Micromagnetic Simulations of Circular Nano-magnets for Room Operable Quantum Cellular Automata

New quantum computing regimes are being explored to replace traditional scaling of metal-oxide-semiconductor (MOS) transistors based on Moore’s Law. Nanomagnets hold significant potential as room operable Quantum Cellular Automata (QCA), the building blocks for quantum computers. Bistability is based on stable ground magnetization states, meaning power dissipation is extremely low, and their small size allows magnetization to be maintained for a long period time. Packing density is on the order of 1010/cm2 and switching frequency in the terahertz range, allowing them to potentially compete with state-of-the-art MOS. This work explores the viability of circular nanomagnets as QCA using micro-magnetic simulations. Circular nanomagnets are special because their magnetization forms a closed vortex when no external field is present meaning logic states can be represented using the chirality the magnetization. These simulations offer insight into how the switching process within these elements evolve since current experimental techniques lack the combined temporal and spatial resolution needed. Entanglement and tunability of interactions through physical contact of elements in linear chains is investigated. Like gears in a mechanical system, the chirality of the magnetization in each nanomagnet is determined through interaction with its neighbors. The quantum exchange force, at the point of contact between elements causes the magnetization vectors to rotate in the same direction giving rise to opposite chiralities in the neighboring elements. Elements in different configurations can potentially be used to implement elementary or complex logic functions. The simulations done herein represent a first step into the exploration of nanomagents for the quantum computing regime.