Our research goal is to interface integrated circuits with the world outside the silicon chip, both by building better sensor read-outs and by interacting with new computing devices. AQUA's research field is the design of integrated circuits, comprising RF, analog, mixed-signal and digital circuits.Building on our expertise in integrated electronics for conventional applications, e.g., sensor read-outs, transceivers, data converters, both in industry and academia. we are now pushing the state-of-the-art of electronic interfaces for sensors and quantum devices. We will continue our quest in the future, by developing integrated electronics that will enable revolutionary applications, such as quantum computing.
Quantum computers hold the promise to ignite the next technological revolution as the classical computer did for last century’s digital revolution, by efficiently solving problems that are intractable by today’s computers, such as large number factorization and simulation of quantum systems. Solid-state quantum processors must be typically cooled at cryogenic temperatures (<<1 K). In addition, a classical electronic controller is required to initialize, control and read out the quantum bits (qubits) at the core of the quantum processor. Currently, the most advanced quantum processors are equipped with less than 100 qubits, thus making it possible to connect a limited number of cables from the cryogenic refrigerator to a room-temperature electronic controller. However, quantum algorithms for practical applications require up to thousands or millions of qubits and of related connections, thus making the wiring to a room-temperature controller unpractical.
As an alternative, we propose a scalable CMOS electronic controller operating at cryogenic temperatures as close as possible to the quantum processor, in order to simplify the interconnect and to provide a solution scalable up to thousands of qubits. Although building a cryogenic CMOS controller is feasible, there are several challenges to be addressed. First, there is not yet a standard cryogenic model that can be embedded in commercial design tools and valid in the GHz-frequency range and/or for nanometer CMOS technologies. Missing reliable models strongly restrain the use of advanced techniques and the complexity of any circuit design. Second, specific cryogenic design techniques must be developed to deal with non-idealities of CMOS devices at cryogenic temperatures. Third, the cooling power of state-of-the-art refrigerators is limited to a few Watts at 4 K and well below 1 W at sub-K temperatures. This poses a strict specification on the power consumption of the electronics, thus forcing the average power consumption of the cryogenic controller below a few milliwatt per qubit.
In addition to quantum computing, advances in cryogenic electronics will also be employed in many other low temperature applications. Examples include cryogenic sensors and/or electronic read-outs for high-energy physics experiments, detectors for radio-astronomy, cryogenic probes for nuclear magnetic resonance (NMR) used in chemical and medical spectroscopy, and instrumentation for spacecraft and orbiting observatories.
More information on the work on cryo-CMOS for quantum computing can be found here.
The presentations of our recent Quantum Electronic Workshop can be found here.