Parametrically induced readout of a superconducting qubit
ORAL
Abstract
One of the basic operations of quantum information is to non-destructively identify the state of a quantum system with high fidelity and within a time that is short compared to its natural decay. In circuit quantum electro-dynamics, this goal is achieved by the dispersive readout scheme, in which the frequency of an ancillary cavity is pulled by an amount depending on the qubit state. Despite its successes, this scheme suffers from the Purcell limit set on the decay time, and from the dephasing induced by spurious photons in the readout cavity. We address these shortcomings with a parametrically driven 3rd order interaction between the qubit excitation number and the cavity coherent state displacement. This interaction can also be described as a so-called “longitudinal” coupling between the qubit z operator and the readout cavity field amplitude, and it differs markedly from the usual "transversal" Jaynes-Cummings coupling between the qubit x operator and the field amplitude. This interaction can be tuned in-situ, and can be turned off altogether. The presentation will report experimental progress towards the realization of this scheme.
*Work supported by: ARO, ONR, NSF, AFOSR, and YINQE
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Presenters
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Steven Touzard
- Applied Physics, Yale University
- Department of Applied Physics, Yale Univ
- Yale Univ