arXiv subjects

Daniel J. Weigand

Publications and source records attributed to Daniel J. Weigand.

2 recordsLinked to original sources

arXiv2019

Realizing modular quadrature measurements via a tunable photon-pressure coupling in circuit-QED

One of the most direct preparations of a Gottesman-Kitaev-Preskill qubit in an oscillator uses a tunable photon-pressure (also called optomechanical) coupling of the form $g \hat{q} a^{\dagger} a$, enabling to imprint the modular value of the position $\hat{q}$ of one oscillator onto the state of an ancilla oscillator. We analyze the practical feasibility of executing such modular quadrature measurements in a parametric circuit-QED realization of this coupling. We provide estimates for the expected GKP squeezing induced by the protocol and discuss the effect of photon loss and other errors on the resulting squeezing.

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arXiv2018

Generating Grid States From Schrödinger Cat States without Post-Selection

Grid (or comb) states are an interesting class of bosonic states introduced by Gottesman, Kitaev and Preskill to encode a qubit into an oscillator. A method to generate or `breed' a grid state from Schrödinger cat states using beam splitters and homodyne measurements is known, but this method requires post-selection. In this paper we show how post-processing of the measurement data can be used to entirely remove the need for post-selection, making the scheme much more viable. We bound the asymptotic behavior of the breeding procedure and demonstrate the efficacy of the method numerically.

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