Enhanced coherence in superconducting circuits via band engineering

Abstract

In superconducting circuits interrupted by Josephson junctions, the dependence of the energy spectrum on offset charges on different islands is $2e$ periodic through the Aharonov-Casher effect and resembles a crystal band structure that reflects the symmetries of the Josephson potential. We show that higher-harmonic Josephson elements described by a $\cos (2\phi )$ energy-phase relation provide an increased freedom to tailor the shape of the Josephson potential and design spectra featuring multiplets of flat bands and Dirac points in the charge Brillouin zone. Flat bands provide noise-insensitive quantum states, and band engineering can help improve the coherence of the system. We discuss a modified version of a flux qubit that achieves in principle no decoherence from charge noise and introduce a flux qutrit that shows a spin-one Dirac spectrum and is simultaneously quote robust to both charge and flux noise.

5 pages, 4 figures

References in corpus (12)

• Charge insensitive qubit design derived from the Cooper pair box
• Hartree-Fock on a superconducting qubit quantum computer
• Suppressing Charge Noise Decoherence in Superconducting Charge Qubits
• Epitaxy of Semiconductor-Superconductor nanowires
• Low-decoherence flux qubit
• A Parity-Protected Superconductor-Semiconductor Qubit
• A long-lived capacitively shunted flux qubit embedded in a 3D cavity
• Reading-out the state inductively and microwave spectroscopy of an interferometer-type charge qubit
• The Cooper Pair Pump as a Quantized Current Source
• Full control of qubit rotations in a voltage-biased superconducting flux qubit
• Suppression of Tunneling in a Superconducting Persistent-Current Qubit
• Weyl points in the multi-terminal Hybrid Superconductor-Semiconductor Nanowire devices

Cited by in corpus (9)

• Berry Phase and Topology in Ultrastrongly Coupled Quantum Light-Matter Systems
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• Non-Abelian monopoles in the multiterminal Josephson effect
• Quantum circuits with multiterminal Josephson-Andreev junctions
• Variational tight-binding method for simulating large superconducting circuits
• Quasiperiodic circuit quantum electrodynamics
• The quartic Blochnium: an anharmonic quasicharge superconducting qubit
• Flux-Tunable Regimes and Supersymmetry in Twisted Cuprate Heterostructures
• SWAP gate between a Majorana qubit and a parity-protected superconducting qubit