The Energy Density of ”Wound” Fields in a Toroidal Universe
نویسنده
چکیده
The observational limits on the present energy density of the Universe allow for a component that redshifts like 1/a and can contribute significantly to the total. We show that a possible origin for such a contribution is that the universe has a toroidal topology with ”wound” scalar fields around its cycles.
منابع مشابه
امواج گرانشی حرارتی در فاز شتاب‌دار کیهان
Gravitational waves are considered in thermal vacuum state. The amplitude and spectral energy density of gravitational waves are found enhanced in thermal vacuum state compared to its zero temperature counterpart. Therefore, the allowed amount of enhancement depends on the upper bound of WMAP-5 and WMAP-7 for the amplitude and spectral energy density of gravitational waves. The enhancement of ...
متن کاملParticle creation in a toroidal universe
Although current astrophysical observations provide precise information on the geometry of the universe [1], its topology remains a mystery. We don’t even know whether the universe is compact or infinite. Nevertheless, lower bounds can be placed on its size for each compact topology (see Ref. [2] and references therein). Amongst the possible topologies for the universe, those with some or all s...
متن کاملNumerical Experiments on String Cosmology
We investigate some classical aspects of fundamental strings via numerical experiments. In particular, we study the thermodynamics of a string network within a toroidal universe, as a function of string energy density and space dimensionality. We find that when the energy density of the system is low, the dominant part of the string is in the form of closed loops of the shortest allowed size, w...
متن کاملLarge Radius Hagedorn Regime in String Gas Cosmology
We calculate the equation of state of a gas of strings at high density in a large toroidal universe and use it to determine the cosmological evolution of background metric and dilaton fields in the entire large radius Hagedorn regime, ðlnSÞ1=d R S (with S the total entropy). The pressure in this regime is not vanishing but of Oð1Þ, while the equation of state is proportional to volume, which ma...
متن کاملEffect of Low-Level He-Ne Laser Irradiation on Biomechanical Property of Wound Healing Process in Healthy and Streptozotocin Induced Diabetic Rats
Purpose: The aim of present investigation was to determine the effects of low- level He-Ne laser therapy on biomechanical property of skin wound of healthy and streptozotocin induced diabetic (STZ-D) rats. Materials and Methods: The study was performed by experimental method.36 male adult Wistar rats weighing above 250 gr. were used. Rats were divided equally into control and experimental group...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2004