Quantum computer based on NV centres in diamond with sulphur doping
We are building a quantum computer based on nitrogen-vacancy (NV) centres in diamond created by ion implementation and developing a scaling technology for far more than 50 qubits.
We are developing NV technology for the construction of a scalable and error-correctable quantum computer. For this purpose, we use qubits of electron and nuclear spins on nitrogen-vacancy (NV) complexes in diamond, which are produced in a precise manner by means of ion implantation. Using a principle we designed, a large artificial molecule is created in the diamond lattice that executes arbitrary quantum algorithms through laser excitation and microwave and radio frequency pulses.
For quantum computing hardware to be able to execute truly useful algorithms, two things are needed: a hardware concept that is scalable to a large number of qubits – at least thousands, but ultimately millions – and a suitable, cost-effective technology for manufacturing this hardware. We believe that we fulfil both conditions. By combining semiconductor planar technology from ion implantation with lithography and metallisation, we fabricate two-dimensional arrays of NV centres, each coupling to multiple nuclear spins. Our approach allows for a low overhead for the control electronics – we only need 20 connections for 1000 qubits, for example. This makes our technology highly scalable, fast, energy-efficient and, importantly, miniaturisable to CMOS/chip level. We believe this brings us closer to our ultimate goal – bringing quantum computing to mobile phones.
Our current activities were sparked by a technological breakthrough – we achieved a very high yield for the generation of NV qubits by nitrogen ion implantation in diamond crystals. This was made possible by the patented co-implantation of sulphur ions, which strongly favours both the formation of NV centres and the loading of negatively charged NV centres, which is important, as only the negatively charged centres act as qubits. For the DLR Quantum Computing Initiative (QCI), we are further developing our Gen1-quantum computer using scalable crossbar arrays for electrical control. Based on already published quantum error correction algorithms for NV centres, we are gradually implementing this important mechanism for increasing the computational accuracy of quantum algorithms in the future.