ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT ttk.bme.hu>]

Dear Colleagues,

We have an online (Microsoft Teams) seminar this week at our Quantum Error
Correction seminar series at BME TTK Theor. Phys.

Thursday, June 22, at 10:00 AM.
https://rb.gy/dnb74

Francesco Battistel (Qblox / QuTech, Delft):
When quantum error correction meets leakage in a superconducting surface
code

Abstract:
Quantum error correcting codes are being implemented in a variety of
experimental platforms. In this talk we review the surface code and we
focus on an implementation with superconducting transmon qubits. Among
other types of error, we consider what happens when the state “leaks” into
higher energy states above the two computational states of a qubit. Leakage
is shown to be particularly damaging since the surface code is not built to
be resistant to it [1]. However, leakage-reduction units can be used to
bring the state back into the qubit subspace. We discuss our
leakage-reduction technique [2] that drives a transmon qubit to transfer
leakage to a neighbouring system (the readout resonator), where it quickly
dissipates into the environment. We show that this substantially improves
the surface-code performance in a realistic parameter regime and we comment
on a recent experimental implementation [3].

[1] https://arxiv.org/abs/2002.07119
[2] https://arxiv.org/abs/2102.08336
[3] https://arxiv.org/abs/2302.09876

About the speaker: Francesco Battistel is Roadmap Leader for Fault-Tolerant
Quantum Computing at Qblox, a quantum control stack manufacturer spinoff of
QuTech, Delft, the Netherlands. He’s focused on developing the scalable
feedback architecture of the quantum control stack that supports
state-of-the-art real-time decoders. Francesco completed his PhD in Barbara
Terhal’s group, where he worked on quantum error correction and leakage,
with a tight collaboration with experimental research on superconducting
qubits at Leo DiCarlo’s lab.

We welcome anybody who is interested.

Best,
 Janos Asboth