雅思阅读 118: The Machines That Happen in Two Places at Once（同时存在于两处的机器）

改编自新华网/中国计算机学会量子计算大会报道（2026年8-9月）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：http://zjnews.zjol.com.cn/zjnews/202609/t20260902_31883856.shtml

Reading Passage

A. An ordinary computer bit is a switch: it is either on or off, zero or one. A quantum bit, or qubit, behaves according to rules that no everyday object obeys. Until it is measured, a qubit can exist in a "superposition" — a blend of zero and one — and two or more qubits can be entangled, so that the fate of one is tied to the fate of another even across a distance. Those two properties, superposition and entanglement, are what make quantum computing so enticing. A machine built from qubits should, in principle, explore vast numbers of possibilities at once and solve certain problems — simulating molecules, cracking certain codes, optimising enormous systems — that would take a conventional supercomputer longer than the age of the universe. For decades this was mathematics on a blackboard. In the last ten years it has become an engineering race, in which governments and technology firms are spending billions to turn a fragile physical effect into a reliable machine. The prize, if it comes, is not faster spreadsheets but answers to problems that ordinary computers, however large, cannot approach in the lifetime of a patient.

B. The catch is that qubits are extraordinarily delicate. Superposition collapses the moment a qubit is touched by almost anything — a tiny vibration, a stray heat particle, an electric field from a nearby wire. Engineers who build quantum computers therefore chill their superconducting circuits to temperatures colder than deep space, isolate them in vacuum chambers, and shield them from every disturbance they can think of. Even then, errors creep in at rates that would make a desktop computer useless. A qubit that holds its state for a fraction of a second is a good one. This is why the central problem of quantum computing is not simply adding more qubits but controlling them well: a machine of a million noisy qubits is worth less than a machine of a few thousand perfect ones. Each extra qubit, after all, also brings an extra way to go wrong. Researchers call the goal "fault tolerance" — a computer that detects and corrects its own errors faster than they accumulate. Everything else, for the moment, is a sideshow.

C. No one has settled on the best way to make a qubit, and that uncertainty is itself a story. Google and IBM have bet heavily on superconducting circuits, the approach that made the early running. Microsoft has staked its reputation on so-called topological qubits, which would be inherently more stable but have been notoriously difficult to build. Physicists at Caltech assembled one of the largest arrays anywhere — six thousand one hundred qubits made from individual neutral atoms held in place by lasers. Other teams pursue trapped ions, photon-based devices and spin qubits etched into silicon. The last of these, long regarded as the quiet also-ran, has lately emerged as a dark horse, because it borrows the same manufacturing techniques used for ordinary computer chips and might, in theory, be scaled up like them. That possibility matters: if a qubit can be made on a silicon line, the path from a thousand qubits to a million becomes, for the first time, an engineering problem rather than a physics one. By 2026, no single technology had won; the field was a crowded race with several lanes still open, and industrial strategy in Washington, Beijing and elsewhere was backing more than one horse at a time.

D. The most important recent progress has been in proving that error correction actually works. In a corrected, or "logical", qubit, many noisy physical qubits are combined so that the errors cancel out — provided the code is well enough designed. Silicon spin teams demonstrated a repetition code in which the logical error rate fell as the code distance increased, exactly as the theory predicts: the more physical qubits you devote to protecting one logical one, the lower the chance of a mistake slipping through. That result is the threshold the field has been chasing. It shows that the path to a reliable quantum computer runs through redundancy, not through hoping for perfect hardware. Yet the same researchers are careful to say what their numbers mean. Demonstrating that error rates fall with larger codes is not the same as running a useful program; the machines that exist today are still experimental, their qubits still too few and too noisy to outperform a classical computer on any real task that matters. The gap between a physics demonstration and a product is, famously, where most quantum companies live.

E. That gap between promise and product is where the politics comes in. In May 2026, the American government announced two billion dollars in support for nine quantum companies, and the following month the President signed an executive order to speed up the building and deployment of quantum machines. Such money reflects a fear of being overtaken — quantum computing is, among other things, a national-security prize, because a sufficiently powerful machine would defeat the encryption that protects the modern internet. But the leading Chinese physicist Xue Qikun, addressing a quantum computing conference in August 2026, struck a deliberately cautious note. A general-purpose, fault-tolerant quantum computer, he warned, remains extremely hard to build, and large-scale commercial use is still some way off; the world, he said, should prepare for a long campaign rather than an overnight breakthrough. The honest summary of the field, then, is this: the physics has been shown to work, the engineering is now advancing on many fronts at once, and the genuinely useful machine — the one that deserves the headlines — has not yet arrived. Anyone promising otherwise, on either side of the market, is selling a story rather than a machine.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. The fragility that defines the engineering problem ii. Why no one has picked a winning qubit technology iii. Error correction — and the gap it has not yet closed iv. Money, strategy and a deliberately cautious note v. How a classical computer bit works vi. The history of the internet vii. Why quantum computers are already obsolete

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. What makes a qubit different from an ordinary bit? A. It is faster because it is bigger. B. It can exist in superposition and become entangled with other qubits. C. It never makes any errors. D. It runs at room temperature.

6. Why is fault tolerance the central goal? A. Qubits are so delicate that a large machine of noisy qubits is less useful than a smaller, corrected one. B. It allows quantum computers to run without electricity. C. It makes the computers smaller than phones. D. It removes the need for superposition.

7. What does the choice between qubit technologies reflect? A. A single clear winner has already emerged. B. The field remains undecided, with several competing approaches still viable. C. Only superconducting qubits are possible. D. Silicon chips have been banned.

8. What did the silicon error-correction demonstration show? A. Error rates rose as codes grew larger. B. The logical error rate fell as code distance increased, as theory predicts. C. Error correction was impossible. D. Quantum computers already outperform classical ones.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. Superconducting circuits in quantum computers are cooled to temperatures colder than deep space.
10. By 2026, one qubit technology had clearly beaten all the others.
11. A useful, fault-tolerant quantum computer is expected to arrive within a few months.
12. Google and IBM have both invested heavily in superconducting circuits.
13. Quantum computing has no relevance to national security.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Qubits exist in a state called (14) __________, and when several are entangled the fate of one is tied to another; the central engineering goal is (15) __________, so that a machine corrects its own errors faster than they accumulate.

答案与解析

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