Quantum oscillations in two coupled charge qubits

TL;DR

This paper reports the experimental observation of quantum oscillations in two coupled charge qubits, demonstrating the feasibility of multi-qubit coupling and entanglement in solid-state quantum systems.

Contribution

It introduces a new coupled charge qubit circuit and demonstrates coherent quantum state mixing and oscillations, advancing multi-qubit quantum computing technology.

Findings

Observation of quantum oscillations reflecting qubit interaction

Evidence of entangled two-qubit states

Demonstration of coupling in solid-state qubits

Abstract

Despite an apparent progress in implementing individual solid-state qubits, there have been no experimental reports so far on multi-bit gates required for building a real quantum computer. Here we report a new circuit comprising two coupled charge qubits. Using a pulse technique, we coherently mix quantum states and observe quantum oscillations whose spectrum reflects interaction between the qubits. Our results demonstrate the feasibility of coupling of multiple solid-state qubits and indicate the existence of entangled two-qubit states.