Monday, June 04, 2007

The Schwinger limit

Physicists are threatening to boil the quantum vacuum! The quantum vacuum is, purportedly, a seething foment of 'virtual' particles and anti-particles; each particle--anti-particle pair is created spontaneously from nothing, and mutually annihilates shortly thereafter. These particles are deemed virtual because they describe trajectories in space-time which violate the relativistic relationship between mass and energy-momentum; they are said to be 'off the mass-shell'.

However, if a force field can be created with a potential gradient greater than the Schwinger limit of 8 x 1018 volts per metre, then this will be sufficient to move the virtual particles onto the mass shell, and for the particle--anti-particle pairs to separate. In effect, these particles will begin to boil from the quantum vacuum. Some physicists are starting to think that high intensity laser technology will, within a few decades, be able to generate electromagnetic fields which exceed the Schwinger limit.

5 comments:

Andrew said...

Bullshit

Gordon McCabe said...

Tourette's can be a most unfortunate affliction.

Andrew said...

I thought I had delivered a marvellous intellectual refutation of the scientific whatsit, and brevity being the soul of wit and elegance, my riposte being all the more valuable. But sadly one can't please all the people all the time.

Eddie said...

We may break it soon. There is theory out there that one can generate many spikes using a femtosecond pulse to excite a plasma. Many harmonics of the plasma are excited in the process by exciting the bulk (not the surface of the plasma). By focusing the harmonics they would add coherently and so give a massive boost to the intensity. It is estimated that with a 5x10^22 W/cm^2 femtosecond pulse we can break the Schwinger limit and the pulse would be sub-attosecond. For more info search "Theory of Relativistic Spikes."

Gordon McCabe said...

Interesting stuff Eddie. I presume the harmonics in a plasma are plasmons, i.e., collective oscillations in the electrons.