Resources for Measurement-Based Quantum Carry-Lookahead Adder

TL;DR

This paper introduces a measurement-based quantum carry-lookahead adder (QCLA) that significantly accelerates quantum addition operations by leveraging MBQC's state transfer capabilities, achieving logarithmic depth and resource trade-offs.

Contribution

The paper presents the first design of a measurement-based quantum carry-lookahead adder, demonstrating its speed advantage and resource considerations over ripple-carry adders.

Findings

QCLA has logarithmic depth, faster than linear-depth ripple adders.

QCLA is about ten times faster for registers over 100 qubits.

Hand optimization reduces spatial resources by approximately 26%.

Abstract

We present the design of a quantum carry-lookahead adder using measurement-based quantum computation. QCLA utilizes MBQC`s ability to transfer quantum states in unit time to accelerate addition. The quantum carry-lookahead adder (QCLA) is faster than a quantum ripple-carry adder; QCLA has logarithmic depth while ripple adders have linear depth. QCLA is an order of magnitude faster than a ripple-carry adder when adding registers longer than 100 qubits but requires a cluster state that is an order of magnitude larger. Hand optimization results in a $\approx$ 26% reduction in spatial resources for the circuit.