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

  title={Quantum Cramer–Rao Bound for a Massless Scalar Field in de Sitter Space},
  author={Marcello Rotondo and Yasusada Nambu},
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… 
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