Stabilizing a Bosonic Qubit Using Colored Dissipation.

Area of Science:

• Quantum computing
• Quantum information science
• Solid-state physics

Background:

• Protected qubits, such as 0-π and bosonic qubits (cat, Gottesman-Kitaev-Preskill/GKP), offer fault tolerance advantages.
• Energy-gap-protected qubits can suffer from performance limitations due to leakage to excited states without dissipative stabilization.
• Existing stabilization methods may not be compatible with the specific properties of certain protected qubits.

Purpose of the Study:

• To propose and demonstrate a scheme for dissipatively stabilizing energy-gap-protected qubits.
• To suppress leakage errors without inducing errors within the protected ground state manifold.
• To apply and validate the technique on Kerr-cat qubits, introducing colored Kerr-cat qubits.

Main Methods:

• Developing a scheme for colored (frequency-selective) dissipation.
• Engineering colored single-photon loss for Kerr-cat qubits.
• Analyzing the suppression of leakage-induced bit-flip errors using linear interactions.

Main Results:

• Successfully applied colored dissipation to stabilize Kerr-cat qubits.
• Significantly suppressed leakage-induced bit-flip errors in colored Kerr-cat qubits.
• Demonstrated the broader applicability of frequency-selective loss to other protected qubit types.

Conclusions:

• Colored dissipation is an effective method for stabilizing energy-gap-protected qubits.
• The proposed technique enhances fault tolerance by mitigating leakage errors.
• Frequency-selective loss offers a versatile approach for protecting various quantum computing architectures.