Since any non-trivial infrared dynamics in strongly correlated electron matter must be controlled by a critical fixed point, we argue that the form of the single-particle propagator can be deduced simply by imposing scale invariance. As a consequence, the unparticle picture proposed by Georgi[1] is the natural candidate to describe such dynamics. Unparticle stuff is scale-invariant matter with no particular mass. Scale invariance dictates that the propagator has an algebraic form which can admit zeros and hence is a candidate to explain the ubiquitous pseudogap state of the cuprates. The non-perturbative electronic state formed out of unparticles we refer to as an un-Fermi liquid. We show that the underlying action of the continuous mass formulation of unparticles can be recast as an action in anti de Sitter space which serves as the generating functional for the propagator. We find that this mapping fixes the scaling dimension of the unparticle to be dU = d/2 + √ d 2 + 4/2 and ensures that the corresponding propagator has zeros with d the spacetime dimension of the unparticle field. Should d = 2 + 1, unparticles acquire the non-trivial phase 2πdU upon interchange. Because dU is non-integer and in general not half-integer, clockwise and counterclockwise interchange of unparticles do not lead to the same phase and time reversal symmetry is broken spontaneously as reported in numerous experiments in the pseudogap phase of the cuprates. The possible relevance of this mechanism to such experiments is discussed. We then formulate the analogous BCS gap using unparticles and find that in contrast to the Fermi liquid case, the transition temperature increases as the attractive interaction strength decreases, indicating that unparticles are highly susceptible to a superconducting instability.

We compute conductivities of strongly-interacting and non-uniform charge densities dual to inhomogeneous anti-de Sitter-black hole spacetimes. Backreacting bulk scalars with periodic boundary profiles, we construct generalizations of ReissnerNordström-AdS that interpolate between those used in two previous studies -one that reports power-law scaling for the boundary optical conductivity and one that does not. We find no evidence for power-law scaling of the conductivity, thereby corroborating the previous negative result that gravitational crystals are insufficient to generate the power-law mid-infrared conductivity observed in cuprate superconductors.

We examine an electron Aharonov-Bohm (AB) interferometer with individual quantum dots connected in parallel to macroscopic leads. Here, we focus on the effect that both inter-dot spin-spin exchange interactions and intra-dot spin flips have on the current and frequency dependent current shot noise. By appropriate control of AB magnetic flux, inter-dot Coulomb repulsion, intra-dot spin flips, and inter-dot spin-spin coupling, the probability amplitudes for the different paths of the interferometer can be controlled leading to broad tunability of both the shape and contrast of interference fringes in the current. We also show that in the shot noise at finite frequencies corresponding to the spin-spin interaction energies the noise shows pronounced super-Poissonian and sub-Poissonian structure. AB flux, which is not an integer multiple of 2π, dramatically suppresses the correlations in the shot noise.

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