arXiv subjects

Vera N. Smolyaninova

Publications and source records attributed to Vera N. Smolyaninova.

At least 19 recordsLinked to original sources

arXiv2024

Electromagnetic signal propagation through lossy media via surface electromagnetic waves

A theory of surface electromagnetic waves in gradient media exhibiting arbitrary surface gradients of dielectric permittivity and magnetic permeability has been developed. Novel low-loss propagating surface wave solutions have been found in the gradient media in which both dielectric permittivity and magnetic permeability are dominated by their imaginary parts. Several examples of gradient geometries in which the surface wave problem may be solved analytically have been found. Examples of practically useful surface wave geometries spanning from radio communication underwater to UV nanophotonics have been demonstrated.

physics.class-ph↗

arXiv2022

Microscopic study of effective 2+1 dimensional gravity in ferrofluid-based hyperbolic metamaterials

Recent theoretical and experimental work demonstrated that nonlinear optics of ferrofluid-based hyperbolic metamaterials exhibits very unusual 2+2-dimensional spatiotemporal dynamics. Here we report a detailed microscopic study of mutual interactions of individual self-focused optical filaments inside this metamaterial. In agreement with theoretical expectations, the observed mutual interactions of individual filaments exhibit strong similarities with general relativity in 2+1 dimensions. This observation is very important since 2+1-dimensional gravity is an exactly solvable theory even in the quantum gravity limit.

physics.optics↗

arXiv2022

Analogue quantum gravity in hyperbolic metamaterials

It is well known that extraordinary photons in hyperbolic metamaterials may be described as living in an effective Minkowski spacetime, which is defined by the peculiar form of the strongly anisotropic dielectric tensor in these metamaterials. Here we demonstrate that within the scope of this approximation the sound waves in hyperbolic metamaterials look similar to gravitational waves, and therefore the quantized sound waves (phonons) look similar to gravitons. Such an analogue model of quantum gravity looks especially interesting near the phase transitions in hyperbolic metamaterials where it becomes possible to switch quantum gravity effects on and off as a function of metamaterial temperature. We also predict strong enhancement of sonoluminescence in ferrofluid based hyperbolic metamaterials, which looks analogous to particle creation in strong gravitational fields.

physics.optics↗

arXiv2020

Hybrid acousto-electromagnetic metamaterial superconductors

Recent theoretical and experimental studies demonstrated that an electromagnetic metamaterial approach is capable of drastically increasing the critical temperature Tc of composite metamaterial superconductors. This progress was achieved by engineering the frequency-dependent dielectric response function of the metamaterial. Here we further extend this approach by introducing the concept of hybrid acousto-electromagnetic hyperbolic metamaterial superconductors, which are projected to exhibit strongly enhanced superconducting properties due to artificially engineered broadband divergency of the Eliashberg electron-phonon spectral density function. Based on the developed approach, a hybrid acousto-electromagnetic metamaterial is proposed, which is made of LSCO/STO nano-alloy.

cond-mat.supr-con↗

arXiv2019

Observation of plasmon-phonons in a metamaterial superconductor using inelastic neutron scattering

Metamaterial approach is capable of drastically increasing the critical temperature, Tc, of composite metal-dielectric superconductors. Tripling of Tc was observed in bulk Al-Al2O3 core-shell metamaterials. A theoretical model based on the Maxwell-Garnett approximation provides a microscopic explanation of this effect in terms of electron-electron pairing mediated by a hybrid plasmon-phonon excitation. We report the first observation of this excitation in Al-Al2O3 core-shell metamaterials using inelastic neutron scattering. This result provides support for this novel mechanism of superconductivity in metamaterials and explains the 50 year old mystery of enhanced Tc in granular aluminium films.

cond-mat.supr-con↗

arXiv2018

Metamaterial Superconductors

Searching for natural materials exhibiting larger electron-electron interactions constitutes a traditional approach to high temperature superconductivity research. Very recently we pointed out that the newly developed field of electromagnetic metamaterials deals with the somewhat related task of dielectric response engineering on a sub-100 nm scale. Considerable enhancement of the electron-electron interaction may be expected in such metamaterial scenarios as in epsilon near zero (ENZ) and hyperbolic metamaterials. In both cases dielectric function may become small and negative in substantial portions of the relevant four-momentum space, leading to enhancement of the electron pairing interaction. This approach has been verified in experiments with aluminium-based metamaterials. Metamaterial superconductor with Tc = 3.9 K have been fabricated, that is three times that of pure aluminium (Tc = 1.2 K), which opens up new possibilities to considerably improve Tc of other simple superconductors. Taking advantage of the demonstrated success of this approach, the critical temperature of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is evaluated. The MgB2-based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of an H2S-based metamaterial projected Tc appears to reach ~250 K.

physics.optics↗

arXiv2017

Enhancement of Coulomb blockade in epsilon near zero and hyperbolic metamaterials

Coulomb interaction of charges in a metamaterial may be expressed via its effective dielectric response function. Coulomb interaction appears considerably enhanced in artificially engineered epsilon near zero (ENZ) and hyperbolic metamaterials. Indeed, very recently it was observed that negative ENZ conditions enhance superconducting properties of a composite metamaterial via enhancement of Cooper pairing. Here we demonstrate that positive ENZ conditions enhance Coulomb repulsion of charges, leading to considerable enhancement of the Coulomb blockade effect in such metamaterials. Similar to high Tc cuprates, in hyperbolic metamaterials superconductivity and the Coulomb blockade-induced charge ordering is predicted to compete with each other.

physics.optics↗

arXiv2017

Ultrathin ultralight acoustic cloak

Existing designs of transformation acoustic cloaks are not easy to implement in many practical situations because of their large dimensions, while scattering cancellation cloaks do not protect the inner cloak volume. Here we report implementation of an acoustic metamaterial exhibiting cylindrical dispersion in an ultra-thin (~1mm) and ultra-lightweight (~3g) acoustic cloak design intended to protect a human-head-size object in air, which combines scattering cancellation in the far-field with efficient sound proofing of the inner cloak volume.

physics.class-ph↗

arXiv2016

Fine tuning and MOND in a metamaterial multiverse

We consider the recently suggested model of a multiverse based on a ferrofluid. When the ferrofluid is subjected to a modest external magnetic field, the nanoparticles inside the ferrofluid form small hyperbolic metamaterial domains, which from the electromagnetic standpoint behave as individual Minkowski universes exhibiting different laws of physics, such as different strength of effective gravity, different versions of MOND and different radiation lifetimes. When the ferrofluid multiverse is populated with atomic or molecular species, and these species are excited using an external laser source, the radiation lifetimes of atoms and molecules in these universes depend strongly on the individual physical properties of each universe via the Purcell effect. Some universes are better fine-tuned than others to sustain the excited states of these species. Thus, the ferrofluid-based metamaterial multiverse may be used to study models of MOND and to illustrate the fine-tuning mechanism in cosmology.

physics.optics↗

arXiv2016

Magnetic liquids under high electric fields as optical diodes

We show and give examples of how unidirectional propagation of light rays in the limit of geometric optics could arise in some magnetic fluids due to the magnetoelectric effect under weak DC magnetic fields and strong DC electric fields around half of their dielectric breakdown. For such liquids as kerosene and transformer oils, one-way propagation of light may occur for 30 nm diameter magnetic nanoparticles (e.g. cobalt) and concentrations of 2% or larger.

physics.optics↗

arXiv2016

Enhancement of critical temperature in fractal metamaterial superconductors

Fractal metamaterial superconductor geometry has been suggested and analyzed based on the recently developed theoretical description of critical temperature increase in epsilon near zero (ENZ) metamaterial superconductors. Considerable enhancement of critical temperature has been predicted in such materials due to appearance of large number of additional poles in the inverse dielectric response function of the fractal. Our results agree with the recent observation (Fratini et al. Nature 466, 841 (2010)) that fractal defect structure promotes superconductivity.

cond-mat.supr-con↗

arXiv2016

Experimental observation of melting of the effective Minkowski spacetime in cobalt-based ferrofluids

Hyperbolic metamaterials were originally introduced to overcome the diffraction limit of optical imaging. Soon thereafter it was realized that they demonstrate a number of novel phenomena resulting from the broadband singular behavior of their density of photonic states. These novel phenomena and applications include microscopy, stealth technologies, enhanced quantum-electrodynamic effects, thermal hyperconductivity, superconductivity, and interesting gravitation theory analogues. Here we describe the behaviour of cobalt nanoparticle-based ferrofluid in the presence of an external magnetic field, and demonstrate that it forms a self-assembled hyperbolic metamaterial, which may be described as an effective 3D Minkowski spacetime for extraordinary photons. Moreover, such photons perceive thermal gradients in the ferrofluid as analogue of gravitational field, which obeys the Newton law. If the magnetic field is not strong enough, the effective Minkowski spacetime gradually melts under the influence of thermal fluctuations. On the other hand, it may restore itself if the magnetic field is increased back to its original value. Direct microscopic visualization of such a Minkowski spacetime melting/crystallization is presented, which is somewhat similar to hypothesized formation of the Minkowski spacetime in loop quantum cosmology and may mimic various cosmological Big Bang scenarios.

physics.optics↗

arXiv2016

The flexibility of optical metrics

We firstly revisit the importance, naturalness and limitations of the so-called optical metrics for describing the propagation of light rays in the limit of geometric optics. We then exemplify their flexibility and nontriviality in some nonlinear material media and in the context of nonlinear theories of the electromagnetism, both underlain by curved backgrounds, where optical metrics could be flat and impermeable membranes only to photons could be conceived, respectively. Finally, we underline and discuss the relevance and potential applications of our analyses in a broad sense, ranging from material media to compact astrophysical systems.

gr-qc↗

arXiv2016

Theoretical modeling of critical temperature increase in metamaterial superconductors

Recent experiments have demonstrated that the metamaterial approach is capable of drastic increase of the critical temperature Tc of epsilon near zero (ENZ) metamaterial superconductors. For example, tripling of the critical temperature has been observed in Al-Al2O3 ENZ core-shell metamaterials. Here, we perform theoretical modelling of Tc increase in metamaterial superconductors based on the Maxwell-Garnett approximation of their dielectric response function. Good agreement is demonstrated between theoretical modelling and experimental results in both aluminium and tin-based metamaterials. Taking advantage of the demonstrated success of this model, the critical temperature of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is evaluated. The MgB2-based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of an H2S-based metamaterial Tc appears to reach ~250K.

cond-mat.supr-con↗

arXiv2015

Using core-shell metamaterial engineering to triple the critical temperature of a superconductor

Recent experiments have shown the viability of the metamaterial approach to dielectric response engineering for moderately enhancing the transition temperature, Tc, of a superconductor. In this report, we demonstrate the use of Al2O3-coated aluminium nanoparticles to form the recently proposed epsilon near zero (ENZ) core-shell metamaterial superconductor with a Tc that is three times that of pure aluminium. IR reflectivity measurements confirm the predicted metamaterial modification of the dielectric function thus demonstrating the efficacy of the ENZ metamaterial approach to Tc engineering. These results provide an explanation for the long known, but not understood, enhancement of the Tc of granular aluminum films.

physics.optics↗

arXiv2015

Experimental demonstration of Luneburg waveguides

Transformation optics gives rise to numerous unusual optical devices, such as novel metamaterial lenses and invisibility cloaks. Very recently Mattheakis et al. have suggested theoretical design of an optical waveguide based on a network of Luneburg lenses, which may be useful in sensing and nonlinear optics applications. Here we report the first experimental realization of such Luneburg waveguides. We have studied wavelength and polarization dependent performance of the waveguides.

physics.optics↗

arXiv2014

Experimental model of topological defects in Minkowski spacetime based on disordered ferrofluid: magnetic monopoles, cosmic strings and the spacetime cloak

Cobalt nanoparticle-based ferrofluid in the presence of external magnetic field forms a self-assembled hyperbolic metamaterial. Wave equation describing propagation of extraordinary light inside the ferrofluid exhibits 2+1 dimensional Lorentz symmetry. The role of time in the corresponding effective 3D Minkowski spacetime is played by the spatial coordinate directed along the periodic nanoparticle chains aligned by the magnetic field. Here we present a microscopic study of point, linear, planar and volume defects of the nanoparticle chain structure and demonstrate that they may exhibit strong similarities with such Minkowski spacetime defects as magnetic monopoles, cosmic strings and the recently proposed spacetime cloaks. Experimental observations of such defects are described.

physics.optics↗

arXiv2014

Metamaterial superconductors

Epsilon near zero (ENZ) conditions have been observed to enhance superconducting properties of a composite metamaterial based on random mixing of superconductor and ferroelectic nanoparticles. Here we analyse several other promising experimental geometries, which may considerably enhance electron pairing interaction in a metamaterial superconductor. The proposed geometries may be fabricated at the current level of nanotechnology development. They enable tuning of both frequency and spatial dispersion of the effective dielectric response function of the metamaterial, thus enabling optimization of the metamaterial superconductor properties.

physics.optics↗