I'm a physics undergraduate, and while I can follow the mathematical formalism of quantum entanglement in my textbooks, I'm struggling to form a truly intuitive, physical picture of what's actually happening between entangled particles that transcends the common "spooky action" pop-science descriptions. For those with a deeper background, can you recommend resources or analogies that helped you move beyond the abstract equations to a more concrete conceptual model? I'm particularly interested in discussions about the mechanism of correlation—not necessarily a hidden variable theory, but a framework for visualizing how the state of one particle is linked to another without violating locality, and how decoherence plays into this from an experimental perspective.
Here's a concise way to build intuition: start with the Bell singlet state, where two qubits are perfectly anti-correlated along any common measurement axis. The key is that the joint state cannot be written as a product of two independent states. Measuring on one side randomizes that side, but the other side’s result is perfectly correlated (anti-correlated) when you compare results across the same axis. If you rotate the second measurement axis by an angle θ, the correlation goes as -cos θ. This is a statement about joint amplitudes, not about signals traveling between particles. Decoherence comes in when the environment becomes entangled with the pair, and you trace it out, turning a pure entangled state into a mixed state, which weakens or washes out the strong quantum correlations. For a gentle but solid start, check Bell test experiments and decoherence basics in accessible terms before diving deeper.