Related Experiment Video
Updated: Jun 24, 2025
15:58
Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
5.8K
Anomalous Long-Distance Coherence in Critically Driven Cavity Magnonics
Ying Yang1, Jiguang Yao1, Yang Xiao2
1Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada.
Physical Review Letters
|June 3, 2024
Summary
Researchers achieved long-distance magnon-photon coherence in cavity magnonics, establishing strong coupling over 2 meters. This breakthrough utilizes critical coupling phenomena for future quantum networks.
Area of Science:
- Quantum physics
- Quantum information science
- Cavity magnonics
Background:
- Quantum networks require remote strong coupling for coherent connections.
- Cavity magnonics offers a platform for studying quantum phenomena.
Purpose of the Study:
- To demonstrate long-distance coherence in cavity magnonics.
- To explore the role of critical coupling in establishing remote strong coupling.
Main Methods:
- Operating cavity magnonics in the linear regime.
- Locally setting the cavity near critical coupling with traveling photons.
- Establishing nonlocal magnon-photon coherence via strong coupling over a 2-m distance.
Main Results:
- Demonstrated long-distance magnon-photon coherence over 2 meters.
- Observed anomalous oscillations in coupling strength.
- Observed clear mode splitting within the cavity linewidth.
- Identified phenomena not explained by conventional coupled-mode theory.
Conclusions:
- Critical coupling phenomena are crucial for harnessing long-distance coherence.
- This work advances the development of quantum networks.
- Potential for using critical phenomena in distributed quantum systems.
Related Concept Videos
01:28Standing Waves in a Cavity
905
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
905
01:23Atomic Nuclei: Nuclear Relaxation Processes
647
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.
647
01:17Magnetic Damping
450
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
450
01:14Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
849
An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local diamagnetic current arising from circulating sigma-bonding electrons induces a magnetic field, Blocal that opposes the applied magnetic field, B0. The effective magnetic field experienced by these nuclei is given by the difference between the applied and local magnetic fields in a phenomenon called local diamagnetic shielding. Essentially,...
849
01:11Atomic Nuclei: Larmor Precession Frequency
1.3K
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession,...
1.3K
01:05Atomic Nuclei: Magnetic Resonance
646
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
646