Quantum entanglement is a connection between particles, as if they hold hands across any distance. Einstein called it ‘spooky action at a distance.’ Usually, heat tears such pairs apart: particles start dashing chaotically, and hands unclasp — entropy, the measure of disorder, rises. But if the system has a strict symmetry law, like conservation of electric charge, particles must stay paired, like in a dance with unbreakable rules. Even at arbitrarily high temperature, their quantum link doesn’t snap.

This explains why after the Big Bang, when the universe was unimaginably hot, symmetries helped the seeds of future structures survive. Most surprising: no energy is needed for protection, just a mathematical rule compels particles to stick together. Moreover, even fermions — particles that normally avoid each other (Pauli principle)—form stable pairs under symmetry in the fiery chaos. In the long run, such invulnerable states will pave the way to quantum computers that don’t mind overheating.