Quantum computing is a rapidly advancing field with significant potential, but it also faces numerous challenges, including scalability. While quantum computers have made significant progress, building large-scale, error-corrected quantum systems with a large number of qubits remains a considerable technical hurdle.
The scalability of quantum computing refers to the ability to increase the number of qubits while maintaining the coherence and reliability of the quantum states. Currently, quantum systems with a few dozen qubits are being developed, but building quantum computers with thousands or millions of qubits, which would enable solving complex problems, is still a considerable engineering feat.
One challenge in scaling up quantum computers is the issue of qubit decoherence. Quantum systems are sensitive to environmental noise and interactions, which can cause errors and degrade the fidelity of the computation. To overcome this, error correction techniques are being developed to protect the quantum states and reduce errors. However, implementing error correction introduces additional overhead in terms of the number of physical qubits required for each logical qubit, which can be a limiting factor in scalability.
Regarding your hypothetical scenario where the time or energy required to engineer a quantum computer increases explosively with the number of qubits, it is difficult to speculate on such a law of the universe without concrete scientific evidence. However, if such a law were to exist, it could pose significant challenges for building large-scale, practical quantum computers. It would require groundbreaking advancements in technology and fundamental understanding to overcome such limitations and achieve scalable quantum computing.
It's worth noting that the field of quantum computing is still evolving, and researchers are actively exploring various approaches to address scalability and other challenges. While we cannot predict the future with certainty, ongoing research and technological advancements are aimed at overcoming these obstacles and realizing the full potential of quantum computing.