Quintessence Definition and 14 Threads

It is often seen in research papers that values of quintessence state parameter $\omega$ is taken between -1 and -1/3. However $\omega=-1$ corresponds to the cosmological constant and -1/3 corresponds to dust phase. Why these two cases are excluded in studying BH extended phase space thermodynamics?

Why the equation of state parameter w for a quintessence field with potential m²Phi² is not in between 0 and 1/3 depending on the energy of its particles relative to the mass of the field instead of the w resulting from formula 9 of https://arxiv.org/pdf/1504.04037.pdf which seems to be...

Hello! I've been working on a code that solves the Friedmann equation with quintessence using a scalar field potential of the form x^(-alpha) where alpha is a free parameter. I would like to plot different values of alpha in the same plot with annotations for each. For now, my code has initial...

Hi everyone, I got the basic ideas quintessence (minimally coupled) and derived the KG equation for scalar field: $$ \ddot{\phi} + 3 H \dot{\phi} + \frac{\partial V(\phi)}{\partial \phi} = 0 $$ where $$H=\frac{\dot{a}}{a}$$ and $\phi$ is the scalar field. There are various models depending...

Hello, I am having trouble deriving the equation of motion for the quintessence field. The equation of motion which I am meant to get at the end point is: (with ' denoting derivative w.r.t time) φ'' + 3Hφ' + dV/dφ = 0 Using the inflaton lagrangian: (although with a generic potential V(φ)...

Currently, the favoured explanations for the accelerating expansion of the universe are the cosmological constant, and various scalar fields, most notably quintessence. All of these are mechanisms dependent on mathematical field properties. My question is: do any alternative hypotheses exist...

Hello! I'm studying various dark energy models, and as a part of the project, I need to be able to numerically solve the Klein-Gordon (KG) equation and the Friedmann Equation (FE) in the context of a canonical scalar field. I wasn't sure whether or not this belonged here or in the computational...

My understanding (haven't worked the equations myself) is that if you try to make the cosmological constant not constant, it gives a nonvanishing divergence for the stress-energy tensor. This would be inconsistent with the Einstein field equations, which require vanishing divergence. So how...

Dear all, As u know, one of the best potentials for quintessence is V=[M]^[4+\alpha] [\phi]^[-\alpha] They usually call M, THE MASS PARAMETER. Who knows what is the value of M for now?

Dear all, I am reading some texts about quintessence. As you one of the best textbooks for cosmology is Weinberg's. in page 90 of his book he states that if we consider astronomical units we can see that a good quintessence potential is V(\phi)= (M^(4+alpha)) * phi ^(-alpha) and M has...

Tonight makes me wish I had discovered this forum earlier! My situation: my capstone course is basically writing a paper about something on the forefront of the scientific frontier. This is neither a report style of paper nor original work, but instead a sort of discussion on the controversy...

Quintessence fields are supposed to slowly roll down a potential V(\phi). Adding constants to the potential obviously does not change the equation of motion for this field, but it does change the pressure, energy density and equation-of-state. In particular, if I choose a sufficiently large...

Hi! I have more questions. 1st. Is there any diference between Cosmological Constant and quintessence? 2nd. If there is, which is? I've only understood that cosmological constant is the energy of the vacuum but I don't know what quitessence is, so please, could somebody tell me if...

Is the pioneer anomaly due to quintessence? I thought this was interesting http://www.arxiv.org/PS_cache/gr-qc/pdf/0407/0407023.pdf