# BRST quantization of cosmological perturbations

## Abstract

BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely related quantization method of Dirac. We describe how both formalisms apply to perturbations in a time-dependent background, and how expectation values of gauge-invariant operators can be calculated in the in-in formalism. Our analysis focuses mostly on the free theory. By appropriate canonical transformations we simplify and diagonalize the free Hamiltonian. BRST quantization in derivative gauges allows us to dramatically simplify the structure of the propagators, whereas Dirac quantization, which amounts to quantization in synchronous gauge, dispenses with the need to introduce ghosts and preserves the locality of the gauge-fixed action.

- Authors:

- Physics Department, St. Lawrence University,Canton, NY 13617 (United States)
- Department of Physics, Syracuse University,Syracuse, NY 13244 (United States)

- Publication Date:

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

- OSTI Identifier:
- 22572180

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 11; Other Information: PUBLISHER-ID: JCAP11(2016)016; OAI: oai:repo.scoap3.org:17885; 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; ACTION INTEGRAL; CANONICAL TRANSFORMATIONS; COSMOLOGICAL MODELS; DIRAC COSMOLOGY; DISTURBANCES; EXPECTATION VALUE; GAUGE INVARIANCE; HAMILTONIANS; PERTURBATION THEORY; PROPAGATOR; QUANTIZATION; QUANTUM FIELD THEORY; SCALAR FIELDS; TIME DEPENDENCE; UNIVERSE

### Citation Formats

```
Armendariz-Picon, Cristian, and Şengör, Gizem.
```*BRST quantization of cosmological perturbations*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/11/016.

```
Armendariz-Picon, Cristian, & Şengör, Gizem.
```*BRST quantization of cosmological perturbations*. United States. doi:10.1088/1475-7516/2016/11/016.

```
Armendariz-Picon, Cristian, and Şengör, Gizem. Tue .
"BRST quantization of cosmological perturbations". United States.
doi:10.1088/1475-7516/2016/11/016.
```

```
@article{osti_22572180,
```

title = {BRST quantization of cosmological perturbations},

author = {Armendariz-Picon, Cristian and Şengör, Gizem},

abstractNote = {BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely related quantization method of Dirac. We describe how both formalisms apply to perturbations in a time-dependent background, and how expectation values of gauge-invariant operators can be calculated in the in-in formalism. Our analysis focuses mostly on the free theory. By appropriate canonical transformations we simplify and diagonalize the free Hamiltonian. BRST quantization in derivative gauges allows us to dramatically simplify the structure of the propagators, whereas Dirac quantization, which amounts to quantization in synchronous gauge, dispenses with the need to introduce ghosts and preserves the locality of the gauge-fixed action.},

doi = {10.1088/1475-7516/2016/11/016},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 11,

volume = 2016,

place = {United States},

year = {Tue Nov 08 00:00:00 EST 2016},

month = {Tue Nov 08 00:00:00 EST 2016}

}