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Quasi-light Storage for Optical Data Packets
Published on: February 6, 2014
Entanglement of light-shift compensated atomic spin waves with telecom light
Y O Dudin1, A G Radnaev, R Zhao
1School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
Physical Review Letters
|January 15, 2011
Summary
Researchers demonstrate entanglement between light polarization qubits and atomic spin-wave qubits, achieving long storage times up to 0.1 seconds. This breakthrough preserves quantum memory-light entanglement through frequency conversion and fiber transmission.
Area of Science:
- Quantum Information Science
- Atomic, Molecular, and Optical (AMO) Physics
- Quantum Communication
Background:
- Quantum entanglement is crucial for quantum information processing and communication.
- Long-term storage of quantum states, particularly entanglement, is a significant challenge.
- Atomic spin-wave qubits offer potential for quantum memory applications.
Purpose of the Study:
- To demonstrate and verify entanglement between a light polarization qubit and an atomic spin-wave qubit.
- To achieve and maintain long storage times for quantum memory.
- To confirm the preservation of entanglement through wavelength conversion and fiber transmission.
Main Methods:
- Entanglement generation via interaction between a 795 nm light polarization qubit and an atomic Rubidium (Rb) spin-wave qubit.
- Spin-wave storage in a 1064 nm optical lattice, stabilized by a magic-valued magnetic field to minimize dephasing.
- Four-wave mixing in cold Rb gas for converting light qubit wavelengths between near-infrared (795 nm) and telecom (1367 nm) bands.
Main Results:
- Violation of Bell's inequality (S=2.65±0.12) confirms entanglement for a storage time of 0.1 seconds.
- Successful wavelength conversion and reconversion of the light qubit, preserving entanglement.
- Continued Bell inequality violation (S=2.66±0.09) after 10 ms storage, demonstrating robustness through conversion stages.
Conclusions:
- Achieved long-duration quantum memory for atomic spin-wave qubits by mitigating dephasing in an optical lattice.
- Demonstrated the feasibility of preserving memory-light entanglement across wavelength conversions and fiber transmission.
- This work is a significant step towards practical quantum communication networks utilizing robust quantum memories.
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