How close to constraining DE to simply be Lambda?

[marcus]

what recent papers have you seen that deal with this question?

Here is one I found by Paolo Serra et al (2009)
http://arxiv.org/abs/0908.3186
No Evidence for Dark Energy Dynamics from a Global Analysis of Cosmological Data
Paolo Serra (UC Irvine), Asantha Cooray (UC Irvine), Daniel E. Holz (Los Alamos National Laboratory), Alessandro Melchiorri (University of Rome), Stefania Pandolfi (University of Rome), Devdeep Sarkar (UC Irvine, University of Michigan)
Physical Review D

Here is another by Tamara Davis et al (2007)
http://inspirehep.net/record/742618
Scrutinizing Exotic Cosmological Models Using ESSENCE Supernova Data Combined with Other Cosmological Probes
Astrophysical Journal

One by Wood-Vasey et al (2007)
http://inspirehep.net/record/741585?ln=en
Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
Astrophysical Journal

As time goes on the constraints on variation seem to tighten. I hear less and less about Lambda being a real "dark energy". I think we are getting closer to accepting it simply as another constant. A small constant amount of curvature. (Not even an energy.)

but this is just my impression from what I read and how I hear people talk. I would like to have some more recent papers that support this point of view with objective evidence.

Also if Lambda is simply a physical constant (a curvature) that appears naturally in the 1915 Einstein equation, along with the other physical constant Newton's G, then there seems to be no reason to relate it to the "vacuum energy" arising in conventional quantum field theory---the unrealistically high value of which is a problem for QFT, but not a concern of General Relativity.

There is also the "WMAP7" report (7-year data from the WMAP mission) of Komatsu et al.
Page 24 has some constraints on the equation of state w. In case Lambda is simply a constant, we would have w = -1. That is about what you get combining latest WMAP+BAO+SN data. The high-z supernova data is the most effective at constraining w. Here is the link.
http://arxiv.org/abs/1001.4538
For example on page 24 in section 5.1 you see:
"The high-z supernova data provide the most stringent limit on w. Using WMAP+BAO+SN, we find w = −0.980±0.053 (68% CL)..."

 

[AndyW]

Thank you for sharing these papers! I have also come across a recent study by Betoule et al. (2014) that uses data from the Supernova Legacy Survey to constrain the equation of state parameter w for dark energy. They find w = -1.023 ± 0.058, which is consistent with a cosmological constant. This further supports the idea that dark energy may simply be a constant rather than a dynamic entity.

Another interesting paper I came across is by Abdalla et al. (2018), which discusses the possibility of modifying general relativity on cosmological scales to explain the accelerated expansion of the universe. They propose a new model that can explain the observed data without the need for dark energy. This is an interesting alternative to the traditional cosmological constant model and highlights the ongoing research and debate in this field.

Overall, it seems that there is still much to be explored and understood about dark energy and its role in the universe. While there are some promising theories and models, more research and data are needed to fully understand this mysterious force.