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Updated: Jun 12, 2026
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Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
rf-SQUID-mediated coherent tunable coupling between a superconducting phase qubit and a lumped-element resonator
M S Allman1, F Altomare, J D Whittaker
1National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305-3328, USA.
Physical Review Letters
|May 21, 2010
Summary
We achieved tunable coupling between a superconducting phase qubit and a resonator using a flux-biased radio frequency superconducting quantum interference device (rf SQUID). This control allows for precise manipulation of quantum interactions for quantum computing applications.
Area of Science:
- Quantum Computing
- Superconducting Circuits
- Quantum Information Science
Background:
- Superconducting qubits are promising for quantum computation.
- Controlling qubit-resonator coupling is crucial for quantum operations.
- Radio frequency superconducting quantum interference devices (rf SQUIDs) offer tunable inductance.
Purpose of the Study:
- To demonstrate coherent tunable coupling between a superconducting phase qubit and a lumped-element resonator.
- To investigate the use of a flux-biased rf SQUID for mediating this coupling.
- To verify the modulation of coupling strength and its effect on quantum phenomena.
Main Methods:
- Utilized a flux-biased rf SQUID in the nonhysteretic regime to mediate coupling.
- Tuned the applied flux bias to modify the effective mutual inductance and coupling energy.
- Observed modulation in phase qubit spectroscopy and vacuum Rabi oscillations to verify coupling strength.
Main Results:
- Successfully demonstrated coherent tunable coupling between the phase qubit and resonator.
- Modulated the coupling strength dynamically from 0 to 100 MHz.
- Observed clear modulation in spectroscopic splitting and vacuum Rabi oscillation frequency.
Conclusions:
- The flux-biased rf SQUID provides effective control over qubit-resonator coupling strength.
- The demonstrated tunability is essential for advanced quantum control and algorithms.
- Experimental results align well with theoretical predictions, validating the approach.
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