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Abstract The generation of a register of highly coherent, but independent, qubits is a prerequisite to performing universal quantum computation. Here we introduce a qubit encoded in two nuclear spin states of a single 87 Sr atom and demonstrate coherence approaching the minute-scale within an assembled register of individually-controlled qubits. While other systems have shown impressive coherence times through some combination of shielding, careful trapping, global operations, and dynamical decoupling, we achieve comparable coherence times while individually driving multiple qubits in parallel. We highlight that even with simultaneous manipulation of multiple qubits within the register, we observe coherence in excess of 10 5 times the current length of the operations, with $${T}_{2}^{{{{{\mathrm{echo}}}}}}=\left(40\pm 7\right)$$ T 2 echo = 40 ± 7 seconds. We anticipate that nuclear spin qubits will combine readily with the technical advances that have led to larger arrays of individually trapped neutral atoms and high-fidelity entangling operations, thus accelerating the realization of intermediate-scale quantum information processors. 

Many emerging, high-speed, reconfigurable optical systems are limited by routing complexity when producing dynamic, two-dimensional (2D) electric fields. We propose a gradient-based inverse-designed, static phase-mask doublet to generate arbitrary 2D intensity wavefronts using a one-dimensional (1D) intensity spatial light modulator (SLM). We numerically simulate the capability of mapping each point in a 49 element 1D array to a distinct $7\times <\#comment/>7$2D spatial distribution. Our proposed method will significantly relax the routing complexity of electrical control signals, possibly enabling high-speed, sub-wavelength 2D SLMs leveraging new materials and pixel architectures. 

Establishing a coherent interaction between a material resonance and an optical cavity is a necessary first step to study semiconductor quantum optics. Here we report on the signature of a coherent interaction between a two-dimensional excitonic transition in monolayer MoSe₂and a zero-dimensional, ultra-low mode volume (V_m ∼ 2(λ/n)³) on-chip photonic crystal nanocavity. This coherent interaction manifests as a dispersive shift of the cavity transmission spectrum, when the exciton-cavity detuning is decreased via temperature tuning. The exciton-cavity coupling is estimated to be ≈6.5 meV, with a cooperativity of ≈4.0 at 80 K, showing our material system is on the verge of strong coupling. The small mode-volume of the resonator is instrumental in reaching the strongly nonlinear regime, while on-chip cavities will help create a scalable quantum photonic platform. 

Prototyping of van der Waals materials on dense nanophotonic devices requires high-precision monolayer discrimination to avoid bulk material contamination. We use the glass transition temperature of polycarbonate, used in the standard dry transfer process, to draw an in situ point for the precise pickup of two-dimensional materials. We transfer transition metal dichalcogenide monolayers onto a large-area silicon nitride spiral waveguide and silicon nitride ring resonators to demonstrate the high-precision contamination-free nature of the modified dry transfer method. Our improved local transfer technique is a necessary step for the deterministic integration of high-quality van der Waals materials onto nanocavities for the exploration of few-photon nonlinear optics on a high-throughput, nanofabrication-compatible platform.