Nano and Quantum Computation
The integrated-circuit transistor has been the workhorse of computer logic for fifty years, a time that has seen a revolution in the power and ubiquity of digital devices. This revolution has involved both a scaling down (in physical size and energy consumption of individual devices) and a scaling up (of system complexity and flexibility) in information processing machines. While scale-up, and diversification, continues, there is a view that the scale-down is finished -- the writ of Moore's law has lapsed.
In fact our research indicates that scale-down is not finished, but that it will take directions radically different from the geometrical scaling of the digital integrated circuit. A multi-disciplinary group at the RWTH and within JARA-FIT ("future of information technology") is committed to pursuing these new routes to scale-down in several related directions:
- Employing radically different geometrical structures, at the nanometer and even near-atomic scale, to process information in an even smaller amount of physical space, and with correspondingly less energy. An emerging research goal for JARA, enabled by these atom-scale devices, is the "zero power" system, in which processing is intimately coupled with energy harvesting via thermoelectric, photovoltaic, electrochemical, and micro-mechanical means.
- Exploring new physical modalities for the representation of information; rather than the electric charge, the workhorse of the last half-century, new physical variables such as electron spin and local chemical configuration come into play. RWTH and JARA researchers are particularly focused on the creation of new non-volatile nanoelectronic devices based on controlled changes of chemical configuration, looking towards scalable non-volatile memories, non-volatile latches for logic operations, the local fusion of memory and logic on chips, as well as various approaches towards neuromorphic computing.
- Using a unique resource of physical objects that emerges at small scale, that of quantum coherence, to provide a toolbox going beyond boolean logic. The big objective in this field is the scalable quantum computer. RWTH/JARA activities will build on its considerable expertise in single-electron quantum dots, pushing out into the frontiers of high-precision control of the quantum-logical state of these devices and their interconnections. New types of quantum-classical machines are moving from concept to development, providing new machines for simulation of quantum systems, attacks on previously intractable questions in computational mathematics, and enablers for long distance secure communication based on quantum cryptography.