出版者・発行元：International Journal of Modern Physics A  

We extend our previous work [Phys. Rev. D 83, 045030 (2011)], which investigated the first-order quantum effect in the Larmor radiation from a moving charge in a spatially homogeneous time-dependent electric field. Specifically, we investigate the quantum Larmor radiation from a moving charge in a monochromatic electromagnetic plane wave background based on the scalar quantum electrodynamics at the lowest order of the perturbation theory. Using the inin formalism, we derive the theoretical formula of the total radiation energy from a charged particle in the initial states being at rest and being in a relativistic motion. Expanding the theoretical formula in terms of the Planck constant ℏ, we obtain the first-order quantum effect on the Larmor radiation. The quantum effect generally suppresses the total radiation energy compared with the prediction of the classical Larmor formula, which is a contrast to the previous work. The reason is explained by the fact that the radiation from a moving charge in a monochromatic electromagnetic plane wave is expressed in terms of the inelastic collisions between an electron and photons of the background electromagnetic waves. © 2012 World Scientific Publishing Company.

DOI： 10.1142/S0217751X12501424

Web of Science

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出版者・発行元：Physical Review D Particles Fields Gravitation and Cosmology  

First-order quantum correction to the Larmor radiation is investigated on the basis of the scalar QED on a homogeneous background of a time-dependent electric field, which is a generalization of a recent work by Higuchi and Walker so as to be extended for an accelerated charged particle in a relativistic motion. We obtain a simple approximate formula for the quantum correction in the limit of the relativistic motion when the direction of the particle motion is parallel to that of the electric field. © 2011 American Physical Society.

DOI： 10.1103/PhysRevD.83.045030

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出版者・発行元：Physical Review D Particles Fields Gravitation and Cosmology  

We investigate the quantum effect on the Larmor radiation from a moving charge in an expanding universe based on the framework of the scalar quantum electrodynamics. A theoretical formula for the radiation energy is derived at the lowest order of the perturbation theory with respect to the coupling constant of the scalar quantum electrodynamics. We evaluate the radiation energy on the background universe so that the Minkowski spacetime transits to the Milne universe, in which the equation of motion for the mode function of the free complex scalar field can be exactly solved in an analytic way. Then, the result is compared with the WKB approach, in which the equation of motion of the mode function is constructed with the WKB approximation which is valid as long as the Compton wavelength is shorter than the Hubble horizon length. This demonstrates that the quantum effect on the Larmor radiation of the order e2 is determined by a nonlocal integration in time depending on the background expansion. We also compare our result with a recent work by Higuchi and Walker, which investigated the quantum correction to the Larmor radiation from a charged particle in a nonrelativistic motion in a homogeneous electric field. © 2011 American Physical Society.

DOI： 10.1103/PhysRevD.83.045015

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出版者・発行元：Physical Review D Particles Fields Gravitation and Cosmology  

A constraint on the viable f(R) model is investigated by confronting theoretical predictions with the multipole power spectrum of the luminous red galaxy sample of the Sloan Digital Sky Survey, data release 7. We obtain a constraint on the Compton wavelength parameter of the f(R) model on the scales of cosmological large-scale structure. A prospect of constraining the Compton wavelength parameter with a future redshift survey is also investigated. The usefulness of the redshift-space distortion for testing the gravity theory on cosmological scales is demonstrated. © 2010 The American Physical Society.

DOI： 10.1103/PhysRevD.81.103517

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出版者・発行元：Physical Review D Particles Fields Gravitation and Cosmology  

We determine a constraint on the growth factor by measuring the damping of the baryon acoustic oscillations in the matter power spectrum using the Sloan digital sky survey luminous red galaxy sample. We obtain an effective upper limit on σ8D1(z=0.3) using the damping of the baryon acoustic oscillation signature, where σ8 is the root mean square overdensity in a sphere of radius 8h-1Mpc and D1(z) is the growth factor at redshift z. The above result assumes that other parameters are fixed and the cosmology is taken to be a spatially flat cold dark matter universe with the cosmological constant. © 2009 The American Physical Society.

DOI： 10.1103/PhysRevD.80.123524

Web of Science

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