Singlet-only Always-on Gapless Exchange Qubits with Baseband Control
arXiv:2501.18589 · doi:10.1103/j1hn-k5m8
Abstract
We propose a singlet-only always-on gapless exchange (SAGE) spin qubit that encodes a single qubit in the spins of four electrons while allowing universal baseband control. While conventional exchange-only qubits suffer from magnetic-field-gradient-induced leakage and coherent errors, for instance due to local nuclear environments and variations in the -factor, the SAGE qubit subspace is protected from coherent errors due to local magnetic field gradients and leakage out of the computational subspace is energetically suppressed due to the exchange interactions between electrons being always-on. Consequently, we find that when magnetic gradient noise dominates over charge noise, coherence times and single-qubit gate infidelities of the SAGE qubit improve by an order of magnitude compared to conventional exchange-only qubits. Moreover, using realistic parameters, two-qubit gates can be performed with a single interqubit exchange pulse with times comparable in duration to conventional exchange-only qubits but with a significantly simplified pulse sequence.
4 pages, 4 figure, plus supplemental material
References in corpus (28)
- Randomized Benchmarking of Quantum Gates
- Semiconductor Spin Qubits
- Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
- Computing with spin qubits at the surface code error threshold
- Fast universal quantum control above the fault-tolerance threshold in silicon
- Universal control of a six-qubit quantum processor in silicon
- The germanium quantum information route
- Allowed and forbidden transitions in artificial hydrogen and helium atoms
- Reduced sensitivity to charge noise in semiconductor spin qubits via symmetric operation
- Characterizing errors on qubit operations via iterative randomized benchmarking
- Probing single electrons across 300 mm spin qubit wafers
- Universal logic with encoded spin qubits in silicon
- Operating semiconductor quantum processors with hopping spins
- Quantifying error and leakage in an encoded Si/SiGe triple-dot qubit
- Fast and high-fidelity state preparation and measurement in triple-quantum-dot spin qubits
- Quantum Dot Cluster State Computing with Encoded Qubits
- Optimized electrical control of a Si/SiGe spin qubit in the presence of an induced frequency shift
- Low charge noise quantum dots with industrial CMOS manufacturing
- 12-spin-qubit arrays fabricated on a 300 mm semiconductor manufacturing line
- A quadrupolar exchange-only spin qubit
- Energetic Suppression of Decoherence in Exchange-Only Quantum Computation
- The exchange-only singlet-only spin qubit
- Magnetic Gradient Fluctuations from Quadrupolar Ge in Si/SiGe Exchange-Only Qubits
- Preparation of Decoherence Free Cluster States with Optical Superlattices
- Highly tunable exchange-only singlet-only qubit in a GaAs triple quantum dot
- A Scalable Architecture for Coherence-Preserving Qubits
- Coherent control of a triangular exchange-only spin qubit
- Two-qubit gates for decoherence-free qubits using a ring exchange interaction