Enhanced (p)reheating in DBI Inflation (2009)
Davis, A. C., Ribeiro, Raquel H.
We study preheating in DBI hybrid inflation. Preheating occurs since the matter fields are non-minimally coupled to the inflaton. Despite the coupling being small, preheating happens as a narrow...
Brane Inflation and Defect Formation (2008)
Brane inflation and the production of topological defects at the end of the inflationary phase are discussed. After a description of the inflationary setup we discuss the properties of the cosmic...
P-term Strings and Semi-local Strings (2007)
P-term potentials can give rise to Nielsen-Olesen or semi-local cosmic strings. We present a general analysis of these cosmic strings where we derive the Bogomol'nyi equations and field profiles for...
Testing Chameleon Theories with Light Propagating through a Magnetic Field (2007)
Brax, P., Davis, A. C., Mota, D. F., Shaw, D. J.
It was recently argued that the observed PVLAS anomaly can be explained by chameleon field theories in which large deviations from Newton's law can be avoided. Here we present the predictions for the...
P-term Potentials from 4-D Supergravity (2007)
P-term inflation arises in some models of brane inflation. Within N=2 supersymmetry the scalar potential contains a vector of Fayet-Iliopoulos (FI) terms $\xi_i$. Depending on the direction of this...
D-term Uplifted Racetrack Inflation. (2007)
P. Brax, DESY Forschung Hochenergiephysik, A.C. Davis, S.C. Davis, R. Jeannerot, M. Postma
Internal report | Preprint
Moduli Corrections to D-term Inflation (2006)
Brax, Ph., Davis, A. C., Davis, Stephen C., Jeannerot, R., Postma, M.
We present a D-term hybrid inflation model, embedded in supergravity with moduli stabilisation. Its novel features allow us to overcome the serious challenges of combining D-term inflation and moduli...
Coupling Hybrid Inflation to Moduli (2006)
Brax, Ph., Davis, A. C., Davis, Stephen C.
Hybrid inflation can be realised in low-energy effective string theory, as described using supergravity. We find that the coupling of moduli to F-term hybrid inflation in supergravity leads to a...
Cosmic D-Strings and Vortons in Supergravity (2006)
Brax, Ph., Davis, A. C., Davis, Stephen C.
Recent developments in string inspired models of inflation suggest that D-strings are formed at the end of inflation. Within the supergravity model of D-strings there are 2(n-1) chiral fermion zero...
Fermionic Zero Modes of Supergravity Cosmic Strings (2006)
Brax, Ph., Davis, A. C., Davis, Stephen C.
Recent developments in string theory suggest that cosmic strings could be formed at the end of brane inflation. Supergravity provides a realistic model to study the properties of strings arising in...
Cosmic superstrings and primordial magnetogenesis (2005)
Davis, A. C., Dimopoulos, Konstantinos
Cosmic superstrings are produced at the end of brane inflation. Their properties are similar to cosmic strings arising in grand unified theories. Like cosmic strings they can give rise to a...
Natural magnetogenesis from inflation. (2002)
Dimopoulos, Konstantinos, Davis, A. C., Prokopec, T., Tornkvist, O.
We consider the gravitational generation of the massive Z boson field of the standard model, due to the natural breaking of its conformal invariance during inflation. The electroweak symmetry...
Microwave Background Constraints on Decaying Defects (2002)
Brandenberger, R H, Carter, B, Davis, A C
Embedded defects are predicted in a host of particle physics theories, in particular in the standard electroweak theory. They can be stabilized by interactions with the cosmological plasma, but will...
Thermal stabilization of superconducting sigma strings and their drum vortons (2002)
Carter, B, Brandenberger, R H, Davis, A C
We discuss various issues related to stabilized embedded strings in a thermal background. In particular, we demonstrate that such strings will generically become superconducting at moderately low...
Fortnum, H.M., Summerfield, A.Q., Marshall, D.H., Davis, A.C., Bamford, J.M.
OBJECTIVE: To estimate the prevalence of confirmed permanent childhood hearing impairment and its profile across age and degree of impairment in the United Kingdom. DESIGN: Retrospective total...
Brane-World Cosmology, Bulk Scalars and Perturbations (2001)
We investigate aspects of cosmology in brane world theories with a bulk scalar field. We concentrate on a recent model motivated from supergravity in singular spaces. After discussing the background...
Natural Magnetogenesis from Inflation (2001)
Dimopoulos, K., Prokopec, T., Tornkvist, O., Davis, A. C.
We consider the gravitational generation of the massive Z-boson field of the standard model, due to the natural breaking of its conformal invariance during inflation. The electroweak symmetry...
On Brane Cosmology and Naked Singularities (2001)
Brane-world singularities are analysed, emphasizing the case of supergravity in singular spaces where the singularity puzzle is naturally resolved. These naked singularities are either time-like or...
Cosmological Evolution on Self-Tuned Branes and the Cosmological Constant (2001)
We consider the cosmological evolution of a bulk scalar field and ordinary matter living on the brane world in the light of the constraints imposed by the matter dominated cosmological evolution and...
Cosmological Solutions of Supergravity in Singular Spaces (2000)
We study brane-world solutions of five-dimensional supergravity in singular spaces. We exhibit a self-tuned four-dimensional cosmological constant when five-dimensional supergravity is broken by an...
Topological defects in lattice gauge theories (2000)
Davis, A. C., Kibble, T. W. B., Rajantie, A., Shanahan, H.
We present a non-perturbative formalism for measuring defect free energies (monopole mass or vortex tension) in three-dimensional SU(2)+adjoint Higgs models. Starting from twisted, translation...
Primordial Spectrum of Gauge Fields from Inflation (2000)
Davis, A C, Dimopoulos, K, Prokopec, Tomislav, Tornkvist, O
We show that conformal invariance of gauge fields is naturally broken in inflation, having as a consequence amplification of gauge fields. The resulting spectrum of the field strength is...
We present a discussion of embedded vortices in general Yang-Mills theories. The origin of a family structure of solutions is shown to be group theoretic in nature and a procedure for its...
Examples of embedded defects (1995)
We present a series of examples designed to clarify the formalism of the companion paper `Embedded Vortices'. After summarising the formalism in a prescriptive sense, we run through several examples,...
The stability of primordial magnetic fields produced by phase transitions (1995)
Primordial magnetic fields seem to be a generic relic of phase transitions in the early universe. We consider a primordial electromagnetic field formed as a result of a second-order phase transition,...
Primordial magnetic fields in hybrid inflation (1995)
We show that, during hybrid inflation, a primordial magnetic field can be created, sufficiently strong to seed the galactic dynamo and generate the observed galactic magnetic fields. Considering the...
Cosmic strings are current-carrying (1995)
A synthesis of previous work done on the microscopic structure of cosmic strings in realistic models is made and reveals that strings are expected to be not only superconducting in the sense of...
Embedded defects and symmetry breaking in flipped SU(5) (1995)
We explicitly show the analogy between the symmetry breaking scheme for the GUT flipped SU(5) with that of the Weinberg-Salam theory of electroweak interactions. This allows us to construct the...
Dynamical gauge bosons from fundamental fermions (1990)
Amati, Daniele, Barbieri, Riccardo, Davis, A C, Veneziano, Gabriele
Davis A C (MRC Institute of Hearing Research, University of Nottingham, University Park, Nottingham NG7 2RD, UK). The prevalence of hearing impairment and reported hearing disability in adults in...
Epidemiology of bacterial meningitis.
This 10 year retrospective study of all causes of bacterial meningitis for children resident in Nottingham District Health Authority area reports an annual incidence rate per 100,000 children aged...