We introduce Port-Based State Preparation (PBSP), a teleportation task where Alice holds a complete classical description of the target state and Bob's correction operations are restricted to only tracing out registers. We show a protocol that implements PBSP with error decreasing exponentially in the number of ports, in contrast to the polynomial trade-off for the related task of Port-Based Teleportation, and we prove that this is optimal when a maximally entangled resource state is used.
As an application, we introduce approximate Universal Programmable Hybrid Processors (UPHP). Here the goal is to encode a unitary as a quantum state, and the UPHP can apply this unitary to a quantum state when knowing its classical description. We give a construction that needs strictly less memory in terms of dimension than the optimal approximate Universal Programmable Quantum Processor achieving the same error. Additionally, we provide lower bounds for the optimal trade-off between memory and error of UPHPs.

中文翻译：

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基于端口的状态准备和应用程序


我们介绍了基于端口的状态准备 （PBSP），这是一个传送任务，其中 Alice 拥有目标状态的完整经典描述，而 Bob 的校正操作仅限于跟踪寄存器。我们展示了一种实现 PBSP 的协议，其误差在端口数量上呈指数级减少，这与基于端口的传送相关任务的多项式权衡形成鲜明对比，我们证明当使用最大纠缠资源状态时，这是最佳的。

作为一个应用程序，我们引入了近似的通用可编程混合处理器 （UPHP）。这里的目标是将幺正态编码为量子态，UPHP 可以在知道量子态的经典描述时将此幺正态应用于量子态。我们给出了一个结构，它在维度上需要的内存比实现相同误差的最佳近似通用可编程量子处理器要少。此外，我们还为 UPHP 的内存和误差之间的最佳权衡提供了下限。