Accelerated quantum control in a three-level system by jumping along the geodesics
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-04-24 |
| Journal | Physical review. A/Physical review, A |
| Authors | Musang Gong, Min Yu, Ralf Betzholz, Yaoming Chu, Pengcheng Yang |
| Institutions | East China Normal University, South China Normal University |
| Citations | 11 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This research demonstrates a novel “jump protocol” for accelerated, high-fidelity quantum state transfer in a three-level system, significantly outperforming traditional adiabatic methods.
- Core Value Proposition: Achieved near-perfect (> 95%) population transfer fidelity in a solid-state spin system (NV center in diamond) using evolution times up to an order of magnitude shorter than Stimulated Raman Adiabatic Passage (STIRAP).
- Speed Improvement: The jump protocol realized full population transfer in as little as 125 ns (for N=1 pulse), whereas STIRAP required times well above 900 ns for comparable fidelity.
- Methodology: The protocol utilizes discrete jumps along the evolution path (geodesics) of control parameters, circumventing the slow driving requirement of the conventional quantum adiabatic theorem.
- Robustness: The jump scheme exhibited superior robustness against environmental magnetic noise (frequency detuning) compared to STIRAP at the same total evolution time (500 ns).
- Platform: The experiment was conducted using the ground state triplet (ms = 0, ±1) of a single negatively charged Nitrogen-Vacancy (NV) center in diamond, leveraging its long coherence time at room temperature.
- Engineering Impact: Provides a powerful, fast, and robust tool for coherent spin manipulation, critical for advancing quantum sensing and quantum computation applications.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Quantum System | NV Center Ground State Triplet | N/A | Three-level system (ms = 0, ±1) |
| Target Transfer Fidelity | > 95 | % | Achieved by the jump protocol |
| Jump Protocol Evolution Time (N=1) | 125 | ns | Time required for full population transfer |
| Jump Protocol Evolution Time (N=4) | 500 | ns | Total duration for four control pulses |
| STIRAP Transfer Efficiency (500 ns) | ~60 | % | Comparison efficiency at the jump protocol’s 500 ns duration |
| Rabi Frequency (Ω/2π) | 4 | MHz | Base frequency used for control steps |
| Single Control Step Duration (τ) | 0.125 | µs | Calculated duration for each discrete jump step (π/Ω) |
| STIRAP Max Pulse Amplitude (ΩS/2π, ΩP/2π) | 8 | MHz | Maximum amplitude used for Gaussian Raman pulses |
| Initialization/Readout Laser Wavelength | 532 | nm | Green laser used for optical control |
| Gyromagnetic Ratio (γ/2π) | 2.8 | MHz/G | Used for calculating Zeeman splitting (δ) |
| Detuning Robustness Range | ± 2 | MHz | Range tested for robustness comparison against magnetic noise |
Key Methodologies
Section titled “Key Methodologies”The experiment utilized a single NV center in diamond to implement the jump protocol, comparing its performance against STIRAP.
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System Preparation:
- The three-level system was defined by the NV center ground state triplet (ms = 0, ±1).
- An external magnetic field was applied to lift the degeneracy of the ms = ±1 states (Zeeman effect).
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State Initialization:
- The electron spin was initialized to the |0> state using a 532 nm green laser controlled by an Acousto-Optical Modulator (AOM).
- A subsequent π-pulse was applied on the |0> ↔ |-1> transition to prepare the initial state for transfer.
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Quantum Control Implementation:
- Two microwave driving fields (Ω-, Ω+) were generated using an Arbitrary Waveform Generator (AWG) to control the |0> ↔ |±1> transitions.
- The Rabi frequency Ω/2π was fixed at 4 MHz.
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Jump Protocol Execution:
- The protocol involved applying N successive control pulses (Jj), where N = 1, 2, 3, or 4.
- Each pulse had a fixed duration τ = 0.125 µs, corresponding to a piecewise constant value of the control parameter θ.
- The total evolution time T was T = Nτ.
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STIRAP Comparison:
- STIRAP used two partially overlapping Gaussian Raman pulses (Stokes ΩS(t) and Pump ΩP(t)) with a maximum amplitude of 8 MHz.
- The STIRAP protocol was tested at total evolution times T = 500 ns, 1200 ns, and 1800 ns.
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Readout and Analysis:
- Population transfer efficiency was measured by tracking the population of the target state |+1>.
- Fluorescence measurement was used to read out the population of |0> (Part I) and |-1> (Part II, requiring an additional π-pulse).
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Robustness Testing:
- The transfer efficiency of both protocols was measured while artificially adding a static frequency detuning (±Δ) to simulate magnetic noise.
- Both protocols were compared at the same total evolution time of T = 500 ns.
Commercial Applications
Section titled “Commercial Applications”The demonstrated accelerated quantum control protocol is highly relevant for technologies requiring fast, high-fidelity manipulation of solid-state quantum systems.
- Quantum Computing:
- Enables the realization of fast, robust quantum gates, particularly for three-level systems (qudits).
- Crucial for minimizing errors caused by limited coherence times in solid-state quantum processors.
- Quantum Sensing and Metrology:
- Improves the speed and fidelity of spin manipulation sequences used in NV-center based sensors for magnetic fields, electric fields, strain, and temperature.
- The enhanced robustness against magnetic noise makes the protocol ideal for deployment in realistic, noisy environments.
- Quantum Information Processing:
- Applicable to various tasks such as quantum-state engineering and quantum simulation utilizing adiabatic passage techniques.
- Hybrid Quantum Systems:
- The method is a promising candidate for controlling interactions in hybrid sensors and quantum systems where NV centers are coupled to other components (e.g., nuclear spins or superconducting circuits).
View Original Abstract
In a solid-state spin system, we experimentally demonstrate a protocol for quantum-state population transfer with an improved efficiency compared to traditional stimulated Raman adiabatic passage (STIRAP). Using the ground-state triplet of the nitrogen-vacancy center in diamond, we show that the required evolution time for high-fidelity state transfer can be reduced by almost one order of magnitude. Furthermore, we establish an improved robustness against frequency detuning caused by magnetic noise as compared to STIRAP. These results provide a powerful tool for coherent spin manipulation in the context of quantum sensing and quantum computation.