In super-conducting quantum compute systems, low level (μT) magnetic fields can contribute to decoherence, fields that are not always successfully managed by shielding.  Ideally it would help to directly measure the μT magnetic fields real time during system operation to better inform follow-on failure analysis post-decoherence. Existing magnetic sensing technologies, while accurate and reliable at 1K regimes, do not reliability extend down to the milli-Kelvin domain.  Paragraf has introduced magnetic sensing components based on a new material system with graphene which enables high sensitivity magnetic field sensing down to milli-Kelvin temperatures. In addition, Paragraf is implementing these graphene-based sensors as 3-axis probes combined with a complete sensing system that would bring additional debugging capability to dilution refrigerator systems.  In this presentation, Paragraf will discuss the problem statement in more detail, provide some background on their graphene technology and describe the system level solution for real time measurement of low level (μT) magnetic fields at 10-15mK.

Tom Wilson, Chief Commercial Officer, Paragraf