Related Experiment Video
Updated: Sep 13, 2025
10:00
Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
12.9K
Optical Protection of Alkali-Metal Atoms from Spin Relaxation
Avraham Berrebi1, Mark Dikopoltsev1,2, Ori Katz1
1The Hebrew University of Jerusalem, Institute of Applied Physics, Jerusalem 9190401, Israel.
Physical Review Letters
|July 31, 2025
Summary
This study introduces an optical technique to reduce relaxation in alkali-metal spins. The method synchronizes Larmor precession, significantly lowering decoherence and improving spin coherence for various applications.
Area of Science:
- Atomic Physics
- Quantum Optics
- Condensed Matter Physics
Background:
- Alkali-metal spins are crucial for quantum technologies but susceptible to relaxation.
- Spin-exchange and hyperfine-changing collisions cause magnetic decoherence.
- Existing methods struggle to mitigate all dominant relaxation channels simultaneously.
Purpose of the Study:
- To present a novel optical technique for suppressing relaxation in alkali-metal spins.
- To protect magnetic coherence from spin-exchange and hyperfine-changing collisions.
- To enhance the spin precession quality factor and maintain a stable gyromagnetic ratio.
Main Methods:
- Utilizing a single off-resonant laser beam to suppress spin relaxation.
- Harnessing a synchronization mechanism for Larmor precession in hyperfine manifolds.
- Experimentally demonstrating the technique on warm cesium vapor.
Main Results:
- Achieved up to a ninefold reduction in decoherence for cesium vapor.
- Provided simultaneous protection against spin-exchange relaxation and cell wall depolarization.
- Substantially enhanced the spin precession quality factor.
- Maintained a stable gyromagnetic ratio independent of spin polarization under frequent collisions.
Conclusions:
- The presented optical technique effectively mitigates dominant relaxation channels in alkali-metal spins.
- This method offers a pathway for improving alkali-metal-based quantum applications and experiments.
- Applicable particularly in anti-relaxation-coated cells for enhanced performance.
Related Concept Videos
01:23Atomic Nuclei: Nuclear Relaxation Processes
724
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.
724
03:06Alkali Metals
20.0K
Group 1 elements are soft and shiny metallic solids. They are malleable, ductile, and good conductors of heat and electricity. The melting points of the alkali metals are unusually low for metals and decrease going down the group, while the density increases going down the group with the exception of potassium (Table 1).
Table 1: Properties of the alkali metals
Table 1: Properties of the alkali metals
20.0K
01:28Atomic Nuclei: Types of Nuclear Relaxation
389
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
389
01:27π Electron Effects on Chemical Shift: Overview
1.1K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.1K
01:03Atomic Nuclei: Nuclear Spin State Overview
1.1K
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...
1.1K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
1.8K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.8K