Asymmetric repitition code for a cat-qubit

The invention relates to a repetition code for a cat qubit comprising a number d of data cat-qubits (4) and at least (d-1) ancillary cat-qubits (6), the number d being greater than or equal to 3, each ancillary cat-qubit (6) being connected to two data cat-qubits (4) by two respective CNOT gates (8) in such a way that no data cat-qubit (4) is connected to more than two ancillary cat-qubits (6), the two-photon dissipation rate of the ancillary cat-qubits being strictly greater than the two-photon dissipation factor of the data cat-qubits. Said repetition code is implemented by carrying out, for each ancillary cat-qubit (6), error correction cycles comprising at least the following steps: a) preparing the ancillary cat-qubit (6) so as to be in a state suitable for the operator X: "|+>" or "|->"; b) activating one of the two CNOT gates (8) connected to said ancillary cat-qubit (6); c) activating the other CNOT gate (8) connected to this ancillary cat-qubit (6); and d) measuring the photon-number parity of said ancillary cat-qubit (6).