اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدInvariant ultraviolet scale corrections to the thermodynamics of degenerate Fermi gas and its implications
53
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We study the invariant Planck scale correction to the thermodynamics of the ideal Fermi gas. We have considered the modified dispersion relation and the cut-off to the maximum possible momentum/energy (Planck energy) of the non-interacting ideal degenerate Fermi gas particles. With such a modification the expression for the degenerate pressure and the total energy gets modified accordingly. We discuss the number density and mass dependence of the degenerate pressure. We found that the degenerate pressure is perturbative in the SR limit. We then take the example of white dwarfs to explore the possible implications. Using this modified degenerate pressure, we calculate the possible modification to the Chandrashekhar limit for white dwarfs using the Magueijo-Smolin (MS) modified dispersion relation. The mass-radius M-R plot shows that the modified/corrected radius of the white dwarf can be greater than, equal to and smaller than the usual special relativity (SR) value for particular masses. We found that the Chandrasekhar mass limit gets a positive correction. We note that the presence of observed white dwarfs having radius smaller than the SR Chandrasekhar limit may find an explanation if they are modeled using a modified dispersion relation. As the correction is perturbative in the SR limit, therefore this correction is solely because of the modified dispersion relation. The value of the obtained degenerate pressure for a given mass is found to be greater than, equal to and smaller than the usual special relativity (SR) value for particular masses as expected. We have also calculated the luminosity of the white dwarf by taking the model of partially degenerate gas and considering the modified radiative envelope equation. The luminosity also gets a negative correction. The correction to luminosity is nonperturbative as expected for such a theory.
قيم البحث
اقرأ أيضاً
We study quantum corrections to an inflationary model, which has the attractive feature of being classically scale-invariant. In this model, quadratic gravity plays along a scalar field in such a way that inflation begins near the unstable point of t
he effective potential and it ends at a stable fixed point, where the scale symmetry is broken and a fundamental mass scale naturally emerges. We compute the one loop corrections to the classical action on the curved background of the model and we report their effects on the classical dynamics with both analytical and numerical methods.
The paper aims to introduce a new symmetry principle in the space-time geometry through the elimination of the classical idea of rest and by including a universal minimum limit of speed in the subatomic world. Such a limit, unattainable by particles,
represents a preferred reference frame associated with a universal background field that breaks Lorentz symmetry. Thus the structure of space-time is extended due to the presence of a vacuum energy density, which leads to a negative pressure at cosmological scales. The tiny values of the cosmological constant and the vacuum energy density shall be successfully obtained, being in good agreement with current observational results.
Many-body quantum systems can exhibit a striking degree of symmetry unparalleled by their classical counterparts. While in real materials SU($N$) symmetry is an idealization, this symmetry is pristinely realized in fully controllable ultracold alkali
ne-earth atomic gases. Here, we study an SU($N$)-symmetric Fermi liquid of $^{87}$Sr atoms, where $N$ can be tuned to be as large as 10. In the deeply degenerate regime, we show through precise measurements of density fluctuations and expansion dynamics that the large $N$ of spin states under SU($N$) symmetry leads to pronounced interaction effects in a system with a nominally negligible interaction parameter. Accounting for these effects we demonstrate thermometry accurate to one-hundredth of the Fermi energy. We also demonstrate record speed for preparing degenerate Fermi seas, reaching $T/T_F = 0.12$ in under 3 s, enabled by the SU($N$) symmetric interactions. This, along with the introduction of a new spin polarizing method, enables operation of a 3D optical lattice clock in the band insulating-regime.
Effects from nonstandard corrections to Newtonian gravity, at large scale, can be investigated using the cosmological structure formation. In particular, it is possible to show if and how a logarithmic correction (as that induced from nonlocal gravit
y) modifies the clustering properties of galaxies and of clusters of galaxies. The thermodynamics of such systems can be used to obtain important information about the effects of such modification on clustering. We will compare its effects with observational data and it will be demonstrated that the observations seem to point to a characteristic scale where such a logarithmic correction might be in play at galactic scales. However, at larger scales such statistical inferences are much weaker, so that a fully reliable statistical evidence for this kind of corrections cannot be stated without further investigations and the use of more varied and precise cosmological and astrophysical probes.
In this work, the role of a time-varying Newton constant under the scale-dependent approach is investigated in the thermodynamics of the Friedman equations. In particular, we show that the extended Friedman equations can be derived either from equili
brium thermodynamics when the non-matter energy momentum tensor is interpreted as a fluid or from non-equilibrium thermodynamics when an entropy production term, which depends on the time-varying Newton constant, is included. Finally, a comparison between black hole and cosmological thermodynamics in the framework of scale--dependent gravity is briefly discussed.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
