# Anisotropic non-gaussianity from rotational symmetry breaking excited initial states

## Abstract

If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B|≲0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and ϵ≃0.01 the difference between these two configurations is about 0.27, which could bemore »

- Authors:

- INFN - Sezione di Bologna, IS FLAG,viale B. Pichat 6/2, I-40127 Bologna (Italy)
- (Italy)
- Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

- Publication Date:

- Sponsoring Org.:
- SCOAP3, CERN, Geneva (Switzerland)

- OSTI Identifier:
- 22572197

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 12; Other Information: PUBLISHER-ID: JCAP12(2016)002; OAI: oai:repo.scoap3.org:18149; cc-by Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANGULAR CORRELATION; ANISOTROPY; BACKGROUND RADIATION; COSMOLOGICAL INFLATION; INFLATIONARY UNIVERSE; PERTURBATION THEORY; QUANTUM MECHANICS; QUANTUM STATES; RELICT RADIATION; ROTATIONAL INVARIANCE; SCALE MODELS; SYMMETRY BREAKING

### Citation Formats

```
Ashoorioon, Amjad, Casadio, Roberto, Dipartimento di Fisica e Astronomia, Alma Mater Università di Bologna,via Irnerio 46, 40126 Bologna, and Koivisto, Tomi.
```*Anisotropic non-gaussianity from rotational symmetry breaking excited initial states*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/12/002.

```
Ashoorioon, Amjad, Casadio, Roberto, Dipartimento di Fisica e Astronomia, Alma Mater Università di Bologna,via Irnerio 46, 40126 Bologna, & Koivisto, Tomi.
```*Anisotropic non-gaussianity from rotational symmetry breaking excited initial states*. United States. doi:10.1088/1475-7516/2016/12/002.

```
Ashoorioon, Amjad, Casadio, Roberto, Dipartimento di Fisica e Astronomia, Alma Mater Università di Bologna,via Irnerio 46, 40126 Bologna, and Koivisto, Tomi. Thu .
"Anisotropic non-gaussianity from rotational symmetry breaking excited initial states". United States.
doi:10.1088/1475-7516/2016/12/002.
```

```
@article{osti_22572197,
```

title = {Anisotropic non-gaussianity from rotational symmetry breaking excited initial states},

author = {Ashoorioon, Amjad and Casadio, Roberto and Dipartimento di Fisica e Astronomia, Alma Mater Università di Bologna,via Irnerio 46, 40126 Bologna and Koivisto, Tomi},

abstractNote = {If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B|≲0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and ϵ≃0.01 the difference between these two configurations is about 0.27, which could be detectable in the future. For purely anisotropic particle creation, the non-Gaussianity can be larger and its anisotropic feature very sharp. The non-gaussianity can then reach f{sub NL}∼30 in the preferred direction while disappearing from the correlations in the orthogonal plane.},

doi = {10.1088/1475-7516/2016/12/002},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 12,

volume = 2016,

place = {United States},

year = {Thu Dec 01 00:00:00 EST 2016},

month = {Thu Dec 01 00:00:00 EST 2016}

}