Hamiltonian quantum gates -- energetic advantage from entangleability

TL;DR

This paper establishes a fundamental link between the energy needed for Hamiltonian quantum gates and their entangleability, suggesting that entanglement can enable more energy-efficient quantum computation.

Contribution

It derives a lower bound on the energy for quantum gates and explores how entangleability can reduce energetic costs in quantum computing.

Findings

Lower bound on energy for implementing quantum gates.

Entangleability can lead to more energy-efficient quantum computation.

Universal quantum computing can be achieved with minimal energy at high complexity.

Abstract

Hamiltonian quantum gates controlled by classical electromagnetic fields form the basis of any realistic model of quantum computers. In this letter, we derive a lower bound on the field energy required to implement such gates and relate this energy to the expected gate error. We study the entangleability (ability to entangle qubits) of Hamiltonians and highlight how this feature of quantum gates can provide a means for more energetically efficient computation. Ultimately, we show that a universal quantum computer can be realized with vanishingly low energetic requirements but at the expense of arbitrarily large complexity.