High-fidelity projective read-out of a solid-state spin quantum register

By L. Robledo, L. Childress, Hannes Bernien, B. Hensen, P. Alkemade, Ronald Hanson. Nature, 2011

695 citations recorded by the source corpus.

Initialization and read-out of coupled quantum systems are essential ingredients for the implementation of quantum algorithms. Single-shot read-out of the state of a multi-quantum-bit (multi-qubit) register would allow direct investigation of quantum correlations (entanglement), and would give access to further key resources such as quantum error correction and deterministic quantum teleportation. Although spins in solids are attractive candidates for scalable quantum information processing, their single-shot detection has been achieved only for isolated qubits. Here we demonstrate the preparation and measurement of a multi-spin quantum register in a low-temperature solid-state system by implementing resonant optical excitation techniques originally developed in atomic physics. We achieve high-fidelity read-out of the electronic spin associated with a single nitrogen–vacancy centre in diamond, and use this read-out to project up to three nearby nuclear spin qubits onto a well-defined state. Conversely, we can distinguish the state of the nuclear spins in a single shot by mapping it onto, and subsequently measuring, the electronic spin. Finally, we show compatibility with qubit control: we demonstrate initialization, coherent manipulation and single-shot read-out in a single experiment on a two-qubit register, using techniques suitable for extension to larger registers. These results pave the way for a test of Bell’s inequalities on solid-state spins and the implementation of measurement-based quantum information protocols.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/a49477027bf74c436f0d4c20b6e3794f583d1c5b

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

In Materials Chemistry

Citations in the corpus

Generation of heralded entanglement between distant hole spins (2015, background): “Our results provide major motivation for investigating possibilities for coherent transfer of the hole spin to a local qubit that exhibits a longer coherence time [14] but lacks an efficient interface to propagating optical photons [28].”
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres (2015, background): “The spins are initialized through optical pumping and read out along the Z axis via spin-dependent fluorescence[25].”
Heralded entanglement between solid-state qubits separated by three metres (2012, methodology): “A 10μs green laser pulse (green line) pumps the NV centre into the desired negative charge state [9].”
Deterministic delivery of remote entanglement on a quantum network (2017, methodology): “2a) proceeds by first initialising each node in |↑〉 by optical pumping [25], followed by a coherent rotation using a microwave pulse [26] to create the state”
Hybrid-Liouvillian formalism connecting exceptional points of non-Hermitian Hamiltonians and Liouvillians via postselection of quantum trajectories (2020, background): “Moreover, such quantum jumps have been experimentally observed in many setups [29–45].”
A Ten-Qubit Solid-State Spin Register with Quantum Memory up to One Minute (2019, methodology): “To perform quantum-state tomography on the two-qubit state, we first measure the electron spin along a chosen axis by appropriate basis rotations followed by Z-basis optical readout [14].”
Quantum exceptional points of non-Hermitian Hamiltonians and Liouvillians: The effects of quantum jumps (2019, background): “[26] L.”