Since the pair consists of an up and down spin electron , a second electron ( hole ) of opposite spin to the incident electron ( hole ) from the normal state forms the pair in the superconductor , and .
The retroreflected hole .
Since the pair consists of an up and down spin electron , a second electron ( hole ) of opposite spin to the incident electron ( hole ) from the normal state forms the pair in the superconductor , and hence the retroreflected hole .