Scalable entanglement of nuclear spins mediated by electron exchange

Abstract

The use of nuclear spins for quantum computation is limited by the difficulty in creating genuine quantum entanglement between distant nuclei. Current demonstrations of nuclear entanglement in semiconductors rely upon coupling the nuclei to a common electron, which is not a scalable strategy. Here we demonstrate a two-qubit Control-Z logic operation between the nuclei of two phosphorus atoms in a silicon device, separated by up to 20 nanometers. Each atoms binds separate electrons, whose exchange interaction mediates the nuclear two-qubit gate. We prepare and measure a nuclear Bell state with a fidelity of 76 +/- 5 $\%$ and a concurrence of 0.67 +/- 0.05. With this method, future progress in scaling up semiconductor spin qubits can be extended to the development of nuclear-spin based quantum computers.

References in corpus (16)

• Semiconductor Spin Qubits
• Universal control of a six-qubit quantum processor in silicon
• Room temperature quantum bit storage exceeding 39 minutes using ionized donors in 28-silicon
• Precision tomography of a three-qubit donor quantum processor in silicon
• Bang-bang control of fullerene qubits using ultra-fast phase gates
• Demonstration of entanglement-by-measurement of solid state qubits
• Probing single electrons across 300 mm spin qubit wafers
• Davies ENDOR revisited: Enhanced sensitivity and nuclear spin relaxation
• Hotter is easier: unexpected temperature dependence of spin qubit frequencies
• Jellybean quantum dots in silicon for qubit coupling and on-chip quantum chemistry
• Beating the thermal limit of qubit initialization with a Bayesian Maxwell's demon
• Tomography of entangling two-qubit logic operations in exchange-coupled donor electron spin qubits
• Single-Step Parity Check Gate Set for Quantum Error Correction
• Scalable Atomic Arrays for Spin-Based Quantum Computers in Silicon
• Improved placement precision of implanted donor spin qubits in silicon using molecule ions
• Error channels in quantum nondemolition measurements on spin systems

Cited by in corpus (4)

• Comparing Schemes for Creating Qudit Graph States from 16- & 128-dimensional Hilbert Space using Donors in Silicon
• Electron readout contrast enhancement in the parallel nuclear regime of an exchange-coupled donor spin qubit system
• Fault-Tolerant Encoding of Logical Qudits in Spin Systems
• Coupling a ${}^{73}$Ge nuclear spin to an electrostatically defined quantum dot