The original version of This story appeared in Quanta Magazine.
Vacuum decay, a process that could end the universe as we know it, could occur 10,000 times sooner than expected. Fortunately, it won’t happen for a very long time yet.
When physicists talk about “The voidThe term sounds like it refers to empty space, and in a sense it does. More specifically, it refers to a set of default values, like the settings on a control board. When the quantum fields that permeate space are at these default values, space is considered to be empty. Small adjustments to the settings create particles: increase the electromagnetic field a little, and you get a photon. Large adjustments, on the other hand, are best thought of as new default values altogether. They create a different definition of empty space, with different characteristics.
A quantum field is special because its default value can change. It is called the Higgs field, and it controls the mass of many fundamental particles, such as electrons and quarks. Unlike all other quantum fields that physicists have discovered, the Higgs field has a default value greater than zero. If the value of the Higgs field is increased or decreased, the mass of electrons and other particles would increase or decrease. If the value of the Higgs field were zero, those particles would have no mass.
We could remain at the non-zero default value for all eternity, if it weren’t for quantum mechanics. A quantum field can…tunnel”, jumping to a new lower energy value even if it does not have enough energy to pass through the higher energy intermediate values, an effect similar to passing through a solid wall.
For this to happen, you need to have a lower energy state to tunnel to. And before building the Large Hadron Collider, physicists thought that the current state of the Higgs field might be the lowest. That belief has now changed.
It has always been known that the curve representing the energy needed for different configurations of the Higgs field looks like a hat with the brim pointing upwards. The current configuration of the Higgs field can be represented as a ball resting on the underside of the brim.
Illustration: Credit: Mark Belan for Quanta Magazine