Synopsis

One Photon Good, Two Better

Physics 5, s13
Quantum interference of pairs of photons emitted by nitrogen-vacancy centers in diamond paves the way for entanglement of distant qubits.
H. Bernien et al., Phys. Rev. Lett. (2012)

Although several powerful quantum algorithms have been put forth for quantum computing, implementing them in a physical device requires suitable qubits, protection from decoherence, and ways to read inputs and write outputs. Nitrogen-vacancy centers (NV) in diamond, which are nitrogen atoms coupled to a lattice vacancy, have pushed to the front of the queue of candidate qubits owing to their easily controllable spin states and stable optical properties. The trick now is to find a way to entangle and manipulate pairs of distant qubits for quantum computations. Hannes Bernien of Delft University of Technology, Netherlands, and colleagues now report in Physical Review Letters their progress on this front in the form of two-photon quantum interference of spatially separated diamond NV centers.

Such NV centers have been experimentally well characterized and researchers have entangled NV spins with photons, but the new work by Bernien et al. takes the next step. If two indistinguishable photons, each entangled with a distant NV center, can exhibit quantum interference then this can be exploited to obtain entanglement of the NV centers themselves. The authors have demonstrated exactly this kind of two-photon quantum interference by carefully isolating the optical transitions of separate NV centers and tuning them into resonance with applied electric fields. Moreover, the authors carried out simulations of the experiment with no free parameters that agree well with the interference data. Their work now sets the stage for controllable entanglement of pairs of NV centers in a bulk material and the possibility of building quantum networks of qubits for information processing. – David Voss


Subject Areas

Quantum InformationOpticsQuantum PhysicsMaterials Science

Related Articles

A Simple Electronic Circuit Manifests a Complex Physical Effect
Atomic and Molecular Physics

A Simple Electronic Circuit Manifests a Complex Physical Effect

Using a single set of measurements of an electronic circuit, researchers have characterized the properties of the topologically protected edge states of a quantum Hall system. Read More »

Classifying the Surface Magnetization of Antiferromagnets
Condensed Matter Physics

Classifying the Surface Magnetization of Antiferromagnets

Group theory and first-principles calculations combine to predict which antiferromagnets have potentially useful net surface magnetization. Read More »

A Better Way to Charge a Quantum Battery
Energy Research

A Better Way to Charge a Quantum Battery

Coupling the charger and battery to a common reservoir induces a direct flow of energy into the battery. Read More »

More Articles