Robust entangling gate for capacitively coupled few-electron singlet-triplet qubits

Abstract

The search of a sweet spot, locus in qubit parameters where quantum control is first-order insensitive to noises, is key to achieve high-fidelity quantum gates. Efforts to search for such a sweet spot in conventional double-quantum-dot singlet-triplet qubits where each dot hosts one electron ("two-electron singlet-triplet qubit"), especially for two-qubit operations, have been unsuccessful. Here we consider singlet-triplet qubits allowing each dot to host more than one electron, with a total of four electrons in the double quantum dots ("four-electron singlet-triplet qubit"). We theoretically demonstrate, using configuration-interaction calculations, that sweet spots appear in this coupled qubit system. We further demonstrate that, under realistic charge noise and hyperfine noise, two-qubit operation at the proposed sweet spot could offer gate fidelities ($\sim 99\%$) that are higher than conventional two-electron singlet-triplet qubit system ($\sim 90\%$). Our results should facilitate realization of high-fidelity two-qubit gates in singlet-triplet qubit systems.

arXiv comment52 pages, 9 figs

References in corpus (90)

• Coupled quantum dots as quantum gates
• An addressable quantum dot qubit with fault-tolerant control fidelity
• A Two Qubit Logic Gate in Silicon
• A >99.9%-fidelity quantum-dot spin qubit with coherence limited by charge noise
• Coherent manipulation of electronic states in a double quantum dot
• A programmable two-qubit quantum processor in silicon
• A simple formula for the average gate fidelity of a quantum dynamical operation
• Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
• Phonon-induced decay of the electron spin in quantum dots
• Universal quantum computation with spin-1/2 pairs and Heisenberg exchange
• Charge-qubit operation of an isolated double quantum dot
• Quantum Coherence in a One-Electron Semiconductor Charge Qubit
• Fidelity benchmarks for two-qubit gates in silicon
• Electrometry Using Coherent Exchange Oscillations in a Singlet-Triplet-Qubit
• Double quantum dot with integrated charge sensor based on Ge/Si heterostructure nanowires
• Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting
• Reduced sensitivity to charge noise in semiconductor spin qubits via symmetric operation
• Fast two-qubit logic with holes in germanium
• A fast "hybrid" silicon double quantum dot qubit
• Scaling of Dynamical Decoupling for Spin Qubits
• Valley Splitting Theory of SiGe/Si/SiGe Quantum Wells
• Two-axis control of a singlet-triplet qubit with an integrated micromagnet
• Valley splitting in strained silicon quantum wells
• Interlaced Dynamical Decoupling and Coherent Operation of a Singlet-Triplet Qubit
• Low disordered, stable, and shallow germanium quantum wells: a playground for spin and hybrid quantum technology
• Gate-controlled quantum dots and superconductivity in planar germanium
• Charge-noise spectroscopy of Si/SiGe quantum dots via dynamically-decoupled exchange oscillations
• Assessment of a silicon quantum dot spin qubit environment via noise spectroscopy
• Theory of phonon-induced spin relaxation in laterally coupled quantum dots
• Coherent Quantum Oscillations in a Silicon Charge Qubit
• Theory of Hole-Spin Qubits in Strained Germanium Quantum Dots
• Electrically Protected Valley-Orbit Qubits in Silicon
• Fast coherent manipulation of three-electron states in a double quantum dot
• Exchange coupling in silicon quantum dots: Theoretical considerations for quantum computation
• Extending the coherence of a quantum dot hybrid qubit
• Spin properties of single electron states in coupled quantum dots
• Pulse-gated quantum dot hybrid qubit
• Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot
• Spin relaxation at the singlet-triplet crossing in a quantum dot
• Resonantly driven singlet-triplet spin qubit in silicon
• Closed-loop control of a GaAs-based singlet-triplet spin qubit with 99.5% gate fidelity and low leakage
• Tunable singlet-triplet splitting in a few-electron Si/SiGe quantum dot
• Single-spin qubits in isotopically enriched silicon at low magnetic field
• Nonadiabatic quantum control of a semiconductor charge qubit
• Quantum gates between capacitively coupled double quantum dot two-spin qubits
• Coherence and Screening in Multi-Electron Spin Qubits
• Achieving High-Fidelity Single-Qubit Gates in a Strongly Driven Charge Qubit with $1/f$ Charge Noise
• Spin filling and orbital structure of the first six holes in a silicon metal-oxide-semiconductor quantum dot
• Screening of charged impurities with multi-electron singlet-triplet spin qubits in quantum dots
• Exchange-based CNOT gates for singlet-triplet qubits with spin orbit interaction
• Strong electron-electron interactions in Si/SiGe quantum dots
• Spin Decay in a Quantum Dot Coupled to a Quantum Point Contact
• Phonon-Mediated Decay of Singlet-Triplet Qubits in Double Quantum Dots
• A natural heavy-hole flopping mode qubit in germanium
• Exchange-based two-qubit gate for singlet-triplet qubits
• Electron spin coherence of shallow donors in natural and isotopically enriched germanium
• Controllable exchange coupling between two singlet-triplet qubits
• Two-Qubit Couplings of Singlet-Triplet Qubits Mediated by One Quantum State
• Negative spin exchange in a multielectron quantum dot
• High-fidelity gates in quantum dot spin qubits
• Spatial Noise Correlations in a Si/SiGe Two-Qubit Device from Bell State Coherences
• Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits
• Spin of a multielectron quantum dot and its interaction with a neighboring electron
• Nuclear Spin Dynamics in Double Quantum Dots: Fixed Points, Transients, and Intermittency
• Electrically controlled quantum gates for two-spin qubits in two double quantum dots
• Single and Double Hole Quantum Dots in Strained Ge/SiGe Quantum Wells
• Theory of Spin Relaxation in Two-Electron Lateral Coupled Quantum Dots
• High-fidelity gate set for exchange-coupled singlet-triplet qubits
• A fast quantum interface between different spin qubit encodings
• Analytic calculation of ground state splitting in symmetric double well potential
• Bell-state tomography in a silicon many-electron artificial molecule
• Adiabatic two-qubit gates in capacitively coupled quantum dot hybrid qubits
• Directly accessible entangling gates for capacitively coupled singlet-triplet qubits
• Configuration interaction calculations of the controlled phase gate in double quantum dot qubits
• Cavity Control over Heavy-Hole Spin Qubits in Inversion-Symmetric Crystals
• Capacitively coupled singlet-triplet qubits in the double charge resonant regime
• Negative exchange interactions in coupled few-electron quantum dots
• Enhancing the dipolar coupling of a $S$-$T_0$ qubit with a transverse sweet spot
• High-Fidelity Entangling Gates for Quantum-Dot Hybrid Qubits Based on Exchange Interactions
• Programmable two-qubit gates in capacitively coupled flopping-mode spin qubits
• Noise-Protected Gate for Six-Electron Double-Dot Qubits
• Low-noise conditional operation of singlet-triplet coupled quantum dot qubits
• Error correction for gate operations in systems of exchange-coupled singlet-triplet qubits in double quantum dots
• Charge noise suppression in capacitively coupled singlet-triplet spin qubits under magnetic field
• Capacitative coupling of singlet-triplet qubits in different inter-qubit geometries
• Simulation of Coupling Strength of Capacitively Coupled Singlet-Triplet Qubits
• Long-range two-hybrid-qubit gates mediated by a microwave cavity with red sidebands
• A robust operating point for capacitively coupled singlet-triplet qubits
• Microscopic theory on magnetic-field-tuned sweet spot of exchange interactions in multielectron quantum-dot systems
• Rapid adiabatic gating for capacitively coupled quantum dot hybrid qubits without barrier control

Cited by in corpus (4)

• Theory on electron-phonon spin dehphasing in GaAs multi-electron double quantum dots
• Universal control of superexchange in linear triple quantum dots with an empty mediator
• Dressed basis sets for the modeling of exchange interactions in double quantum dots
• Exploring Entanglement Spectrum and Phase Diagram in multi-electron Quantum Dot Chains