Related Experiment Video
Updated: Jan 20, 2026
01:17
Spin–Spin Coupling: One-Bond Coupling
1.4K
Spin Heat Engine Coupled to a Harmonic-Oscillator Flywheel.
D von Lindenfels1, O Gräb1, C T Schmiegelow1
1QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany.
Physical Review Letters
|September 7, 2019
Summary
Researchers built a microscopic heat engine using a single-electron spin in a trapped ion. Intrinsic quantum fluctuations fundamentally limit the performance of this novel quantum heat engine.
Area of Science:
- Quantum thermodynamics
- Single-ion physics
- Microscopic heat engines
Background:
- Quantum systems offer new possibilities for exploring fundamental thermodynamic principles.
- Single-electron spins provide a controllable quantum system for thermodynamic studies.
Purpose of the Study:
- To realize and characterize a heat engine operating on a single-electron spin.
- To investigate the role of quantum fluctuations in the performance of microscopic heat engines.
Main Methods:
- Utilized a trapped ^{40}Ca^{+} ion with its valence electron spin as the working medium.
- Emulated heat reservoirs via optical pumping to control spin polarization.
- Coupled the spin to the ion's harmonic oscillator (flywheel) using spin-dependent optical forces.
- Characterized the flywheel state by reconstructing the Husimi Q function.
Main Results:
- Successfully operated a heat engine using a single-electron spin.
- Quantified deposited energy and fluctuations in the flywheel during engine operation.
- Determined the ergotropy of the flywheel, revealing extractable work.
- Demonstrated that intrinsic fluctuations fundamentally limit the engine's performance.
Conclusions:
- A single-electron spin can function as the working medium in a heat engine.
- Quantum fluctuations are a critical factor limiting the efficiency and performance of microscopic heat engines.
- This work provides insights into the thermodynamics of quantum systems and the operation of quantum heat engines.
Related Concept Videos
01:17Spin–Spin Coupling: One-Bond Coupling
1.4K
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,...
1.4K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.6K
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...
1.6K
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.5K
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...
1.5K
01:08NMR Spectroscopy: Spin–Spin Coupling
3.0K
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...
3.0K
08:44Evaluating the Heat Transfer of a Spin-and-Chill
8.0K
Source: Michael G. Benton and Kerry M. Dooley, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
The Spin-and-Chill uses heat transfer and fluid flow fundamentals to chill beverages from room temperature to 38 °F in as little as 2 min. It would take a refrigerator approximately 240 min and an ice chest approximately 40 min to achieve an equivalent temperature change. This is accomplished Spin and Chill by spinning a can or bottle at up to 500 rpm, which...
The Spin-and-Chill uses heat transfer and fluid flow fundamentals to chill beverages from room temperature to 38 °F in as little as 2 min. It would take a refrigerator approximately 240 min and an ice chest approximately 40 min to achieve an equivalent temperature change. This is accomplished Spin and Chill by spinning a can or bottle at up to 500 rpm, which...
8.0K
01:08Spin–Spin Coupling Constant: Overview
1.5K
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...
1.5K