Long-Range Interaction Enhanced Adiabatic Quantum Computers

Abstract

A quantum computer is not necessarily alone, e.g., thousands and millions of quantum computers are simultaneously working together for adiabatic quantum computers based on nuclear spins. Long-range interaction is inevitable between these nuclear spin qubits. Here we investigate the effect of long-range dipolar interaction between different adiabatic quantum computers. Our analytical and numerical results show that the dipolar interaction can enhance the final fidelity in adiabatic quantum computation for solving the factorization problem, when the overall interaction is negative. The enhancement will become more prominent if a single quantum computer encounters an extremely small energy gap which occurs more likely for larger-size systems.

Quantum Computing by Cooling

“…QCR is an open system usually coupled to Markovian bath [28][29][30]. For interaction enhanced quantum computing, the interaction is between different quantum computers not between a system and a bath [31]. We also note that an early work indicates that non-Markovian bath could improve the performance of a quantum refregirator [32].…”

Balancing the Quantum Speed Limit and Instantaneous Energy Cost in Adiabatic Quantum Evolution

“…DOI: 10.1088/0256-307X/41/4/040202 Quantum adiabatic control plays an important role in almost all areas of quantum physics. [1][2][3][4][5][6][7] However, it encounters serious limitation for quantum platforms with short decoherence times, such as superconducting quantum circuits, [8,9] since it requires the sufficiently slow change of Hamiltonian in the whole quantum evolution process. [10][11][12][13] In recent years, speeding up adiabatic processes has garnered increasing attention, and various approaching paths have emerged, e.g., designing new adiabatic conditions to break the constraints of the traditional approximation adiabatic condition, [14][15][16][17][18][19][20] extending the classical optimal control theory to quantum systems [21,22] for exploring the time-optimal adiabatic trajectory, [23,24] and using shortcut-to-adiabaticity (STA) techniques, [25,26] such as counter-diabatic (CD) driving, [27] to suppress nonadiabatic transitions.…”