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Published on: April 4, 2017
Mesoscopic atomic entanglement for precision measurements beyond the standard quantum limit
J Appel1, P J Windpassinger, D Oblak
1Danish National Research Foundation Center for Quantum Optics, The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark.
Summary
Researchers squeezed quantum fluctuations using entanglement in 100,000 cold cesium atoms, enhancing precision measurements. An optimal decoherence level was found to maximize entanglement via a two-color quantum nondemolition measurement.
Area of Science:
- Quantum Information Science
- Atomic Physics
- Precision Measurement
Background:
- Squeezing quantum fluctuations via entanglement is crucial for advancing quantum information science and precision measurements.
- Entanglement-based squeezing of two-level atoms can significantly enhance the precision of atomic clocks, sensors, metrology, and spectroscopy.
Purpose of the Study:
- To demonstrate metrologically relevant squeezing and entanglement in a large ensemble of cold cesium atoms.
- To investigate the role of decoherence in quantum measurement-assisted entanglement generation.
- To compare the efficacy of a two-color quantum nondemolition (QND) scheme with a single-color QND measurement for entanglement.
Main Methods:
- Utilized a two-color quantum nondemolition (QND) measurement on the atomic clock levels of approximately 10^5 cold cesium atoms.
- Employed entanglement to squeeze quantum fluctuations within the atomic ensemble.
- Analyzed the impact of measurement-induced decoherence on entanglement generation.
Main Results:
- Achieved 3.4 dB of metrologically relevant squeezing and entanglement in a large ensemble of cold cesium atoms.
- Identified an optimal level of decoherence, induced by the quantum measurement, that maximizes generated entanglement.
- Demonstrated advantages of the two-color QND scheme for entanglement generation over single-color QND measurements.
Conclusions:
- The study successfully demonstrates a practical method for generating significant quantum squeezing and entanglement in a large atomic system.
- Optimizing measurement-induced decoherence is a key factor for maximizing entanglement in such systems.
- The two-color QND approach offers enhanced capabilities for entanglement generation in quantum metrology applications.
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