Speaker: Dr. Andrew J. Kerman
Affiliation: MIT Lincoln Laboratory
Title: Quantum Error Suppression with Superconducting Qubits
Time: 3:00 pm EST (refreshments available at 2:30 pm)
Date: Wednesday, March 21, 2018
Location: LPS Downstairs Conference Room
Abstract:
The operational coherence of superconducting qubits in quantum information processing applications has improved dramatically in recent years, due to combination of improvements in materials, fabrication processes, qubit circuit design, and modes of operation. However, it now appears that substantial further progress will likely require as yet unknown advances that go beyond incremental engineering improvements. One possible exception to this is the use of passive quantum error suppression (QES), the best-known example of which is dynamical decoupling of noise from pulsed gate operations in quantum computing. In this talk, I will focus on a different kind of QES in which encoded logical qubit states are protected (passively) from errors by adding chosen energy penalty terms to the system Hamiltonian such that physical error processes can only occur if the environment can supply a large energy.
I will describe two new kinds of superconducting circuits which provide the key capabilities needed to realize this kind of QES. First, a new type of superconducting flux qubit called the Josephson phase-slip qubit, which naturally emulates a zero-field vector magnetic moment, and makes full anisotropic Heisenberg interactions between such moments possible; and second, a new type of coupling circuit which can produce strong, four-spin interactions between these vector moments. I will show full quantum simulations of the resulting logical qubits, and briefly describe how they can be used in the context of both quantum annealing and quantum computation.
Biography:
Dr. Andrew J. Kerman is currently a senior staff member in the Quantum Information and Integrated Nanosystems Group, pursuing research in superconducting microelectronic devices for quantum and classical applications. Previously, he was a member of the Optical Communications Technology Group, where he developed superconducting single-photon-detector technology and systems. Prior to joining Lincoln Laboratory in 2004, he was a postdoctoral researcher at the MIT/Harvard Center for Ultracold Atoms, as well as at the Yale University Physics Department. Most recently, Dr. Kerman has worked on the design of superconducting Josephson-junction-based quantum bits (qubits) and has been developing novel means to improve their coherence and to generate multiqubit entanglement for quantum information processing. He has also made seminal contributions to the understanding and design of superconducting nanowire single-photon detectors (SNSPD) and was responsible for the design and construction of the ground-based SNSPD system used in the NASA Lunar Laser Communication Demonstration in 2013. Dr. Kerman has authored or coauthored numerous papers on superconducting devices, including Josephson-junction-based qubits, SNSPDs, and quantum-phase-slip circuits. He has also published extensively in the areas of laser cooling and trapping of atoms and molecules and cold atomic collisions. Dr. Kerman received a BS degree in physics and mathematics from Williams College and a PhD degree in physics from Stanford University.