High-fidelity gates in quantum dot spin qubits

Abstract

Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet (ST) and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance (LQR), and a gate-like process known as stimulated Raman adiabatic passage (STIRAP). These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling $g$ and the detuning $\epsilon$, which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity ($f$) for fixed $g$ as a function of the other control parameters; this yields an $f^{\text{opt}}(g)$ that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound $f^{\text{max}}$ that is specific to the qubit-gate combination. We show that similar gate fidelities ($\sim 99.5$%) should be attainable for ST qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields $\Delta B$ produced by nuclear spins.

20 pages, 7 figures

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• A single-atom electron spin qubit in silicon
• Electrically driven single electron spin resonance in a slanting Zeeman field
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• Dynamically Error-Corrected Gates for Universal Quantum Computation
• Coherent spin manipulation in an exchange-only qubit
• Dynamic Nuclear Polarization with Single Electron Spins
• Universal pulse sequence to minimize spin dephasing in the central spin decoherence problem
• Universal set of quantum gates for double-dot spin qubits with fixed interdot coupling
• Fast coherent manipulation of three-electron states in a double quantum dot
• A simple approach to the Landau-Zener formula

Cited by in corpus (23)

• Stimulated Raman adiabatic passage in physics, chemistry and beyond
• Quantum control and process tomography of a semiconductor quantum dot hybrid qubit
• High fidelity resonant gating of a silicon based quantum dot hybrid qubit
• Extending the coherence of a quantum dot hybrid qubit
• A decoherence-free subspace in a charge quadrupole qubit
• Achieving High Fidelity Single Qubit Gates in a Strongly Driven Silicon Quantum Dot Hybrid Qubit
• Two-body Wigner molecularization in asymmetric quantum dot spin qubits
• Coherent Tunneling by Adiabatic Passage of an exchange-only spin qubit in a double quantum dot chain
• Imaging stars with quantum error correction
• Universal Set of Quantum Gates for Double-Dot Exchange-Only Spin Qubits with Intradot Coupling
• High-fidelity single-qubit gates in a strongly driven quantum dot hybrid qubit with $1/f$ charge noise
• Signatures of atomic-scale structure in the energy dispersion and coherence of a Si quantum-dot qubit
• High Fidelity Singlet-Triplet $S$-$T_{-}$ Qubits in Inhomogeneous Magnetic Fields
• High fidelity ac gate operations of the quantum dot hybrid qubit
• Multi-qubit gates protected by adiabaticity and dynamical decoupling applicable to donor qubits in silicon
• Coherent Control with User-Defined Passage
• Optimization of STIRAP-based state transfer under dissipation
• Charge noise suppression in capacitively coupled singlet-triplet spin qubits under magnetic field
• Robust population transfer of spin states by geometric formalism
• Long-range two-hybrid-qubit gates mediated by a microwave cavity with red sidebands
• Robust entangling gate for capacitively coupled few-electron singlet-triplet qubits
• A robust operating point for capacitively coupled singlet-triplet qubits
• Stimulated Raman adiabatic passage-like protocols for amplitude transfer generalize to many bipartite graphs