Diamond-based quantum technologies
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-03-01 |
| Journal | Photoniques |
| Authors | Toeno van der Sar, T. H. Taminiau, Ronald Hanson |
| Institutions | QuTech, Delft University of Technology |
| Citations | 2 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive Summaryâ- Platform Foundation: The technology utilizes optically accessible electron spins associated with atomic defects (primarily Nitrogen-Vacancy, NV) embedded in the diamond carbon lattice, serving as robust quantum bits (qubits).
- Performance Advantage: This platform uniquely combines exceptionally long quantum coherence times (exceeding minutes) with stable operation across a wide temperature range, from cryogenic conditions up to room temperature.
- Quantum Sensing: NV centers function as atom-sized magnetic field sensors, enabling high-resolution magnetometry and imaging of electrical currents and spin waves with spatial resolution down to ~50 nm.
- Quantum Computation: Modular quantum processors have been demonstrated with up to 10 fully-connected qubits, capable of performing quantum algorithms and molecular simulations, incorporating basic quantum error correction.
- Scalability Mechanism: Scaling is achieved through a hybrid architecture: short-range coupling (10-50 nm) via magnetic dipole interaction, and long-range entanglement links established via optical photons (demonstrated over >1 km).
- Strategic Importance: Diamond-based quantum systems are central to the four pillars of the EU Quantum Technologies Flagship: communication, computation, simulation, and sensing/metrology.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Operating Temperature Range | Cryogenic to Room | Temperature | Suitable for diverse applications, including biological in-situ sensing. |
| Maximum Qubit Count (Demonstrated) | Up to 10 | Qubits | Fully-connected quantum processors [7]. |
| Quantum Coherence Time | Exceeding minutes | Time | Demonstrated in multi-qubit processors. |
| Spatial Resolution (Sensing) | ~50 | nm | Achieved using NV spin in a diamond nanotip (AFM scanning). |
| Magnetic Coupling Distance | 10-50 | nm | Typical short-range coupling distance between defect centers. |
| Entanglement Distance (Demonstrated) | >1 | km | Long-range entanglement link established via photons. |
| Sensing Frequency Range | DC to GHz | Frequency | Tuned using spin-control techniques (ESR/NMR methods). |
| Nuclear Qubit Source | ~1 | % | Natural abundance of Carbon-13 isotopes in diamond lattice. |
| Defect Types Studied | NV, SiV, SnV | N/A | Primary optically active atomic defects explored for quantum applications. |
Key Methodologies
Section titled âKey Methodologiesâ- Defect Engineering: Utilizing specific atomic defects (Nitrogen-Vacancy, Silicon-Vacancy, Tin-Vacancy) created within the diamond lattice to serve as optically active, isolated electron spin centers.
- Optical Initialization and Readout: Preparing and measuring the electron spin state of the defect center using Spin-Dependent Photoluminescence (SDPL) via laser excitation (Fig. 1a).
- Spin Control (ESR): Applying DC magnetic fields to measure the Electron Spin Resonance (ESR) frequency (Zeeman interaction) and using GHz fields to control the spin state and quantify spin relaxation (Fig. 1c, 1d).
- Modular Quantum Processor Architecture: Creating multi-qubit systems by coupling the central electron spin to nearby nuclear spins (e.g., Carbon-13) and other electron spins (other defects) in the vicinity.
- Qubit Interconnection: Implementing two primary coupling mechanisms for scalability:
- Short-range magnetic dipole interaction (10-50 nm).
- Long-range optical connection using photonic channels (photons) for linking distant defect centers (Fig. 2).
- Remote Entanglement Protocol: Generating entanglement between distant nodes by creating a quantum entangled state between an electron spin and a photonic mode, followed by single-photon detection behind a beam splitter (Fig. 4a).
- Sensing Configurations: Employing three distinct hardware setups for quantum sensing (Fig. 1e):
- High-density, shallowly implanted NV layers placed directly onto a sample (high speed/sensitivity).
- NV-containing diamond nanostructures deposited onto a sample or injected into biological systems (nanometer proximity).
- NV in a diamond nanotip scanned using an Atomic Force Microscope (AFM) (highest spatial resolution, ~50 nm).
Commercial Applications
Section titled âCommercial Applicationsâ- Quantum Sensing & Metrology:
- High-resolution magnetometry for imaging magnetic fields and electrical transport in quantum materials (e.g., graphene).
- Imaging spin waves in magnets for low-heat information transport studies.
- Detecting nuclear spins in few-cubic-nanometer volumes.
- Biomedical and Life Sciences:
- Development of magnetic endoscopes for medical imaging.
- In-situ sensing within biological samples (e.g., single cells) to provide insight into cellular metabolism and transport pathways via temperature sensitivity.
- Quantum Computation and Simulation:
- Realization of scalable quantum processors for complex algorithms and molecular quantum simulations.
- Development of quantum error correction schemes necessary for fault-tolerant computation.
- Quantum Networks and Communication:
- Establishing the physical layer for a quantum internet (pan-European goal).
- Enabling fundamentally secure communication based on quantum physics.
- Facilitating cloud computation with perfect privacy and secure leader election protocols.
- Materials Science and Nanotechnology:
- Microscopy tools capable of âlooking throughâ opaque materials (e.g., electrodes on a chip) by imaging magnetic fields.
- High-resolution imaging of magnetic and quantum materials for scientific experiments and industrial use.
View Original Abstract
Optically accessible spins associated with defects in diamond provide a versatile platform for quantum science and technology. These spins combine multiple key characteristics, including long quantum coherence times, operation up to room temperature, and the capability to create long-range entanglement links through photons. These unique properties have propelled spins in diamond to the forefront of quantum sensing, quantum computation and simulation, and quantum networks.