Coherent spin-state transfer via Heisenberg exchange

Area of Science:

• Quantum Information Science
• Quantum Computing
• Condensed Matter Physics

Background:

• Quantum information science promises advancements in computing, communication, and sensing.
• Quantum error correction is essential for fault-tolerant quantum processing but requires high qubit connectivity.
• Electron spin qubits, naturally favoring linear arrangements, face challenges in achieving high connectivity.

Purpose of the Study:

• To experimentally demonstrate the transmission of electron spin states in an array of spin qubits.
• To showcase the use of Heisenberg exchange interaction for scalable qubit state transfer.
• To enable multi-qubit gates and error correction in spin-based quantum computers.

Main Methods:

• Utilized a semiconductor quadruple quantum dot array to host electron spin qubits.
• Precisely controlled wavefunction overlap between electrons to engineer Heisenberg exchange coupling.
• Executed coherent SWAP operations for bidirectional state transfer without physical electron movement.

Main Results:

• Successfully transmitted both single-spin and entangled states across the qubit array.
• Demonstrated the efficacy of Heisenberg exchange interaction for controlled quantum state transfer.
• Verified the scalability of the state transfer process for a larger number of qubits.

Conclusions:

• Heisenberg exchange interaction provides a viable mechanism for scalable state transfer in spin qubit arrays.
• This technique is crucial for enabling essential operations like multi-qubit gates and quantum error correction.
• The findings pave the way for developing more robust and powerful spin-based quantum computers.