Universal quantum computation using quantum annealing with transverse field Ising Hamiltonian

  In the field of quantum computation, two distinctive architectures have emerged: gate-type quantum computers and quantum annealing. Gate-type quantum computation involves the sequential application of quantum gates to perform calculations, enabling universal quantum computation. However, the scalability of gate-type quantum computers poses substantial experimental challenges, limiting them to utilizing only around a hundred qubits with current technology.

  In contrast, quantum annealing offers an alternative approach, focused on solving combinatorial optimization problems by preparing the ground state of an Ising Hamiltonian. Quantum annealers, such as those developed by D-Wave Systems, have made thousands of qubits available for such tasks. Yet, achieving universal quantum computation with the quantum annealing architecture requires many ancillary qubits and complicated interactions, rendering it impractical with current technology.

  In this paper, we present a practical method for implementing universal quantum computation within the conventional quantum annealing architecture using the transverse field Ising Hamiltonian. Our innovative approach relies on an adiabatic transformation of the Hamiltonian, changing from transverse fields to a ferromagnetic interaction regime, where the ground states become degenerate. Notably, our proposal is compatible with D-Wave devices, opening up possibilities for realizing large-scale gate-type quantum computers.

This research bridges the gap between quantum annealing and gate-type quantum computation, offering a promising path toward the development of scalable quantum computing platforms.