Improved readout of qubit-coupled Gottesman-Kitaev-Preskill states

Understand

The Gottesman-Kitaev-Preskill encoding of a qubit in a harmonic oscillator is a promising building block towards fault-tolerant quantum computation.

• Recently, this encoding was experimentally demonstrated for the first time in trapped-ion and superconducting circuit systems.
• However, these systems lack some of the Gaussian operations which are critical to efficiently manipulate the encoded qubits.
• In particular, homodyne detection, which is the preferred method for readout of the encoded qubit, is not readily available, heavily limiting the readout fidelity.