Quantum mechanics does not imply that the world outside our past light cone is non-existent. The notion that events or entities beyond our past light cone do not exist or have no physical reality is a misunderstanding or misinterpretation of quantum mechanics.
The concept of the "quantum eraser" refers to a thought experiment or experimental setup that demonstrates certain aspects of quantum entanglement and wave-particle duality. It explores the behavior of quantum systems and the role of measurement and observation.
In the quantum eraser experiment, entangled particle pairs are created and separated, such that measurements performed on one particle can affect the behavior or measurement outcomes of its entangled partner, even if they are spacelike separated (outside each other's light cones). This phenomenon is known as quantum entanglement, where the measurement of one particle instantaneously affects the state of the other, regardless of the spatial separation.
However, it's important to note that this entanglement and its effects do not imply that the world outside our past light cone is non-existent or inaccessible. The influence of entanglement does not involve any transfer of information or signals faster than the speed of light, violating causality or contradicting the principles of relativity.
The nature of quantum entanglement and its implications for causality and the existence of events outside our past light cone is an active area of research and debate in physics. Various interpretations of quantum mechanics offer different perspectives on how to understand and reconcile these phenomena with our understanding of the physical world. However, none of these interpretations suggest that events or entities beyond our past light cone do not exist or lack physical reality.