Two-photon processes and production of charmed-quark-antiquark bound states

1976 ◽  
Vol 13 (9) ◽  
pp. 2563-2566 ◽  
Author(s):  
Jnanadeva Maharana
Keyword(s):  
Bound States ◽  
Two Photon ◽  
Charmed Quark

Spectrum of Charmed Quark-Antiquark Bound States

1992 ◽  
pp. 18-21
Author(s):  
E. Eichten ◽  
K. Gottfried ◽  
T. Kinoshita ◽  
J. Kogut ◽  
K.D. Lane ◽  
...  
Keyword(s):  
Bound States ◽  
Charmed Quark

Resonant Two-Photon Photoelectron Imaging and Intersystem Crossing from Excited Dipole-Bound States of Cold Anions

2019 ◽  
Vol 10 (15) ◽  
pp. 4339-4344 ◽  
Author(s):  
Guo-Zhu Zhu ◽  
Ling Fung Cheung ◽  
Yuan Liu ◽  
Chen-Hui Qian ◽  
Lai-Sheng Wang
Keyword(s):  
Bound States ◽  
Intersystem Crossing ◽  
Photoelectron Imaging ◽  
Two Photon

Spectrum of Charmed Quark-Antiquark Bound States

1975 ◽  
Vol 34 (6) ◽  
pp. 369-372 ◽  
Author(s):  
E. Eichten ◽  
K. Gottfried ◽  
T. Kinoshita ◽  
J. Kogut ◽  
K. D. Lane ◽  
...  
Keyword(s):  
Bound States ◽  
Charmed Quark

scholarly journals Spectral collapse in multiqubit two-photon Rabi model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. F. Lo
Keyword(s):  
Bound States ◽  
Energy Difference ◽  
Bound State ◽  
Potential Well ◽  
Critical Coupling ◽  
Nonlocal Potential ◽  
Two Photon ◽  
Rabi Model ◽  
Continuous Energy Spectrum ◽  
Bound State Problem

AbstractWe have shown that the smallest possible singel-qubit critical coupling strength of the N-qubit two-photon Rabi model is only 1/N times that of the two-photon Rabi model. The spectral collapse can thus occur at a more attainable value of the critical coupling. For both of the two-qubit and three-qubit cases, we have also rigorously demonstrated that at the critical coupling the system not only has a set of discrete eigenenergies but also a continuous energy spectrum. The discrete eigenenergy spectrum can be derived via a simple one-to-one mapping to the bound state problem of a particle of variable effective mass in the presence of a finite potential well and a nonlocal potential. The energy difference of each qubit, which specifies both the depth of the finite potential well and the strength of the nonlocal potential, determines the number of bound states available, implying that the extent of the incomplete spectral collapse can be monitored in a straightforward manner.

scholarly journals Revealing the Target Electronic Structure with Under-Threshold RABBIITT

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 66
Author(s):  
Anatoli Kheifets
Keyword(s):  
Electronic Structure ◽  
Bound States ◽  
Energy Levels ◽  
Laser Frequency ◽  
Target Atom ◽  
Oscillator Strengths ◽  
Ionization Threshold ◽  
Discrete Energy ◽  
Two Photon

The process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) reveals the target atom electronic structure when one of the transitions proceeds from below the ionization threshold. Such an under-threshold RABBITT resonates with the target bound states and thus maps faithfully the discrete energy levels and the corresponding oscillator strengths. We demonstrate this sensitivity by considering the Ne atom driven by the combination of the XUV and IR pulses at the fundmanetal laser frequency in the 800 and 1000 nm ranges.

scholarly journals Renormalised Perturbation Theory of Resonant Multiphoton Ionisation

1995 ◽  
Vol 48 (5) ◽  
pp. 835
Author(s):  
K Unnikrishnan
Keyword(s):  
Perturbation Theory ◽  
Cross Sections ◽  
Bound States ◽  
Resonance Region ◽  
Short Pulses ◽  
Total Cross Sections ◽  
Two Photon ◽  
Continuum States ◽  
The Mean ◽  
Good Agreement

Perturbation theory of multiphoton ionisation due to a classical electromagnetic field is modified to allow for intermediate resonances with bound states. Complex energies, generally associated with resonances, do not enter into this formalism. For a monochromatic field of frequency u, a constant ionisation rate can then be defined unambiguously and only such continuum states are excited which correspond to the absorption of energy in integral multiples of hu. As an application, differential and total cross sections for the two-photon ionisation of hydrogen, for frequencies below the n = 3 resonance region, are obtained in closed form. Existing data for generalised cross sections, calculated numerically using the complex coordinate method, are in good agreement with the present results. Finally, the mean fractional ionisation resulting from a pulse of finite duration is estimated on the basis of the associated power spectrum. For short pulses, the time dependence of ionisation exhibits a departure from that expected of a time-independent rate.

Spectrum of Charmed Quark-Antiquark Bound States.

1976 ◽  
Vol 36 (21) ◽  
pp. 1276-1276 ◽  
Author(s):  
E. Eichten ◽  
K. Gottfried ◽  
T. Kinoshita ◽  
J. Kogut ◽  
K. D. Lane ◽  
...  
Keyword(s):  
Bound States ◽  
Charmed Quark

scholarly journals Manipulating the spectral collapse in two-photon Rabi model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. F. Lo
Keyword(s):  
Bound States ◽  
Photon Number ◽  
Energy Difference ◽  
Potential Well ◽  
Critical Coupling ◽  
Two Photon ◽  
Extra Term ◽  
Rabi Model ◽  
Continuous Energy Spectrum ◽  
Quadratic Coupling

Abstract We have investigated the eigenenergy spectrum of the two-photon Rabi model with a full quadratic coupling, particularly the special feature “spectral collapse”. The critical coupling strength is reduced by half from that of the two-photon Rabi model, implying that the spectral collapse can now occur at a more attainable value of the critical coupling. At the critical coupling some discrete eigenenergy levels still survive below the continuous energy spectrum, i.e. an incomplete spectral collapse, and the set of discrete eigenenergies has a one-to-one mapping with that of a particle of variable effective mass in a finite potential well. Since the energy difference between the two atomic levels specifies the depth of the potential well, the number of bound states available (or the extent of the “spectral collapse”) can be straightforwardly monitored. Obviously, this bears a great resemblance to the spectral collapse of the two-photon Rabi model, at least qualitatively. Moreover, since the full quadratic coupling includes an extra term proportional to the photon number operator only, our analysis indicates that one may manipulate the critical coupling of the two-photon Rabi model by incorporating an adjustable proportionality constant to this extra term.

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