E. Knill

Faithful conversion of propagating quantum information to mechanical motion

  1. A. P. Reed,
  2. K. H. Mayer,
  3. J. D. Teufel,
  4. L. D. Burkhart,
  5. W. Pfaff,
  6. M. Reagor,
  7. L. Sletten,
  8. X. Ma,
  9. R. J. Schoelkopf,
  10. E. Knill,
  11. and K. W. Lehnert
We convert propagating qubits encoded as superpositions of zero and one photons to the motion of a micrometer-sized mechanical resonator. Using quantum state tomography, we determine
the density matrix of both the propagating photons and the mechanical resonator. By comparing a sufficient set of states before and after conversion, we determine the average process fidelity to be Favg=0.83+0.03−0.06 which exceeds the classical bound for the conversion of an arbitrary qubit state. This conversion ability is necessary for using mechanical resonators in emerging quantum communication and modular quantum computation architectures.
arxiv pdf