Yes, it is theoretically possible to build a computer that utilizes principles of quantum mechanics to perform computations. Such a computer is commonly known as a quantum computer.
Unlike classical computers that use bits to represent and process information, quantum computers use quantum bits, or qubits, which can exist in multiple states simultaneously thanks to a property called superposition. This property allows quantum computers to perform certain calculations much faster than classical computers for certain types of problems.
Quantum computers make use of other quantum mechanical phenomena as well, such as entanglement and quantum interference. Entanglement enables the correlation of qubits in a way that the state of one qubit can be dependent on the state of another, even if they are physically separated. Quantum interference allows for the constructive or destructive interference of probability amplitudes, enhancing the likelihood of obtaining the correct answer when performing certain computations.
Building a practical quantum computer is an active area of research and technological development. Several approaches are being pursued, including superconducting circuits, trapped ions, topological qubits, and others. While quantum computers have the potential to solve certain problems exponentially faster than classical computers, there are still significant engineering and technical challenges to overcome before they can be scaled up to perform useful computations on a large scale.
It's worth noting that quantum computers are not intended to replace classical computers entirely. They are expected to excel at specific computational tasks, such as factorization of large numbers (which has implications for cryptography), optimization problems, simulation of quantum systems, and machine learning algorithms specifically designed for quantum computers. Classical computers will continue to be important for general-purpose computing tasks.