Demonstration of a quantum error detection code using a square lattice of four superconducting qubits.
The ability to detect and deal with errors when manipulating quantum systems is a fundamental requirement for fault-tolerant quantum computing. Unlike classical bits that are subject to only digital bit-flip errors, quantum bits are susceptible to a much larger spectrum of errors, for which any complete quantum error-correcting code must account. Whilst classical bit-flip detection can be realized via a linear array of qubits, a general fault-tolerant quantum error-correcting code requires extending into a higher-dimensional lattice. Here we present a quantum error detection protocol on a two-by-two planar lattice of superconducting qubits. The protocol detects an arbitrary quantum error on an encoded two-qubit entangled state via quantum non-demolition parity measurements on another pair of error syndrome qubits. This result represents a building block towards larger lattices amenable to fault-tolerant quantum error correction architectures such as the surface code.
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
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Córcoles
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Easwar
E
Magesan
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Srikanth J
SJ
Srinivasan
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Andrew W
AW
Cross
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
M
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Steffen
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Jay M
JM
Gambetta
IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA.
Jerry M
JM
Chow