Simple operation sequences to couple and interchange quantum information between spin qubits of different kinds

TL;DR

This paper presents simplified sequences of exchange interactions for efficiently coupling and converting quantum information between various quantum dot spin qubits, enhancing the practicality of quantum dot quantum computing.

Contribution

It introduces minimal operation sequences for entangling different spin qubit types using exchange interactions, simplifying quantum information transfer in quantum dot systems.

Findings

Single-exchange interaction sequences enable entanglement between different qubit types.

The sequences maintain some single-qubit interactions during entangling operations.

Quantum information conversion between qubit types is feasible with these sequences.

Abstract

Efficient operation sequences to couple and interchange quantum information between quantum dot spin qubits of different kinds are derived using exchange interactions. In the qubit encoding of a single-spin qubit, a singlet-triplet qubit, and an exchange-only (triple-dot) qubit, some of the single-qubit interactions remain on during the entangling operation; this greatly simplifies the operation sequences that construct entangling operations. In the ideal setup, the gate operations use the intra-qubit exchange interactions only once. The limitations of the entangling sequences are discussed, and it is shown how quantum information can be converted between different kinds of quantum dot spin qubits.