Atomic test of higher-order interference
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-05-18 |
| Journal | Physical review. A/Physical review, A |
| Authors | Kai Sheng Lee, Zhao Zhuo, Christophe Couteau, David Wilkowski, Tomasz Paterek |
| Institutions | Centre for Quantum Technologies, National University of Singapore |
| Citations | 4 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research proposes a high-precision atomic test of higher-order quantum interference, directly challenging the assumptions of canonical quantum mechanics (Bornâs rule).
- Core Objective: To test the validity of Bornâs rule by measuring the Sorkin parameter (S3), which quantifies hypothetical third-order interference. Canonical quantum mechanics predicts S3 = 0.
- System Architecture: A Ramsey interferometer implemented using fermionic 87Sr atoms in a three-level (tripod) energy configuration, replacing spatial slits with energy eigenstates.
- Precision Improvement: The proposed setup is estimated to achieve a figure of merit (Îș) precision down to 10-5, representing an order of magnitude improvement over state-of-the-art experiments using photons or nuclear magnetic resonance (NMR) (previously 10-4).
- Methodology: The experiment uses generalized Raman transitions (Tritter) to prepare and close the superposition loop. The âslitsâ are blocked using three distinct methods: state transfer, controlled dephasing, or spontaneous emission.
- Scalability: Due to parallel processing of approximately 105 independent atoms per run, the system can achieve a total sample size greater than 1010 within a week, enabling the high precision estimate.
- Theoretical Constraint: The results will constrain both deviations from the Born rule and non-quantum parameters in generalized quantum mechanics models.
Technical Specifications
Section titled âTechnical SpecificationsâThe following specifications are based on the proposed implementation using 87Sr atoms in a cold atomic gas loaded into an optical lattice.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Atomic Isotope | 87Sr | N/A | Fermionic isotope used for the three-level system. |
| External Magnetic Field | 10-2 | T | Static field applied to induce Zeeman splitting. |
| Ground State Zeeman Shift (ÎŽ) | 2Ï Ă 18.2 | kHz | Energy splitting between ground states. |
| Excited State Zeeman Shift (ÎŽâ) | 2Ï Ă 8.5 | MHz | Larger shift for the 3P1 excited state. |
| Tritter Transition Wavelength | 689 | nm | Intercombination line (1S0 â 3P1) used for the Tritter. |
| Excited State Linewidth (Î) | 2Ï Ă 7.5 | kHz | Natural linewidth of the 3P1 state. |
| Rabi Frequency (Ω) | 2Ï Ă 0.1 | MHz | Chosen frequency for the Tritter operation. |
| Laser Intensity (Tritter) | 100 | mW/cm2 | Feasible intensity corresponding to the chosen Ω. |
| Detuning (Î) | 2Ï Ă 1 | MHz | Detuning used for adiabatic elimination of the excited state. |
| Tritter Operation Time (Ï) | 44 | ”s | Time required for the Tritter to create an even superposition. |
| Excited State Lifetime (1/Î) | 21 | ”s | Used in the spontaneous emission blocking method. |
| Estimated Precision (Îș) | 10-5 | N/A | Projected figure of merit for the Sorkin parameter test. |
| Atoms Processed per Run | ~105 | N/A | Independent atoms measured simultaneously. |
| Total Sample Size (1 week) | > 1010 | N/A | Projected total number of measurements. |
Key Methodologies
Section titled âKey MethodologiesâThe experiment is structured as a three-path Ramsey interferometer, replacing spatial paths with energy eigenstates.
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Initial State Preparation (Tritter UT):
- Atoms are initially prepared in a pure ground state (e.g., |1>).
- A generalized Raman transition (Tritter UT) is applied using three driving lasers in the tripod configuration (Fig. 2).
- The Tritter operation time (Ï = 44 ”s) is chosen to create an even coherent superposition over the three ground states.
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Slit Blocking Analogues (Blockers):
- State Transfer: The population of the blocked state is transferred to a long-lived state outside the three-level subspace (e.g., metastable 3P0 states).
- Controlled Dephasing: Lasers are used to selectively couple the blocked state to an excited level, removing coherences (off-diagonal elements of the density matrix) without changing the population. This method mathematically ensures S3 = 0.
- Spontaneous Emission (Primary Method): Resonant lasers couple the blocked ground state to a corresponding excited state (e.g., |2> to |e2>). The excited state then spontaneously and incoherently decays back to the ground states, effectively removing the coherence associated with the blocked path.
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Free Evolution (T):
- After blocking, the remaining atoms evolve freely for time T. The interference fringes depend on the product of the Zeeman shift (ÎŽ) and the evolution time (T).
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Final Measurement (Tritter UT-1 and Detection):
- A second Tritter (UT-1) closes the interferometer loop.
- The final probability (Pc) of the atom being in the initial ground state (|1>) is measured via shot-noise-limited fluorescence detection.
- The experiment is repeated for all seven combinations of open/blocked states to calculate the Sorkin parameter S3 and the figure of merit Îș.
Commercial Applications
Section titled âCommercial ApplicationsâThis research is fundamental quantum physics, but the techniques developed for high-precision control and measurement of atomic coherence are critical for advanced quantum technologies.
-
Quantum Computing and Simulation:
- The precise control over multi-level energy superpositions (Tritter operation) is directly applicable to building high-fidelity quantum gates and complex quantum simulators using neutral atoms.
- The development of robust, non-destructive âblockingâ mechanisms (state filtering/dephasing) is essential for error correction and state preparation in quantum processors.
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Quantum Metrology and Sensing:
- The use of Ramsey interferometry with high-coherence atomic states (87Sr) provides a platform for ultra-sensitive measurements.
- This technology informs the design of next-generation atomic clocks and inertial sensors (gyroscopes, accelerometers) that rely on precise control of atomic wave packets.
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Fundamental Physics Validation:
- The ability to constrain deviations from Bornâs rule at the 10-5 level provides crucial experimental data for developing and validating generalized theories of quantum mechanics.
View Original Abstract
The canonical quantum formalism predicts that the interference pattern registered in multislit experiments should be a simple combination of patterns observed in two-slit experiments. This has been linked to the validity of Bornâs rule and verified in precise experiments with photons, nuclear spins, nitrogen-vacancy centers in diamond, and large molecules. Due to the expected universal validity of Bornâs rule, it is instructive to conduct similar tests with yet other physical systems. Here we discuss analogs of triple-slit experiment using atoms allowing tripod energy level configuration, as realizable, e.g., with alkaline-earth-metal-like atoms. We cover all the stages of the setup including various ways of implementing analogs of slit blockers. The precision of the final setup is estimated and offers improvement over the previous experiments.