Bubbles that Change the Universe: What is False Vacuum ✦
Imagine a ball sitting in a small dip on a slope: give it a nudge, and it rolls downhill. That’s how an unstable vacuum can decay, spawning bubbles of a new phase. Physicists modeled this process for a flat quantum system and proved that everything hinges on a critical bubble size. And what if our own vacuum is unstable too?
Emptiness can be different. The lowest energy state is true vacuum, and any higher one is false. False vacuum resembles supercooled water: liquid at subzero, it instantly freezes from a single ice crystal. Here it's the same: the birth of a true vacuum bubble of critical size triggers irreversible growth. Alan Guth and Stephen Hawking suggested that this is how the universe began.
Recently, scientists using a computer model found out: everything depends on the bubble's initial size. The critical scale is vanishingly small, but it is the boundary between calm and catastrophe.
It is possible that the Universe is teetering in a false vacuum due to an unstable Higgs field — decay could begin at any moment.
Such fragility helps make quantum computers more reliable and protects quantum memory. Moreover, such transitions drove the inflationary expansion of the early Universe and shed light on quantum thermal effects.
🎯 Sidney Coleman came up with the concept, inspired by supercooled water.
🎬 In Liu Cixin's trilogy 'Remembrance of Earth's Past', false vacuum decay is a weapon that wipes out civilizations: just triggering a chain reaction is enough.