International Clock and Oscillator Networking - ICON

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Time is the quantity, which can be measured to the highest precision of all metrological quantities. We all benefit from this extraordinary precision in our everyday lives, as precision time enables synchronization of data packets in ultrafast broadband communication and the determination of our position by computing the flight times of radiofrequency signals in Satellite Navigation to nanosecond precision. These economically important applications rely on microwave atomic clocks, which in their commercial form are precise to 1 part in 10^14. We are currently facing a revolution in timing accuracy due to the invention of optical clocks and accessible ways of counting optical frequencies, which has already been recognised by the Nobel Price in Physics in 2005. These novel clocks already reach stabilities beyond 1 part in 10^18, more than 4 orders of magnitude beyond the state-of-the art. However, while the clock technology is progressing rapidly, there is still a lot to learn about how such a precision can be transferred to the user community in a practical and efficient way. Microwave links, such as used in current satellite time transfers, are impractically slow for such precision, while optical fibre links need expensive dedicated fibre connections and are limited to a few 100 km, making intercontinental connections impractical. In addition, at 10^-18 precision, effects such as general relativity coupling gravity to frequency are coming into play and make the transfer dependent on deformation of the continental plates in Earth tides and larger rain falls. ICON brings together world leading transportable optical clocks and world leading optical link space infrastructure to explore the limits of precision time transfer. Including work on making transportable clocks more compact and robust with world-leading atom chip concepts, we are aiming at bringing precision time to everyone - first researchers relying on precision oscillators and later in commercial applications for the benefit of wider society.