Optimal randomness certification from one entangled bit

Understand

By performing local projective measurements on a two-qubit entangled state one can certify in a device-independent way up to one bit of randomness.

• We show here that general measurements, defined by positive-operator-valued measures, can certify up to two bits of randomness, which is the optimal amount of randomness that can be certified from an entangled bit.
• General measurements thus provide an advantage over projective ones for device-independent randomness certification.