**Cyclic Model: Image from Astronomy Magazine, April 2009
(click image to see movie version)**

**The Cyclic Universe: **
Popular Intro: Endless Universe: The Big Bang and Beyond (Broadway Books, 2008).
(Somewhat dated -- emphasizes M-theory and colliding brane picture whereas this is not required.
Simpler versions, including next few examples, use ordinary quantum fields in ordinary spacetime.)
**The simplest cyclic/ekpyrotic model: gaussian fluctuations, stable, and minimal tuning
**Scale-invariant perturbations in ekpyrotic cosmologies without fine-tuning
of initial conditions
PRD
(A. Levy, A. Ijjas and PJS)
**The Higgs, the cyclic universe, and geodesic completeness
**Cyclic Cosmology, Conformal Symmetry and the Metastability of the Higgs
Physics Letters
(I. Bars, S-H. Chen, PJS, N. Turok)
**Cosmological predictions if fundamental physics is scale-free:
**Large scale and small-scale properties of the universe appear to be scale-free,
so it is useful to compare predictions of scale-free inflation models with
scale-free cyclic models to see which is simpler and more predictve
Physical Review D
(A. Ijjas, PJS, A. Loeb)
**Can cyclic Cosmology be made geodesically complete?
**Sailing through the big crunch-big bang transition
Physical Review D
(I. Bars, PJS, N. Turok)
**New approach for generating density fluctuations with small non-gaussianity in ekpyrotic/cyclic models
in a cyclic universe
**General mechanism for producing scale-invariant perturbations and small

non-Gaussianity in ekpyrotic models
Physical Review D
(A. Ijjas, J-L. Lehners, PJS)
**A new non-ekpyrotic cyclic approach to smoothing and flattening the universe
**The anamorphic universe
JCAP
(A. Ijjas and PJS)
**Planck2013 implications for the cyclic universe
**Planck2013 results support the simplest cyclic models
Preprint
(J.-L. Lehners and PJS)
**Introduction to conformal symmetry for cosmologists
**Local Conformal Symmetry in Physics and Cosmology
Preprint
(I. Bars, S-H. Chen, PJS, N. Turok)
**A new approach for tracking the universe through a big crunch/big bang transition
**Antigravity and the big crunch/big Bang Transition
Physics Letters
(I. Bars, S-H. Chen, PJS, N. Turok)
**Naturally explaining the amplitude of density perturbations in cyclic models
**PRL 106, 081301 (2011)
(J.-L. Lehners & PJS)
**Can the bounce be non-singular?**
PRL 105, 261301 (2010) (see also PRD84, 083520)
(B.-K. Xue & PJS)
**Dark Energy & the Return of the Phoenix Universe**
PRD 79, 063503 (2009)
(J.-L. Lehners & PJS)
**Generation of Gravitational Waves in the Cyclic Universe **
(Subdominant) Primordial perturbations
(Dominant) 2nd Order Scalar-induced g-waves
**Non-gaussianity: A Key Prediction of the Cyclic Model**
How to compute non-gaussianity in cyclic models
An Intuitive Approach, 2nd Order
An Intuitive Approach, 3rd Order
**Predictions of Spectral tilt**
Inflationary vs. Cyclic Model Predictions
**Generation of Density Perturbations in the Cyclic Universe (Linear Order)**
PRD76, 103501 (2007)
(J.-L. Lehners, P. McFadden, PJS & N. Turok)
**Why the cosmological constant is small and positive (a cyclic solution)**
SCIENCE 312, 1180 (2006)
(PJS & N. Turok)
**The Cyclic Model of the Universe**
Original Paper (SCIENCE)
More detailed description
(PJS & N. Turok)
**For Fun:**
Cyclocosmos: Poetic Rendition of the Cyclic Model by Bill Robinson
George Carlin on the cyclic universe
Jim Carrey, Stephen Hawking and the Ekpyrotic Universe
Cosmocard: Summary of Basic Cosmological Parameters