arXiv subjects

Maxim Vavilin

Publications and source records attributed to Maxim Vavilin.

5 recordsLinked to original sources

arXiv2024

The electromagnetic scalar product in spatially-bounded domains

Many physically interesting quantities of the electromagnetic field can be computed using the electromagnetic scalar product. However, none of the existing expressions for such scalar product are directly applicable when the fields are only known in a spatially-bounded domain, as is the case for many numerical Maxwell solvers. In here, we derive an expression for the electromagnetic scalar product between radiation fields that only involves integrals over closed spatial surfaces. The expression readily leads to formulas for the number of photons, energy, and helicity of generic polychromatic light pulses of incoming or outgoing character. The capabilities of popular Maxwell solvers in spatially-bounded computational domains are thereby augmented, for example, by a straightforward method for normalizing emitted fields so that they contain a single photon.

physics.optics↗

arXiv2024

Computing the interaction of light pulses with objects moving at relativistic speeds

The interaction of light with short light pulses is relevant in optical traps, optical tweezers, and many other applications. The theoretical description of such polychromatic light-matter interaction is challenging, and more so when the object is moving with respect to the light source, albeit with constant speed. Light sails are futuristic examples where such speed should reach the relativistic regime. In here, we provide a methodology for the theoretical and numerical analysis of the interaction of light pulses with objects moving with constant speed. The methodology allows one, in particular, to readily compute the transfer of fundamental quantities such as energy and momentum from the light pulse to the object. As an example, we compute the transfer of energy and momentum between a given pulse and a silicon sphere moving at relativistic speeds. The methodology, however, is valid for generic pulses and objects. Particularizing the equations to the case of zero speed allows one to treat static or quasi-static objects. The method is based on the polychromatic T-matrix formalism, which leverages the many publicly available resources for computing T-matrices.

physics.optics↗

arXiv2024

A Framework for Formulating Polychromatic Theories of Emission

The emission of energy as electromagnetic radiation is ubiquitous, in particular because objects release thermal energy in the form of photons. Most theories of thermal radiation assume that the thermal emissions originate from a continuum of elementary monochromatic sources, uncorrelated to each other. The universality of thermal radiation motivates the consideration of theories that allow for more general kinds of elementary emissions. In here, we introduce a framework for formulating polychromatic theories of emission in the electromagnetic Hilbert space, whose computational side is based on the transition matrix, or T-matrix. Each photon is emitted as a coherent polychromatic pulse. The spectra of the different emitted pulses are derived using the natural resonance frequencies of the given finite-size object. Each resonance belongs to one of the orthogonal subspaces which decompose the absorption operator according to the symmetries of the object. Energy conservation in the steady-state is ensured by equalizing the absorption and emission of energy at each individual subspace. The framework can accommodate general illuminations, and produce emissions with frequencies that are much suppressed in or even absent from the illumination, resulting in different rates of emission and absorption of photons. This makes the framework suitable for describing other kinds of emissions, such as luminescence, in the Hilbert space.

physics.optics↗

arXiv2023

A scalar product for computing fundamental quantities in matter

We introduce a systematic way to obtain expressions for computing the amount of fundamental quantities such as helicity and angular momentum contained in static matter, given its charge and magnetization densities. The method is based on a scalar product that we put forward, which is invariant under the ten-parameter conformal group in three-dimensional Euclidean space. Such group is obtained as the static restriction (frequency $ω=0$) of the symmetry group of Maxwell equations: The fifteen-parameter conformal group in 3+1 Minkowski spacetime. In an exemplary application, we compute the helicity and angular momentum squared stored in a magnetic Hopfion.

physics.optics↗

arXiv2023

The Polychromatic T-matrix

The T-matrix is a powerful tool that provides the complete description of the linear interaction between the electromagnetic field and a given object. In here, we generalize the usual monochromatic formalism to the case of polychromatic field-matter interaction. The group of transformations of special relativity provides the guidance for building the new formalism, which is inherently polychromatic. The polychromatic T-matrix affords the direct treatment of the interaction of electromagnetic pulses with objects, even when the objects move at constant relativistic speeds.

physics.optics↗