Fraunhofer IPMS: New cryostat systems bring qubit research up to date

Whether in medicine, materials development or traffic planning – quantum computing is set to play a key role in future research. Qubits, the memory components for the development of complex quantum mechanical systems, are proving to be fragile and prone to errors despite their versatility. Superconducting chips or circuits stabilize the fragile qubit states, but must be cooled down to the millikelvin range.

In order to ultimately realize a complex system such as a quantum computer, all other technical components such as circuits, memory chips or components for thermal insulation must also function at these temperatures. The cryostats at the CNT make it possible to test a wide variety of structures, materials and circuits under these extremely cold conditions.

Cooler, more efficient and expandable – new systems offer the best test conditions

The cryostat “SD dilution refrigerator system” (SD cryostat for short) from the Finnish company Bluefors offers particular advantages with regard to the current inventory at Fraunhofer IPMS thanks to its versatility and the options for expansion. This makes it possible to retrofit electrical cables to suit the respective requirements and also to install additional components for signal generation or processing at warmer cooling levels. The SD cryostat is used for CMOS or memory technology development to create stable digital circuits and systems that can function under extreme conditions. These are part of the ongoing research projects “ARCTIC” and “QSolid” at Fraunhofer IPMS. In addition, systems in which the individual subcomponents are located in different temperature ranges, such as interposers, are also to be tested, which is also a goal of the “QSolid” project.
 
The “L-Type Rapid” cryostat from the Munich-based company Kiutra has a kind of elevator with which the samples are loaded into the sample chamber, which means that only the samples themselves need to be cooled rather than the entire system. The shortened cooling and warm-up time of the sample chamber results in an increased throughput of samples to be analyzed. The cryostat can also generate a strong magnetic field, such as that found in some quantum computers. It does not use the usual helium mixture for cooling and achieves the extremely low temperatures in the millikelvin range solely by using helium-4 and discharging several magnets to achieve even lower temperatures. These alternative methods reduce costs and allow test processes to be carried out more effectively and quickly. The L-Type Rapid is primarily used in the characterization of thin films and superconducting resonators for the selection of qubits.

Samples could previously be cooled down to 1.7 K at the CNT. The new systems now extend the measuring range down to 30mK. The qubit and control chips of established quantum computer concepts also work at these temperatures. The process development of the necessary components such as superconductors or cryo-electronics will accelerate immensely with the commissioning of the new low-temperature measuring devices. Research and analysis, which are inextricably linked to the development of quantum processors in order to ensure their low error rates and high performance, will be promoted by the use of the new devices. The new cryostats expand the measurement capacities that the CNT can offer its partners in funded projects or as a direct service. The goal of a sovereign quantum computer with Saxon roots is coming ever closer thanks to the funding and the ambition of the researchers.

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Further links

👉 www.ipms.fraunhofer.de 

Photo: Fraunhofer IPMS