Outputs (71)

Charge-swapping q balls (2014)
Journal Article
Copeland, E. J., Saffin, P. M., & Zhou, S. Y. (2014). Charge-swapping q balls. Physical Review Letters, 113(23), https://doi.org/10.1103/PhysRevLett.113.231603

© 2014 American Physical Society. Q balls are nontopological solitonic solutions to a wide class of field theories that possess global symmetries. Here we show that in these same theories there also exists a tower of novel composite Q-ball solutions... Read More about Charge-swapping q balls.

Oscillon lifetime in the presence of quantum fluctuations (2014)
Journal Article
Saffin, P. M., Tognarelli, P., & Tranberg, A. (2014). Oscillon lifetime in the presence of quantum fluctuations. Journal of High Energy Physics, 2014(8), Article 125. https://doi.org/10.1007/JHEP08%282014%29125

We consider the stability of oscillons in 2+1 space-time dimensions, in the presence of quantum fluctuations. Taking the oscillon to be the inhomogeneous mean field of a self-interacting quantum scalar field, we compare its classical evolution to the... Read More about Oscillon lifetime in the presence of quantum fluctuations.

Ensemble fermions for electroweak dynamics and the fermion preheating temperature (2013)
Journal Article
Mou, Z.-G., Tranberg, A., & Saffin, P. M. (2013). Ensemble fermions for electroweak dynamics and the fermion preheating temperature. Journal of High Energy Physics, 2013(11), https://doi.org/10.1007/JHEP11%282013%29097

We refine the implementation of ensemble fermions for the electroweak sector of the Standard Model, introduced previously. We consider the behavior of different observables as the size of the ensemble is increased and show that the dynamics converges... Read More about Ensemble fermions for electroweak dynamics and the fermion preheating temperature.

Gravitational waves from oscillon preheating (2013)
Journal Article
Zhou, S.-Y., Copeland, E. J., Easther, R., Finkel, H., Mou, Z.-G., & Saffin, P. M. (2013). Gravitational waves from oscillon preheating. Journal of High Energy Physics, 2013, Article 26. https://doi.org/10.1007/JHEP10%282013%29026

Oscillons are long-lived, localized excitations of nonlinear scalar fields which may be copiously produced during preheating after inflation, leading to a possible oscillon-dominated phase in the early Universe. For example, this can happen after axi... Read More about Gravitational waves from oscillon preheating.

Adiabatic and isocurvature perturbation projections in multi-field inflation (2013)
Journal Article
Gordon, C., & Saffin, P. M. (2013). Adiabatic and isocurvature perturbation projections in multi-field inflation. Journal of Cosmology and Astroparticle Physics, 2013(8), Article 021. https://doi.org/10.1088/1475-7516/2013/08/021

Current data are in good agreement with the predictions of single field inflation. However, the hemispherical asymmetry seen in the cosmic microwave background data, may hint at a potential problem. Generalizing to multi-field models may provide one... Read More about Adiabatic and isocurvature perturbation projections in multi-field inflation.

Duality and decay of macroscopic F-strings (2013)
Journal Article
Skliros, D. P., Copeland, E. J., & Saffin, P. M. (2013). Duality and decay of macroscopic F-strings. Physical Review Letters, 111(4), Article 041601. https://doi.org/10.1103/PhysRevLett.111.041601

We study the decay of fundamental string loops of arbitrary size L/min(n,m)≫√α′, labeled by (n, m; λn, ¯λm), where n, m correspond to left- and right-mover harmonics and λn, ¯λm to polarization tensors, and find that a description in terms of the rec... Read More about Duality and decay of macroscopic F-strings.

The covariance of multi-field perturbations, pseudo-susy and fNL (2012)
Journal Article
Saffin, P. M. (2012). The covariance of multi-field perturbations, pseudo-susy and fNL. Journal of Cosmology and Astroparticle Physics, 2012(9), Article 002. https://doi.org/10.1088/1475-7516/2012/09/002

We reconsider cosmological perturbation theory for multi-component scalars, enforcing covariance in field-space, and ensuring that phyical observations are independent of field re-definitions. We use the formalism to clarify some issues in the litera... Read More about The covariance of multi-field perturbations, pseudo-susy and fNL.

Classical duals, Legendre transforms and the Vainshtein mechanism (2012)
Journal Article
Padilla, A., & Saffin, P. M. (2012). Classical duals, Legendre transforms and the Vainshtein mechanism. Journal of High Energy Physics, 2012(7), Article 122. https://doi.org/10.1007/JHEP07%282012%29122

We show how to generalize the classical duals found by Gabadadze {et al} to a very large class of self-interacting theories. This enables one to adopt a perturbative description beyond the scale at which classical perturbation theory breaks down in t... Read More about Classical duals, Legendre transforms and the Vainshtein mechanism.

Self-tuning and the derivation of a class of scalar-tensor theories (2012)
Journal Article
Charmousis, C., Copeland, E. J., Padilla, A., & Saffin, P. M. (2012). Self-tuning and the derivation of a class of scalar-tensor theories. Physical Review D, 85(10), Article 104040. https://doi.org/10.1103/PhysRevD.85.104040

We have recently proposed a special class of scalar tensor theories known as the Fab Four. These arose from attempts to analyse the cosmological constant problem within the context of Horndeski's most general scalar tensor theory. The Fab Four togeth... Read More about Self-tuning and the derivation of a class of scalar-tensor theories.

Dynamical simulations of electroweak baryogenesis with fermions (2012)
Journal Article
Saffin, P. M., & Tranberg, A. (2012). Dynamical simulations of electroweak baryogenesis with fermions. Journal of High Energy Physics, 2012(2), Article 102. https://doi.org/10.1007/JHEP02%282012%29102

We perform real-time numerical lattice simulations of a one-family version of the Standard Model. We model the quantum fermions using the ensemble method and treat the bosonic scalar and non-abelian gauge fields classically. Our main interest is elec... Read More about Dynamical simulations of electroweak baryogenesis with fermions.