Publications (6)18.36 Total impact
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ABSTRACT: Within the context of holography we study the general class of $d=4$ conformal field theories after applying a universal helical deformation. At finite temperature we construct the associated black hole solutions of Einstein gravity, numerically, by exploiting a Bianchi $VII_0$ ansatz for the bulk $D=5$ metric. At $T=0$ we show that they flow in the IR to exactly the same CFT. The deformation gives rise to a finite, nonzero DC thermal conductivity along the axis of the helix, which we determine analytically in terms of black hole horizon data. We also calculate the AC thermal conductivity along this axis and show that it exhibits Drudelike peaks.12/2014; 
Article: Competing pwave orders
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ABSTRACT: We construct electrically charged, asymptotically $AdS_5$ black hole solutions that are dual to $d=4$ CFTs in a superfluid phase with either pwave or $(p+ip)$wave order. The two types of black holes have nonvanishing charged twoform in the bulk and appear at the same critical temperature in the unbroken phase. Both the pwave and the $(p+ip)$wave phase can be thermodynamically preferred, depending on the mass and charge of the twoform, and there can also be first order transitions between them. The pwave black holes have a helical structure and some of them exhibit the phenomenon of pitch inversion as the temperature is decreased. Both the pwave and the $(p+ip)$wave black holes have zero entropy density ground states at zero temperature and we identify some new ground states which exhibit scaling symmetry, including a novel scenario for the emergence of conformal symmetry in the IR.Classical and Quantum Gravity 10/2013; 31(5). · 3.56 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Semilocal quantum critical behaviour in $D1$ spacetime dimensions can be holographically described by metrics that are conformal to $AdS_2\times\mathbb{R}^{D2}$, with the conformal factor characterised by a parameter $\eta$. We analyse such "$\eta$geometries" in a topdown setting by focussing on the $U(1)^4$ truncation of D=4 N=8 gauged supergravity. The model has extremal black hole solutions carrying three nonzero electric or magnetic charges which approach $AdS_4$ in the UV and an $\eta=1$ geometry in the IR. Adding a fourth charge provides a mechanism to resolve the singularity of the $\eta$geometry, replacing it with an $AdS_2\times\mathbb{R}^2$ factor in the IR, while maintaining a large region where the $\eta$geometry scaling is approximately valid. Some of the magnetically charged black hole solutions preserve supersymmetry while others just preserve it in the IR. Finally, we show that $\eta$geometries, with various values of $\eta$, can be obtained from the dimensional reduction of geometries consisting of $AdS$ or Lifshitz geometries with flat directions.Journal of High Energy Physics 12/2012; 2013(3). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The stability properties of a family of magnetic $AdS_{3}\times \mathbb{R}^{2}$ solutions of D=5, SO(6) gauged SUGRA are investigated in more detail. We construct an analogous family of magnetic $AdS_{2}\times \mathbb{R}^{2}$ solutions of D=4, SO(8) gauged SUGRA, including a family of supersymmetric solutions, and also investigate their stability. We construct supersymmetric domain walls that interpolate between AdS_5 and an $AdS_3\times\mathbb{R}^2$ solution and also between AdS_4 and an $AdS_2\times\mathbb{R}^2$ solution which provide stable zero temperature ground states for the corresponding dual CFTs. We also construct new families of electric $AdS_{2}\times \mathbb{R}^{3}$ and $AdS_{2}\times \mathbb{R}^{2}$ solutions.Classical and Quantum Gravity 12/2011; 29(19). · 3.56 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate spatially modulated instabilities of magnetically charged $AdS_{2}\times\mathbb{R}^2$, $AdS_{3}\times\mathbb{R}^2$ and $AdS_{2}\times\mathbb{R}^3$ backgrounds in a broad class of theories, including those arising from KK reductions of ten and eleven dimensional supergravity. We show that magnetically charged black brane solutions in D=4,5 spacetime dimensions, whose zero temperature near horizon limit approach these backgrounds, can have instabilities that are dual to phases with current density waves that spontaneously break translation symmetry. Our examples include spatially modulated instabilities for a new class of magnetic black brane solutions of D=5 SO(6) gauged supergravity, that we construct in closed form, which are dual to new phases of N=4 SYM theory.Journal of High Energy Physics 09/2011; · 5.62 Impact Factor 
Publication Stats
54  Citations  
18.36  Total Impact Points  
Top Journals
Institutions

2011–2013

Imperial College London
Londinium, England, United Kingdom
