Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Remarks on the formulation of the cosmological constant/dark energy
  problems   Associated with the cosmic acceleration are the old and new cosmological
constant problems, recently put into the more general context of the dark
energy problem. In broad terms, the old problem is related to an unexpected
order of magnitude of this component while the new problem is related to this
magnitude being of the same order of the matter energy density during the
present epoch of cosmic evolution. Current plans to measure the equation of
state certainly constitute an important approach; however, as we discuss, this
approach is faced with serious feasibility challenges and is limited in the
type of conclusive answers it could provide. Therefore, is it really too early
to seek actively for new tests and approaches to these problems? In view of the
difficulty of this endeavor, we argue here that a good place to start is by
questioning some of the assumptions underlying the formulation of these
problems and finding new ways to put this questioning to the test. First, we
calculate how much fine tuning the cosmic coincidence problem represents. Next,
we discuss the potential of some cosmological probes such as gravitational
lensing to identify novel tests to probe dark energy questions and assumptions.
Then, motivated by some theorems in General Relativity, we discuss if the full
identification of the cosmological constant with vacuum energy is
unquestionable. Also, we point out the relevance of experiments at the
interface of astrophysics and quantum field theory, such as the Casimir effect
in gravitational and cosmological contexts. We conclude that challenging some
of the assumptions underlying the cosmological constant problems and putting
them to the test may prove useful and necessary to make progress on these
questions. (Abridged)

19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph