Hour: From 12:00h to 13:00h
Place: Seminar Room
SEMINAR: Hole spin-cQED: a bright future
Coherent spin-photon interfaces between microwave photons and spins in silicon quantum dots are now routinely achieved [1-3]. The key ingredient in resolving this outstanding challenge was the engineering of a large electric-dipole moment linked to the spin, achieve by delocalizing a spin within a double-quantum dot under the influence of spin-orbit interaction. These spin qubits, also known as flopping-mode spin qubits, have enabled the first SWAP operations between spin qubits separated by over 250 micrometers [4], paving the way to address the wiring challenges in dense spin qubit processors.
However, the coherence properties of flopping mode spin qubits reported to date remain limited, hindering their use in practical applications. Here, we report on a hole spin delocalized in a double quantum dot formed in a silicon nanowire MOS device coupled to a high impedance superconducting microwave resonator [3]. With Rabi frequencies exceeding 100 MHz and coherence times in the microsecond range, we show that delocalized spins can achieve high qubit quality factors, enabling high-fidelity gate operations.
Furthermore, we present a comprehensive analysis of the mechanisms limiting spin relaxation and dephasing in a hybrid spin cQED architecture. Our findings reveal that spin relaxation is dominated by radiative decay due to a structured electromagnetic environment (Purcell effect); while dephasing is limited by photon shot noise at operational points where the spin is first-order insensitive to charge noise. This suggests that with an optimized cQED architecture considerably longer coherence times can still be achieved. Our first approach in creating high-quality spin-cQED environments using semi-industrial flip-chip technology for 3D integration will be discussed.
With strong spin-photon coupling and promising single-qubit properties demonstrated here, hole spin flopping-mode qubits emerge as a promising platform for scalable quantum architectures.
References:
- Samkharadze et al. Science, 359 (2018)
- Mi et al. Nature, 555 (2018)
- Yu et al. Nat. Nanotechnol. 18 (2023)
- Dijkema et al. Nat. Phys. 21 (2025)
Hour: From 12:00h to 13:00h
Place: Seminar Room
SEMINAR: Hole spin-cQED: a bright future
Coherent spin-photon interfaces between microwave photons and spins in silicon quantum dots are now routinely achieved [1-3]. The key ingredient in resolving this outstanding challenge was the engineering of a large electric-dipole moment linked to the spin, achieve by delocalizing a spin within a double-quantum dot under the influence of spin-orbit interaction. These spin qubits, also known as flopping-mode spin qubits, have enabled the first SWAP operations between spin qubits separated by over 250 micrometers [4], paving the way to address the wiring challenges in dense spin qubit processors.
However, the coherence properties of flopping mode spin qubits reported to date remain limited, hindering their use in practical applications. Here, we report on a hole spin delocalized in a double quantum dot formed in a silicon nanowire MOS device coupled to a high impedance superconducting microwave resonator [3]. With Rabi frequencies exceeding 100 MHz and coherence times in the microsecond range, we show that delocalized spins can achieve high qubit quality factors, enabling high-fidelity gate operations.
Furthermore, we present a comprehensive analysis of the mechanisms limiting spin relaxation and dephasing in a hybrid spin cQED architecture. Our findings reveal that spin relaxation is dominated by radiative decay due to a structured electromagnetic environment (Purcell effect); while dephasing is limited by photon shot noise at operational points where the spin is first-order insensitive to charge noise. This suggests that with an optimized cQED architecture considerably longer coherence times can still be achieved. Our first approach in creating high-quality spin-cQED environments using semi-industrial flip-chip technology for 3D integration will be discussed.
With strong spin-photon coupling and promising single-qubit properties demonstrated here, hole spin flopping-mode qubits emerge as a promising platform for scalable quantum architectures.
References:
- Samkharadze et al. Science, 359 (2018)
- Mi et al. Nature, 555 (2018)
- Yu et al. Nat. Nanotechnol. 18 (2023)
- Dijkema et al. Nat. Phys. 21 (2025)