Related papers: Refractive index in holographic superconductors
Superconductivity, an emergence of a macroscopic quantum state, gives rise to unique electromagnetic responses leading to perfect shielding of magnetic field and zero electrical resistance. In this paper, we propose that superconductors…
The IR dynamics of effective holographic theories capturing the interplay between charge density and the leading relevant scalar operator at strong coupling are analyzed. Such theories are parameterized by two real exponents…
Wave equations containing spatial derivatives which are higher than second order arise naturally in the context of condensed matter systems. The solutions of such equations contain more than two modes and consequently, the range of possible…
Following our recent theoretical and experimental results that show how zero-permittivity metamaterials may provide anomalous tunneling and energy squeezing through ultranarrow waveguide channels, here we report an experimental…
Bi-metricity and Hawking radiation are exhibit in non-relativistic moving magnetohydrodynamics (MHD) plasma medium generating two Riemannian effective spacetimes. The first metric is a flat metric although the speed of "light" is given by a…
We study holographic superconductors in a Ho\v{r}ava-Lifshitz black hole without the condition of the detailed balance. We show that it is easier for the scalar hair to form as the parameter of the detailed balance becomes larger, but…
The magnetic response of type-II superconductors can be irreversible due to two different reasons: vortex pinning and barriers for flux penetration. Even without bulk pinning and in absence of a microscopic Bean-Lingston surface barrier for…
Based on an attractive $U$ Hubbard model on a lattice with up to second neighbor hopping we derive an effective Hamiltonian for phase fluctuations. The superconducting gap is assumed to have s-wave symmetry. The effective Hamiltonian we…
We use gauge/gravity duality to explore strongly coupled superconductors with dynamical exponent $z=2$. In the probe limit we numerically establish background solutions for the matter fields and plot the condensate versus the dimensionless…
We investigate the prospect of achieving negative permittivity and permeability at optical frequencies in a dielectric crystal containing stoichiometric rare-earth ions. We derive the necessary transition linewidth, ion density and electric…
We analyse the optical (or microwave) tunnelling properties of electromagnetic waves passing through thin films presenting a specific index profile providing a cut-off frequency, when they are used below this frequency. We show that…
We show that a thin superconductor slab illuminated by a desired pattern of light behaves as a completely controllable two-dimensional photonic media that could be applied in a wide range of optical devices. In this case, the permittivity…
We investigate theoretically and numerically the photonic band structure in the optical domain of an array of core-shell metal-semiconductor nanowires. Corresponding negative-index photonic bands are calculated, showing isotropic…
A type of 3-dimensional optical negative-refractive-index metamaterials composed of all dielectric nanospheres is proposed and demonstrated theoretically. The metamaterials are constructeded by pairing together two kinds of dielectric…
We construct holographic superconductors from Einstein-Maxwell-dilaton gravity in 3+1 dimensions with two adjustable couplings $\alpha$ and the charge $q$ carried by the scalar field. For the values of $\alpha$ and $q$ we consider, there is…
The dynamical conductivity of interacting multiband electronic systems derived in Ref.[1] is shown to be consistent with the general form of the Ward identity. Using the semiphenomenological form of this conductivity formula, we have…
Under the framework of the viscous chromohydrodynamics, the gluon self-energy is derived for the quark-gluon plasma with shear viscosity. The viscous electric permittivity and magnetic permeability are evaluated from the gluon self-energy,…
The holographic approach to study strongly coupled superconductors in the presence of dark matter is reviewed. We discuss the influence of dark matter on the superconducting transition temperature of both s-wave and p-wave holographic…
Two microring resonators, one with gain and one with loss, coupled to each other and to a bus waveguide, create an effective non-Hermitian potential for light propagating in the waveguide. Due to geometry, coupling for each microring…
A remarkable property of intrinsic graphene is that upon doping, electrons and holes travel through the monolayer thick material with constant velocity which does not depend on energy up to about $0.3$ eV (Dirac fermions), as though the…