The production of spinless hadron pairs via virtual photon exchange in uniform magnetic fields

1983 ◽  
Author(s):  
D. White
Keyword(s):  
Magnetic Fields ◽  
Virtual Photon ◽  
Photon Exchange ◽  
Hadron Pairs

scholarly journals Experimental Separation of Virtual Photon Exchange and Electron Transfer in Interatomic Coulombic Decay of Neon Dimers

2007 ◽  
Vol 99 (15) ◽  
Author(s):  
T. Jahnke ◽  
A. Czasch ◽  
M. Schöffler ◽  
S. Schössler ◽  
M. Käsz ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Virtual Photon ◽  
Photon Exchange

scholarly journals Estimating the radiative part of QED effects in systems with supercritical charge

2019 ◽  
Vol 201 ◽  
pp. 09010
Author(s):  
Artem Roenko ◽  
Konstantin Sveshnikov
Keyword(s):  
Virtual Photon ◽  
Effective Interaction ◽  
Superheavy Nuclei ◽  
Energy Contribution ◽  
Photon Exchange ◽  
Self Energy ◽  
Lower Continuum ◽  
Qed Effects ◽  
Electron Magnetic Moment ◽  
Dynamical Screening

The effective interaction of the electron magnetic moment anomaly with the Coulomb fileld of superheavy nuclei is investigated by taking into account its dynamical screening at small distances. The shift of the electronic levels, caused by this interaction, is considered for H-like atoms and for compact nuclear quasi-molecules, non-perturbatively both in Zα and (partially) in α/π. It is shown that the levels shift reveals a non-monotonic behavior in the region Zα 1 and near the threshold of the lower continuum decreases both with the increasing the charge and with enlarging the size of the system of Coulomb sources. The last result is generalized to the total self-energy contribution to the levels shift and so to the possible behavior of radiative QED effects with virtual photon exchange near the lower continuum in the supercritical region.

scholarly journals Perturbativity vs nonperturbativity in QED-effects for H-like atoms with Zα > 1

2017 ◽  
Vol 32 (22) ◽  
pp. 1750130 ◽  
Author(s):  
A. Roenko ◽  
K. Sveshnikov
Keyword(s):  
Growth Rate ◽  
Virtual Photon ◽  
Coulomb Field ◽  
Energy Contribution ◽  
Photon Exchange ◽  
Self Energy ◽  
Lower Continuum ◽  
Quark Structure ◽  
Qed Effects ◽  
Complete Dependence

The behavior of levels near the threshold of the lower continuum in superheavy H-like atoms with [Formula: see text], caused by the interaction [Formula: see text] of the electron’s magnetic anomaly (AMM) dynamically screened at small distances [Formula: see text], with the Coulomb field of atomic nucleus is considered by taking into account the complete dependence of electron’s wave function (WF) on [Formula: see text]. It is shown that the calculation of the contribution caused by [Formula: see text] via both the quark structure and the whole nucleus, considered as a uniformly charged extended Coulomb source, leads to results, which coincide within the accepted precision of calculations. It is also shown that there appears some difference in results between perturbative and nonperturbative methods of accounting for the contribution from [Formula: see text] within the corresponding Dirac equation (DE) in favor of the latter. Moreover, the growth rate of the contribution from [Formula: see text] reaches its maximum at [Formula: see text], while by further increase of [Formula: see text] into the supercritical region [Formula: see text], the shift of levels caused by [Formula: see text] near the lower continuum decreases monotonically to zero. The last result is generalized to the whole self-energy contribution to the shift of levels and so to the possible behavior of radiative QED-effects with virtual photon exchange near the lower continuum.

scholarly journals Circuit QED with qutrits: Coupling three or more atoms via virtual-photon exchange

2017 ◽  
Vol 96 (4) ◽  
Author(s):  
Peng Zhao ◽  
Xinsheng Tan ◽  
Haifeng Yu ◽  
Shi-Liang Zhu ◽  
Yang Yu
Keyword(s):  
Virtual Photon ◽  
Circuit Qed ◽  
Photon Exchange

Calculated Coronal Magnetic Fields and Their Comparison with the Coronal Structures as Observed during Five Solar Eclipses

1994 ◽  
Vol 144 ◽  
pp. 559-564
Author(s):  
P. Ambrož ◽  
J. Sýkora
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Coronal Magnetic Field ◽  
Coronal Magnetic Fields ◽  
Solar Eclipses ◽  
Coronal Structures

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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