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

@article{Rotondo2017QuantumCB, title={Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space}, author={Marcello Rotondo and Yasusada Nambu}, journal={Universe}, year={2017}, volume={3}, pages={71} }

How precisely can we estimate cosmological parameters by performing a quantum measurement on a cosmological quantum state? In quantum estimation theory, the variance of an unbiased parameter estimator is bounded from below by the inverse of measurement-dependent Fisher information and ultimately by quantum Fisher information, which is the maximization of the former over all positive operator-valued measurements. Such bound is known as the quantum Cramer –Rao bound. We consider the evolution of…

## 4 Citations

### Parameter estimation for a Lorentz invariance violation

- PhysicsInternational Journal of Modern Physics D
- 2019

We employ techniques from quantum estimation theory (QET) to estimate the Lorentz violation parameters in the (1+3)-dimensional flat spacetime. We obtain and discuss the expression of the quantum…

### Late-time quantum radiation by a uniformly accelerated detector in de Sitter spacetime

- PhysicsPhysical Review D
- 2018

We investigate the quantum radiation emitted by a uniformly accelerated Unruh-DeWitt detector in de Sitter spacetime. We find that there exists a non-vanishing quantum radiation at late times in the…

### Vacuum state in de Sitter spacetime with static charts

- PhysicsPhysical Review D
- 2018

We study the free massive scalar field in de Sitter spacetime with static charts. In particular, we find positive-frequency modes for the Bunch-Davies vacuum state natural to the static charts as…

### QMetrology from QCosmology: Study with entangled two qubit open quantum system in De Sitter space

- Physics
- 2020

In this paper, our prime objective is to apply the techniques of {\it parameter estimation theory} and the concept of {\it Quantum Metrology} in the form of {\it Fisher Information} to investigate…

## References

SHOWING 1-10 OF 15 REFERENCES

### Pointer states for primordial fluctuations in inflationary cosmology

- Physics
- 2006

Primordial fluctuations in inflationary cosmology acquire classical properties through decoherence when their wavelengths become larger than the Hubble scale. Although decoherence is effective, it is…

### Quantum parameter estimation using general single-mode Gaussian states

- Physics, Computer Science
- 2013

We calculate the quantum Cramer--Rao bound for the sensitivity with which one or several parameters, encoded in a general single-mode Gaussian state, can be estimated. This includes in particular the…

### Inflationary spectra and partially decohered distributions

- Physics
- 2005

It is generally expected that decoherence processes will erase the quantum properties of the inflationary primordial spectra. However, given the weakness of gravitational interactions, one might end…

### Semiclassicality and decoherence of cosmological perturbations

- Physics
- 1996

Transition to the semiclassical behaviour and the decoherence process for inhomogeneous perturbations generated from the vacuum state during an inflationary stage in the early Universe are considered…

### Decoherence and the Appearance of a Classical World in Quantum Theory, second edition

- Physics
- 1996

1 Introduction.- 2 Basic Concepts and Their Interpretation.- 3 Decoherence Through Interaction with the Environment.- 4 Decoherence in Quantum Field Theory and Quantum Gravity.- 5 Consistent…

### Why do cosmological perturbations look classical to us

- Physics
- 2008

According to the inflationary scenario of cosmology, all structure in the Universe can be traced back to primordial fluctuations during an accelerated (inflationary) phase of the very early Universe.…

### Quantum Fields in Curved Space

- Physics
- 1980

This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black hole…

### Explicit dimensional renormalization of quantum field theory in curved space-time

- Physics
- 1978

The dimensional renormalization of scalar and spinor field theories quantized in a conformally flat (k = 0) Robertson-Walker space-time is discussed. The theories considered are conformally invariant…

### Entanglement of Dirac fields in an expanding spacetime

- Physics
- 2010

We study the entanglement generated between Dirac modes in a 2-dimensional conformally flat Robertson-Walker universe. We find radical qualitative differences between the bosonic and fermionic…