The agent causing this expansion is termed as dark energy and it violates the strong
energy condition. Cosmological observations reveal that our universe is approximately homogeneous and isotropic at large scales [1] described by the standard FRW model.
The Null
Energy Condition (NEC) in the bulk imposes some constraints on the class of non-relativistic field theories dual to the hyperscaling violating backgrounds, namely, that the critical exponents must satisfy [72, 75]
From above, it is clear that the energy density of anisotropic fluids ([p.sub.[phi]] = [p.sub.z] = [p.sub.t] tangential stress) violates the weak
energy condition (WEC) [30].
Secondly, the plot of weak
energy condition (WEC), dominant
energy condition (DEC), and strong
energy condition (SEC) for non-interacting and interacting cases is shown in Figures 7 and 8, respectively.
It possesses negatively large pressure which violates the strong
energy condition (p + 3[rho] < 0, where p and [rho] are pressure and energy density, respectively) but its complete characteristics are still not known.
Abreu and Sasaki [24] studied the effects of null
energy condition (NEC) and weak
energy condition (WEC) with noncommutative wormhole.
Yurtsever, "Wormholes, time machines, and the weak
energy condition," Physical Review Letters, vol.
As ordinary matter, DM satisfies the strong
energy condition. Dark energy, instead, is more peculiar still, given that it does not share the clustering properties of ordinary matter or DM, as it violates the strong
energy condition.
The energy density of null dust satisfies the null
energy condition (NEC).
The time machine spacetime discussed in [35-39] violated the weak
energy condition (WEC) and the strong
energy condition (SEC) is violated in [40-43].
Moreover, since [rho]([phi]) = -(3/4)[[beta].sup.2](t) is negative for real nonzero values of [beta](t), the weak
energy condition is not respected by a real nonzero [[phi].sub.[mu]].
Soma, "Lorentzian wormholes in higher-derivative gravity and the weak
energy condition," Physical Review D, vol.
