The Experts below are selected from a list of 248259 Experts worldwide ranked by ideXlab platform
V I Korobov - One of the best experts on this subject based on the ideXlab platform.
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coulomb three body Bound State problem variational calculations of nonrelativistic energies
Physical Review A, 2000Co-Authors: V I KorobovAbstract:It is known that variational methods are the most powerful tool for studying the Coulomb three-body Bound-State problem. However, they often suffer from loss of stability when the number of basis functions increases. This problem can be cured by applying the multiprecision package designed by D. H. Bailey. We consider variational basis functions of the type exp(2anr12bnr22gnr12) with complex exponents. The method yields the best available energies for the ground States of the helium atom and the positive hydrogen molecular ion as well as many other known atomic and molecular systems.
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coulomb three body Bound State problem variational calculations of nonrelativistic energies
Physical Review A, 2000Co-Authors: V I KorobovAbstract:It is known that variational methods are the most powerful tool for studying the Coulomb three-body Bound-State problem. However, they often suffer from loss of stability when the number of basis functions increases. This problem can be cured by applying the multiprecision package designed by D. H. Bailey. We consider variational basis functions of the type $\mathrm{exp}(\ensuremath{-}{\ensuremath{\alpha}}_{n}{r}_{1}\ensuremath{-}{\ensuremath{\beta}}_{n}{r}_{2}\ensuremath{-}{\ensuremath{\gamma}}_{n}{r}_{12})$ with complex exponents. The method yields the best available energies for the ground States of the helium atom and the positive hydrogen molecular ion as well as many other known atomic and molecular systems.
Yan Peng - One of the best experts on this subject based on the ideXlab platform.
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no hair theorem for Bound State massless static scalar fields outside horizonless neumann compact stars
Physics Letters B, 2019Co-Authors: Yan PengAbstract:Abstract We study no-hair theorem for horizonless objects, being subject to Neumann Boundary conditions. For massive scalar fields, a no hair theorem for Neumann compact stars was proved by us in a previous paper, where the nonzero scalar field mass condition is essential in the proof. In the present work, for massless scalar fields, we prove a no hair theorem, which claims that Bound-State massless static scalar fields cannot exist outside asymptotically flat horizonless neutral Neumann compact stars.
Kyohei Mukaida - One of the best experts on this subject based on the ideXlab platform.
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dark matter Bound State formation at higher order a non equilibrium quantum field theory approach
Journal of High Energy Physics, 2020Co-Authors: Tobias Binder, Burkhard Blobel, J Harz, Kyohei MukaidaAbstract:The formation of meta-stable dark matter Bound States in coannihilating scenarios could efficiently occur through the scattering with a variety of Standard Model bath particles, where light bosons during the electroweak cross over or even massless photons and gluons are exchanged in the t-channel. The amplitudes for those higher-order processes, however, are divergent in the collinear direction of the in- and out-going bath particles if the mediator is massless. To address the issue of collinear divergences, we derive the Bound-State formation collision term in the framework of non-equilibrium quantum field theory. The main result is an expression for a more general cross section, which allows to compute higher-order Bound-State formation processes inside the primordial plasma background in a comprehensive manner. Based on this result, we show that next-to-leading order contributions, including the bath-particle scattering, are i) collinear finite and ii) generically dominate over the on-shell emission for temperatures larger than the absolute value of the binding energy. Based on a simplified model, we demonstrate that the impact of these new effects on the thermal relic abundance is significant enough to make it worthwhile to study more realistic coannihilation scenarios.
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rapid Bound State formation of dark matter in the early universe
Physical Review Letters, 2020Co-Authors: Tobias Binder, Kyohei Mukaida, Kalliopi PetrakiAbstract:The thermal decoupling description of dark matter (DM) and co-annihilating partners is reconsidered. If DM is realized at around the TeV-mass region or above, even the heaviest electroweak force carriers could act as long-range forces, leading to the existence of meta-stable DM Bound States. The formation and subsequent decay of the latter further deplete the relic density during the freeze-out process on top of the Sommerfeld enhancement, allowing for larger DM masses. While so far the Bound-State formation was described via the emission of an on-shell mediator ($W^{\pm}$, $Z$, $H$, $g$, photon or exotic), we point out that this particular process does not have to be the dominant scattering-Bound State conversion channel in general. If the mediator is coupled in a direct way to any relativistic species present in the Early Universe, the Bound-State formation can efficiently occur through particle scattering, where a mediator is exchanged virtually. To demonstrate that such a virtually stimulated conversion process can dominate the on-shell emission even for all temperatures, we analyze a simplified model where DM is coupled to only one relativistic species in the primordial plasma through an electroweak-scale mediator. We find that the Bound-State formation cross section via particle scattering can exceed the on-shell emission by up to several orders of magnitude.
Tobias Binder - One of the best experts on this subject based on the ideXlab platform.
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dark matter Bound State formation at higher order a non equilibrium quantum field theory approach
Journal of High Energy Physics, 2020Co-Authors: Tobias Binder, Burkhard Blobel, J Harz, Kyohei MukaidaAbstract:The formation of meta-stable dark matter Bound States in coannihilating scenarios could efficiently occur through the scattering with a variety of Standard Model bath particles, where light bosons during the electroweak cross over or even massless photons and gluons are exchanged in the t-channel. The amplitudes for those higher-order processes, however, are divergent in the collinear direction of the in- and out-going bath particles if the mediator is massless. To address the issue of collinear divergences, we derive the Bound-State formation collision term in the framework of non-equilibrium quantum field theory. The main result is an expression for a more general cross section, which allows to compute higher-order Bound-State formation processes inside the primordial plasma background in a comprehensive manner. Based on this result, we show that next-to-leading order contributions, including the bath-particle scattering, are i) collinear finite and ii) generically dominate over the on-shell emission for temperatures larger than the absolute value of the binding energy. Based on a simplified model, we demonstrate that the impact of these new effects on the thermal relic abundance is significant enough to make it worthwhile to study more realistic coannihilation scenarios.
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rapid Bound State formation of dark matter in the early universe
Physical Review Letters, 2020Co-Authors: Tobias Binder, Kyohei Mukaida, Kalliopi PetrakiAbstract:The thermal decoupling description of dark matter (DM) and co-annihilating partners is reconsidered. If DM is realized at around the TeV-mass region or above, even the heaviest electroweak force carriers could act as long-range forces, leading to the existence of meta-stable DM Bound States. The formation and subsequent decay of the latter further deplete the relic density during the freeze-out process on top of the Sommerfeld enhancement, allowing for larger DM masses. While so far the Bound-State formation was described via the emission of an on-shell mediator ($W^{\pm}$, $Z$, $H$, $g$, photon or exotic), we point out that this particular process does not have to be the dominant scattering-Bound State conversion channel in general. If the mediator is coupled in a direct way to any relativistic species present in the Early Universe, the Bound-State formation can efficiently occur through particle scattering, where a mediator is exchanged virtually. To demonstrate that such a virtually stimulated conversion process can dominate the on-shell emission even for all temperatures, we analyze a simplified model where DM is coupled to only one relativistic species in the primordial plasma through an electroweak-scale mediator. We find that the Bound-State formation cross section via particle scattering can exceed the on-shell emission by up to several orders of magnitude.
Jianlin Zhao - One of the best experts on this subject based on the ideXlab platform.
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harmonic mode locking of Bound State solitons fiber laser based on mos 2 saturable absorber
Optics Express, 2015Co-Authors: Yadong Wang, Dong Mao, Xuetao Gan, Lei Han, Yi Zhang, Wuyun Shang, Shijia Hua, Jianlin ZhaoAbstract:We present a kind of harmonic mode locking of Bound-State solitons in a fiber laser based on molybdenum disulfide (MoS2) saturable absorber (SA). The mode locker is fabricated by depositing MoS2 nanosheets on a D-shaped fiber (DF). In the fiber laser, two solitons form the Bound-State pulses with a temporal separation of 3.4 ps, and the Bound-State pulses are equally distributed at a repetition rate of 125 MHz, corresponding to 14th harmonics of fundamental cavity repetition rate (8.968 MHz). Single- and multiple-pulses emissions are also observed by changing the pump power and optimizing the DF based MoS2 SA. Our experiment demonstrates an interesting operation regime of mode-locked fiber laser, and shows that DF based MoS2 SA can work as a promising high-power mode locker in ultrafast lasers.