Black Holes, Vacuums and Negative energy electrons

[ed84c]

I was reading that a 'vacuum' is infact full of negative energy electrons, i.e. electrons that aparantly only interact with photons to create themselves and a positron; as to the dirac exclusion principle. I was curious that inside a black hole (in the area inside the schwarzchild radius) whether these 'virtual particles' exist? If they are 'virtual' (and therefore in a stable state do not exist) they would not be affected gravity, unless they are made real by a photon.

[Aeschylus]

What you are talking about is the Dirac sea, which is basically an infinite number (making them usuually unoticeable) of electrons filling all the negative energy states (thus making it impossible for a 'normal' elctron to sponaeously emit a photon and move down into one of these negative staes because of the Pauli exclusion principle). In this mdoel the creation of an elctron positron pair from a photon can simply be viewed as the absorption of a photon by one of these negative energy state electrons which then moves up into a vacant postive energy state creating a 'normal' electron and also a vacant negative enrgy state. This vacant negative energy state behaves just like a particle in it's own right - this particle is a positron.

 

Of course these days we do not think of things in terms of the Dirac sea, instaed we think of elctrons and psotirons in terms of the Dirac field.

[Severian]

There are a number of things wrong with the original post.

 

First of all, the Dirac sea doesn't exist. It is only a sort of handwavy picture used to confuse undergraduates - it isn't really there.

 

Secondly, a 'virtual' particle is one which disobeys the equation [math]E^2=p^2c^2+m^2c^4[/math]. We call this being 'off mass-shell'. And a virtual particle feels gravity just like a normal one does. In fact, all particles are at least slightly virtual, because how off-shell they are determines how long they live. A completely on-shell particle will live forever, so it cannot interact and cannot be observed (and therefore doesn't exist).

 

Incidentally, antiparticles (like the positron) also behave exactly like their partners the electrons under gravity. In real models (and even in the dirac model) the antiparticles have a positive mass.