biostudies-literatureUnknown7(1)Kockum AFWe propose a new method for frequency conversion of photons which is both versatile and deterministic. We show that a system with two resonators ultrastrongly coupled to a single qubit can be used to realise both single- and multiphoton frequency-conversion processes. The conversion can be exquisitely controlled by tuning the qubit frequency to bring the desired frequency-conversion transitions on or off resonance. Considering recent experimental advances in ultrastrong coupling for circuit QED and other systems, we believe that our scheme can be implemented using available technology.Scientific reports5313https://www.ebi.ac.uk/biostudies/studies/S-EPMC5509682biostudies-literatureFrequency conversion in ultrastrong cavity QED.PMC5509682Kockum AFMacri VGarziano LNori FSavasta SfalseFrequency conversion in ultrastrong cavity QED.We propose a new method for frequency conversion of photons which is both versatile and deterministic. We show that a system with two resonators ultrastrongly coupled to a single qubit can be used to realise both single- and multiphoton frequency-conversion processes. The conversion can be exquisitely controlled by tuning the qubit frequency to bring the desired frequency-conversion transitions on or off resonance. Considering recent experimental advances in ultrastrong coupling for circuit QED and other systems, we believe that our scheme can be implemented using available technology.2017-01-01T00:00:00Z2017 Jul2026-05-05T09:38:52.173Z2019-03-27T02:50:23ZS-EPMC55096822870625110.1038/s41598-017-04225-3