Manipulating Fock states of a harmonic oscillator while preserving its linearity

K Juliusson (1) , S Bernon (1) , Xin Zhou (1) , V Schmitt (1) , H Le Sueur (2) , P Bertet (1) , D Vion (1) , M Mirahimi (3) , P Rouchon (4) , D Esteve (1)

1 QUANTRONICS - Quantronics Group
2 CSNSM AN
3 QUANTIC - QUANTum Information Circuits
4 CAS - Centre Automatique et Systèmes

We present a new scheme for controlling the quantum state of a harmonic oscillator by coupling it to an anharmonic multilevel system (MLS) with rst to second excited state transition frequency on-resonance with the oscillator. In this scheme that we call 'ef-resonant', the spurious oscillator Kerr non-linearity inherited from the MLS is very small, while its Fock states can still be selectively addressed via an MLS transition at a frequency that depends on the number of photons. We implement this concept in a circuit-QED setup with a microwave 3D cavity (the oscillator, with frequency 6.4 GHz and quality factor QO = 2E6) embedding a frequency tunable transmon qubit (the MLS). We characterize the system spectroscopically and demonstrate selective addressing of Fock states and a Kerr non-linearity below 350 Hz. At times much longer than the transmon coherence times, a non-linear cavity response with driving power is also observed and explained.

Mots clés: qubit; microwave cavity; circuit-QED; quantum electrodynamics

Domaines: Physique [physics]

K Juliusson, S Bernon, Xin Zhou, V Schmitt, H Le Sueur, et al.. Manipulating Fock states of a harmonic oscillator while preserving its linearity. 2016. ⟨cea-01346391v1⟩