Correlation dynamics of nitrogen vacancy centers located in crystal cavities
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-10-06 |
| Journal | Scientific Reports |
| Authors | AbdelâHaleem AbdelâAty, Heba Kadry, A.âB. A. Mohamed, Hichem Eleuch |
| Institutions | Sohag University, Prince Sattam Bin Abdulaziz University |
| Citations | 23 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive Summaryâ- Core Value Proposition: This theoretical study demonstrates the feasibility of controlling and maximizing non-classical correlations (NCCs) between two spatially separated Nitrogen-Vacancy (N-V) centers embedded in photonic crystal nanocavities.
- Methodology: The system dynamics were solved using a time-dependent SchrĂśdinger equation incorporating a non-Hermitian Hamiltonian to model the open quantum system (dissipation effects).
- Key Control Parameters: The dynamics of NCCs (quantified by Log-Negativity, Skew Information, and Bell function) are highly sensitive to the N-V center/cavity coupling strength (g) and the cavity-cavity hopping constant (J).
- Maximal Correlation Achievement: Under strong coupling conditions (g >> J) and zero decay (x = 0.0), the system achieved maximal violation of the Bell inequality, with the Bell function M(t) reaching 2â2 (approx. 2.828).
- Dissipation Effects: The decay rate (x) generally has a destructive effect on N-V center correlations, causing rapid deterioration. However, strong cavity-cavity hopping (J >> g) can overcome the decay rateâs influence on cavity correlations.
- Hierarchy Confirmation: The results confirm the established hierarchy of quantum resources, where Bell nonlocality (M > 2) implies entanglement, which in turn implies the existence of Skew-Information correlations (LQU and UIN).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Qubit Type | Nitrogen-Vacancy (N-V) Center | Defect | Used as solid-state qubits in diamond. |
| System Architecture | Two N-V Centers, Two Nanocavities | N/A | Coupled system within a planar photonic crystal (PC). |
| Reference Coupling Strength | g | Dimensionless | N-V center to cavity field coupling (set as reference unit). |
| Large Coupling Regime | J = 0.1g | Dimensionless | N-V coupling (g) is much > cavity hopping (J). |
| Competition Regime | J = g | Dimensionless | N-V coupling (g) equals cavity hopping (J). |
| Large Hopping Regime | J = 10g | Dimensionless | Cavity hopping (J) is much > N-V coupling (g). |
| Decay Rate (Simulated) | x = 0.0, 0.1g | Dimensionless | Represents spontaneous emission (kappa) and cavity decay (gamma). |
| Maximal Bell Function (M) | 2â2 (approx. 2.828) | Dimensionless | Achieved under unitary interaction (x=0.0) in the large coupling case. |
| Bell Nonlocality Threshold | > 2 | Dimensionless | Value required to detect non-classical correlation. |
| Maximal Log-Negativity (N) | ~1.0 | Dimensionless | Achieved for N-V centers in the large coupling case (x=0.0). |
| Correlation Generation Speed | Very Fast | N/A | Observed when J = g (competition case) for cavity correlations. |
Key Methodologies
Section titled âKey Methodologiesâ- Physical System Modeling: Defined the system as two N-V centers (three-level A-type structure) interacting with two single-mode nanocavities within a planar photonic crystal (PC).
- Hamiltonian Construction: Formulated the total Hamiltonian (H) in the interaction picture, comprising three components:
- HNV-C: Effective interaction between N-V centers and cavity fields (coupling strength g).
- Hh: Direct coupling (hopping) between the two nanocavities (constant J).
- Hd: Non-Hermitian Hamiltonian accounting for dissipation (decay rates gamma and kappa).
- Analytical and Numerical Solution: Solved the time-dependent SchrĂśdinger equation (d/dt ih|psi(t)> = Heff|psi(t)>) numerically to obtain the system wave function |psi(t)>.
- Initial State Preparation: Investigated two initial conditions for the N-V centers: the uncorrelated state (|Ψ(0)> = |1102g1g2>) and the maximally correlated state (|Ψ(0)> = 1/â2 [|e1g2> + |g1e2>]|0102>).
- Correlation Analysis: Extracted the reduced density matrices for the N-V centers (rhoN-V) and the nanocavities (rhoCav) by tracing out the non-target subsystems.
- Quantification Metrics: Quantified the generated bipartite non-classical correlations (NCCs) using four measures: Log-Negativity (N), Local Quantum Uncertainty (L), Uncertainty Induced Non-locality (U), and Maximum Bell Function (M).
- Regime Testing: Performed simulations across three distinct physical regimes (g >> J, g = J, J >> g) to analyze the robustness and magnitude of NCCs against the decay rate x.
Commercial Applications
Section titled âCommercial ApplicationsâThe research focuses on fundamental control mechanisms for solid-state quantum systems, directly supporting the development of next-generation quantum technologies:
- Solid-State Quantum Computing: N-V centers in diamond are prime candidates for robust, room-temperature qubits. The ability to control correlations is essential for building scalable quantum registers and performing multi-qubit operations.
- Quantum Memory and Storage: N-V Diamond (NVD) systems are highly recommended for quantum storage due to their long decoherence times and stability. This work informs the design of memory architectures where data fidelity relies on controlled correlations.
- Integrated Quantum Photonics: Utilizing planar photonic crystals and nanocavities provides a platform for miniaturized, integrated quantum circuits, enabling the scalable production of quantum devices.
- Quantum Communication Networks: The study of correlation dynamics between spatially separated centers is critical for implementing quantum repeaters and high-fidelity quantum state transfer (QST) over optical networks.
- Single Photon Sources: N-V centers are used for implementing photostable single-photon laser sources, a key component for secure quantum cryptography and communication protocols.