Talk Title: The power and limitations of constant-time quantum computation
Abstract: In this talk I will survey the landscape of models of "constant-time" quantum computing, where the computation time is independent of the system size. The most interesting models usually involve some kind of non-local operation such as measure and feedforward, many-qubit gates, and so on. These models are motivated by both practical concerns (e.g., near-term hardware is depth-limited) as well as fundamental theory questions (e.g., how do different many-qubit gates compare?).
These constant-time models are *powerful*, capable of preparing interesting classes of states and performing interesting computations. Many of these models are surprisingly *equivalent, *enabling transfer of techniques, results, and questions. Finally, I will discuss how these models uncover fascinating links between many-body physics and deep questions in computational complexity theory.