Our expertise in quantum computing

At Fraunhofer IAF, we conduct research in the field of cryogenic electronics and diamond for quantum computing. Our goal is to contribute advances in the performance of entangled qubits and quantum memories, and to use innovative quantum hardware to reduce error rates and increase the computing times achievable with quantum computers.

We cover the entire value chain, from the development of new material structures and process technologies through the associated characterization and packaging technologies as well as the demonstration of powerful quantum memories and processors.

Isotope controlled synthesis of wide-bandgap semiconductors

The material synthesis of semiconductors with a wide bandgap (diamond or SiC) plays a key role in device development. Using plasma-enhanced chemical vapor deposition (PECVD) for synthesis makes it possible to generate customized material properties in diamond, which are essential for the realization of color center based qubits.

For a scalable quantum computer concept, especially color centers will be embedded in isotopically controlled diamond layers in the future. The isotope-controlled growth serves to minimize or selectively adjust the nuclear spin density, e.g. of ¹³C atoms, in the crystal lattice.

Microwave sources (1 – 5 GHz)

In order to control and monitor qubits in quantum computers, signal sources are needed that generate tailor-made signal pulses for each qubit. Future quantum computers will require integrated signal sources to enable further scalability of the number of qubits.

Cryogenic electronics

Low-noise amplifiers in the frequency range of about 5 GHz are central components in the quantum computers’ readout circuit and are operated in current systems at temperatures of about 4 K (approx. -269 °C). Fraunhofer IAF’s mHEMT technology is specially optimized for the development of ultra-low noise amplifiers and operation at low temperatures. Thus, it is possible to realize amplifiers with noise properties close to physical limits.

Cryogenic Measurement Technology

Providing a read-out of the entangled state of qubits requires cryogenic temperatures. The Fraunhofer IAF cryogenic sample station enables DC measurements and measurements of scattering parameters and noise temperatures for cryogenically cooled single components and integrated circuits within a cryogenic chamber up to temperatures of 5 K (approx. -268 °C). The data collected allows the performance of electronic and optoelectronic devices to be determined and further improved.

The operation of components at temperatures close to absolute zero requires special assembly and connection technology. Fraunhofer IAF has the experience to guarantee the mechanical requirements on the one hand and to enable the dissipation of the heat generated by active components on the other. We are also working on novel approaches to allow a higher integration density of (opto-) electronic devices in future quantum computers.

1-qubit and 2-qubit gates (10 nm technology on 4" substrates)

The qubits will be generated deterministically and positioned in an array at distances of 25 nm from each other. Depending on the degree of coupling, different qubits can then be interleaved and 1-qubit and 2-qubit gate operations can be performed.

Spin- and photon-based qubit arrays

Color centers are generated in diamond layers of only a few nanometers. Individual qubit arrays are interlaced with each other using photon-based components to enable scalable qubit architectures.

We use ¹³C nuclear spins as quantum memory. These nuclear spins can be controlled and read out via an adjacent color center.

We develop light sources, waveguides and detectors for polarized light.

In order to advance the practical application of quantum computers, a joint, coordinated approach to development of hardware and software is essential. For this reason, Fraunhofer IAF is establishing a new Quantum Information research group "Quantum Information", which will deal with topics at the interface between hardware and software.

We research questions such as: Which microwave pulses are required to address qubits in order to program quantum gates? Which methods can be used to characterize and model the defects occurring on quantum computer hardware? Which quantum algorithms are particularly resistant to errors?