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Optical Loss: Principles and Applications
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
M.M. Rad, Halit Eren, Martin Maier
Light or visible light is the portion of electromagnetic spectrum that is visible to the human eye. Visible light corresponds to the wavelength range from 390 to 750 nm. However, in physics, the term light often comprises the two adjacent regions of infrared (higher wavelengths) and ultraviolet (lower wavelengths), not visible to the human eye. Primary properties of light are intensity, propagation direction, wavelength (frequency), polarization, and phase. The light speed in vacuum is however one of the fundamental constants of nature and is about 300,000 km/s.
Kinematical Lie Algebras and Invariant Functions of Algebras
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2019
J. M. Escobar, J. Núñez, P. Pérez-Fernández
Finally, and as the last example which we point out of the use of Lie algebras in Kinematics, we cite a paper by Khrushchev and Leznov [7] in which they consider a deformation of the canonical algebra for kinematic observables of quantum field theory in Minkowski space-time under the condition of Lorentz invariance. The relativistically invariant algebra which they obtain depends on additional fundamental constants M, L, and H with the dimensions of mass, length and action, respectively. They observe that in some limiting cases the algebra can be represented by the well-known Snyder or Yang algebras, whereas in the general case, the algebra represents a class of Lie algebras, which consists of both simple algebras and semidirect sums of simple and integrable algebras, some of which are not invariant under the T and C transformations.
Cold ion chemistry within Coulomb crystals
Published in Molecular Physics, 2019
One significant advantage of cryogenic conditions for spectroscopic studies of complex molecular ions is, of course, that fewer rotational and vibrational states are populated at low temperatures – significantly simplifying the resulting spectra and enhancing the spectral resolution that can be achieved. While such low temperature measurements have been made using 22-pole traps with buffer gas cooling for a number of years [40,41], Coulomb crystals allow new high resolution methods, such as quantum logic spectroscopy [42] (discussed in more detail below) to be explored. With the many added benefits offered by cryogenic conditions, one can envisage the detailed spectroscopic study of a range of complex molecular ions within Coulomb crystals in the near future. The CryPTEx apparatus has already seen the Coulomb crystallisation of highly-charged ions – paving the way for detailed spectroscopic studies and providing a methodology whereby the time dependence of fundamental constants such as the fine structure constant, α, could potentially be measured [43].
Controlled preparation and vibrational excitation of single ultracold molecular hydrogen ions
Published in Molecular Physics, 2022
Christian Wellers, Magnus R. Schenkel, Gouri S. Giri, Kenneth R. Brown, Stephan Schiller
Trapped ultracold molecular ions are an emerging class of systems allowing highly precise spectroscopic measurements that have relevance in fundamental physics (for a general introduction to low-energy experiments in fundamental physics, see [1,2]). Such measurements enable tests of quantum electrodynamics (QED) of three-body systems [3–5], the determination of some fundamental constants of atomic physics, and searches for physics beyond the Standard Model [4]. As a future perspective, molecular ions could become ideal systems suitable for testing the constancy of the electron-proton mass ratio [6–11].