Final answer:
Rare Earth atoms are utilized in quantum memory due to their long coherence times, ability to maintain quantum states, and strong interactions with light. They enable stable storage and manipulation of quantum information, contrasting the traditional magnetic memory methods, and are fundamental for efficient quantum computing.
Step-by-step explanation:
Rare Earth atoms are used for quantum memory due to their unique quantum mechanical properties which are suitable for quantum computing. These atoms can be controlled precisely and exhibit long coherence times, which means they can maintain their quantum states for longer, providing the stability that is necessary for storing quantum information. Moreover, they interact strongly with light, making them suitable for high fidelity manipulation and readout of quantum information. Rare Earth atoms, embedded in materials like crystals, present an organized and clean system that minimizes interactions with the environment, thereby preserving the quantum information.
In contrast to traditional magnetic-based memory storage that relies on the orientation of magnetic fields in ferromagnetic domains, quantum memory requires the ability to manipulate the quantum states of particles, such as photons or atoms, to store information. The discovery of giant magnetoresistance, which led to advances in classical computer memory, underscores the continuous search for materials that can further improve memory devices. In quantum computing, quantum dots and other nanostructured materials harness quantum-tunneling phenomena, similar to the tunneling that occurs in STM and in the development of nano-electronics, to create potential wells that trap electrons, thus enabling memory storage at the quantum level.
The capability to encode information in quantum bits — by exploiting the superposition and entanglement of quantum states — allows quantum computers to perform certain types of calculations much more efficiently than classical computers, which operate solely on binary digits. The exploitation of properties such as superposition and entanglement is crucial for the progress of quantum computing, and Rare Earth atoms serve as a powerful medium to achieve this.