Artificial atoms, also known as qubits, in quantum computers can be created using various physical systems. Here are a few examples of how qubits are created in different platforms:
Superconducting qubits: Superconducting qubits are one of the most widely used platforms in quantum computing research. They are typically created using Josephson junctions, which are small devices made from superconducting materials. By applying an external magnetic field or current, the Josephson junction can exhibit quantum behavior, acting as a qubit. The two main types of superconducting qubits are the transmon qubit and the flux qubit, both of which exploit the quantum behavior of superconducting circuits.
Trapped ion qubits: Trapped ion qubits use individual ions that are trapped and manipulated using electromagnetic fields. Typically, laser beams are used to cool and trap the ions in a vacuum chamber. The internal energy levels of the ions serve as the qubit states. The qubits are manipulated by applying laser pulses and magnetic fields to induce transitions between the energy levels, effectively creating a qubit with long coherence times.
Semiconductor qubits: Semiconductor quantum dots can also be used to create qubits. These are tiny regions within a semiconductor material that can confine a small number of electrons. By controlling the voltages applied to the electrodes surrounding the quantum dot, researchers can manipulate the electron's spin state, which serves as the qubit. Semiconductor qubits offer the potential for integration with existing semiconductor technologies.
Topological qubits: Topological qubits are an emerging area of research in quantum computing. They rely on exotic properties of certain materials, such as topological superconductors or certain types of topological insulators. These materials have special properties that make the qubits inherently robust against certain types of errors. The qubits in these systems are created by manipulating the topological properties of the materials, which can protect the quantum information from decoherence.
These are just a few examples of the platforms used to create qubits in quantum computers. Each platform has its own set of challenges and advantages, and researchers are actively exploring and developing new methods for creating and manipulating qubits to enhance their coherence times, controllability, and scalability.