Bell's inequality violation with spins in silicon
Juan P Dehollain1,2, Stephanie Simmons1,2, Juha T Muhonen1,2
1Centre for Quantum Computation and Communication Technology, UNSW Australia, Sydney, New South Wales 2052, Australia.
Nature Nanotechnology
|November 17, 2015
Summary
Researchers demonstrated a violation of Bell
Area of Science:
- Quantum physics
- Quantum computing
- Solid-state physics
Background:
- Bell's theorem establishes the existence of quantum entangled states beyond classical physics.
- Experimental violation of Bell's inequality is crucial for quantum computing and requires high fidelity in quantum state manipulation and measurement.
Purpose of the Study:
- To experimentally demonstrate a violation of the Bell/Clauser-Horne-Shimony-Holt inequality.
- To benchmark the performance of quantum devices utilizing entangled states.
Main Methods:
- Utilized the electron and nuclear spins of a single phosphorus atom in a silicon nanoelectronic device.
- Performed two-qubit state tomography to assess state fidelity.
Main Results:
- Achieved a Bell/Clauser-Horne-Shimony-Holt inequality violation with Bell signals up to 2.70(9).
- Prepared entangled states with fidelity exceeding 96% to the target maximally entangled Bell states.
Conclusions:
- Demonstrated complete control over the two-qubit Hilbert space of a phosphorus atom.
- Highlighted the nuclear qubit's role in expanding the computational basis and enhancing readout fidelity for quantum information processing.
Related Concept Videos
01:08Spin–Spin Coupling Constant: Overview
1.6K
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...
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...
1.6K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.9K
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...
1.9K
01:27Biasing of Metal-Semiconductor Junctions
810
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
810
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.7K
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...
1.7K
01:17Spin–Spin Coupling: One-Bond Coupling
1.6K
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,...
1.6K
01:08Atomic Nuclei: Nuclear Spin
5.7K
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
5.7K