اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدHiding Lorentz Invariance Violation with MOND
77
0
0.0
(
0
)
تأليف
R.H. Sanders
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Hov{r}ava gravity is a attempt to construct a renormalizable theory of gravity by breaking the Lorentz Invariance of the gravitational action at high energies. The underlying principle is that Lorentz Invariance is an approximate symmetry and its violation by gravitational phenomena is somehow hidden to present limits of observational precision. Here I point out that a simple modification of the low energy limit of Hov{r}ava gravity in its non-projectable form can effectively camouflage the presence of a preferred frame in regions where the Newtonian gravitational field gradient is higher than $cH_0$; this modification results in the phenomenology of MOND at lower accelerations.
قيم البحث
اقرأ أيضاً
We employ techniques from quantum estimation theory (QET) to estimate the Lorentz violation parameters in the 1+3-dimensional flat spacetime. We obtain and discuss the expression of the quantum Fisher information (QFI) in terms of the Lorentz violati
on parameter $sigma_0$ and the momentum k of the created particles. We show that the maximum QFI is achieved for a specific momentum $k_{mathrm{max}}$. We also find that the optimal precision of estimation of the Lorentz violation parameter is obtained near the Planck scale.
In this paper, we have applied the Lorentz-invariance-violation (LIV) class of dispersion relations (DR) with the dimensionless parameter n = 2 and the sign of LIV {eta}_+ = 1, to phenomenologically study the effect of quantum gravity in the strong g
ravitational field. Specifically, we have studied the effect of the LIV-DR induced quantum gravity on the Schwarzschild black hole thermodynamics. The result shows that the effect of the LIV-DR induced quantum gravity speeds up the black hole evaporation, and its corresponding black hole entropy undergoes a leading logarithmic correction to the reduced Bekenstein-Hawking entropy, and the ill defined situations (i.e. the singularity problem and the critical problem) are naturally bypassed when the LIV-DR effect is present. Also, to put our results in a proper perspective, we have compared with the earlier findings by another quantum gravity candidate, i.e. the generalized uncertainty principle (GUP). Finally, we conclude from the inert remnants at the final stage of the black hole evaporation that, the GUP as a candidate for describing quantum gravity can always do as well as the LIV-DR by adjusting the model-dependent parameters, but in the same model-dependent parameters the LIV-DR acts as a more suitable candidate.
Highly energetic, variable and distant sources such as Active Galactic Nuclei provide a good opportunity to evaluate effects due to the emission and the propagation of high energy photons. In this note, a study of possible energy-dependent time-lags
with PKS 2155-304 light curve as measured by H.E.S.S. in July 2006 is presented. These time-lags could either come from the emission processes or also sign a Lorentz Symmetry breaking as predicted in some Quantum Gravity models. A Cross-Correlation function and a Wavelet Transform were used to measure the time-lags. The 95% Confidence Limit on the Quantum Gravity energy scale based on the statistical and systematic error evaluation was found to be 7x10^17 GeV considering a linear correction in the standard photon dispersion relations and assuming that emission-induced time-lags are negligible. For now, this limit is the best ever obtained with a blazar.
The assumption of Lorentz invariance is one of the founding principles of Modern Physics and violation of it would have profound implications to our understanding of the universe. For instance, certain theories attempting a unified theory of quantum
gravity predict there could be an effective refractive index of the vacuum; the introduction of an energy dependent dispersion to photons could in turn lead to an observable Lorentz invariance violation signature. Whilst a very small effect on local scales the effect will be cumulative, and so for very high energy particles that travel very large distances the difference in arrival times could become sufficiently large to be detectable. This proceedings will look at testing for such Lorentz invariance violation (LIV) signatures in the astronomical lightcurves of gamma-ray emitting objects, with particular notice being given to the prospects for LIV testing with, the next generation observatory, the Cherenkov Telescope Array.
The Newton limit of gravity is studied in the presence of Lorentz-violating gravitational operators of arbitrary mass dimension. The linearized modified Einstein equations are obtained and the perturbative solutions are constructed and characterized.
We develop a formalism for data analysis in laboratory experiments testing gravity at short range and demonstrate that these tests provide unique sensitivity to deviations from local Lorentz invariance.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
