The field of quantum computing holds enormous promise for advancements in human health, drug discovery, and artificial intelligence. Quantum computers have the ability to solve incredibly complex problems millions of times faster than traditional supercomputers. However, a major obstacle that researchers face is the challenge of connecting qubits—or quantum bits—with atomic precision.
A research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has made a groundbreaking discovery in the field of quantum computing. They are the first to successfully use a femtosecond laser to create and “annihilate” qubits on demand with precision by doping silicon with hydrogen. This advancement could pave the way for the creation of quantum computers that utilize programmable optical qubits or “spin-photon qubits” to connect quantum nodes across a remote network.
The Impact of the New Method
The new method developed by the research team involves forming programmable defects called “color centers” in silicon using a gas environment. These color centers serve as candidates for special telecommunications qubits or “spin-photon qubits” that emit photons capable of carrying encoded information in electron spin over long distances. By annealing silicon with an ultrafast femtosecond laser, the researchers were able to precisely pinpoint where these qubits should form.
Through their experiments, the research team uncovered a quantum emitter known as the Ci center. This emitter has a simple structure, remains stable at room temperature, and exhibits promising spin properties. The presence of hydrogen during the process of silicon processing with a low femtosecond laser intensity was found to facilitate the creation of the Ci color centers. Increasing the laser intensity was shown to enhance the mobility of hydrogen, passivating undesirable color centers without causing damage to the silicon lattice.
The ability to reliably create color centers and form qubits at programmable locations within a material like silicon represents a significant step towards practical quantum networking and computing. The team plans to further explore the integration of optical qubits in quantum devices such as reflective cavities and waveguides. They also aim to discover new spin photon qubit candidates optimized for specific applications.
The use of femtosecond lasers to manipulate qubits at the atomic level represents a major breakthrough in quantum computing research. The ability to precisely control the formation of qubits in materials like silicon opens up new possibilities for the development of quantum networks and computing systems. This pioneering work by the team at Lawrence Berkeley National Laboratory highlights the immense potential of quantum technologies in revolutionizing various fields and industries.