Dual-Rail Microwave Cavity Qubits

Dual-Rail qubits were originally proposed for optical quantum computation and communication, and the logical states are represented by a single photon which can be in one of two different modes. This talk will discuss recent experimental and theoretical progress extending this concept to a single microwave photon shared between two superconducting microwave cavities.

Single-qubit gates require only simple beam-splitter operations between the two cavities and can now be performed with very high fidelity. Novel two-qubit entangling gates are also being developed. The most common error, loss of the photon, can be efficiently converted to an ‘erasure error,’ heralded by the change in the total photon number from 1 to 0. The fact that erasure errors have heralded locations will make them much easier to correct in error correcting codes constructed from dual-rail qubits.

Steven M. Girvin

Sterling Professor of Physics and Professor of Applied Physics, Yale Quantum Institute, Yale University on February 20, 2026 at 10:15 AM in EB2 1231

After graduating from a high school class of five students in the small village of Brant Lake, New York, Robert J. Girvin earned his undergraduate degree in physics from Bates College. He went on to complete his Ph.D. in theoretical physics at Princeton University in 1977.

Girvin joined the Yale University faculty in 2001, where he is Sterling Professor of Physics and professor of applied physics. From 2007 to 2017, he served as Yale’s deputy provost for research, overseeing strategic planning for research across the university. From 2019 to 2021, he served as founding director of the Co-Design Center for Quantum Advantage, one of five national quantum information science research centers funded by the U.S. Department of Energy.

Along with experimental physicists Michel Devoret and Robert Schoelkopf, Girvin co-developed circuit quantum electrodynamics (circuit QED), the leading architecture for building quantum computers based on superconducting microwave circuits.

Girvin is a foreign member of the Royal Swedish Academy of Sciences and a member of the U.S. National Academy of Sciences. In 2007, he and collaborators Allan H. MacDonald and James P. Eisenstein were awarded the Oliver E. Buckley Prize from the American Physical Society for their work on the fractional quantum Hall effect.

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