The performance of many ultra-low noise electronic devices such as SQUIDs, photon detectors, single-electron transistors or Q-bits is often limited by non-thermal noise of unknown origin. It is generally believed that this noise and decoherence in Q-bits is caused by the presence of low energy states in materials, often referred as two-level systems, while “fluctuators “ would be more appropriate term. These localized objects can undergo translational changes , like change of coordinates or spatial distribution (like atom “jumping” in between two close quasi-equilibrium positions or localized electrons), or orientational changes (rotators, like spins of localized electrons or nuclear spins). Fluctuators have different channels to interact with each other and to interfere with device operation.


This invention suggests to reduce the noise in Q-bits and other low-noise electronic and superconducting devises devices by synthesizing special materials where several classes of fluctuators (two-level systems) are excluded (or, their number is substantially reduced) both in the volume of materials and on the boundaries and interfaces. This invention also suggests materials with low number of disorder and internal degrees of freedom, or number of internal states in the material accessible at low temperatures. This invention suggests also how practical devises (SQUIDs, resonators, Q-bits, etc) and systems can be produced out of this materials without introducing new fluctuators in the process.


LLNL’s invention eliminates several important classes of fluctuators/two-level systems in materials to lower noise/ increase coherence time of superconducting devises, or to investigate contributions of different material-related noise/ decoherence mechanisms by separating them (switching on/ off separately). Currently, none of these methods are available.

Potential Applications

This invention can be used to improve the performance of any device or sensor that requires extremely low electromagnetic noise, such as SQUIDs, single-electron transistors, photon detectors, microwave mixers, etc. This includes Q-bits, where the invention can be used to increase coherence time, and superconducting computers, where decrease of internal noise of components can increase speed of operation and decrease heat production by the components.

Development Status

LLNL has filed a patent application covering this invention.

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