Decoherence of an exchange qubit by hyperfine interaction

Abstract

We study three-electron-spin decoherence in a semiconductor triple quantum dot with a linear geometry. The three electron spins are coupled by exchange interactions J_{12} and J_{23}, and we clarify inhomogeneous and homogeneous dephasing dynamics for a logical qubit encoded in the (S=1/2,S_{z} =1/2) subspace. We first justify that qubit leakage via the fluctuating Overhauser field can be effectively suppressed by sufficiently large Zeeman and exchange splittings. For J_{12}=J_{23} and the case of J_{12} and J_{23} being different, we construct an effective pure dephasing Hamiltonian with the Zeeman splitting much larger than the exchange splitting. Both effective Hamiltonians have the same order of magnitude as that for a single-spin qubit, and the relevant dephasing time scales are of the same order as those for a single spin. We provide estimates of the dynamics of three-spin free induction decay, the decay of a Hahn spin echo, and the decay of echoes from a CPMG pulse sequence for GaAs quantum dots.

arXiv comment15 pages, 8 figures

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Cited by in corpus (21)

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• Environmental noise spectroscopy with qubits subjected to dynamical decoupling
• Three-electron spin qubits
• Coupling of three-spin qubits to their electric environment
• The asymmetric resonant exchange qubit under the influence of electrical noise
• A quadrupolar exchange-only spin qubit
• Characterizing gate operations near the sweet spot of an exchange-only qubit
• Long distance coupling of resonant exchange qubits
• The exchange-only singlet-only spin qubit
• Spin blockade and coherent dynamics of high-spin states in a three-electron double quantum dot
• Highly tunable exchange-only singlet-only qubit in a GaAs triple quantum dot
• Leakage and sweet spots in triple-quantum-dot spin qubits: A molecular-orbital study
• Anisotropic $g$-tensors in hole quantum dots: The role of the transverse confinement direction
• Characterisation of an exchange-based two-qubit gate for resonant exchange qubits
• Wigner-molecularization-enabled dynamic nuclear field programming
• Hyperfine-induced dephasing in three-electron spin qubits
• Benchmarking of dynamically corrected gates for the exchange-only spin qubit in $1/f$ noise environment
• Optimisation of electrically-driven multi-donor quantum dot qubits
• Optimizing electrically controlled echo sequences for the exchange-only qubit
• Decoherence in Exchange-Coupled Quantum Spin Qubit Systems: Impact of Multiqubit Interactions and Geometric Connectivity
• Transport-induced suppression of nuclear field fluctuations in multi-quantum-dot systems