Title
Bulk and Shear Viscosity in the Early Universe Cosmology: Dissipative QCD Cosmology,Used
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We consider the evolution of a flat, isotropic and homogeneous FriedmannLemaitreRobertsonWalker Universe, filled with a causal bulk viscous cosmological fluid, that can be characterized by an ultrarelativistic equation of state, and bulk viscosity coefficient obtained from recent lattice Quantum Chromodynamics calculations. The basic equation for the Hubble parameter is derived under the assumption that the total energy in the Universe is conserved. By assuming a power law dependence of bulk viscosity coefficient, temperature and relaxation time on energy density, an approximate solution of the field equations has been obtained, in which we utilized equations of state from recent lattice Quantum Chromodynamics simulations and heavyion collisions to derive an evolution equation. In viscous cosmology, there is no evidence for singularity. For example, both Hubble parameter and scale factor have a finite value at time equal to zero. To avoid any controversial argumentation about the validity of the equations of states and the above conclusions, we restrict the discussion at the QCD era.
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Shipping & Returns
Shipping
We ship your order within 2–3 business days for USA deliveries and 5–8 business days for international shipments. Once your package has been dispatched from our warehouse, you'll receive an email confirmation with a tracking number, allowing you to track the status of your delivery.
Returns
To facilitate a smooth return process, a Return Authorization (RA) Number is required for all returns. Returns without a valid RA number will be declined and may incur additional fees. You can request an RA number within 15 days of the original delivery date. For more details, please refer to our Return & Refund Policy page.
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Warranty
We provide a 2-year limited warranty, from the date of purchase for all our products.
If you believe you have received a defective product, or are experiencing any problems with your product, please contact us.
This warranty strictly does not cover damages that arose from negligence, misuse, wear and tear, or not in accordance with product instructions (dropping the product, etc.).
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Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
We accept payments with :
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