The quantum eraser does not always erase

In this paper we will first look at a particular quantum eraser setup to show that this type of experiments can be understood in an intuitive manner if we are willing to take a complex nonlinear approach, without the need to invoke Niels Bohr's complementarity or quantum entanglement between two particles. We will then discuss a recent experiment of the same type that does not erase the interference pattern when which-path information is available, and argue that this result is in clear contradiction with the orthodox interpretation of quantum mechanics but perfectly understandable in the framework of nonlinear quantum physics.