Fraunhofer Institute for Mechanics of Materials IWMThe SiQuRe II research project investigated the conditions for robust quantum states in coupled spin systems consisting of NV centers and 13C atoms in order to tap into their potential as qubits for solid-state-based quantum computers. The aim was to characterize essential quantum properties and analyze the scalability of these systems.
Modeling and simulation of NV-based qubit registers
Completed research project
Project description
The SiQuRe II research project used models and computer simulation methods from theoretical quantum physics to investigate the conditions under which a coupled spin system consisting of NV centers and several 13C atoms exhibits robust quantum states that can be used as a qubit system for building solid-state quantum computers. The characterization and certification of essential quantum properties, such as entanglement content, were investigated with regard to scalability.
Furthermore, this project addressed the question of what possibilities current and future QC hardware offers for contributing to the solution of materials and quantum physics problems. To this end, simple models of theoretical solid-state physics were implemented on the IBM Quantum System One and solved using hybrid variational algorithms incorporating appropriate error correction and error mitigation techniques. Various methods for simulating designed open quantum systems were also implemented and their respective performance tested on the IBM Quantum System One, and techniques for simulating open many-body systems in collective spin baths were further developed.
In addition, the accuracy with which register states of variable entanglement content, different structure (e.g., W, GHZ, Werner states), and increasing size can be reliably produced and certified on the IBM Quantum System One was tested. The degree of entanglement of the states prepared in this way was measured directly projectively or estimated downwards as appropriate.
This joint project was carried out as part of the Baden-Württemberg Quantum Computing Competence Center.
Fraunhofer IWM subproject:
- Modeling of dissipative NVCR, calculation of the coherence time T2, which determines how long computing operations can be performed with the registers. Analysis of the dependence of the coherence time T2 on the number and arrangement of surrounding 13C and 14N atoms as well as the applied external magnetic field.
- Implementation of model systems inspired by solid-state physics on IBM Q hardware, investigation of fermionic clusters with a successive increase in system size, use of available error correction methods.
Transfer of project results to the following Fraunhofer IWM R&D services for companies:
- Description and modeling of coupled NV-13C spin registers (NVCR) from the atomistic structure via spin models with environmental influences to quantum information theory for the entanglement content.
- Determination of limit values/tolerances for the future construction of individual NVCRs and the coupling of several NVCRs “on-chip.”
- Quantification of essential quantum properties of NVCRs of different dimensions, taking into account real materials environment properties.
- Development of diagnostics/certification protocols and investigation of scaling behavior with the size of the quantum registers.
- Implementation/benchmarking of suitable effective models of theoretical materials and quantum physics on the IBM Quantum System One.
