“…The nearest neighbor constraints have been considered in proposals for a range of potential technological realizations of quantum computers such as ion traps [4,32,38], nitrogen-vacancy centers in diamonds [38,55], quantum dots emitting linear cluster states linked by linear optics [10,21], laser manipulated quantum dots in a cavity [26] and superconducting qubits [13,40,34]. They are also considered in realizations of specific types of circuits and architectures, such as surface codes [49], Shor's algorithm [15], the Quantum Fourier Transform (QFT) [48], circuits for modular multiplication and exponentiation [35], quantum adders on the 2D NTC architecture [8], factoring [42], fault-tolerant circuits [33], error correction [16], and more recently, IBM QX architectures [50,56,57,14].…”