensional reduction of type IIB string theory on AdS5×S5. We focus on spin-1 and spin-2 sectors of perturbations and compute the linearized hydrodynamic transport coefficients up to the third order in gradient expansion. We also determine the radius of convergence of the hydrodynamic mode in spin-1 sector and the lowest non-hydrodynamic modes in spin-2 sector. Analytically, we find that all the hydrodynamic quantities have the same critical exponent near the critical point θ = $$ \frac{1}{2} $$ 1 2 . Moreover, we propose a relation between symmetry enhancement of the underlying theory and vanishing of the only third order hydrodynamic transport coefficient θ1, which appears in the shear dispersion relation of a conformal theory on a flat background.

scholarly journals Quantum critical scaling and holographic bound for transport coefficients near Lifshitz points

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Gian Andrea Inkof ◽  
Joachim M. C. Küppers ◽  
Julia M. Link ◽  
Blaise Goutéraux ◽  
Jörg Schmalian
Keyword(s):  
Field Theory ◽  
Transport Coefficients ◽  
Massless Scalar ◽  
Famous Conjecture ◽  
Strongly Coupled ◽  
Spatial Anisotropy ◽  
Anisotropic Scaling ◽  
Geometric Ratio ◽  
Anisotropic Systems ◽  
Gauge Gravity

Abstract The transport behavior of strongly anisotropic systems is significantly richer compared to isotropic ones. The most dramatic spatial anisotropy at a critical point occurs at a Lifshitz transition, found in systems with merging Dirac or Weyl point or near the superconductor-insulator quantum phase transition. Previous work found that in these systems a famous conjecture on the existence of a lower bound for the ratio of a shear viscosity to entropy is violated, and proposed a generalization of this bound for anisotropic systems near charge neutrality involving the electric conductivities. The present study uses scaling arguments and the gauge-gravity duality to confirm the previous analysis of universal bounds in anisotropic Dirac systems. We investigate the strongly-coupled phase of quantum Lifshitz systems in a gravitational Einstein-Maxwell-dilaton model with a linear massless scalar which breaks translations in the boundary dual field theory and sources the anisotropy. The holographic computation demonstrates that some elements of the viscosity tensor can be related to the ratio of the electric conductivities through a simple geometric ratio of elements of the bulk metric evaluated at the horizon, and thus obey a generalized bound, while others violate it. From the IR critical geometry, we express the charge diffusion constants in terms of the square butterfly velocities. The proportionality factor turns out to be direction-independent, linear in the inverse temperature, and related to the critical exponents which parametrize the anisotropic scaling of the dual field theory.

A DIRECT TEST OF THE GAUGE/GRAVITY DUALITY AND THE STRING THEORETICAL DESCRIPTION OF A BLACK HOLE

2008 ◽  
Vol 23 (14n15) ◽  
pp. 2161-2164 ◽  
Author(s):  
JUN NISHIMURA
Keyword(s):  
Black Hole ◽  
Theoretical Description ◽  
Direct Test ◽  
Strongly Coupled ◽  
Open Strings ◽  
Large N ◽  
Brane Solution ◽  
Gauge Gravity ◽  
Gravity Duality ◽  
Microscopic Origin

We perform a direct test of the gauge/gravity duality by studying one-dimensional U (N) gauge theory with 16 supercharges at finite temperature using Monte Carlo simulation. In the 't Hooft large-N limit and in the strong coupling limit, the model is expected to have a dual gravity description in terms of the near-extremal black 0-brane solution in ten-dimensional type IIA supergravity. Our results provide the first example, in which the microscopic origin of the black hole thermodynamics is accounted for by solving explicitly the strongly coupled dynamics of the open strings attached to the D-branes.

A New Method for Displacement Analysis of Multi-Loop Spatial Linkages Based on Ordered Simple-Opened-Chains

1996 ◽  
Author(s):  
Xian-Wen Kong ◽  
Ting-Li Yang
Keyword(s):  
Continuation Method ◽  
The Other ◽  
New Method ◽  
New Approach ◽  
Strongly Coupled ◽  
Displacement Analysis ◽  
Cpu Time ◽  
Base Points ◽  
Weakly Coupled ◽  
Spatial Linkages

Abstract This paper presents systematically a new method for the displacement analysis (DA) of multi-loop spatial linkages (MLSLs) based on ordered simple-opened-chains (SOCs). In performing DA, a MLSL is converted into not a set of base points, a set of isolated links or a tree with/without isolated links in common use, but a weakly coupled MLSL in this paper. The characteristics of the proposed method are: (a) The number of unknowns in the set of equations for displacement analysis (EDA) of a MLSL is reduced to the minimum; (b) All the possible configurations corresponding to a given set of inputs of a weakly coupled MLSL or a strongly coupled MLSL with the coupled degree k = 1 can be obtained quickly. As compared with the other two methods available to find all the solutions to the DA in the case of MLSL with k = 1, the proposed method is superior to the resultant method in that it is applicable to more complex MLSLs and superior to the continuation method in that it takes much less CPU time to find all the solutions; (c) The set of EDA can be formulated and solved automatically; and (d) The new approach makes it possible to perform the kinematic and kineto-static analyses in a unified and simplified way.

Transport properties of the two-component strongly coupled plasma

1987 ◽  
Vol 37 (3) ◽  
pp. 405-421 ◽  
Author(s):  
R. Cauble ◽  
W. Rozmus
Keyword(s):  
Transport Model ◽  
Memory Function ◽  
Transport Coefficients ◽  
Operator Method ◽  
Power Coefficient ◽  
Strongly Coupled ◽  
Two Component ◽  
Strongly Coupled Plasma ◽  
Dynamics Simulations ◽  
Chain Approximation

The systematic derivation of transport coefficients for the semi-classical two-component strongly coupled plasma is presented. Starting from a detailed kinetic memory function formulation, a hydrodynamic projection operator method is applied to find a transport model equivalent to the two-Sonine polynomial approximation. The electron thermal conductivity K, d.c. electrical conductivity σ, and the thermoelectric power coefficient are expressed in terms of exact static correlation functions, which are calculated in the hypernetted chain approximation. Numerical values of k and σ are given and comparisons are made with other theories and molecular dynamics simulations of strongly coupled hydrogen. Predictions of σ and k for strongly coupled carbon are also presented.

scholarly journals Modified Sonine approximation for granular binary mixtures

2009 ◽  
Vol 623 ◽  
pp. 387-411 ◽  
Author(s):  
VICENTE GARZÓ ◽  
FRANCISCO VEGA REYES ◽  
JOSÉ MARÍA MONTANERO
Keyword(s):  
Transport Coefficients ◽  
Direct Simulation Monte Carlo ◽  
Boltzmann Distribution ◽  
Three Dimensions ◽  
Navier Stokes ◽  
State Distribution ◽  
New Approach ◽  
Viscosity Coefficients ◽  
Stokes Transport ◽  
Simulation Monte Carlo

We evaluate in this work the hydrodynamic transport coefficients of a granular binary mixture in d dimensions. In order to eliminate the observed disagreement (for strong dissipation) between computer simulations and previously calculated theoretical transport coefficients for a monocomponent gas, we obtain explicit expressions of the seven Navier–Stokes transport coefficients by the use of a new Sonine approach in the Chapman–Enskog (CE) theory. This new approach consists of replacing, where appropriate in the CE procedure, the Maxwell–Boltzmann distribution weight function (used in the standard first Sonine approximation) by the homogeneous cooling state distribution for each species. The rationale for doing this lies in the well-known fact that the non-Maxwellian contributions to the distribution function of the granular mixture are more important in the range of strong dissipation we are interested in. The form of the transport coefficients is quite common in both standard and modified Sonine approximations, the distinction appearing in the explicit form of the different collision frequencies associated with the transport coefficients. Additionally, we numerically solve by the direct simulation Monte Carlo method the inelastic Boltzmann equation to get the diffusion and the shear viscosity coefficients for two and three dimensions. As in the case of a monocomponent gas, the modified Sonine approximation improves the estimates of the standard one, showing again the reliability of this method at strong values of dissipation.

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