Skip to main content

Testing the Quasi-static Approximation in f(R) Gravity Simulations

  • Chapter
  • First Online:

Part of the book series: Springer Theses ((Springer Theses))

Abstract

In recent years, theories of modified gravity have become a subject of great interest in alternative approaches to modelling the observed acceleration of the Universe. Einstein’s theory of General Relat6ivity (GR) has been the underlying gravity theory in the standard cosmological model of \(\varLambda \)CDM, the dark energy (\(\varLambda \)) and (cold) dark matter (CDM) components of which remain unresolved challenges to cosmologists.

This is a preview of subscription content, log in via an institution.

Buying options

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   84.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD   109.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD   109.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

Notes

  1. 1.

    The content of this chapter is based on the article Bose et al. ‘Testing the quasi-static approximation in f(R) gravity simulations’, Journal of Cosmology and Astroparticle Physics, Volume 2015, Issue 2, published 24 February 2015. Reproduced with permission. All rights reserved, https://doi.org/10.1088/1475-7516/2015/02/034.

  2. 2.

    It is often argued that one should make \(|d^h|\) as small as practically possible, instead of stopping at \(|d^h|\sim \tau ^h/3\), to prevent the numerical errors in solving the differential equation at individual steps from accumulating over the many time steps of a simulation. While this is true to a certain extent, it is not clear that the discretisation error itself will not accumulate in this case (recall that, if \(d^h\) could be brought to zero, then the remaining error is completely from the discretisation). Again, the way to get away from this problem is to reduce the discretisation error by increasing the (spatial) resolution, and then check for convergence.

  3. 3.

    The kick is by the sudden increase in the non-relativistic \(\rho _m\), as can be seen from \(\mathrm {d} V_{\mathrm {eff}} / \mathrm {d} f_R = -\left[ R - f_R R + 2 f(R) + 8\uppi G \rho _m\right] /3\) – because of the quick change in \(\rho _m\), \(f_{R,\mathrm{min}}\) is changed while the true \(f_R\) needs time to respond to this.

  4. 4.

    Note that we can use \(a_e\) in the above expressions and estimates, because electrons are the last species of standard-model particles that become non-relativistic.

References

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Sownak Bose .

Rights and permissions

Reprints and permissions

Copyright information

© 2018 Springer International Publishing AG, part of Springer Nature

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Bose, S. (2018). Testing the Quasi-static Approximation in f(R) Gravity Simulations. In: Beyond ΛCDM . Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-96761-5_5

Download citation

Publish with us

Policies and ethics