Three staff in the Non-conventional Computing Technologies department (1425) recently made high-profile technical communications: Kenneth Rudinger coauthored a paper published in Physical Review Letters on a robust method for phase estimation for qubits: “Experimental demonstration of cheap and accurate phase estimation.” His co-authors were Shelby Kimmel, Joint Center for Quantum Information and Computer Science (QuICS) at UMD; and Daniel Lobser and Peter Maunz of Sandia’s Photonic Microsystems Technologies department. The paper presents a targeted, but efficient and very useful subset of information on qubit performance that is part of the more comprehensive, but also more laborious analysis developed at Sandia, known as Gate Set Tomography. Michael Frank presented “Foundations of Generalized Reversible Computing” at the 9th Conference on Reversible Computing, held in July in Kolkata, India. Michael’s paper and presentation summarize his development of a new theory of Generalized Reversible Computing (GRC), based on a rigorous quantitative formulation of Landauer’s Principle, that precisely characterizes the minimum requirements for a computation to avoid information loss and energy dissipation. He shows that a much broader range of computations are reversible than has been previously identified. Andrew Landahl presented a well-received overview talk on quantum computing at the recent, invitation-only, Salishan conference on High Speed Computing (http://salishan.ahsc-nm.org/). His talk, Quantum Computing: Cladogenesis Beyond Exascale HPC, was part of a session on quantum computing that aimed to acquaint the audience of leaders in conventional high-performance computing with the elements of quantum information processing.
![FIG. 1: (a) RPE and (b) GST experimental sequences. Each sequence starts with the state p and ends with the two-outcome measurement M. (a) An RPE sequence consists of repeating the gate in question either L orL + 1 times. (b) In GST, a gate sequence Fi is applied to simulate a state preparation potentially different from p. This is followed by [L/|gk|I] applications of a germ—a short gate sequence gk of length |gk|. Finally, a sequence Fj is applied to simulate a measurement potentially different from M.](https://www.sandia.gov/app/uploads/sites/210/2022/06/Aidun_580.jpg)