Duality and scale invariant magnetic fields from bouncing universes

Debika Chowdhury, L. Sriramkumar, Rajeev Kumar Jain

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Resumé

Recently, we numerically showed that, for a nonminimal coupling that is a simple power of the scale factor, scale invariant magnetic fields arise in a class of bouncing universes. In this work, we analytically evaluate the spectrum of magnetic and electric fields generated in a subclass of such models. We illustrate that, for cosmological scales which have wave numbers much smaller than the wave number associated with the bounce, the shape of the spectrum is preserved across the bounce. Using the analytic solutions obtained, we also illustrate that the problem of backreaction is severe at the bounce. Finally, we show that the power spectrum of the magnetic field remains invariant under a two-parameter family of transformations of the nonminimal coupling function.

OriginalsprogEngelsk
Artikelnummer083512
TidsskriftPhysical Review D
Vol/bind94
Udgave nummer8
Antal sider11
ISSN2470-0010
DOI
StatusUdgivet - 2016

Fingeraftryk

universe
magnetic fields
power spectra
electric fields

Citer dette

Chowdhury, Debika ; Sriramkumar, L. ; Jain, Rajeev Kumar. / Duality and scale invariant magnetic fields from bouncing universes. I: Physical Review D. 2016 ; Bind 94, Nr. 8.
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Duality and scale invariant magnetic fields from bouncing universes. / Chowdhury, Debika; Sriramkumar, L.; Jain, Rajeev Kumar.

I: Physical Review D, Bind 94, Nr. 8, 083512, 2016.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Duality and scale invariant magnetic fields from bouncing universes

AU - Chowdhury, Debika

AU - Sriramkumar, L.

AU - Jain, Rajeev Kumar

PY - 2016

Y1 - 2016

N2 - Recently, we numerically showed that, for a nonminimal coupling that is a simple power of the scale factor, scale invariant magnetic fields arise in a class of bouncing universes. In this work, we analytically evaluate the spectrum of magnetic and electric fields generated in a subclass of such models. We illustrate that, for cosmological scales which have wave numbers much smaller than the wave number associated with the bounce, the shape of the spectrum is preserved across the bounce. Using the analytic solutions obtained, we also illustrate that the problem of backreaction is severe at the bounce. Finally, we show that the power spectrum of the magnetic field remains invariant under a two-parameter family of transformations of the nonminimal coupling function.

AB - Recently, we numerically showed that, for a nonminimal coupling that is a simple power of the scale factor, scale invariant magnetic fields arise in a class of bouncing universes. In this work, we analytically evaluate the spectrum of magnetic and electric fields generated in a subclass of such models. We illustrate that, for cosmological scales which have wave numbers much smaller than the wave number associated with the bounce, the shape of the spectrum is preserved across the bounce. Using the analytic solutions obtained, we also illustrate that the problem of backreaction is severe at the bounce. Finally, we show that the power spectrum of the magnetic field remains invariant under a two-parameter family of transformations of the nonminimal coupling function.

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JO - Physical Review D

JF - Physical Review D

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