Outputs (37)

Classical decay rates of oscillons (2020)
Journal Article
Zhang, H.-Y., Amin, M. A., Copeland, E. J., Saffin, P. M., & Lozanov, K. D. (2020). Classical decay rates of oscillons. Journal of Cosmology and Astroparticle Physics, 2020(07), 055-055. https://doi.org/10.1088/1475-7516/2020/07/055

Oscillons are extremely long-lived, spatially-localized field configurations in real-valued scalar field theories that slowly lose energy via radiation of scalar waves. Before their eventual demise, oscillons can pass through (one or more) exceptiona... Read More about Classical decay rates of oscillons.

Shift-symmetric orbital inflation: Single field or multifield? (2020)
Journal Article
Achúcarro, A., Copeland, E. J., Iarygina, O., Palma, G. A., Wang, D.-G., & Welling, Y. (2020). Shift-symmetric orbital inflation: Single field or multifield?. Physical Review D, 102(2), Article 021302(R). https://doi.org/10.1103/physrevd.102.021302

We present a new class of two-field inflationary attractor models, known as shift-symmetric orbital inflation, whose behavior is strongly multifield but whose predictions are remarkably close to those of single-field inflation. In these models, the f... Read More about Shift-symmetric orbital inflation: Single field or multifield?.

Constraints on the cosmic string loop collapse fraction from primordial black holes (2020)
Journal Article
James-Turner, C., Weil, D. P. B., Green, A. M., & Copeland, E. J. (2020). Constraints on the cosmic string loop collapse fraction from primordial black holes. Physical Review D, 101(12), Article 123526. https://doi.org/10.1103/physrevd.101.123526

A small fraction, f , of cosmic string loops can collapse to form Primordial Black Holes (PBHs). Constraints on the abundance of PBHs can therefore be used to constrain f. We update these calculations, taking into account the PBH extended mass functi... Read More about Constraints on the cosmic string loop collapse fraction from primordial black holes.

Understanding the suppression of structure formation from dark matter-dark energy momentum coupling (2020)
Journal Article
Chamings, F. N., Avgoustidis, A., Copeland, E. J., Green, A. M., & Pourtsidou, A. (2020). Understanding the suppression of structure formation from dark matter-dark energy momentum coupling. Physical Review D, 101(4), https://doi.org/10.1103/physrevd.101.043531

Models in which scalar field dark energy interacts with dark matter via a pure momentum coupling have previously been found to potentially ease the structure formation tension between early-and late-universe observations. In this article we explore t... Read More about Understanding the suppression of structure formation from dark matter-dark energy momentum coupling.

Experiment to Detect Dark Energy Forces Using Atom Interferometry (2019)
Journal Article
Sabulsky, D., Dutta, I., Hinds, E., Elder, B., Burrage, C., & Copeland, E. J. (2019). Experiment to Detect Dark Energy Forces Using Atom Interferometry. Physical Review Letters, 123(6), 1-6. https://doi.org/10.1103/PhysRevLett.123.061102

The accelerated expansion of the universe motivates a wide class of scalar field theories that modify General Relativity (GR) on large scales. Such theories require a screening mechanism to suppress the new force in regions where the weak field limit... Read More about Experiment to Detect Dark Energy Forces Using Atom Interferometry.

Inflation in loop quantum cosmology (2019)
Journal Article
Bhardwaj, A., Copeland, E. J., & Louko, J. (2019). Inflation in loop quantum cosmology. Physical Review D, 99(6), Article 063520. https://doi.org/10.1103/physrevd.99.063520

We develop a consistent analytic approach to determine the conditions under which slow-roll inflation can arise when the inflaton is the same scalar field that is responsible for the bounce in loop quantum cosmology (LQC). We find that the requiremen... Read More about Inflation in loop quantum cosmology.

Dark Energy after GW170817 Revisited (2019)
Journal Article
Copeland, E. J., Kopp, M., Padilla, A., Saffin, P. M., & Skordis, C. (2019). Dark Energy after GW170817 Revisited. Physical Review Letters, 122(6), Article 061301. https://doi.org/10.1103/physrevlett.122.061301

We revisit the status of scalar-tensor theories with applications to dark energy in the aftermath of the gravitational wave signal GW170817 and its optical counterpart GRB170817A. At the level of the cosmological background, we identify a class of th... Read More about Dark Energy after GW170817 Revisited.

Dynamical systems applied to cosmology: dark energy and modified gravity (2018)
Journal Article
Bahamonde, S., Böhmer, C. G., Carloni, S., Copeland, E. J., Fang, W., & Tamanini, N. (2018). Dynamical systems applied to cosmology: dark energy and modified gravity. Physics Reports, 775-777, 1-122. https://doi.org/10.1016/j.physrep.2018.09.001

The Nobel Prize winning confirmation in 1998 of the accelerated expansion of our Universe put into sharp focus the need of a consistent theoretical model to explain the origin of this acceleration. As a result over the past two decades there has been... Read More about Dynamical systems applied to cosmology: dark energy and modified gravity.

Gravitational waves from asymmetric oscillon dynamics? (2018)
Journal Article
Amin, M. A., Braden, J., Copeland, E. J., Giblin, J. T., Solorio, C., Weiner, Z. J., & Zhou, S.-Y. (2018). Gravitational waves from asymmetric oscillon dynamics?. Physical Review D, 98(2), 1-6. https://doi.org/10.1103/physrevd.98.024040

It has been recently suggested that oscillons produced in the early universe from certain asymmetric potentials continue to emit gravitational waves for a number of e-folds of expansion after their formation, leading to potentially detectable gravita... Read More about Gravitational waves from asymmetric oscillon dynamics?.

The shape dependence of chameleon screening (2018)
Journal Article
Burrage, C., Copeland, E. J., Moss, A., & Stevenson, J. A. (2018). The shape dependence of chameleon screening. Journal of Cosmology and Astroparticle Physics, 2018(1), https://doi.org/10.1088/1475-7516/2018/01/056

Chameleon scalar fields can screen their associated fifth forces from detection by changing their mass with the local density. These models are an archetypal example of a screening mechanism, and have become an important target for both cosmological... Read More about The shape dependence of chameleon screening.