Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 45: Transport: Quantum Coherence and Quantum Information Systems - Experiment (jointly with MA, HL)
HL 45.5: Talk
Wednesday, March 22, 2017, 10:30–10:45, HSZ 03
Towards a scalable 3D quantum memory — •Edwar Xie1,2,3, Frank Deppe1,2,3, Daniel Repp2, Peter Eder1,2,3, Michael Fischer1,2,3, Jan Goetz1,2,3, Kirill G. Fedorov1, Achim Marx1, and Rudolf Gross1,2,3 — 1Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany — 2Physik-Department, TU München, 85748 Garching, Germany — 3Nanosystems Initiative Munich (NIM), 80799 München, Germany
For superconducting qubits dispersively coupled to 3D cavity resonators both T1-and T2-times in excess of 100 µs have been achieved. However, the 3D cavities are bulky in comparison with their (slightly less coherent) 2D counterparts. A more scalable device can be built by exploiting the multi-mode structure of the 3D cavity. Here, we present an experimental study on such a device: a transmon qubit capacitively coupled to two distinct modes of a single 3D cavity. We engineer the fundamental and the first harmonic mode of a single cavity in such a way, that the former one couples well to the external feedline, whereas the latter does not. The qubit is dispersively coupled to both modes with a rate g/2π ≃ 60 MHz. Using a second-order coupling protocol, we observe an enhancement in qubit lifetime by a factor of 3 compared to the pure qubit lifetime and find that this value is not limited by fundamental constraints.
The authors acknowledge support from DFG through FE 1564/1-1, the doctorate program ExQM of the Elite Network of Bavaria and the IMPRS ‘Quantum Science and Technology’.