Dynamics of two coupled semiconductor spin qubits in a noisy environment

Abstract

We theoretically consider the temporal dynamics of two coupled spin qubits (e.g., semiconductor quantum dots) driven by the inter-qubit spin-spin coupling. The presence of environmental noise (e.g., charge traps, nuclear spins, random magnetic impurities) is accounted for by including random magnetic field and random inter-qubit coupling terms in the Hamiltonian. Both Heisenberg coupling and Ising coupling between the spin qubits are considered, corresponding respectively to exchange and capacitive gates as appropriate for single spin and singlet-triplet semiconductor qubit systems, respectively. Both exchange (Heisenberg) and capacitive (Ising) coupling situations can be solved numerically exactly even in the presence of noise, leading to the key findings that (i) the steady-state return probability to the initial state remains close to unity in the presence of strong noise for many, but not all, starting spin configurations, and (ii) the return probability as a function of time is oscillatory with a characteristic noise-controlled decay toward the steady-state value. We also provide results for the magnetization dynamics of the coupled two-qubit system. Our predicted dynamics can be directly tested in the already existing semiconductor spin qubit setups providing insight into their coherent interaction dynamics. Retention of the initial state spin memory even in the presence of strong environmental noise has important implications for quantum computation using spin qubits.

11.5 pages, 18 figures. Added new figures to emphasize the effects of charge noise. Expanded the introduction and conclusion to discuss how to experimentally verify our results and to connect it with previous work on larger spin systems. Published in Phys. Rev. B; this is the published version

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Cited by in corpus (9)

• Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits
• Environmental noise effects on entanglement fidelity of exchange-coupled semiconductor spin qubits
• Pulse sequences for suppressing leakage in single-qubit gate operations
• Coherence time analysis in semiconducting hybrid qubit under realistic experimental conditions
• Exact analytical treatment of multiqubit noisy dynamics in exchange-coupled semiconductor spin qubits
• Semiconducting double-dot exchange-only qubit dynamics in presence of magnetic and charge noises
• Spin flip locking by the tunneling and relaxation in a driven double quantum dot with spin-orbit coupling
• A generalized model of the noise spectrum of a two-level fluctuator in the presence of an electron subbath
• Entanglement between distant atoms mediated by a hybrid quantum system consisting of superconducting flux qubit and resonators