Talk accepted by QCTiP 2024!

Paper on reversing unknown quantum processes is selected for talk in QCTiP 2024 🎉

Our paper Reversing Unknown Quantum Processes via Virtual Combs: for Channels with Limited Information by Chengkai Zhu, Yin Mo, Yu-Ao Chen, and Xin Wang was selected for a talk at QCTiP 2024!

For QCTiP 2024: The third Quantum Computing Theory in Practice (QCTiP) conference, hosted by the Quantum Software Lab and the University of Edinburgh from the 16th-18th April, 2024. Building on the success of the previous Heilbronn quantum algorithms meetings (2010-2019) held in Bristol and Cambridge, QCTiP serves as a platform for fostering discussions among theorists and practitioners in the field of quantum computing.

For the paper Reversing Unknown Quantum Processes via Virtual Combs: for Channels with Limited Information: We introduce the notion of virtual combs by lifting the positivity requirement on quantum combs. Physically, a virtual comb corresponds to sampling quantum combs with positive and negative coefficients and performing post-processing. We find that the simulation of the inverse of an unknown channel could be achieved with a virtual comb under certain conditions. For depolarizing channels, we unveil the remarkable capability of an $n$-slot virtual comb to exactly reverse a depolarizing channel with an unknown noise parameter among $n+1$ possible candidates. A worst-case error decay of $\mathcal{O}(n^{-1})$ is unveiled for depolarizing channels within a specified noise region. Moreover, we show that virtual combs can universally reverse unitary operations and investigate the trade-off between the slot number and the sampling overhead.