Cosmological dynamics in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>f</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mi>R</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:math>gravity

Guo, Junqi; Frolov, A.

doi:10.1103/physrevd.88.124036

Cited by 75 publications

(74 citation statements)

References 43 publications

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“…Unfortunately, Ref. [26] gave the essence of "nogo theorem" in the thin brane limit (RS-2 model with an infinite extra dimension) that the localization for a vector field seems to require a richer brane structure, for examples, the de Sitter brane [28][29][30][31], the brane world with finite extra dimension [27], or a six-dimensional stringlike model [32].…”

Section: Introductionmentioning

confidence: 99%

Generalized geometrical coupling for vector field localization on thick brane in asymptotic anti–de Sitter spacetime

et al. 2020

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It is known that a five-dimensional free vector field AM cannot be localized on Randall-Sundrum (RS)-like thick branes, namely, the thick branes embedded in asymptotic Anti-de Sitter (AdS) spacetime. In order to localize a vector field on the RS-like thick brane, an extra coupling term should be introduced. In this paper, we generalize the geometrical coupling mechanism by adding two mass terms (αRg M N AM AN + βR M N AM AN ) into the action. We decompose the fundamental vector field AM into three parts: transverse vector partÂµ, scalar parts φ and A5. Then, we find that the transverse vector partÂµ decouples from the scalar parts. In order to eliminate the tachyonic modes ofÂµ, the two coupling parameters α and β should satisfy a relation. Combining the restricted condition, we can get a combination parameter as γ = 3 2 ± √ 1 + 12α. Only if γ > 1/2, the zero mode ofÂµ can be localized on the RS-like thick brane. We also investigate the resonant character of the vector partÂµ for the general RS-like thick brane with the warp factor A(z) = − ln(1 + k 2 z 2 )/2 by choosing the relative probability method. The result shows that, only for γ > 3, the massive resonant Kaluza-Klein modes can exist. The number of resonant Kaluza-Klein states increases with the combination parameter γ, and the lifetime of the first resonant state can be long enough as the age of our universe. This indicates that the vector resonances might be considered as one of the candidates of dark matter. Combining the conditions of experimental observations, the constrain shows that the parameter k has a lower limit with k 10 −17 eV, the combination parameter γ should be greater than 57, and accordingly, the mass of the first resonant state should satisfy m1 10 −15 eV.

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Section: Introductionmentioning

confidence: 99%

Generalized geometrical coupling for vector field localization on thick brane in asymptotic anti–de Sitter spacetime

et al. 2020

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“…For instance, if the Z c (3900) and X(3872) are isovector and isoscalar DD * molecular states, respectively [23], the production mechanisms for the Y (4260) → Z c (3900)π and Y (4260) → γX(3872) should be closely related, which leads to the prediction of a large radiative decay rate for the Y (4260) → γX(3872) [24]. This result was confirmed by the most recent BESIII measurement [25].…”

Section: Introductionmentioning

confidence: 99%

Y(4260)as the firstS-wave open charm vector molecular state?

et al. 2014

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Since its first observation in 2005, the vector charmonium Y (4260) has turned out to be one of the prime candidates for an exotic state in the charmonium spectrum. It was recently proposed that the Y (4260) should have a prominent D1D + c.c. molecular component that is strongly correlated with the production of the charged Zc(3900). In this paper we demonstrate that the nontrivial cross section line shapes of e + e − → J/ψππ and hcππ can be naturally explained by the molecular scenario. As a consequence we find a significantly smaller mass for the Y (4260) than previous studied. In the e + e − →DD * π + c.c. process, with the inclusion of an additional S-waveD * π contribution constrained from data on the DD * invariant mass distribution, we obtain a good agreement with the data of the angular distributions. We also predict an unusual line shape of Y (4260) in this channel that may serve as a smoking gun for a predominantly molecular nature of Y (4260). Improved measurements of these observables are therefore crucial for a better understanding of the structure of this famous resonance.

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“…The unique advantages of the stroboscopic MOKE detection allow for a direct, sensitive measure of the spin precession phase and other spintronic parameters induced by local spin-orbit torques in ST-FMR devices. Our combinatorial technique will be useful for future characterizations of spin-torque oscillators, magnonic circuits, and tunnelling junctions, where measuring the dynamics of individual nanomagnets are needed [10,35,37,41,42,[51][52][53][54].…”

Section: Resultsmentioning

confidence: 99%

Simultaneous Optical and Electrical Spin-Torque Magnetometry with Phase-Sensitive Detection of Spin Precession

Sağlam

Zhang

et al. 2019

Phys. Rev. Applied

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Spin-based coherent information processing and encoding utilize the precession phase of spins in magnetic materials. However, the detection and manipulation of spin precession phases remain a major challenge for advanced spintronic functionalities. By using simultaneous electrical and optical detection, we demonstrate the direct measurement of the precession phase of Permalloy ferromagnetic resonance driven by the spin-orbit torques from adjacent heavy metals. The spin Hall angle of the heavy metals can be independently determined from concurrent electrical and optical signals. The stroboscopic optical detection also allows spatially measuring local spin-torque parameters and the induced ferromagnetic resonance with comprehensive amplitude and phase information. Our study offers a route towards future advanced characterizations of spin-torque oscillators, magnonic circuits, and tunnelling junctions, where measuring the current-induced spin dynamics of individual nanomagnets are required.Magneto-optical Kerr effect (MOKE) provides an alternative approach to "directly" access to the magnetization states. Both in-plane and out-of-plane magnetic moments can be detected [30] by the choice of different Kerr configurations. Recently, MOKE-based detection of electrically-induced SOTs have been reported [31][32][33][34], but only with quasi-static magnetization configurations, where the SOT is treated as an "effective field" that tilts the static magnetization of the FM. On the other hand, stroboscopic techniques [35][36][37][38][39], in which both the pump and probe are modulated at the dynamic excitation frequency, offer unique advantages in tracking both the amplitude and the phase information of the magnetization precession, and thus are more suitable in studying SOTdriven spin dynamics.Here, we report a simultaneous electrical and optical measurement of spin-torque ferromagnetic resonance (ST-FMR), with the capability to extract the spin precession phase driven by the SOTs. We show that the spin Hall angle of heavy metals can be directly extracted from the measured optical phase of spin dynamics, in-arXiv:1901.01923v1 [cond-mat.mes-hall]

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Cosmological dynamics inf(R)gravity

Cited by 75 publications

References 43 publications

Generalized geometrical coupling for vector field localization on thick brane in asymptotic anti–de Sitter spacetime

Generalized geometrical coupling for vector field localization on thick brane in asymptotic anti–de Sitter spacetime

Y(4260)as the firstS-wave open charm vector molecular state?

Simultaneous Optical and Electrical Spin-Torque Magnetometry with Phase-Sensitive Detection of Spin Precession

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