Abstract
We provide a proof that Gaussian entanglement can provide up to 6dB of advantage in the error probability exponent compared to using a classical light source of the same signal brightness for the task of discriminating between the presence of two arbitrary objects (whose shapes are known). The proof is based on a perturbative expansion in the high loss and low signal brightness regime of the joint state of the reflected signal and the stored idler mode with which the signal is entangled.