The authors discuss the existence of pseudo almost periodic solutions of differential equations with piecewise constant argument by means of introducing new concept, pseudo almost periodic sequence.
We study the cosmology of a quintessence scalar held which is equivalent to a non-barotropic perfect fluid of constant pressure.The coincidence problem is alleviated by such a quintessence equation-of-state that inter...We study the cosmology of a quintessence scalar held which is equivalent to a non-barotropic perfect fluid of constant pressure.The coincidence problem is alleviated by such a quintessence equation-of-state that interpolates between plateau of zero at large redshifts and plateau of minus one as the redshift approaches to zero.The quintessence Geld is neither a unified dark matter nor a mixture of cosmological constant and cold dark matter,relying on the facts that the quintessence density contrasts of sub-horizon modes would undergo a period of late-time dechne and the squared sound speeds of quintessence perturbations do not vanish.What a role does the quintessence play is dynamic dark energy,its clustering could remarkably reduce the growth rate of the density perturbations of non-relativistic matters.展开更多
文摘The authors discuss the existence of pseudo almost periodic solutions of differential equations with piecewise constant argument by means of introducing new concept, pseudo almost periodic sequence.
基金Supported in part by National Natural Science Foundation of China under Grant No.11235010
文摘We study the cosmology of a quintessence scalar held which is equivalent to a non-barotropic perfect fluid of constant pressure.The coincidence problem is alleviated by such a quintessence equation-of-state that interpolates between plateau of zero at large redshifts and plateau of minus one as the redshift approaches to zero.The quintessence Geld is neither a unified dark matter nor a mixture of cosmological constant and cold dark matter,relying on the facts that the quintessence density contrasts of sub-horizon modes would undergo a period of late-time dechne and the squared sound speeds of quintessence perturbations do not vanish.What a role does the quintessence play is dynamic dark energy,its clustering could remarkably reduce the growth rate of the density perturbations of non-relativistic matters.
