  That event horizons generate quantum correlations via the Hawking effect is
well known. We argue, however, that the creation of entanglement can be
modulated as desired, by appropriately illuminating the horizon. We adapt
techniques from quantum information theory to quantify the entanglement
produced during the Hawking process and show that, while ambient thermal noise
(e.g., CMB radiation) degrades it, the use of squeezed inputs can boost the
non-separability between the interior and exterior regions in a controlled
manner. We further apply our ideas to analog event horizons concocted in the
laboratory and insist that the ability to tune the generation of entanglement
offers a promising route towards detecting quantum signatures of the elusive
Hawking effect.
