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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Symmetry-protected collisions between strongly interacting photons
Jeff D Thompson1,2, Travis L Nicholson3, Qi-Yu Liang3
1Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature
|January 25, 2017
Summary
Researchers achieved controlled photon-photon interactions in an ultracold atomic gas, demonstrating a robust phase shift essential for quantum technologies. This breakthrough enables advancements in single-photon switches and quantum logic gates.
Area of Science:
- Quantum Physics
- Atomic Physics
- Optics
Background:
- Realizing robust quantum phenomena in strongly interacting systems is a key challenge in modern physical science.
- Exploring various platforms like condensed-matter systems, trapped atoms, and photons for quantum applications.
- Photon-photon interactions are typically negligible but have been engineered in specific systems.
Purpose of the Study:
- To demonstrate a controlled and coherent exchange collision between two photons.
- To achieve a significant phase shift accompanying the photon-photon interaction.
- To explore the robustness and underlying mechanisms of these engineered interactions.
Main Methods:
- Utilizing coherent coupling between light and Rydberg excitations in an ultracold atomic gas.
- Engineering strong interactions between individual photons.
- Measuring the phase shift resulting from photon-photon collisions.
Main Results:
- Demonstrated a controlled and coherent exchange collision between two photons.
- Observed a robust π/2 phase shift (measured as 0.48(3)π) independent of precise experimental parameters.
- Achieved this effect with minimal photon absorption, indicating high fidelity.
Conclusions:
- The engineered photon-photon interaction provides a robust mechanism for quantum control.
- This work opens avenues for developing single-photon switches and all-optical quantum logic gates.
- Enables the exploration of novel quantum many-body phenomena involving strongly interacting photons.
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