# The cosmological constant problem and quintessence

@article{Sahni2002TheCC, title={The cosmological constant problem and quintessence}, author={Varun Sahni}, journal={Classical and Quantum Gravity}, year={2002}, volume={19}, pages={3435-3448} }

I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as k4. A cutoff at the Planck or electroweak scale leads to a cosmological constant which is, respectively, 10123 or 1055 times larger than the observed value, Λ/8πG 10−47 GeV4. The absence of a fundamental symmetry which could set the value of Λ to either zero or a very small…

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## References

SHOWING 1-10 OF 72 REFERENCES

### eb 2 00 2 The cosmological constant problem and quintessence

- Physics
- 2002

I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum…

### The cosmological constant and cold dark matter

- PhysicsNature
- 1990

THE cold dark matter (CDM) model1–4 for the formation and distribution of galaxies in a universe with exactly the critical density is theoretically appealing and has proved to be durable, but recent…

### Nonperturbative effects of vacuum energy on the recent expansion of the universe

- Physics
- 1999

We show that the vacuum energy of a free quantized field of very low mass can significantly alter the recent expansion of the universe. The effective action of the theory is obtained from a…

### Quintessence, cosmic coincidence, and the cosmological constant

- Physics
- 1999

Recent observations suggest that a large fraction of the energy density of the Universe has negative pressure. One explanation is vacuum energy density; another is quintessence in the form of a…

### Scalar tensor gravity and quintessence

- Physics
- 1999

Scalar fields with inverse power-law effective potentials may provide a negative pressure component to the energy density of the universe today, as required by cosmological observations. In order to…

### Likely Values of the Cosmological Constant

- Physics
- 1997

In theories in which the cosmological constant takes a variety of values in different "subuniverses," the probability distribution of its observed values is conditioned by the requirement that there…

### Cosmological consequences of a rolling homogeneous scalar field.

- PhysicsPhysical review. D, Particles and fields
- 1988

It is argued that a number of models in which the energy density of the scalar field red-shifts in a specific manner are studied could reconcile the low dynamical estimates of the mean mass density with the negligibly small spatial curvature preferred by inflation.

### Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant

- Physics
- 1998

We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that…

### Nonminimal coupling and quintessence

- Physics
- 2000

Recent studies of type Ia supernovas with redshifts up to about $z\ensuremath{\lesssim}1$ reveal evidence for a cosmic acceleration in the expansion of the Universe. The most straightforward…