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Large Collective Lamb Shift of Two Distant Superconducting Artificial Atoms
P Y Wen1,2, K-T Lin3, A F Kockum4,5
1Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
Physical Review Letters
|December 24, 2019
Summary
Researchers observed a collective Lamb shift in superconducting qubits, a quantum energy shift mediated by virtual photons. This significant finding advances understanding of quantum interactions and qubit behavior.
Area of Science:
- Quantum optics
- Superconducting quantum computing
Background:
- Virtual photons mediate interactions between atoms, causing collective Lamb shifts.
- Observing collective Lamb shifts is difficult due to radiative decay and direct atom-atom interactions.
Purpose of the Study:
- To experimentally observe and quantify the collective Lamb shift in a controlled quantum system.
- To investigate methods for overcoming challenges in measuring collective Lamb shifts.
Main Methods:
- Utilizing two superconducting qubits coupled via a transmission line terminated by a mirror.
- Implementing a mirror to suppress radiative decay and isolate the collective Lamb shift.
- Measuring the collective Lamb shift relative to qubit transition frequency and linewidth.
Main Results:
- Measured a collective Lamb shift of 0.8% of the qubit transition frequency.
- Observed a collective Lamb shift twice the transition linewidth.
- Demonstrated qubit interaction via the transmission line, even without decay from one qubit.
Conclusions:
- The experimental setup successfully isolated and measured the collective Lamb shift.
- The results validate the role of virtual photons in mediating qubit interactions.
- This work provides a pathway for studying quantum phenomena in engineered environments.
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