Related papers: Energy Gaps in a Spacetime Crystal
The quantum Hall effect is generally understood for free electron gases, in which topologically protected edge states between Landau levels (LLs) form conducting channels at the edge of the sample. In periodic crystals, the LLs are…
Photonic time crystals (PTCs) are materials whose dielectric permittivity is periodically modulated in time, giving rise to bandgaps not in energy-as in conventional photonic crystals-but in momentum, known as k-gaps. These k-gaps enable…
Towards the development of strategies for tailoring spin-wave band gaps in magnonic crystals, this work examines the band gap properties in a one-dimensional magnonic crystal with double periodicity. A long and narrow yttrium iron garnet…
We introduce the stochastic band structure, a method giving the dispersion relation for waves propagating in periodic media or along waveguides, and subject to material loss or radiation damping. Instead of considering an explicit or…
In this letter we show that, at its fundamental level, phantom dark energy is a fluid made up of time crystals that permeate the fabric of space-time. In turn, any well-behaved stable theory of a non-canonical scalar field that acts as…
We study possible quantum states of two correlated electrons in a two-dimensional crystal and find a metastable energy band of the electron pair between the two lowest single-electron bands. These metastable states result from the interplay…
We analyze transmission of electromagnetic waves through a periodic band-gap structure consisting of slabs of a left-handed metamaterial and air. Using the effective parameters of the metamaterial derived from its microscopic structure, we…
Using an optical potential with subwavelength resolution in the form of sharp $\delta$-like peaks, new potential landscapes are created with increased anharmonicity in placement of lattice band energies and more favorable energy scales. In…
Density functional theory applied to a simple ionic material, MgO, is used as a model system to clarify several aspects of electronic driven mechanism to compensate for the diverging electrostatic potential in the polar structures. We…
The spectrum of excitations a two-dimensional, planar honeycomb lattice of two-level atoms coupled by the in-plane electromagnetic field may exhibit band gaps that can be opened either by applying an external magnetic field or by breaking…
We present a micromagnetic analysis of spin-wave propagation in a magnonic crystal realized as a permalloy spin-wave waveguide with a spatial periodical variation of its saturation magnetization. Frequency band gaps were clearly observed in…
We introduce a systematic method for constructing a class of lattice structures that we call ``partial line graphs''.In tight-binding models on partial line graphs, energy bands with flat energy dispersions emerge.This method can be applied…
We create wave-matter space-time metamaterials using optical trapping forces to manipulate mass-spring chains and create zero-frequency and zero-wavenumber band gaps: the bosonic nature of phonons, and hence this elastodynamic setting,…
Time-varying media offer a platform to realize novel and exotic wave effects, including photonic time crystals characterized by momentum band gaps with exponential wave amplification. Here we focus on the quantum electrodynamical properties…
The calculation of the discrete atomistic energy of a crystal near the continuum limit encounters difficulties caused by the geometric discrepancy between the continuum region occupied by the body, and the discrete collection of lattice…
Certain lattices with specific geometries have one or more spectral bands that are strictly flat, i.e. the electron energy is independent of the momentum. This can occur robustly irrespective of the specific couplings between the lattices…
We demonstrate that a Bose-Einstein condensate in an optical lattice forms a reconfigurable matter-wave structure with a band-gap spectrum, which resembles a nonlinear photonic crystal for light waves. We study in detail the case of a…
We present it ab initio calculations of the electronic energy loss of charged particles moving outside a magnesium surface, from a realistic description of the one-electron band structure and a full treatment of the dynamical electronic…
We investigate the optical response of an atomic Bose-Einstein condensate with a vortex lattice. We find that it is possible for the vortex lattice to act as a photonic crystal and create photonic band gaps, by enhancing the refractive…
A theoretical investigation is made of the dispersion characteristics of plasmons in a two-dimensional periodic system of semiconductor (dielectric) cylinders embedded in a dielectric (semiconductor) background. We consider both square and…