| 1. |
- Bull, James N., et al.
(författare)
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Action spectroscopy of deprotomer-selected hydroxycinnamate anions
- 2021
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 75:2
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Tidskriftsartikel (refereegranskat)abstract
- Tandem ion mobility mass spectrometry-coupled laser excitation is used to record photodetachment, photoisomerization and photodepletion action spectra for a series of deprotomer-selected hydroxycinnamate anions, including deprotonated caffeic, ferulic and sinapinic acids. This molecular series accounts for most hydroxycinnainic moieties found in nature. Phenoxide deprotomers for para and ortho structural isomers have similar photodetachment action spectra that span the 350-460nm range with the maximum response occurring between 420 and 440 nm. None of the phenoxide deprotomers showed evidence for E -> Z photoisomerization. In contrast, photoexcitation of the carboxylate deprotomers of caffeic and ferulic acids and the meta-phenoxide deprotomer of caffeic acid initiates intramolecular proton transfer to give the para-phenoxide deprotomer. Photoexcitation of the carboxylate deprotomer of sinapinic acid and ortho-coumaric acid does not result in intramolecular proton transfer, presumably due to substantial barriers for rearrangement. For deprotonated meta-coumaric acid, interconversion between the phenoxide and carboxylate deprotomers occurs in the ion mobility spectrometer drift region where the effective ion temperature is T-eff approximate to 299 K.
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| 2. |
- Busto, David, et al.
(författare)
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Probing electronic decoherence with high-resolution attosecond photoelectron interferometry
- 2022
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 76:7
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Quantum coherence plays a fundamental role in the study and control of ultrafast dynamics in matter. In the case of photoionization, entanglement of the photoelectron with the ion is a well-known source of decoherence when only one of the particles is measured. Here, we investigate decoherence due to entanglement of the radial and angular degrees of freedom of the photoelectron. We study two-photon ionization via the 2s2p autoionizing state in He using high spectral resolution photoelectron interferometry. Combining experiment and theory, we show that the strong dipole coupling of the 2s2p and 2p2 states results in the entanglement of the angular and radial degrees of freedom. This translates, in angle-integrated measurements, into a dynamic loss of coherence during autoionization. Graphic Abstract: [Figure not available: see fulltext.]. © 2022, The Author(s).
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| 3. |
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| 4. |
- Ekman, Robin, 1991-, et al.
(författare)
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Short-scale quantum kinetic theory including spin-orbit interactions
- 2021
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Ingår i: European Physical Journal D. - : Springer. - 1434-6060 .- 1434-6079. ; 75:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a quantum kinetic theory for spin-1/2 particles, including the spin-orbit interaction, retaining particle dispersive effects to all orders in ℏ, based on a gauge-invariant Wigner transformation. Compared to previous works, the spin-orbit interaction leads to a new term in the kinetic equation, containing both the electric and magnetic fields. Like other models with spin-orbit interactions, our model features "hidden momentum". As an example application, we calculate the dispersion relation for linear electrostatic waves in a magnetized plasma, and electromagnetic waves in a unmagnetized plasma. In the former case, we compare the Landau damping due to spin-orbit interactions to that due to the free current. We also discuss our model in relation to previously published works.
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| 5. |
- Gürkan, Nilhan, et al.
(författare)
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Toward a measurement of the effective gauge field and the Born-Huang potential with atoms in chip traps
- 2022
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Ingår i: European Physical Journal D. - : Springer Nature. - 1434-6060 .- 1434-6079. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- We study magnetic traps with very high trap frequencies where the spin is coupled to the motion of the atom. This allows us to investigate how the Born–Oppenheimer approximation fails and how effective magnetic and electric fields appear as the consequence of the non-adiabatic dynamics. The results are based on exact numerical diagonalization of the full Hamiltonian describing the coupling between the internal and external degrees of freedom. The position in energy and the decay rate of the trapping states corresponding to the imaginary part of the resonances of this Hamiltonian are computed using the complex rotation method.
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| 6. |
- Hu, Wenxiang, et al.
(författare)
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A network of superconducting gravimeters as a detector of matter with feeble nongravitational coupling
- 2020
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 74:6
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Tidskriftsartikel (refereegranskat)abstract
- Hidden matter that interacts only gravitationally would oscillate at characteristic frequencies when trapped inside of Earth. For small oscillations near the center of the Earth, these frequencies are around 300 mu Hz. Additionally, signatures at higher harmonics would appear because of the non-uniformity of Earth's density. In this work, we use data from a global network of gravimeters of the International Geodynamics and Earth Tide Service (IGETS) to look for these hypothetical trapped objects. We find no evidence for such objects with masses on the order of 10(14) kg or greater with an oscillation amplitude of 0.1r(e). It may be possible to improve the sensitivity of the search by several orders of magnitude via better understanding of the terrestrial noise sources and more advanced data analysis.
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| 7. |
- Lassègues, Pierre, et al.
(författare)
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Field and intensity correlations : the Siegert relation from stars to quantum emitters
- 2022
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 76:12
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Tidskriftsartikel (refereegranskat)abstract
- The Siegert relation relates field and intensity temporal correlations. After a historical review of the Siegert relation and the Hanbury Brown and Twiss effect, we discuss the validity of this relation in two different domains. We first show that this relation can be used in astrophysics to determine the fundamental parameters of stars, and that it is especially important for the observation with stellar emission lines. Second, we check the validity of this relation for moving quantum scatterers illuminated by a strong driving field.
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| 8. |
- Mogan, Shane Carberry R., et al.
(författare)
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Electron impact ionization in the icy Galilean satellites' atmospheres
- 2023
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Ingår i: European Physical Journal D. - : Springer Nature. - 1434-6060 .- 1434-6079. ; 77:2
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Tidskriftsartikel (refereegranskat)abstract
- Electron impact ionization is critical in producing the ionospheres on many planetary bodies and, as discussed here, is critical for interpreting spacecraft and telescopic observations of the tenuous atmospheres of the icy Galilean satellites of Jupiter (Europa, Ganymede, and Callisto), which form an interesting planetary system. Fortunately, laboratory measurements, extrapolated by theoretical models, were developed and published over a number of years by K. Becker and colleagues (see Deutsch et al. in Adv At Mol Opt Phys 57:87-155, 2009) to provide accurate electron impact ionization cross sections for atoms and molecules, which are crucial to correctly interpret these measurements. Because of their relevance for the Jovian icy satellites, we provide useful fits to the complex, semiempirical Deutsch-Ma spexpressioncing diexpressioneresis rk formula for energy-dependent electron impact ionization cross sections of gas-phase water products (i.e., H2O, H-2, O-2, H, O). These are then used with measurements of the thermal plasma in the Jovian magnetosphere to produce ionization rates for comparison with solar photo-ionization rates at the icy Galilean satellites.
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| 9. |
- Orel, Ann, et al.
(författare)
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Dissociative electron attachment to MgCN
- 2020
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 74:1
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Tidskriftsartikel (refereegranskat)abstract
- Dissociative electron attachment (DEA) to the molecule MgCN and its isomer MgNC has been proposed as a possible source of CN- in the interstellar media. We have carried out electron scattering calculations using the complex Kohn Variational Method as a function of the internal degrees of freedom of the molecule to obtain the resonance energy surfaces and autoionization widths. We use these data as input to form the Hamiltonian relevant to the nuclear dynamics. The multidimensional time-dependent Schrodinger equation is solved using the MultiConfiguration Time-Dependent Hartree (MCTDH) approach. We compute the DEA cross sections and discuss the implications for CN- formation in circumstellar envelopes.
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| 10. |
- Shen, Jianqi, et al.
(författare)
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Supersymmetric gauge potentials in multiphoton transition of atoms and squeezed-vacuum-state driven supersymmetric "isospin" evolution
- 2020
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Ingår i: European Physical Journal D. - : SPRINGER. - 1434-6060 .- 1434-6079. ; 74:3
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Tidskriftsartikel (refereegranskat)abstract
- Energy spectrum of a multiphoton-transition Jaynes-Cummings model with supersymmetry breaking and some relevant topics such as multiphoton dark state (photon-atom dark-state polariton) and multiphoton coherent population trapping are considered in this paper. We show that for a moving atom, because of Doppler effect and the relativistic electromagnetic induction for the incident optical field, there appears supersymmetric gauge potentials induced by the multiphoton transition and then this can lead to some interesting physical effects such as supersymmetric "spin" Hall effect and supersymmetric Aharonov-Bohm effect of atoms. Both supersymmetric vectorial gauge potential and scalar gauge potential can drive the population transition in the supersymmetric "isospin" doublet states in this Jaynes-Cummings model. As an illustrative example, we address the quantum collapse and revival in atomic population inversion driven by squeezed vacuum states and displaced squeezed vacuum states in such a multiphoton-transition Jaynes-Cummings model. It can be found that different from a coherent state that drives the Jaynes-Cummings model, where quantum collapse-revival effect in atomic level population inversion can be exhibited, a squeezed vacuum state, which excites the Jaynes-Cummings model, cannot give rise to the quantum collapse and revival because there is no Fock-state probability peak in the distribution function in the squeezed vacuum state. If, however, the Jaynes-Cummings model with multiphoton transition is driven by a displaced squeezed vacuum state, it can exhibit the effect of collapse and revival in the energy-level population inversion. In addition, we shall consider the interaction among atom paths (spatial wavefunctions), atomic internal levels and the photon field. Such a coupling leads to an atomic path-level-photon entangled state, and the traditional atomic-level quantum Rabi oscillation and quantum collapse-revival effect that occurred in time domain would be exhibited in the atom spatial wavefunctions (or in atomic paths).
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