Related Experiment Video
Updated: Apr 5, 2026
09:00
Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
10.6K
Readout Sweet Spots for Spin Qubits with Strong Spin-Orbit Interaction.
Domonkos Svastits1,2, Bence Hetényi3, Gábor Széchenyi4
1Budapest University of Technology and Economics, Department of Theoretical Physics, Institute of Physics, Műegyetem rakpart 3., H-1111 Budapest, Hungary.
Physical Review Letters
|April 3, 2026
Summary
Quantum computing readout errors are modeled for semiconductor spin qubits. A readout sweet spot is identified to improve fidelity and minimize errors in charge-sensing techniques.
Area of Science:
- Quantum Computing
- Quantum Information Science
- Semiconductor Physics
Background:
- Qubit readout schemes deviate from ideal projective measurements, limiting quantum computing performance.
- Charge-sensing-based readout is crucial for semiconductor spin qubits in double quantum dots.
Purpose of the Study:
- To model charge-sensing readout for semiconductor spin qubits.
- To identify and quantify error mechanisms affecting readout fidelity.
Main Methods:
- Modeling charge-sensing readout in double quantum dots.
- Quantifying errors from charge noise, residual tunneling, and g-tensor modulation.
Main Results:
- Charge noise, residual tunneling, and g-tensor modulation degrade readout fidelity.
- These errors induce mixed postmeasurement states and leakage from the computational subspace.
- A readout sweet spot is identified for state-of-the-art systems, optimizing readout fidelity.
Conclusions:
- The developed framework aids in creating effective readout error mitigation strategies.
- Optimizing readout performance is essential for advancing quantum protocols and error correction circuits.
![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)
Related Concept Videos
01:03Atomic Nuclei: Nuclear Spin State Overview
2.2K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
2.2K
01:08NMR Spectroscopy: Spin–Spin Coupling
3.8K
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...
3.8K
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
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.7K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
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
01:20Spin–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