A second pass: the Hawking effect

In this section we make a more complete analysis of the information paradox.

We have noted that the existence of remnants is a problem for quantum theory. But how are remnants to be constructed? We will see that it does not seem possible to make them in classical physics. But we will find that quantum processes seem to automatically lead to the creation of remnants. The relevant process is called 'Hawking radiation', which we explain.

The crucial point about this radiation is the radiated particles are 'entangled' with what is left behind in the remnant. We explain the notion of quantum entanglement, and set up a notation to deal with it in more detail in later sections.

We then return to the four basic approaches to resolving the paradox, and see how they each aim to deal with the problem.