# Inflationary dynamics of kinetically-coupled gauge fields

## Abstract

We investigate the inflationary dynamics of two kinetically-coupled massless U(1) gauge fields with time-varying kinetic-term coefficients. Ensuring that the system does not have strongly coupled regimes shrinks the parameter space. Also, we further restrict ourselves to systems that can be quantized using the standard creation, annihilation operator algebra. This second constraint limits us to scenarios where the system can be diagonalized into the sum of two decoupled, massless, vector fields with a varying kinetic-term coefficient. Such a system might be interesting for magnetogenesis because of how the strong coupling problem generalizes. We explore this idea by assuming that one of the gauge fields is the Standard Model U(1) field and that the other dark gauge field has no particles charged under its gauge group. We consider whether it would be possible to transfer a magnetic field from the dark sector, generated perhaps before the coupling was turned on, to the visible sector. We also investigate whether the simple existence of the mixing provides more opportunities to generate magnetic fields. We find that neither possibility works efficiently, consistent with the well-known difficulties in inflationary magnetogenesis.

- Authors:

- CP3-Origins, Center for Cosmology and Particle Physics Phenomenology, University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)

- Publication Date:

- OSTI Identifier:
- 22525885

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANNIHILATION OPERATORS; COUPLING; FIELD ALGEBRA; INFLATIONARY UNIVERSE; LIMITING VALUES; MAGNETIC FIELDS; MIXING; SPACE; STANDARD MODEL; STRONG-COUPLING MODEL; U-1 GROUPS; VECTOR FIELDS

### Citation Formats

```
Ferreira, Ricardo Z., and Ganc, Jonathan, E-mail: ferreira@cp3.dias.sdu.dk, E-mail: ganc@cp3.dias.sdu.dk.
```*Inflationary dynamics of kinetically-coupled gauge fields*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/04/029.

```
Ferreira, Ricardo Z., & Ganc, Jonathan, E-mail: ferreira@cp3.dias.sdu.dk, E-mail: ganc@cp3.dias.sdu.dk.
```*Inflationary dynamics of kinetically-coupled gauge fields*. United States. doi:10.1088/1475-7516/2015/04/029.

```
Ferreira, Ricardo Z., and Ganc, Jonathan, E-mail: ferreira@cp3.dias.sdu.dk, E-mail: ganc@cp3.dias.sdu.dk. Wed .
"Inflationary dynamics of kinetically-coupled gauge fields". United States.
doi:10.1088/1475-7516/2015/04/029.
```

```
@article{osti_22525885,
```

title = {Inflationary dynamics of kinetically-coupled gauge fields},

author = {Ferreira, Ricardo Z. and Ganc, Jonathan, E-mail: ferreira@cp3.dias.sdu.dk, E-mail: ganc@cp3.dias.sdu.dk},

abstractNote = {We investigate the inflationary dynamics of two kinetically-coupled massless U(1) gauge fields with time-varying kinetic-term coefficients. Ensuring that the system does not have strongly coupled regimes shrinks the parameter space. Also, we further restrict ourselves to systems that can be quantized using the standard creation, annihilation operator algebra. This second constraint limits us to scenarios where the system can be diagonalized into the sum of two decoupled, massless, vector fields with a varying kinetic-term coefficient. Such a system might be interesting for magnetogenesis because of how the strong coupling problem generalizes. We explore this idea by assuming that one of the gauge fields is the Standard Model U(1) field and that the other dark gauge field has no particles charged under its gauge group. We consider whether it would be possible to transfer a magnetic field from the dark sector, generated perhaps before the coupling was turned on, to the visible sector. We also investigate whether the simple existence of the mixing provides more opportunities to generate magnetic fields. We find that neither possibility works efficiently, consistent with the well-known difficulties in inflationary magnetogenesis.},

doi = {10.1088/1475-7516/2015/04/029},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 04,

volume = 2015,

place = {United States},

year = {Wed Apr 01 00:00:00 EDT 2015},

month = {Wed Apr 01 00:00:00 EDT 2015}

}