Optimal quantum estimation of the Unruh-Hawking effect.

We address on general quantum-statistical grounds the problem of optimal detection of the Unruh-Hawking effect. We show that the effect signatures are magnified up to potentially observable levels if the scalar field to be probed has high mean energy from an inertial perspective: The Unruh-Hawking effect acts like an amplification channel. We prove that a field in a Fock inertial state, probed via photon counting by a noninertial detector, realizes the optimal strategy attaining the ultimate sensitivity allowed by quantum mechanics for the observation of the effect. We define the parameter regime in which the effect can be reliably revealed in laboratory experiments, regardless of the specific implementation.