Integrating a nonreciprocal amplifier with a 3D transmon qubit
ORAL
Abstract
In conventional superconducting qubit dispersive readout schemes, the measurement signal is routed from the readout cavity to the amplification chain using magnetic circulators. These circulators allow for a modular approach in which the amplifiers and qubit-cavity system can be developed separately, but their intrinsic loss and the required wiring significantly reduce the measurement efficiency.
Improvement in measurement efficiency can be achieved by integrating the qubit-cavity system with a nonreciprocal amplifier [1]. In the absence of an intermediate circulator, the cavity and amplifier merge into a single quantum system in which the fragile qubit state must coexist with a large amplified readout signal.
Here we discuss experimental progress toward further integration of a 3D transmon qubit with a multi-mode resonant circuit that acts as a readout cavity with built-in signal gain. We will focus on the delicate balance between large gain and low backaction and between fast readout and long qubit lifetime.
[1] F. Lecocq, et al, ArXiv:2009.08863
Improvement in measurement efficiency can be achieved by integrating the qubit-cavity system with a nonreciprocal amplifier [1]. In the absence of an intermediate circulator, the cavity and amplifier merge into a single quantum system in which the fragile qubit state must coexist with a large amplified readout signal.
Here we discuss experimental progress toward further integration of a 3D transmon qubit with a multi-mode resonant circuit that acts as a readout cavity with built-in signal gain. We will focus on the delicate balance between large gain and low backaction and between fast readout and long qubit lifetime.
[1] F. Lecocq, et al, ArXiv:2009.08863
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Presenters
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Benton Miller
- University of Colorado, Boulder