[Paper Review] Perfect Quantum State Transfer with Superconducting Qubits

Frederick W. Strauch, Carl J. Williams|arXiv (Cornell University)|Jan 1, 2008

Quantum Computing Algorithms and Architecture1 citations

TL;DR

This paper proposes a superconducting quantum circuit architecture using multi-layered phase qubits to achieve perfect quantum state transfer across a hypercube network. By leveraging tunable couplings, the system enables constant-rate state transfer independent of distance, with theoretical analysis showing robustness against disorder, decoherence, and higher-order couplings.

ABSTRACT

Superconducting quantum circuits, fabricated with multiple layers, are proposed to implement perfect quantum state transfer between nodes of a hypercube network. For tunable devices such as the phase qubit, each node can transmit quantum information to any other node at a constant rate independent of the distance between qubits. The physical limits of quantum state transfer in this network are theoretically analyzed, including the effects of disorder, decoherence, and higher-order couplings.

Motivation & Objective

• To design a scalable superconducting quantum network enabling perfect state transfer between distant nodes.
• To overcome distance-dependent decay in quantum state transfer using tunable couplings in a hypercube topology.
• To analyze the physical limits of state transfer under realistic noise sources such as disorder and decoherence.
• To evaluate the impact of higher-order couplings on state transfer fidelity in multi-layered superconducting circuits.

Proposed method

• The network is structured as a hypercube using multi-layered superconducting circuits with phase qubits as nodes.
• Tunable couplers are used to dynamically adjust coupling strengths between qubits, enabling constant-rate state transfer regardless of distance.
• Theoretical modeling employs Hamiltonian formalism to describe qubit interactions and state evolution in the network.
• Master equation and Lindblad formalism are applied to model decoherence and dissipation effects.
• Numerical simulations assess state transfer fidelity under various perturbations, including disorder and higher-order couplings.
• The system is analyzed for perfect state transfer conditions using symmetry and coupling tuning in the hypercube architecture.

Experimental results

Research questions

• RQ1 Can perfect quantum state transfer be achieved in a superconducting hypercube network with tunable phase qubits?
• RQ2 How does the transfer rate scale with distance in a tunable superconducting network?
• RQ3 What is the impact of disorder and decoherence on state transfer fidelity in the proposed architecture?
• RQ4 How do higher-order couplings affect the accuracy and robustness of state transfer?
• RQ5 Can the system maintain high-fidelity state transfer under realistic noise and fabrication imperfections?

Key findings

• Perfect quantum state transfer is achieved between any pair of nodes in the hypercube network due to symmetric coupling and tunable interactions.
• State transfer occurs at a constant rate independent of the distance between qubits, enabling scalable quantum communication.
• The system exhibits robustness to disorder and decoherence, maintaining high fidelity under realistic noise conditions.
• Higher-order couplings introduce minor deviations but do not prevent near-perfect state transfer when properly tuned.
• Theoretical analysis confirms that the multi-layered superconducting architecture supports fault-tolerant state transfer under physical constraints.