Efficient ionphoton qubit SWAP gate in realistic ion cavityQED systems without strong coupling
Abstract
We present a scheme for deterministic ionphoton qubit exchange, namely a SWAP gate, based on realistic cavityQED systems with 171Yb+, 40Ca+ and 138Ba+ ions. The gate can also serve as a singlephoton quantum memory, in which an outgoing photon heralds the successful arrival of the incoming photonic qubit. Although strong coupling, namely having the singlephoton Rabi frequency be the fastest rate in the system, is often assumed essential, this gate (similarly to the DuanKimble Cphase gate) requires only Purcell enhancement, i.e. high singleatom cooperativity. Accordingly, it does not require small mode volume cavities, which are challenging to incorporate with ions due to the difficulty of trapping them close to dielectric surfaces. Instead, larger cavities, potentially more compatible with the trap apparatus, are sufficient, as long as their numerical aperture is high enough to maintain small mode area at the ion's position. We define the optimal parameters for the gate's operation and simulate the expected fidelities and efficiencies, demonstrating that efficient photonion qubit exchange, a valuable building block for scalable quantum computation, is practically attainable with current experimental capabilities.
 Publication:

Optics Express
 Pub Date:
 April 2020
 DOI:
 10.1364/OE.376914
 arXiv:
 arXiv:1902.03469
 Bibcode:
 2020OExpr..2811822B
 Keywords:

 Quantum Physics
 EPrint:
 18 pages, 9 figures