Physicists trace particles back to the quantum vacuum

"Quantum physics paints a strange picture of the world, one filled with spooky connections, unsettling uncertainties andperhaps oddest of allparticles that spontaneously spring into being from the void. These so-called virtual particles have indirect effects that scientists have measured before. But now, for the first time, researchers have traced the evolution of these something-out-of-nothing particles directly. Physicists at the Relativistic Heavy Ion Collider (RHIC) at Long Island's Brookhaven National Laboratory found pairs of subatomic particles with an uncanny correlation in the direction of their spin."

"Particle spin is a quantum property that can point either up or down. Most groups of particles will have a random mix of up and down spins, but the researchers found that a particular kind of particle that has been produced at the collider has often come in pairs with matching spin directions. These pairs, the scientists think, must be direct descendants of sets of virtual particles that spontaneously arose out of nothing from the quantum vacuum."

The quantum vacuum contains fluctuating fields that produce virtual particle–antiparticle pairs through Heisenberg's uncertainty principle. Very short-lived quantum states can borrow uncertain energy and create particle pairs that normally annihilate almost immediately. At the Relativistic Heavy Ion Collider, experimental conditions produced particles whose spin directions showed unexpected correlations. A specific particle species appeared frequently in paired states with matching spin orientations, instead of a random up/down mix. The spin alignment suggests that these particle pairs evolved directly from virtual pairs that briefly emerged from the vacuum and then became observable under collider conditions.

Read at www.scientificamerican.com