Directly accessible entangling gates for capacitively coupled singlet-triplet qubits

Abstract

The recent experimental advances in capacitively coupled singlet-triplet qubits, particularly the demonstration of entanglement, opens the question of what type of entangling gates the system's Hamiltonian can produce directly via a single square pulse. We address this question by considering the system's Hamiltonian from first principles and using the representation of its nonlocal properties in terms of local invariants. In the analysis we include the three different ways in which the system can be biased and their effect on the generation of entangling gates. We find that, in one of the possible biasing modes, the Hamiltonian has an especially simple form, which can directly generate a wide range of different entangling gates including the iSWAP gate. Moreover, using the complete form of the Hamiltonian we find that, for any biasing mode, a CNOT gate can be generated directly.

10 pages, 5 figures

References in corpus (7)

• Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
• Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization
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Cited by in corpus (3)

• A robust operating point for capacitively coupled singlet-triplet qubits
• Rapid adiabatic gating for capacitively coupled quantum dot hybrid qubits without barrier control
• On the validity of microscopic calculations of double-quantum-dot spin qubits based on Fock-Darwin states