With the dark energy phenomena explored over a decade, in this present work we discuss a specific case of the generalized Einstein-aether theories, in which the modified Friedmann equation is similar to that in the Dv...With the dark energy phenomena explored over a decade, in this present work we discuss a specific case of the generalized Einstein-aether theories, in which the modified Friedmann equation is similar to that in the Dvali- Gabadadze-Porrati （DGP） brahe world model. We compute the joint statistic constraints on model parameters in this specific case by using the recent type Ia supernovae （SNe Ia） data, the cosmic microwave background （CMB） shift parameter data, and the baryonic acoustic oscillations （BAOs） data traced by the S1oan Digital Sky Survey （SDSS）. Furthermore, we analyze other constrains from the observational Hubble parameter data （OHD）. The comparison with the standard cosmological model （cosmological constant A cold dark matter （ACDM） model） is dearly shown; also we comment on the interesting relation between the coupling constant M in this model and the special accelerate scale in the modified Newtonian dynamies （MOND） model initially given by Milgrom with the hope for interpreting the galaxy rotation curves without introducing mysterious dark matter.展开更多
In Einstein-aether theory,violating Lorentz invariance permits some super-luminal communications,and the universal horizon can trap excitations traveling at arbitrarily high velocities.To better understand the nature ...In Einstein-aether theory,violating Lorentz invariance permits some super-luminal communications,and the universal horizon can trap excitations traveling at arbitrarily high velocities.To better understand the nature of these universal horizons,we first modify the ray tracing method,and then use it to study their surface gravity in charged Einstein-aether black hole spacetime.Instead of the previous result by Cropp et al.,our results show that the surface gravity of the universal horizon is dependent on the specific dispersion relation,k_(uh)-2(z-1)k_(uh)/z,where z denotes the power of the leading term in the superluminal dispersion relation,characterizing different species of particles.And the associated Hawking temperatures also are different with z.These findings,which coincide with those derived by the tunneling method,provide some full understanding of black hole thermodynamics in Lorentz-violating theories.展开更多
基金Supported by Natural Science Foundation of China under Grant Nos. 11075078 and 10675062by the project of knowledge Innovation Program (PKIP) of Chinese Academy of Sciences (CAS) under Grant No. KJCX2.YW.W10 through the KITPC astrophysics and cosmology programmes where we have initiated this present work
文摘With the dark energy phenomena explored over a decade, in this present work we discuss a specific case of the generalized Einstein-aether theories, in which the modified Friedmann equation is similar to that in the Dvali- Gabadadze-Porrati （DGP） brahe world model. We compute the joint statistic constraints on model parameters in this specific case by using the recent type Ia supernovae （SNe Ia） data, the cosmic microwave background （CMB） shift parameter data, and the baryonic acoustic oscillations （BAOs） data traced by the S1oan Digital Sky Survey （SDSS）. Furthermore, we analyze other constrains from the observational Hubble parameter data （OHD）. The comparison with the standard cosmological model （cosmological constant A cold dark matter （ACDM） model） is dearly shown; also we comment on the interesting relation between the coupling constant M in this model and the special accelerate scale in the modified Newtonian dynamies （MOND） model initially given by Milgrom with the hope for interpreting the galaxy rotation curves without introducing mysterious dark matter.
基金supported by the National Natural Science Foundation of China(Grant No.11247013)Hunan Provincial Natural Science Foundation of China(Grant Nos.2015JJ2085,and QSQC1203)the Special Fund of the National Natural Science Foundation of China(Grant No.11447168)
文摘In Einstein-aether theory,violating Lorentz invariance permits some super-luminal communications,and the universal horizon can trap excitations traveling at arbitrarily high velocities.To better understand the nature of these universal horizons,we first modify the ray tracing method,and then use it to study their surface gravity in charged Einstein-aether black hole spacetime.Instead of the previous result by Cropp et al.,our results show that the surface gravity of the universal horizon is dependent on the specific dispersion relation,k_(uh)-2(z-1)k_(uh)/z,where z denotes the power of the leading term in the superluminal dispersion relation,characterizing different species of particles.And the associated Hawking temperatures also are different with z.These findings,which coincide with those derived by the tunneling method,provide some full understanding of black hole thermodynamics in Lorentz-violating theories.
