Deterministic amplification of Schrödinger cat states in circuit quantum electrodynamics

Jaewoo Joo*, Matthew Elliott, Daniel K L Oi, Eran Ginossar, Timothy P. Spiller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Perfect deterministic amplification of arbitrary quantum states is prohibited by quantum mechanics, but determinism can be achieved by compromising between fidelity and amplification power. We propose a dynamical scheme for deterministically amplifying photonic Schrödinger cat states, which show great promise as a tool for quantum information processing. Our protocol is designed for strongly coupled circuit quantum electrodynamics and utilizes artificial atomic states and external microwave controls to engineer a set of optimal state transfers and achieve high fidelity amplification. We compare analytical results with full simulations of the open, driven Jaynes-Cummings model, using realistic device parameters for state of the art superconducting circuits. Amplification with a fidelity of 0.9 can be achieved for sizable cat states in the presence of cavity and atomic-level decoherence. This tool could be applied to practical continuous-variable information processing for the purification and stabilization of cat states in the presence of photon losses.

Original languageEnglish
Article number023028
Pages (from-to)1-11
Number of pages11
JournalNew Journal of Physics
Issue number2
Publication statusPublished - 5 Feb 2016


  • amplification of quantum states
  • cat states
  • circuit quantum electrodynamics
  • quantum optics
  • superconducting circuits

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