科研之友
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摘要
The creation of composite quantum gates that implement quantum response functions (U) over cap(theta) dependent on some parameter of interest theta is often more of an art than a science. Through inspired design, a sequence of L primitive gates also depending on theta can engineer a highly nontrivial (U) over cap(theta) that enables myriad precision metrology, spectroscopy, and control techniques. However, discovering new, useful examples of (U) over cap(theta) requires great intuition to perceive the possibilities, and often brute force to find optimal implementations. We present a systematic and efficient methodology for composite gate design of arbitrary length, where phase-controlled primitive gates all rotating by theta act on a single spin. We fully characterize the realizable family of (U) over cap(theta), provide an efficient algorithm that decomposes a choice of (U) over cap(theta) into its shortest sequence of gates, and show how to efficiently choose an achievable (U) over cap(theta) that, for fixed L, is an optimal approximation to objective functions on its quadratures. A strong connection is forged with classical discrete-time signal processing, allowing us to swiftly construct, as examples, compensated gates with optimal bandwidth that implement arbitrary single-spin rotations with subwavelength spatial selectivity.
- 出版日期2016-12-28
- 单位MIT
