Related Experiment Video
Updated: Jul 23, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Coherent Coupling of Remote Spin Ensembles via a Cavity Bus
T Astner1, S Nevlacsil1, N Peterschofsky1
1Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria.
Physical Review Letters
|April 22, 2017
Summary
We demonstrate coherent coupling between two distant nitrogen-vacancy electron spin ensembles using cavity quantum electrodynamics. This enables direct detection of interactions and transverse coupling via virtual photons.
Area of Science:
- Quantum physics
- Cavity quantum electrodynamics
- Spin ensembles
Background:
- Nitrogen-vacancy (NV) centers in diamond are promising solid-state qubits.
- Controlling interactions between spatially separated spin ensembles is crucial for quantum networks.
Purpose of the Study:
- To achieve and detect coherent coupling between two macroscopically separated NV electron spin ensembles.
- To investigate transverse ensemble-ensemble coupling mediated by a cavity.
Main Methods:
- Utilizing a cavity quantum electrodynamics system to mediate interactions.
- Analyzing cavity transmission spectra to observe collective multiensemble states.
- Operating in the dispersive limit to study virtual photon exchange.
Main Results:
- Directly observed coherent coupling between the two separated NV spin ensembles.
- Detected bright and dark collective multiensemble states.
- Measured an increased coupling strength to the cavity mode.
- Demonstrated transverse ensemble-ensemble coupling via virtual photons.
Conclusions:
- Coherent coupling between distant spin ensembles is achievable in a cavity QED system.
- Cavity-mediated interactions provide a pathway for controlling remote quantum systems.
- This work advances the development of quantum communication and distributed quantum computing.
Related Concept Videos
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:17Spin–Spin Coupling: One-Bond Coupling
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by: