Your guide to quantum computing.
0%
Menu
What Is Quantum? The Technology The Different Quantum Computers Changing the World The Security Story Investing Landscape Learn (curriculum) Companies Applications Glossary Timeline Evaluating Claims Courses Quantum, But Friendly Inside a Quantum Computer Quantum in the Real World Quantum Computing Foundations Quantum Circuits, Algorithms, and Industry Fault-Tolerant Quantum Computing and Technical Strategy My Progress News FAQ Additional Resources Ask Quantum AI Agents ★ Saved
About About us Methodology Contact Disclaimer
My Progress
0%

Quantum Curious

See full progress
SAVE YOUR PROGRESS

Progress lives in this browser and is lost if you log out or clear it: unless you save it with your email. Same email on any device = same progress.

Dark mode

Guided View
New to all this? We add extra plain-English hints and reminders as you learn. Same lessons, with the help built in.

Expert View
You just want the lessons: clean, fast and compact, with no extra reminders. This is the default view.

Interface language

About The Quantum Register

The Quantum Register exists for one reason: quantum physics is the most fascinating thing humans have ever figured out, and almost every explanation of it is either dumbed into mush or buried in math. We think there's a third way.

What we make. Plain-English explainers, a structured three-tier academy, a glossary at three depths, honest company and application directories, and real quantum news. One site that takes you from "what is a qubit" to reading research announcements critically. A mini quiz ends every section, a check ends every module, and retakes are unlimited, so testing yourself never feels like a trap.

What we believe. Simple doesn't mean wrong. Every simplification is chosen to preserve the real idea, and where the honest answer is "nobody knows yet" (like when quantum computers become useful) we say exactly that. The Methodology page explains how lessons are checked.

The news and the money. Quantum is also an industry now, so we aggregate real news from reputable outlets (always credited, always linking out) and teach how the investment landscape works, as education. We never recommend buying or selling anything, ever.

Free, and yours. Courses are free, no account required. Progress lives in your browser; add your email only if you want it saved across devices. That's the entire "account system": no passwords, no spam.

Editorial standards

No invented figures. We never fabricate a qubit count, fidelity number, funding round, or date. Where a specific figure hasn't been verified against a primary source yet, the page says so openly instead of guessing. You will see "to be verified" notes on company profiles rather than confident-looking made-up numbers.

Evidence tags. Milestone claims on the timeline and elsewhere carry a small tag showing the strength of their sourcing:

Peer-reviewedPeer-reviewed: Published in a refereed venue. peer-reviewed publication · PreprintPreprint: arXiv or similar, not yet refereed. preprint, not yet peer-reviewed · VendorVendor: Company announcement, not independently verified. company announcement · DisputedDisputed: A credible published challenge exists. claim disputed by researchers · AnalystAnalyst: Market research or projection, not a technical result. analyst estimate · OfficialOfficial: Standards body or institutional primary source. government / standards body

Vendor claims are labeled as vendor claims. A company announcing its own breakthrough is news, not proof. We report it, tag it, and note when independent researchers dispute it. The timeline keeps disputes visible instead of quietly deleting them.

Research-only. Everything here about companies and investing is education about how the landscape works. Nothing on this site is investment advice or a recommendation to buy or sell anything.

Corrections. Spot an error? We fix things fast — tell us here. Material corrections are noted on the affected page.

The whole site in eight sentences

  1. Quantum computing is not a universally faster replacement for classical computing. It is a specialized model that exploits superposition, entanglement, and interference for a limited set of problem classes.
  2. A classical bit is either 0 or 1. A qubit is described by amplitudes; measurement produces a classical outcome according to probabilities determined by those amplitudes.
  3. Quantum advantage does not come from reading every possible answer simultaneously. It comes from arranging interference so amplitudes of useful answers grow while unhelpful ones shrink.
  4. The strongest long-term use case is likely simulation of quantum systems: chemistry, materials, catalysts, batteries, pharmaceuticals, and portions of fundamental physics.
  5. Today's systems are noisy. The key transition is from physical qubits to reliable logical qubits created through error correction.
  6. Quantum sensing is related but distinct and may deliver meaningful commercial applications sooner: navigation, imaging, clocks, field detection, diagnostics.
  7. Cybersecurity preparation should not wait: NIST finalized three principal post-quantum standards in 2024 and continues to expand the portfolio.
  8. AI and quantum computing may reinforce one another. AI helps calibrate, control, and decode quantum hardware; quantum may eventually accelerate selected workloads.

Eight things to remember

  1. Quantum computers are different, not universally faster.
  2. The core resource is controlled interference across a coherent quantum state.
  3. Measurement returns samples; it does not reveal every amplitude.
  4. Useful machines require reliable logical qubits, not merely large physical-qubit counts.
  5. Quantum simulation is the clearest long-term application, while sensing and post-quantum cybersecurity may create nearer-term value.
  6. Classical and quantum systems will work together in hybrid architectures.
  7. The correct benchmark is always the best end-to-end classical alternative.
  8. Timelines remain uncertain, so technical milestones should matter more than promotional forecasts.

These are the takeaways the whole site keeps returning to: if you retain nothing else, retain these.

Quantum, But Friendly

How Small Is Small?The Spinning CoinBit vs QubitSpooky Friends Final test

Inside a Quantum Computer

The Golden ChandelierHow It ThinksGood At, Bad At Final test

Quantum in the Real World

Quantum You Already OwnThe Great Quantum RaceFollowing the Quantum Money Final test

The Academy

Quantum Computing FoundationsQuantum Circuits, Algorithms, and IndustryFault-Tolerant Quantum Computing and Technical Strategy The full curriculum

Quick answers

GlossaryFAQ Additional ResourcesAsk Quantum Quantum News