# Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space

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## Abstract

**:**

## 1. Introduction

## 2. Massless Scalar Field in an Expanding Universe

## 3. Fisher Information of the Scalar Field

## 4. Fisher Information in de Sitter Universe

## 5. Quantum-to-Classical Transition of Cosmological Perturbations

## 6. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

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**Figure 1.**(

**Left**) Evolution of squeezing parameter and squeezing phase for $k=1$; (

**Right**) Evolution of Fisher informations divided by ${G}^{2}$ for $k=1$.

**Figure 2.**(

**Left**) Evolution of squeezing parameters for $k=1$; (

**Right**) Evolution of Fisher informations divided by ${G}^{2}$ for $k=1$.

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Rotondo, M.; Nambu, Y.
Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space. *Universe* **2017**, *3*, 71.
https://doi.org/10.3390/universe3040071

**AMA Style**

Rotondo M, Nambu Y.
Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space. *Universe*. 2017; 3(4):71.
https://doi.org/10.3390/universe3040071

**Chicago/Turabian Style**

Rotondo, Marcello, and Yasusada Nambu.
2017. "Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space" *Universe* 3, no. 4: 71.
https://doi.org/10.3390/universe3040071