Apparently this is the year for breakthroughs in self-correcting computer hardware. After hearing about Jeongwan Haah’s new self-correcting topological quantum memory at QIP, I just learned, via BBC news, about a new type of (classical) self correcting circuit: one which heals itself when one of the wires cracks! The full paper can be found here, and it is mostly quite readable. The basic idea is to start with a standard classical wire made of (for example) gold. The researchers sprinkled the wire with tiny capsules filled with a metal alloy (Ga-In) which is liquid at room temperature and has high conductivity. Then they bent the circuit board until it cracked, breaking the wire, and hence the circuit. Within milliseconds, the capsules also broke, the cracks filled with the liquid metal, and conductivity was restored. Self correcting, indeed!
One thing I didn’t understand is how the liquid metal stays in the cracks. I guess that at the scale they are working at, the surface tension alone is sufficient to keep the liquid metal in place?