Holographic Kondo and Fano resonances

Erdmenger, Johanna; Hoyos, Carlos; O’Bannon, Andy; Papadimitriou, Ioannis; Probst, Jonas; Wu, Jackson M. S.

doi:10.1103/physrevd.96.021901

Cited by 13 publications

(27 citation statements)

References 49 publications

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“…We can expect that such a phase transition actually occurs in the strong magnetic field Kondo effect, and it would be relevant to the recent work on the Kondo phase diagram [34]. In addition to the standard saddle point approximation, in the large N limit, we can also apply another non-perturbative method, called the AdS/CFT correspondence, to the Kondo problem [35,36,37,38,39,40]. See also [41].…”

Section: Discussionmentioning

confidence: 94%

Conformal field theory analysis of the QCD Kondo effect

Kimura

Ozaki

2019

Phys. Rev. D

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We study non-perturbative aspects of QCD Kondo effect, which has been recently proposed for the finite density and strong magnetic field systems, using conformal field theory describing the low energy physics near the IR fixed point. We clarify the symmetry class of QCD Kondo effect both for the finite density and magnetic field systems, and show how the IR fixed point is non-perturbatively characterized by the boundary condition, which incorporates the impurity effect in Kondo problem. We also obtain the low temperature behavior of several quantities of QCD Kondo effect in the vicinity of the IR fixed point based on the conformal field theory analysis. † Recently, a novel type of the Kondo effect induced by color degrees of freedom, so-called QCD Kondo effect, is proposed [1]. QCD Kondo effect is a Kondo effect realized in high density quark matter with a heavy quark impurity. It is well known that there are three important ingredients for the appearance of the Kondo effect: (i) Fermi surface, (ii) quantum fluctuations (loop effects), (iii) non-Abelian property of interaction. In the QCD Kondo effect, the last condition (iii) corresponds to the color exchange interaction mediated by gluon between a light quark near the Fermi surface and the heavy quark impurity. Near the Fermi surface, the system becomes effectively (1+1)-dimensional. This dimensional reduction plays an essential role for the appearance of the Kondo effect. As a later development of the QCD Kondo effect, one of the authors together with the others have proposed the magnetically induced QCD Kondo effect [2]. In strong magnetic field, the dimensional reduction to (1+1)dimensions also occurs. This (1+1)-dimensional dynamics gives rise to magnetically induced QCD Kondo effect.A lot of approaches to the non-perturbative regime of the Kondo effect have been developed, since the standard perturbative analysis does not work below the typical energy scale, due to the asymptotic freedom. The Conformal Field Theory (CFT) is one of such approaches to study the IR fixed point of the Kondo effect [3,4,5,6,7,8]. See also a review article [9]. In the CFT approach, the impurity effect is treated as the boundary condition. Thus we can discuss the non-trivial boundary behavior using the boundary CFT

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Section: Discussionmentioning

confidence: 94%

Conformal field theory analysis of the QCD Kondo effect

Kimura

Ozaki

2019

Phys. Rev. D

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“…Such Fano resonances clearly arise from the mechanism of refs. [21][22][23], namely the breaking of (0 + 1)-dimensional conformal symmetry at the Wilson line.…”

Section: Scatteringmentioning

confidence: 99%

“…A key observation of refs. [21][22][23] was that systems in which (0+1)-dimensional conformal symmetry is broken, for example by an RG flow induced by a relevant operator or by an operator VEV, will generically give rise to Fano resonances. The reason is simple.…”

Section: Scatteringmentioning

confidence: 99%

Holographic Wilson lines as screened impurities

Evans

O’Bannon

Rodgers

2020

J. High Energ. Phys.

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In Landau Fermi liquids, screened impurities support quasi-bound states, representing electrons bound to the impurity but making virtual excursions away. Signals of these quasi-bound states are electron-impurity scattering phase shifts and the corresponding resonances in cross sections. We consider large-N , strongly-coupled (3+1)-dimensional N = 4 supersymmetric SU (N ) Yang-Mills theory on the Coulomb branch, where an adjoint scalar has a non-zero expectation value that breaks SU (N ) → SU (N −1)×U (1). In the holographic dual we re-visit well-known solutions for a probe D3-brane that describe this theory with a symmetric-representation Wilson line "impurity." We present evidence that the adjoint scalar screens the Wilson line, by showing that quasi-bound states form at the impurity, producing U (1)-impurity scattering phase shifts and corresponding resonances in cross sections. The quasi-bound states appear holographically as quasi-normal modes of probe D3-brane fields, even in the absence of a black hole horizon, via a mechanism that we argue is generic to screened defects in holography. We also argue that well-known generalisations of these probe D3-brane solutions can describe lattices of screened Wilson/'t Hooft line impurities.

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“…In principle, the Kondo model could be used as a testing ground for the applicability of holography to condensed matter as this problem has an exact solution [7,8]. Thus far, encoding Kondo physics within the gauge-gravity setup [1][2][3][4] has led to two key results which suggests that perhaps much more of Kondo physics can be extracted within this technique: 1) the emergence of a dynamical scale below which the Kondo coupling diverges and 2) power-law scalings of the IR resistivity and entropy. The exponent is governed by the dimension of the irrelevant operator that flows the theory away from the IR fixed point.…”

Section: Introductionmentioning

confidence: 99%

“…The AdS 3 radius L is set to unity. The AdS 2 -brane is localized at x = 0 and has an induced metric g (2) ; the boundary field theory is located at a fixed inverse-radial cutoff, z = ǫ, and has induced metric γ. g (3) is the bulk AdS 3 metric.…”

Section: Introductionmentioning

confidence: 99%

Log-rise of the resistivity in the holographic Kondo model

et al. 2018

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We study a single-channel Kondo effect using a recently developed [1][2][3][4] holographic large-N technique. In order to obtain resistivity of this model, we introduce a probe field. The gravity dual of a localized fermionic impurity in 1 þ 1-dimensional host matter is constructed by embedding a localized two-dimensional Anti-de Sitter (AdS 2 )-brane in the bulk of three-dimensional AdS 3 . This helps us construct an impurity charge density which acts as a source to the bulk equation of motion of the probe gauge field. The functional form of the charge density is obtained independently by solving the equations of motion for the fields confined to the AdS 2 -brane. The asymptotic solution of the probe field is dictated by the impurity charge density, which in turn affects the current-current correlation functions and hence the resistivity. Our choice of parameters tunes the near-boundary impurity current to be marginal, resulting in a log T behavior in the UV resistivity, as is expected for the Kondo problem. The resistivity at the IR fixed point turns out to be zero, signaling a complete screening of the impurity.

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Holographic Kondo and Fano resonances

Cited by 13 publications

References 49 publications

Conformal field theory analysis of the QCD Kondo effect

Conformal field theory analysis of the QCD Kondo effect

Holographic Wilson lines as screened impurities

Log-rise of the resistivity in the holographic Kondo model

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