Quantum Zeno and Zeno-like effects in nitrogen vacancy centers
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-12-01 |
| Journal | Scientific Reports |
| Authors | Jing Qiu, Yangyang Wang, Zhangâqi Yin, Mei Zhang, Qing Ai |
| Institutions | Tsinghua University, Beijing Normal University |
| Citations | 17 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Quantum Zeno Effects in NV Centers
Section titled âTechnical Documentation & Analysis: Quantum Zeno Effects in NV CentersâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates the Quantum Zeno Effect (QZE) and Quantum Zeno-Like Effect (QZLE) in a solid-state system, utilizing a Nitrogen Vacancy (NV) center coupled to a proximal 13C nuclear spin in diamond. This work validates the use of MPCVD diamond as a robust platform for advanced quantum information processing (QIP) and sensing applications.
- Core Achievement: Realization of QZE and QZLE in a 13C nuclear spin by controlling the electron spin of an adjacent NV center.
- Material Requirement: The experiment relies on the exceptional spin coherence properties of the NV center, necessitating ultra-high purity, low-strain Single Crystal Diamond (SCD).
- Key Performance Metric: Demonstrated long nuclear spin coherence time (T2n ~1 second) at room temperature (300 K), enabling the execution of approximately 2 x 104 measurement cycles within the total experiment time (100 ms).
- Methodology: QZE/QZLE is achieved through finite-frequency, imperfect measurements modulated by microwave pulses (Rabi frequency < 10 MHz) and subsequent electron spin initialization via 532 nm optical pumping.
- 6CCVD Value Proposition: 6CCVD provides the necessary foundationâhigh-quality, custom-engineered SCD substratesâcritical for achieving and extending these long coherence times and integrating complex microwave and optical control systems.
Technical Specifications
Section titled âTechnical SpecificationsâThe following parameters and performance metrics were extracted from the analysis of the NV center system used to demonstrate QZE/QZLE:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Material System | NV Center in Diamond | N/A | Solid-state qubit platform |
| Zero-Field Splitting (D) | 2.87 | GHz | Ground state 3A spin-triplet |
| Operating Temperature | Room Temperature | K | 300 K |
| Nuclear Spin Coherence (T2n) | ~1 | second | 13C nuclear spin |
| Electron Spin Coherence (T2e) | 58 | ”s | Electron spin dephasing time |
| Total Experiment Time (T) | 100 | ms | Restricted to T << T2n |
| Single Cycle Duration (Ï) | ~5 | ”s | Sum of free evolution (âtf) and measurement (âtm) |
| Measurement Pulse Duration (âtm) | ~2 | ”s | Microwave pulse width |
| Optical Pumping Pulse | ~140 | ns | 532 nm light for electron spin initialization |
| Maximum Rabi Frequency (Ω) | < 10 | MHz | Limited by 13C hyperfine coupling (130 MHz) |
| Applied Magnetic Field (Bz) | < 200 | G | Required for secular approximation validity |
| Hyperfine Coupling (Azz) | 130 | MHz | 13C in the first coordination shell |
Key Methodologies
Section titled âKey MethodologiesâThe demonstration of QZE and QZLE relies on a precise, repetitive cycle of free evolution, microwave-induced transition, and optical initialization.
- Material Preparation: Utilization of a negatively-charged NV center (S=1) in diamond, coupled to a nearest-neighbor 13C nuclear spin (I=1/2).
- Initial State Preparation: Electron spin is initialized into the ground state |0> via circulatory optical excitation-emission (532 nm light pulse, ~140 ns duration). The nuclear spin is prepared in an arbitrary state.
- Free Evolution (âtf): The system evolves freely under the Hamiltonian HF for a time interval âtf.
- Measurement Pulse (âtm): A microwave pulse (duration ~2 ”s) is applied, driving the transition between the electronic spin states |0,â> and |-1,â>. The driving frequency is set to be resonant with this transition while being largely detuned from the |0,â> and |-1,â> transition.
- Repolarization/Decoupling: After measurement, the electron spin is re-initialized to |0> via optical pumping. Crucially, the 13C nuclear spin is designed to be well isolated and unperturbed during this optical process.
- QZE/QZLE Observation: The conventional QZE and QZLE are observed by modulating key parameters (Rabi frequency Ω, magnetic field Bz, and cycle times âtf, âtm) to control the eigenvalues of the nuclear spin state evolution operator.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe success of QZE/QZLE experiments hinges on the quality and precise engineering of the diamond substrate. 6CCVD is uniquely positioned to supply the foundational materials and customization services required to replicate and advance this research.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the long coherence times (T2n ~1s) and high fidelity required for QIP, researchers need diamond with extremely low nitrogen and other impurity concentrations.
| Material Requirement | 6CCVD Solution | Technical Advantage |
|---|---|---|
| Ultra-High Purity Substrate | Optical Grade Single Crystal Diamond (SCD) | SCD grown via MPCVD ensures minimal defects and strain, maximizing T2e and T2n coherence times at room temperature. |
| Isotopic Control (13C) | Custom Isotope-Enriched SCD | While the paper uses naturally occurring 13C, 6CCVD can supply SCD grown using precursors enriched in 13C (to increase qubit density) or highly depleted in 13C (12C > 99.995%) to further suppress nuclear spin bath decoherence and extend T2e. |
| Boron Doping (Optional Extension) | Boron-Doped Diamond (BDD) | For applications requiring conductive diamond electrodes or integrated sensors, 6CCVD offers BDD films with controlled doping levels. |
Customization Potential
Section titled âCustomization PotentialâThe integration of microwave and optical control systems demands precise material dimensions and surface quality. 6CCVD offers full customization to meet complex experimental setups:
- Custom Dimensions: 6CCVD supplies plates and wafers up to 125 mm (PCD) and custom SCD sizes. We can provide substrates up to 10 mm thick, suitable for high-power microwave integration and robust mounting.
- Precision Polishing: The experiment relies on 532 nm optical pumping. 6CCVD guarantees Ra < 1 nm polishing for SCD surfaces, ensuring minimal scattering loss and optimal optical access for high-fidelity initialization and readout.
- Integrated Metalization: The control scheme requires precise microwave delivery. 6CCVD offers in-house metalization services (Au, Pt, Pd, Ti, W, Cu) for creating custom microwave striplines, coplanar waveguides, or contact pads directly on the diamond surface, facilitating seamless integration of the Rabi frequency control mechanism.
- Laser Cutting and Shaping: We provide custom laser cutting services to shape substrates for specific geometries required by microwave resonators or cryostat mounts.
Engineering Support
Section titled âEngineering SupportâThe successful implementation of QZE/QZLE requires careful tuning of the magnetic field (Bz < 200 G) and precise control over the hyperfine interaction (Azz).
6CCVDâs in-house PhD team specializes in the physics of NV centers and MPCVD growth parameters. We offer expert consultation on:
- Material Selection: Assisting researchers in selecting the optimal isotopic purity and nitrogen concentration (P1 centers) to balance qubit density and coherence time for similar Quantum Zeno Effect projects.
- Interface Optimization: Advising on surface termination and metalization schemes to minimize microwave loss and maximize coupling efficiency for Rabi frequency control (Ω).
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.