Repeated quantum error correction on a continuously encoded qubit by real-time feedback

Reliable quantum information processing in the face of errors is a major fundamental and technological challenge. Quantum error correction protects quantum states by encoding a logical quantum bit (qubit) in multiple physical qubits. To be compatible with universal fault-tolerant computations, it is essential that states remain encoded at all...

Robust quantum-network memory using decoherence-protected subspaces of nuclear spins

The realization of a network of quantum registers is an outstanding challenge in quantum science and technology. We experimentally investigate a network node that consists of a single nitrogen-vacancy center electronic spin hyperfine coupled to nearby nuclear spins. We demonstrate individual control and readout of five nuclear spin qubits...

Loophole-free Bell test using electron spins in diamond: Second experiment and additional analysis

The recently reported violation of a Bell inequality using entangled electronic spins in diamonds (Hensen et al., Nature 526, 682–686) provided the first loophole-free evidence against local-realist theories of nature. Here we report on data from a second Bell experiment using the same experimental<br/>setup with minor modifications. We find a...

Manipulating a spin qubit by the backaction of sequential partial adaptive measurements

We report the control-free manipulation of a nuclear spin qubit in diamond, using only the backaction of sequential partial measurements with real-time feedback.

Quantum state steering by real-time adaptive measurements on a single nuclear spin

We present our most recent results on partial measurements of a nuclear spin in which the inevitable measurement back-action is controllably reduced. The post-selected measurement results can give rise to weak values. By using a real-time adaptive scheme the quantum state can be tuned using only measurements.