Related Experiment Video
Updated: Apr 18, 2026
15:58
Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
6.2K
Enhanced coherence between condensates formed resonantly at different times
Optics Express
|January 22, 2015
Summary
We achieved long-lasting coherence between exciton-polariton condensates using many-body interactions. This coherence surpasses laser pulse duration and depends on particle density and interaction strength.
Area of Science:
- Quantum Optics
- Condensed Matter Physics
Background:
- Exciton-polariton condensates are Bose-Einstein condensates formed by light-matter quasiparticles.
- Achieving and maintaining coherence in these systems is crucial for quantum applications.
Purpose of the Study:
- To demonstrate and investigate long-lasting coherence between independently created exciton-polariton condensates.
- To understand the role of many-body interactions in enhancing coherence times.
Main Methods:
- Resonant optical injection to create exciton-polariton condensates at different times.
- Time-resolved measurements to probe coherence and dephasing dynamics.
- Systematic variation of particle density, interaction strength, and temperature.
Main Results:
- Coherence was demonstrated between condensates created at different times, persisting longer than individual particle dephasing times.
- Coherence time significantly exceeded the injecting laser pulse duration, increasing with particle density.
- Coherence enhancement critically depends on many-body interactions, particle density, and temperature, but not particle mass.
Conclusions:
- Many-body interactions are key to achieving robust coherence in exciton-polariton condensates.
- The findings offer new methods for studying ultrafast dynamics and coherence in quantum matter.
- This work opens new avenues for research in quantum coherence and many-body physics.
Related Concept Videos
01:12Double Resonance Techniques: Overview
872
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
872
01:04¹³C NMR: ¹H–¹³C Decoupling
2.2K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
2.2K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.8K
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...
1.8K
01:14Sound Waves: Resonance
3.8K
Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical boundary conditions (i.e., has a node at each end). A node is defined as a fixed point where the string does not move. The symmetrical boundary conditions result in some frequencies resonating and producing standing waves, while other frequencies interfere destructively. Sound waves can resonate in a hollow tube, and the frequencies of the sound...
3.8K
01:27¹H NMR: Long-Range Coupling
2.9K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
2.9K
01:19Concept of Resonance and its Characteristics
7.0K
If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano strings and many other musical instruments. Conversely, to achieve small-amplitude oscillations as in a car's suspension system, heavy damping is required. Heavy damping reduces the amplitude, but the tradeoff is that the system responds at more frequencies. Speed bumps and gravel roads prove that even a car's suspension system is not...
7.0K