- General description
xPand (2012-2018) is a package for Mathematica in which tools are provided to
compute formally the cosmological perturbations around a homogeneous
spacetime. It is developed by Cyril Pitrou, Xavier
Roy and Obinna Umeh. It is based on the xAct distribution for efficient tensor
- Downloading and installing
You first need to download and install xAct.
Then you can download the tarball of xPand's last released version (currently 0.4.3).
See the installation notes in order to install it correctly in your local Mathematica distribution.
Once installed, the documentation is available in your Documentation
Center of Mathematica (Help->Documentation Center->Add-Ons->xAct
Packages->xPand). Again see the installation notes to make sure you
have the appropriate documentation. If you wish to have a glance at
the package, you can download the pdf dump of the documentation.
The details of the algorithm are available in an associated publication.
Please cite it along with the page http://www.xact.es/xPand/ if you use it.
- Articles acknowledging the use of xPand
- Yang-Yang Wang, Jian-Yang Zhu and Xiao-Min Zhang,
Two-field warm inflation and its scalar perturbations on large scales,
- Pedro Carrilho and Karim A. Malik,
Isocurvature initial conditions for second order Boltzmann solvers,
- N. Bartolo, P. Karmakar, S. Matarrese and M. Scomparin,
Cosmic structures and gravitational waves in ghost-free scalar-tensor theories of gravity,
- C. Fidler, T. Tram, C. Rampf, R. Crittenden, K. Koyama and D. Wands,,
General relativistic weak-field limit and Newtonian N-body simulations,
- S. R. Goldberg, C. Gallagher and T. Clifton,
Perturbation theory for cosmologies with nonlinear structure,
- N. Frusciante and G. Papadomanolakis,
Tackling non-linearities with the effective field theory of dark energy and modified gravity,
- S. Anselmi, S. Kumar, D. López Nacir and G. D. Starkman,
Failures of homogeneous and isotropic cosmologies in extended quasidilaton massive gravity,
- G. Cabass, E. Pajer and F.Schmidt,
How Gaussian can our Universe be?,
- O. Umeh,
Imprint of non-linear effects on HI intensity mapping on large scales,
- A. Ricciardone and G.Tasinato,
Primordial gravitational waves in supersolid inflation,
- S. R. Goldberg, T. Clifton, K. A. Malik,
Cosmology on all scales: a two-parameter perturbation expansion,
- T. Nakama, T. Suyama,
Primordial black holes as a novel probe of primordial gravitational waves. II: Detailed analysis,
- A. Frederico, N. Bartolo, P. Karmakar, S. Matarrese,
Cosmological perturbations in mimetic Horndeski gravity,
- P. Carrilho, K. A. Malik,
Vector and tensor contributions to the curvature perturbation at second order,
- S. Anselmi, D. L. Nacir, G. D. Starkman,
Extreme parameter sensitivity in quasidilaton massive gravity,
- G. Ballesteros,
The effective theory of fluids at NLO and implications for dark energy ,
JCAP 1503 (2015) 03.
The programs in this page are distributed as free software under the
GNU General Public License.
They are distributed in the hope that they will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
for more details.