関連する実験動画
Updated: Dec 26, 2025
14:58
Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping
Published on: June 3, 2015
15.3K
シリコンの単一の高スピン・コアの一貫的な電気制御
Serwan Asaad1, Vincent Mourik1, Benjamin Joecker1
1Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia.
Nature
|March 13, 2020
まとめ
研究者は,シリコンの局所電場を使用して,単一のアンチモニー-123核の一貫した量子制御を実証しました. この電気制御方法は 核スピンの相関性を高め スケール可能な量子コンピューティングの道を開きます
科学分野:
- 量子情報科学
- 固体物理学
- 量子コンピューティング
背景:
- 核スピンは,様々な科学分野や初期の量子コンピューティングの提案で使用されている一貫した量子システムです.
- 個々の原子核を制御することは 量子コンピュータのスケーリングに不可欠ですが 磁場を使用する現在の方法は 局所化やスクリーニングが困難です
- 既存の電気制御方法は,電子-核の超微細相互作用に依存し,核のスピン相関性を低下させます.
研究 の 目的:
- 局所的な電場を使って 単一の核のコヒーレントな量子制御を証明する
- 核スピン操作における磁場制御と電子媒介の電気駆動の限界を克服する.
- シリコンベースの量子装置における 電気制御された核スピンの可能性を 探求する.
主な方法:
- シリコンナノ電子装置内の局所電場を利用して,単一の123Sb (スピン-7/2) 原子核を制御する.
- 核電四極相互作用の電気変調を分析するために理論的モデルを使用した.
- 核スピン移行のユニークなアドレッサビリティのためのレバレッジされた格子ストレイン.
主要な成果:
- 純粋に電気的な手段を用いて単一の123Sbの量子制御を達成した.
- クープリングされた電子スピンを要求する方法よりもかなり長い0.1秒のスピン脱相時間を実証した.
- 核電四極相互作用の電気調節は理論的分析によって定量的に支持された.
結論:
- 高スピン四極核は,局所的な電場を使用して一貫して制御することができ,磁場制御の代替案を提供します.
- この完全電気制御法では,核のスピンコヒーレンスが保たれ,相変化時間がかなり長くなります.
- シリコンの量子ドットと 電気的に制御可能な原子核を統合することで 拡張可能なハイブリッド量子コンピュータの 実現が期待されます
関連する概念動画
01:03Atomic Nuclei: Nuclear Spin State Overview
1.8K
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...
1.8K
01:08Atomic Nuclei: Nuclear Spin
4.7K
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...
4.7K
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
2.2K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
2.2K
01:23Atomic Nuclei: Nuclear Relaxation Processes
1.2K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
1.2K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.5K
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...
1.5K
01:08Spin–Spin Coupling Constant: Overview
1.4K
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...
1.4K