论文标题
通过曲率耦合到超导腔的曲率耦合，在编码自旋量子上进行了调节的纵向大门
Modulated longitudinal gates on encoded spin-qubits via curvature couplings to a superconducting cavity
论文作者
论文摘要
我们提出了基于编码自旋速度的能量曲率耦合到超导腔的纠缠操作，从而探索了对栅极电压变化的非线性量子响应。对于两个小问题（$ n $ qubit）纠缠的门，我们通过时间调制的纵向$σ_z$ - 耦合探索获得的几何阶段，即使在速度和腔体远远不受谐振的情况下，即使在速度和腔体远处也提供10秒的NS门时间。无需偶极矩：与谐振器的量子横向$σ_x$ - 在所编码的感兴趣的旋转量子保持点的完整最佳点（三量子点三电子换出 - 仅量子量子乘或双量子量子点dot-triplet-triplet-triplet Qubit）。这种方法允许在门操作过程中始终在启动，仅交换量子位，以保持其“甜点”，最大程度地减少电荷噪声并消除始终在静态的静态纵向Qubit-qubit耦合。 We calculate the main gate errors due to the (1) diffusion (Johnson) noise and (2) damping of the resonator, the (3) $1/f$-charge noise qubit gate dephasing and $1/f$-noise on the longitudinal coupling, (4) qubit dephasing and ac-Stark frequency shifts via photon fluctuations in the resonator, and (5) spin-dependent resonator frequency移动（通过“色散样”静态曲率耦合），其中大多数与非零值级曲率曲率（量子电容）相关。在最佳制度下，使用类似旋转回波的误差抑制，可以通过实验现有的参数来实现$ 10^{ - 2} -2} -10^{ - 3} $的门不忠。所提出的方案似乎适用于两个自旋量子或一组自旋量子的远程自旋到旋转纠缠：量子计算的重要资源。
We propose entangling operations based on the energy curvature couplings of encoded spin qubits to a superconducting cavity, exploring the non-linear qubit response to a gate voltage variation. For a two-qubit ($n$-qubit) entangling gate we explore acquired geometric phases via a time-modulated longitudinal $σ_z$-coupling, offering gate times of 10s of ns even when the qubits and the cavity are far detuned. No dipole moment is necessary: the qubit transverse $σ_x$-coupling to the resonator is zero at the full sweet spot of the encoded spin qubit of interest (a triple quantum dot three-electron exchange-only qubit or a double quantum dot singlet-triplet qubit). This approach allows always-on, exchange-only qubits, for example, to stay on their "sweet spots" during gate operations, minimizing the charge noise and eliminating an always-on static longitudinal qubit-qubit coupling. We calculate the main gate errors due to the (1) diffusion (Johnson) noise and (2) damping of the resonator, the (3) $1/f$-charge noise qubit gate dephasing and $1/f$-noise on the longitudinal coupling, (4) qubit dephasing and ac-Stark frequency shifts via photon fluctuations in the resonator, and (5) spin-dependent resonator frequency shifts (via a "dispersive-like" static curvature coupling), most of them associated with the non-zero qubit energy curvature (quantum capacitance). Using spin-echo-like error suppression at optimal regimes, gate infidelities of $10^{-2}-10^{-3}$ can be achieved with experimentally existing parameters. The proposed schemes seem suitable for remote spin-to-spin entanglement of two spin-qubits or a cluster of spin-qubits: an important resource of quantum computing.
