Quantum logic with weakly coupled qubits

TL;DR

This paper develops a versatile method for constructing CNOT quantum gates in systems with weak, complex couplings, expanding the applicability beyond symmetric interaction models.

Contribution

It introduces a simple, intuitive CNOT construction applicable to weakly and arbitrarily coupled qubits, addressing more realistic quantum architectures.

Findings

Provides a universal CNOT gate design for weakly coupled qubits.

Extends solutions to common special cases with variations.

Enhances quantum gate design for complex coupling scenarios.

Abstract

There are well-known protocols for performing CNOT quantum logic with qubits coupled by particular high-symmetry (Ising or Heisenberg) interactions. However, many architectures being considered for quantum computation involve qubits or qubits and resonators coupled by more complicated and less symmetric interactions. Here we consider a widely applicable model of weakly but otherwise arbitrarily coupled two-level systems, and use quantum gate design techniques to derive a simple and intuitive CNOT construction. Useful variations and extensions of the solution are given for common special cases.