Practice Tests
IELTS Reading (AC) Task 1 #148

A. Quantum computing represents a fundamentally new paradigm in computation, based on the principles of quantum mechanics. Unlike classical computers that store and process information in bits, which can be either a 0 or a 1, quantum computers use quantum bits, or qubits. Thanks to the quantum phenomena of superposition and entanglement, a qubit can exist as a 0, a 1, or both simultaneously, and the state of one qubit can be instantly correlated with the state of another, even at a distance.

B. This ability to exist in multiple states at once gives quantum computers an exponential advantage in processing power for certain types of problems. While a classical computer must test possibilities one by one, a quantum computer can explore a vast number of possibilities simultaneously. This makes them exceptionally well-suited for solving complex optimisation problems, breaking modern cryptographic codes, and simulating molecular interactions with a level of detail that is impossible for even the most powerful supercomputers today.

C. The potential applications are transformative. In medicine and materials science, quantum computers could be used to design new drugs and novel materials by precisely simulating their molecular structures and behaviours. In finance, they could optimise investment strategies and perform complex risk analysis. They also pose a significant threat to current cybersecurity standards, as a sufficiently powerful quantum computer could break the encryption that protects most of our digital information, necessitating the development of new, "quantum-resistant" cryptography.

D. Despite their immense promise, building a large-scale, fault-tolerant quantum computer is an enormous scientific and engineering challenge. Qubits are incredibly fragile and sensitive to their environment, requiring extremely cold temperatures and isolation from any external interference to maintain their quantum state. The field is still in its nascent stages, with current devices being small and prone to errors. However, research is progressing rapidly, and while they may not replace our everyday computers, quantum computers are poised to revolutionise science, industry, and security in the coming decades.