Macroscopic Quantum Electrodynamics

In recent years, matter-wave diffraction at nanomechanical structures has been used by several research groups to explore the quantum nature of atoms and molecules, to prove the existence of weakly bound molecules or to explore atom-surface interactions with high sensitivity. The particles' Casimir-Polder interaction with the diffraction grating leads to significant changes in the amplitude distribution of the diffraction pattern. This becomes particularly intriguing in the thin-grating limit, i.e. when the size of a complex molecule becomes comparable with the grating thickness and its rotation period comparable to the transit time through the mask. Here we analyze the predictive power of a Green's function scattering model and the constraints imposed by the finite control over real-world experimental factors on the nanoscale.

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“…as the ratio between the exact Casimir-Polder potential for an infinite plate [21] and the potential in first-order of the Born series…”

Section: Effective Slit Approximationmentioning

confidence: 99%

A Green's function approach to modeling molecular diffraction in the limit of ultra‐thin gratings

et al. 2015

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“…In the following derivation we shall not assume this restriction and shall consider the emitter near a surface with an arbitrary shape. This will be possible by noting that ImG(ω) is a real and symmetric matrix 41 , which means it can be diagonalized. Choosing a basis where the imaginary part of the Green's function is diagonal and using Eq.…”

Section: Relation Between the Tpse And The Purcell Factorsmentioning

confidence: 99%

Quantum two-photon emission in a photonic cavity

et al. 2019

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We derive a new expression for the two-photon spontaneous emission (TPSE) rate of an excited quantum emitter in the presence of arbitrary bodies in its vicinities. After investigating the influence of a perfectly conducting plate on the TPSE spectral distribution (Purcell effect), we demonstrate the equivalence of our expression with the more usual formula written in terms of the corresponding dyadic Green's function. We establish a general and convenient relation between the TPSE spectral distribution and the corresponding Purcell factors of the system. Next, we consider an emitter close to a dielectric medium and show that, in the near field regime, the TPSE spectral distribution is substantially enhanced and changes abruptly at the resonance frequencies. Finally, motivated by the suppression that may occur in the one-photon spontaneous emission of an excited atom between two parallel conducting plates, we discuss the TPSE for this same situation and show that complete suppression can never occur for s → s transitions.

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“…For the following considerations, we assume that the particles are embedded in a homogeneous media, described by the Green function for the bulk material ,, with wavenumber and relative coordinate ϱ = r – r ′ with its absolute value ϱ = | ϱ | and its unit vector e ϱ = ϱ /ϱ. The bold δ-function denotes the product of the Dirac−δ-function and the unit tensor I , δ ( ϱ ) = δ( ϱ ) I .…”

Section: Particle’s Orientationmentioning

confidence: 99%

“…With such a spatially distributed polarizability density α(ϱ), one can introduce the complete polarizability of the particle by its multiplication with the frequency dependent part With respect to the Born series expansion of the scattering Green function , the resulting van der Waals potential has to be integrated over the particle volumes with the pointwise van der Waals potential where we have used the nonretarded free-space scattering Green function, because the considered effects ensue on small length scales. Note that, due to the scattering Green function, the relative coordinate between both particles is along the x -direction, r = ( x , 0, 0).…”

Section: Van Der Waals Interaction Between Extended Particlesmentioning

confidence: 99%

“…The interaction between two neutral but polarizable particles when they are closely brought together is described by van der Waals forces. They are caused by ground-state fluctuations of the electromagnetic field, which result in a mostly attractive force between both particles. Typically, the interacting particles are considered to be pointlike.…”

Section: Introductionmentioning

confidence: 99%

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Orientational Dependence of the van der Waals Interactions for Finite-Sized Particles

et al. 2018

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Dispersion forces, especially van der Waals forces as interactions between neutral and polarizable particles act at small distances between two objects. Their theoretical origin lies in the electromagnetic interaction between induced dipole moments caused by the vacuum fluctuations of the ground-state electromagnetic field. The resulting theory well describes the experimental situation in the limit of the point dipole assumption. At smaller distances, where the finite size of the particles has to be taken into account, this description fails and has to be corrected by higher orders of the multipole expansion, such as quadrupole moments and so on. With respect to the complexity of the spatial properties of the particles this task requires a considerable effort. In order to describe the van der Waals interaction between such particles, we apply the established method of a spatially spread out polarizability distribution to approximate the higher orders of the multipole expansion. We thereby construct an effective theory for effects from anisotropy and finite size on the van der Waals potential.

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Macroscopic Quantum Electrodynamics

Cited by 7 publications

References 37 publications

A Green's function approach to modeling molecular diffraction in the limit of ultra‐thin gratings

A Green's function approach to modeling molecular diffraction in the limit of ultra‐thin gratings

Quantum two-photon emission in a photonic cavity

Orientational Dependence of the van der Waals Interactions for Finite-Sized Particles

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