Program
Full Program | Thursday | Friday | Saturday | All Sessions | Posters | Talks
SESSION 11: Superconductor qubits (experiment) (Pavilion I - III)Chair: Andrew Landahl (Sandia) | |
| 10:45 am - 11:30 am | Robert Schoelkopf, (Yale) Extending the lifetime of quantum information through error correction | Abstract. In quantum error correction (QEC) one redundantly encodes an arbitrary bit of quantum information into a larger collection of quantum states, whose symmetry properties allow error syndrome measurements to project the state into a known error space without disturbing the qubit, and enable the recovery from errors via simple operations. Given the considerable overhead inherent in traditional proposals, realizing a QEC protocol at the "break-even" point, which extends the lifetime of information beyond the system's highest quality constituent, remains a difficult and outstanding challenge. Here we demonstrate a fully operational quantum error correction system, based on a logical encoding comprised of superpositions of cat states in a superconducting cavity. This system uses real-time classical feedback to encode, track the naturally occurring errors, decode, and correct, all without the need for post-selection. Using this hardware-efficient approach we reach, for the first time, the break-even point for QEC and preserve quantum information through active means. |
| 11:30 am - 12:00 pm | Ryan Babbush, Martinis group (Google) The promise of variational quantum algorithms | Abstract. Recent work has shown that parameterized short quantum circuits can generate powerful variational ansätze for ground states of classically intractable fermionic models. This observation inspires hope that even without error correction, quantum computers may provide insight into problems of industrial importance such as quantum chemistry and superconductivity. As the number of qubits in superconducting devices keeps increasing, their dynamics are becoming prohibitively expensive to simulate classically. In anticipation of such a platform, we use devices with up to nine superconducting qubits to explore the viability of variational approaches. We discuss experiments showing surprising robustness to control errors, including the first quantum simulation of molecular energies to obtain chemical precision without precompilation. Nevertheless, with current gate fidelities it seems unlikely that variational approaches parameterized in terms of conventional logic gates will scale to the classically intractable regime. Instead, we propose to form variational ansätze at the level of hardware by parameterizing quantum circuits in terms of the experimentalist’s control knobs. We discuss an ongoing experiment to simulate Fermi-Hubbard models in this way. We conclude by asking how experiments can guide the design and analysis of quantum variational algorithms. |
SQuInT Chief Organizer
Prof. Akimasa Miyake
amiyake@unm.edu
SQuInT Co-Organizer
Prof. Elohim Becerra
fbecerra@unm.edu
SQuInT Founder
Prof. Ivan Deutsch
ideutsch@unm.edu
SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850
