Science
Quantum Computing Quiz
Qubits, superposition, entanglement — Shor, Grover, and the race for quantum advantage
Qubits, superposition, entanglement — Shor, Grover, and the race for quantum advantage
Google's 2024 Willow quantum chip achieved a landmark that the entire field had been racing toward: below-threshold error correction. For the first time, errors decreased exponentially as the system scaled up — rather than multiplying — meaning that adding more physical qubits actually made the computer more reliable rather than less. The 105-qubit Willow chip completed a benchmark computation in under five minutes that would take today's fastest classical supercomputers an estimated 10 septillion years, demonstrating the staggering potential of quantum mechanics applied to information processing. The race toward fault-tolerant quantum computers is no longer purely theoretical — it is a technology competition reshaping the future of cryptography, drug discovery, and artificial intelligence.
Each round presents 10 randomized questions from a pool of 50, with four multiple-choice options and instant feedback after every answer. Your final score comes with a performance tier and shareable results.
You'll cover the foundational concepts of qubits, superposition, entanglement and decoherence; hardware approaches from superconducting qubits to trapped ions, photonic, neutral atoms, and topological qubits; landmark algorithms including Shor's and Grover's; key milestones from Google's Sycamore to IBM's Condor and Google's Willow; quantum error correction and the NISQ era; the threat to RSA encryption; and the global race among companies like IBM, IonQ, Quantinuum, and PsiQuantum.
A qubit (quantum bit) is the basic unit of quantum information. Unlike a classical bit, which can only be 0 or 1, a qubit can exist in a superposition of both states simultaneously. When measured, it collapses to a definite 0 or 1, but while in superposition it encodes both possibilities. A system of n qubits can represent 2^n states simultaneously, giving quantum computers their potential for exponential speedups on certain problems.
Quantum supremacy (now often called quantum advantage) refers to the point at which a quantum computer performs a specific task faster than any classical computer could in a practical timeframe. Google claimed to achieve this in October 2019 with its 53-qubit Sycamore processor, which completed a benchmark calculation in 200 seconds that Google estimated would take the world's fastest classical supercomputer 10,000 years. IBM disputed the claim, suggesting 2.5 days was achievable classically with the right algorithm.
RSA encryption relies on the mathematical difficulty of factoring very large numbers — a classical computer would take longer than the age of the universe to factor a 2048-bit RSA key. Shor's algorithm, developed in 1994, can factor large integers exponentially faster on a quantum computer. A sufficiently powerful quantum computer running Shor's algorithm could break RSA-2048 in hours. This is why NIST standardized post-quantum cryptography algorithms in 2024, replacing vulnerable systems before cryptographically-relevant quantum computers (CRQCs) exist.
Last updated: May 2026