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Conditional π-Phase Shift of Single-Photon-Level Pulses at Room Temperature
Steven Sagona-Stophel1, Reihaneh Shahrokhshahi1, Bertus Jordaan1
1Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.
Physical Review Letters
|January 7, 2021
Summary
Researchers achieved room-temperature photon-photon interactions using Rb87 vapor, enabling large phase shifts on single-photon pulses. This breakthrough advances quantum information science and quantum computing applications.
Area of Science:
- Quantum Information Science
- Quantum Optics
- Atomic Physics
Background:
- Photon-photon interactions are crucial for quantum information science but technically challenging.
- Previous implementations required cryogenic temperatures, limiting practical applications.
Purpose of the Study:
- To demonstrate room-temperature photon-photon interactions with large phase shifts.
- To develop a robust interface for quantum information processing.
Main Methods:
- Utilized Rubidium-87 (Rb87) vapor in a double-Λ atomic configuration.
- Employed a single-photon probe pulse triggered by a few-photon signal field.
- Applied homodyne tomography and maximum-likelihood estimation for quantum state reconstruction.
Main Results:
- Achieved large phase shifts (≈π) on a single-photon probe pulse at room temperature.
- Observed input-output fidelities exceeding 90% for phase-shifted output states.
- Demonstrated high overlap (>90%) with ideal coherent states.
Conclusions:
- This work presents the first room-temperature, noise-free photon-photon interface.
- It is a significant milestone for quantum logic gates and non-demolition photon detection.
- Enables advancements in quantum computing and communication technologies.
