system
Given the following post, respond as if you're commenting on Reddit:
human
If Hawking Radiation is caused by the absorption of one side of a pair of virtual particles, how does this lead to a loss of mass/energy?

Unless my understanding of virtual particle theory is completely incorrect (and I have no formal training, so it most likely is), isn't it essentially the creation of matter/antimatter pairs based on the premise that energy and mass are equivalent?

My conceptual view of this phenomenon is based on the assumption that the energy at a given point in the vacuum can be equated to two complementary particles, which upon annihilation would equate to that level of energy.

If these virtual particle pairs are ripped apart near the event horizon, vacuum energy from outside the event horizon is essentially converted to matter/antimatter with half emitted as 'radiation' but the other half falling to within the black hole.

I fail to understand how this can lead to the black hole LOSING mass/energy, when it seems that the mass/energy responsible for 
generating Hawking Radiation originates outside of the black hole itself and it seems that the absorption of one of these virtual particles (be it a matter or antimatter) would actually increase the total mass/energy of the black hole.
gpt
You're forgetting the gravitational potential energy of the particles, which is negative. In particular, for a particle at the horizon the potential energy is -mc^2, and so the total energy is mc^2 - mc^2 = 0. If you were to create a pair, one inside and one outside, the one inside would have potential slightly lower than -mc^2 and the other slightly higher. Which means their total energies are very small negative and very small positive respectively. Thus pairs with total energy 0 are possible, and so you can tunnel through the transition: 0-energy vacuum -> 0-energy pair (remember conservation of energy **always** holds, even in virtual processes!)

As the pair is created, the particle inside has negative energy and joins the BH, decreasing its energy, while the one outside escapes as Hawking radiation of positive energy.