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Inverse magnetic catalysis in dense holographic matter
 JHEP 1103 (2011) 033 [arXiv:1012.4785 [hepth
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Magnetic Field Induced Quantum Criticality via new Asymptotically AdS5 Solutions
, 2010
"... Using analytical methods, we derive and extend previously obtained numerical results on the low temperature properties of holographic duals to fourdimensional gauge theories at finite density in a nonzero magnetic field. We find a new asymptotically AdS5 solution representing the system at zero te ..."
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Cited by 13 (4 self)
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Using analytical methods, we derive and extend previously obtained numerical results on the low temperature properties of holographic duals to fourdimensional gauge theories at finite density in a nonzero magnetic field. We find a new asymptotically AdS5 solution representing the system at zero temperature. This solution has vanishing entropy density, and the charge density in the bulk is carried entirely by fluxes. The dimensionless magnetic field to charge density ratio for these solutions is bounded from below, with a quantum critical point appearing at the lower bound. Using matched asymptotic expansions, we extract the low temperature thermodynamics of the system. Above the critical magnetic field, the low temperature entropy density takes a simple form, linear in the temperature, and with a specific heat coefficient diverging at the critical point. At the critical magnetic field, we derive the scaling law s ∼ T 1/3 inferred previously from numerical analysis. We also compute the full scaling function describing the region near the critical point, and identify the dynamical critical exponent: z = 3. These solutions are expected to holographically represent boundary theories in which strongly interacting fermions are filling up a Fermi sea. They are fully topdown constructions in which both the bulk and boundary theories have well known embeddings in string theory.
Charge Expulsion from Black Brane Horizons
 and Holographic Quantum Criticality in the Plane,” arXiv:1202.2085 [hepth
"... Quantum critical behavior in 2+1 dimensions is established via holographic methods in a 5+1dimensional Einstein gravity theory with gauge potential form fields of rank 1 and 2. These fields are coupled to one another via a trilinear ChernSimons term with strength k. The quantum phase transition ..."
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Cited by 7 (1 self)
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Quantum critical behavior in 2+1 dimensions is established via holographic methods in a 5+1dimensional Einstein gravity theory with gauge potential form fields of rank 1 and 2. These fields are coupled to one another via a trilinear ChernSimons term with strength k. The quantum phase transition is physically driven by the expulsion of the electric charge from inside the black brane horizon to the outside, where it gets carried by the gauge fields which acquire charge thanks to the ChernSimons interaction. At a critical value k = kc, zero temperature, and any finite value of the magnetic field, the IR behavior is governed by a nearhorizon Lifshitz geometry. The associated dynamical scaling exponent depends on the magnetic field. For k < kc, the flow towards low temperature is governed by a ReissnerNordstromlike black brane whose charge and entropy density are nonvanishing at zero temperature. For k> kc, the IR flow is towards the purely magnetic brane in AdS6. Its nearhorizon geometry is AdS4 × R2, so that the entropy density vanishes quadratically with temperature, and all charge is carried by the gauge fields outside of the horizon.
HOLOGRAPHIC CHIRAL MAGNETIC SPIRAL
, 2010
"... We study the ground state of baryonic/axial matter at zero temperature chiralsymmetry broken phase under a large magnetic field, in the framework of holographic QCD by SakaiSugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored agai ..."
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Cited by 4 (3 self)
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We study the ground state of baryonic/axial matter at zero temperature chiralsymmetry broken phase under a large magnetic field, in the framework of holographic QCD by SakaiSugimoto. Our study is motivated by a recent proposal of chiral magnetic spiral phase that has been argued to be favored against previously studied phase of homogeneous distribution of axial/baryonic currents in terms of meson supercurrents dictated by triangle anomalies in QCD. Our results provide an existence proof of chiral magnetic spiral in strong coupling regime via holography, at least for large axial chemical potentials, whereas we don’t find the phenomenon in the case of purely baryonic chemical potential. MIRAMARE – TRIESTE
External Fields and the Dynamics of Fundamental Flavours
 in Holographic Duals of Large N Gauge Theories,” arXiv:1012.5450 [hepth
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Quantum phase transition in a DpDq system
 Phys.Rev. D82 (2010) 086013
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Charged Magnetic Brane Correlators and Twisted Virasoro Algebras,” Phys
 Rev. D
"... Prior work using gauge/gravity duality has established the existence of a quantum critical point in the phase diagram of 3+1dimensional gauge theories at finite charge density and background magnetic field. The critical theory, obtained by tuning the dimensionless charge density to magnetic field ..."
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Cited by 2 (2 self)
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Prior work using gauge/gravity duality has established the existence of a quantum critical point in the phase diagram of 3+1dimensional gauge theories at finite charge density and background magnetic field. The critical theory, obtained by tuning the dimensionless charge density to magnetic field ratio, exhibits nontrivial scaling in its thermodynamic properties, and an associated nontrivial dynamical critical exponent. In the present work, we analytically compute low energy correlation functions in the background of the charged magnetic brane solution to 4+1dimensional EinsteinMaxwellChernSimons theory, which represents the bulk description of the critical point. Results are obtained for neutral scalar operators, the stress tensor, and the U(1)current. The theory is found to exhibit a twisted Virasoro algebra, constructed from a linear combination of the original stress tensor and chiral U(1)current. The effective speed of light in the IR is renormalized downward for one chirality, but not the other, by finite density, a behavior that is consistent with a Luttinger liquid description of fermions in the lowest Landau level. The results obtained here do not directly shed light on the mechanism driving the phase transition, and we comment on why this is so.
A Quantum Critical Point from Flavours on a Compact Space
 JHEP
, 2014
"... Abstract: We analyse a 2 + 1 dimensional defect field theory on a two sphere in an external magnetic field. The theory is holographically dual to probe D5branes in global AdS5 × S5 background. At any finite magnetic field only the confined phase of the theory is realised. There is a first order qua ..."
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Cited by 1 (0 self)
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Abstract: We analyse a 2 + 1 dimensional defect field theory on a two sphere in an external magnetic field. The theory is holographically dual to probe D5branes in global AdS5 × S5 background. At any finite magnetic field only the confined phase of the theory is realised. There is a first order quantum phase transition, within the confined phase of theory, ending on a quantum critical point of a second order phase transition. We analyse the condensate and magnetisation of theory and construct its phase diagram. We study the critical exponents near the quantum critical point and find that the second derivatives of the free energy, with respect to the bare mass and the magnetic field, diverge with a critical exponent of −2/3. Next, we analyse the meson spectrum of the theory and identify a massless mode at the critical point signalling a diverging correlation length of the quantum fluctuations. We find that the derivative of the meson mass with respect to the bare mass also diverges with a critical exponent of −2/3. Finally, our studies of the magnetisation uncover a persistent diamagnetic response similar to that in mesoscopic systems, such as quantum dots and nano tubes. ar X iv