# The IR-resummed Effective Field Theory of Large Scale Structures

## Abstract

We present a new method to resum the effect of large scale motions in the Effective Field Theory of Large Scale Structures. Because the linear power spectrum in ΛCDM is not scale free the effects of the large scale flows are enhanced. Although previous EFT calculations of the equal-time density power spectrum at one and two loops showed a remarkable agreement with numerical results, they also showed a 2% residual which appeared related to the BAO oscillations. We show that this was indeed the case, explain the physical origin and show how a Lagrangian based calculation removes this differences. We propose a simple method to upgrade existing Eulerian calculations to effectively make them Lagrangian and compare the new results with existing fits to numerical simulations. Our new two-loop results agrees with numerical results up to k∼ 0.6 h Mpc{sup −1} to within 1% with no oscillatory residuals. We also compute power spectra involving momentum which is significantly more affected by the large scale flows. We show how keeping track of these velocities significantly enhances the UV reach of the momentum power spectrum in addition to removing the BAO related residuals. We compute predictions for the real space correlation function around the BAO scalemore »

- Authors:

- Stanford Institute for Theoretical Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, U.S.A (United States)
- School of Natural Sciences, Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ 08540 (United States)

- Publication Date:

- OSTI Identifier:
- 22381995

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 02; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRELATION FUNCTIONS; FIELD THEORIES; FORECASTING; LAGRANGIAN FUNCTION; ORIGIN; POWER DENSITY; SENSITIVITY; SPACE; SPECTRA; VELOCITY

### Citation Formats

```
Senatore, Leonardo, and Zaldarriaga, Matias, E-mail: senatore@stanford.edu, E-mail: matiasz@ias.edu.
```*The IR-resummed Effective Field Theory of Large Scale Structures*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/02/013.

```
Senatore, Leonardo, & Zaldarriaga, Matias, E-mail: senatore@stanford.edu, E-mail: matiasz@ias.edu.
```*The IR-resummed Effective Field Theory of Large Scale Structures*. United States. doi:10.1088/1475-7516/2015/02/013.

```
Senatore, Leonardo, and Zaldarriaga, Matias, E-mail: senatore@stanford.edu, E-mail: matiasz@ias.edu. Sun .
"The IR-resummed Effective Field Theory of Large Scale Structures". United States.
doi:10.1088/1475-7516/2015/02/013.
```

```
@article{osti_22381995,
```

title = {The IR-resummed Effective Field Theory of Large Scale Structures},

author = {Senatore, Leonardo and Zaldarriaga, Matias, E-mail: senatore@stanford.edu, E-mail: matiasz@ias.edu},

abstractNote = {We present a new method to resum the effect of large scale motions in the Effective Field Theory of Large Scale Structures. Because the linear power spectrum in ΛCDM is not scale free the effects of the large scale flows are enhanced. Although previous EFT calculations of the equal-time density power spectrum at one and two loops showed a remarkable agreement with numerical results, they also showed a 2% residual which appeared related to the BAO oscillations. We show that this was indeed the case, explain the physical origin and show how a Lagrangian based calculation removes this differences. We propose a simple method to upgrade existing Eulerian calculations to effectively make them Lagrangian and compare the new results with existing fits to numerical simulations. Our new two-loop results agrees with numerical results up to k∼ 0.6 h Mpc{sup −1} to within 1% with no oscillatory residuals. We also compute power spectra involving momentum which is significantly more affected by the large scale flows. We show how keeping track of these velocities significantly enhances the UV reach of the momentum power spectrum in addition to removing the BAO related residuals. We compute predictions for the real space correlation function around the BAO scale and investigate its sensitivity to the EFT parameters and the details of the resummation technique.},

doi = {10.1088/1475-7516/2015/02/013},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 02,

volume = 2015,

place = {United States},

year = {Sun Feb 01 00:00:00 EST 2015},

month = {Sun Feb 01 00:00:00 EST 2015}

}