Introduction to Cosmology and String Theory

Gauge/gravity duality applied to condensed matter systems

“…Which mesons condense first in D3/Dp systems depends on the details of the system. 4 The general lesson from these D3/Dp systems is that the p-wave superfluid phase transition appears to be vector meson condensation, which is in line with our weak-coupling intuition.…”

“…Any closed string that wrap the null circle is massless, hence when T = 0 and we compactify x − the supergravity approximation becomes unreliable [182]. As emphasized in [182], if the spacetime has momentum in the x − direction then the x − circle is no longer 4 Supersymmetric Sch5 solutions do exist [187,188], obtained by using different directions of the S 5 (besides the Hopf fiber) in the TsT transformation, which are very similar in form to the solution above. We leave a thorough analysis of probe branes in those backgrounds for the future.…”

“…In fact, there are no models for quantum critical theories in (2+1)-and higher dimensions for which analytical results for processes like transport can be obtained. 4 The AdS/CFT correspondence, however, provides a set of exact solutions for the quantum critical transport in 2+1 dimensions [42,43].…”

“…It is quite remarkable that the theory is also scale invariant after quantization. 4 In fact, scale invariance is part of a larger symmetry, the conformal symmetry group SO(4, 2). Moreover, the Lagrangian is also invariant under N = 4 supersymmetry with R-symmetry group SU (4) R .…”

“…In fact at the lowest temperatures we can reliably access in the probe limit, the main features of the spectral measure are five largely isolated peaks in the (k x , k y ) plane, two on the k x axis, two on the k y axis, and one at the origin. 4 We cannot resist drawing an analogy between our system and certain experimentallyrealized p-wave superconductors (see also [170]). 5 In that context, a reduction of the Fermi surface to certain points in momentum space has been proposed for the ruthenate compound Sr 2 RuO 4 [171]: the p-wave state is supported by ferromagnetic fluctuations that increase the propensity for electrons to form spin triplet Cooper pairs, with an odd (p-wave) Cooper pair wave function.…”