Superpositions of Lorentzians as the class of causal functions

Dirdal, Christopher A.; Skaar, Johannes

doi:10.1103/physreva.88.033834

Cited by 15 publications

(15 citation statements)

References 22 publications

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“…That is, we are going to design an event cloak so that the device itself, despite its many complications, seems to an observer to be acting like a simple homogeneous and isotropic material that follows the standard Lorentz model. Naturally, since this is a linear system, the method could be straightforwardly generalised to encompass a sum of Lorentz oscillators as well [28]; and it is worth noting that with careful parameter choice, the Drude model for material response can be encoded within the Lorentz model. We also show how to define material responses as differential equations for polarisation 2-forms, and this methodology is general enough to also handle many other (i.e.…”

Section: Introductionmentioning

confidence: 99%

On spacetime transformation optics: temporal and spatial dispersion

et al. 2016

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The electromagnetic implementation of cloaking, the hiding of objects from sight by diverting and reassembling illuminating electromagnetic fields has now been with us ten years, while the notion of hiding events is now five. Both schemes as initially presented neglected the inevitable dispersion that arises when a designed medium replaces vacuum under transformation. Here we define a transformation design protocol that incorporates both spacetime transformations and dispersive material responses in a natural and rigorous way. We show how this methodology is applied to an event cloak designed to appear as a homogeneous and isotropic but dispersive medium. The consequences for spacetime transformation design in dispersive materials are discussed, and some parameter and bandwidth constraints identified.

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Section: Introductionmentioning

confidence: 99%

On spacetime transformation optics: temporal and spatial dispersion

et al. 2016

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“…Both broadband absorbers and polarization convertors could be designed with Lorentz‐type dispersion . Since Lorentz dispersion can be used as a basic building block for materials with complex dispersion obeying the Kramers–Kronig relations, it may be generalized to many functional metasurfaces.…”

Section: Principles and Methodologiesmentioning

confidence: 99%

Methodologies for On‐Demand Dispersion Engineering of Waves in Metasurfaces

Guo

et al. 2019

Advanced Optical Materials

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IntroductionMetasurfaces and surface waves are two booming research branches in modern optics and wave physics. As 2D counterparts of 3D metamaterials, metasurfaces have inherited many unusual properties of artificially structured metamaterials, e.g., negative refraction, super-resolution imaging, and invisibility. [1][2][3][4][5][6] Nevertheless, owing to the reduced dimension, metasurfaces are much easier to fabricate, thus providing possibilities to transform theoretical innovations to practical applications. [7,8] In principle, the mechanisms of light-matter interaction in metasurfaces are related to the exotic physical properties of surface waves on metasurfaces. There are many kinds of surface waves propagating along interfaces of two kinds of media, such as surface plasmons, Dyakonov, Bloch, and Tamm surface waves. [9,10] Surface plasmons require that one of the media has negative permittivity; Dyakonov surface waves require linear anisotropy of at least one of the media. Bloch and Tamm surface waves require periodic permittivity of one of the media truncated by the interface or along the interface. In this paper, we would like to highlight the Dispersion is one common yet critical property of all kinds of waves. It is related to the spatial and spectral evolution of waves in structured materials. This review gives a summary of the methodologies used for the on-demand dispersion engineering of waves in metasurfaces, which possess many unusual properties such as extremely short wavelength, diffraction-less directional propagation, and tunable phase shift, resulting in many exciting applications with performances beyond the limitations set by traditional geometric and physical optics. Since most metasurfaces could be continuously transformed from simple thin films, the methodologies proposed here are universal and may be applied to analyze and design various functional metasurfaces. Dispersion EngineeringWithout loss of generality, the geometry of almost all metasurfaces could be continuously transformed from simple thin films. The transformation process is illustrated in Figure 1. First, by stacking and bending multilayers, one obtain the superlens, planar hyperlens, and curved hyperlenses. [26][27][28] The hyperbolic dispersion in anisotropic metal-dielectric structures may lead to the formation of Dyakonov plasmons, which are similar to Dyakonov waves on anisotropic dielectric materials. [29][30][31][32][33][34] Second, a 90° rotation of the multilayer would result a 1D grating, which can be either periodic or gradient. Third,

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“…[44] presents one particular design. In appendix C, we show that the optimization problem (26) can be solved to a desired precision following the kernel properties of the Lorentzian function [45][46][47].…”

Section: A Circuit-qed Proposalmentioning

confidence: 99%

Artificial quantum thermal bath: Engineering temperature for a many-body quantum system

Shabani

Neven

2016

Phys. Rev. A

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Temperature determines the relative probability of observing a physical system in an energy state when that system is energetically in equilibrium with its environment. In this paper, we present a theory for engineering the temperature of a quantum system different from its ambient temperature. We define criteria for an engineered quantum bath that, when coupled to a quantum system with Hamiltonian H, drives the system to the equilibrium state e −H/T Tr(e −H/T ) with a tunable parameter T . This is basically an analog counterpart of the digital quantum metropolis algorithm. For a system of superconducting qubits, we propose a circuit-QED approximate realization of such an engineered thermal bath consisting of driven lossy resonators. Our proposal opens the path to simulate thermodynamical properties of many-body quantum systems of size not accessible to classical simulations. Also we discuss how an artificial thermal bath can serve as a temperature knob for a hybrid quantum-thermal annealer.

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Superpositions of Lorentzians as the class of causal functions

Cited by 15 publications

References 22 publications

On spacetime transformation optics: temporal and spatial dispersion

On spacetime transformation optics: temporal and spatial dispersion

Methodologies for On‐Demand Dispersion Engineering of Waves in Metasurfaces

Artificial quantum thermal bath: Engineering temperature for a many-body quantum system

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