What Is Quantum Information?
The starting point for everything else on QuantumO: what makes information quantum, and why it matters.
QuantumO · quantum information education
Quantum information, made understandable.
Explore the ideas behind qubits, superposition, entanglement, quantum computing, and the technologies shaping the next era of information.
Featured lesson
Demistifying the Qubit
The qubit, explained without jargon: how it stores information, why superposition is not an object being in two places at once, and what happens when you measure it.
BeginnerqubitsDuration pendingPublication date pending
Transcript
Transcript not available yet. Transcripts are published with each video and are stored as an editable CMS field.
Start here
Start with the fundamentals
Six short lessons that build the vocabulary everything else depends on. No physics background required.
What Is a Qubit?
How a qubit differs from a bit, and what physical systems can act as one.
Superposition Explained
What superposition actually claims, and the wording to avoid.
Quantum Entanglement
Correlations without communication — what Bell tests established and what they did not.
Measurement and Probability
How amplitudes become outcomes, and why quantum experiments are run repeatedly.
Classical vs. Quantum Computing
A side-by-side comparison, including where quantum offers no advantage.
Guided sequences
Learning paths
Follow a numbered sequence from first principles onward. No account needed — every lesson is open.
Quantum Basics
No physics background required
Start here. Six short lessons that build the vocabulary and intuition everything else depends on.
- What Is Quantum Information?The field in one lesson.
- What Is a Qubit?The basic unit, and how it differs from a bit.
- Superposition ExplainedCombined amplitudes, not two places at once.
- Measurement and ProbabilityHow amplitudes become outcomes.
- Quantum EntanglementCorrelations no classical model reproduces.
- Classical vs. Quantum ComputingWhat each machine is good at.
Quantum Computing
Gates, circuits, algorithms, and hardware
How a quantum program is actually built and run, and what limits today's machines.
- How Does Quantum Computing Work?Prepare, evolve, measure.
- Quantum Gates and CircuitsThe building blocks.
- Why Quantum Error Correction Is NecessaryNoise and the cost of protection.
- Quantum Hardware BasicsPlatforms and trade-offs.
Quantum Communication
Entanglement, teleportation, networking, and cryptography
How quantum information moves between places, and what that means for security.
- Quantum EntanglementThe shared resource.
- What Is Quantum Teleportation?Moving a state, not matter.
- Quantum CommunicationPhotons, loss, and repeaters.
- Is Quantum Communication Secure?What QKD does and does not promise.
From the channel
Latest videos
Demistifying the Qubit
The qubit, explained without jargon: how it stores information, why superposition is not an object being in two places at once, and what happens when you measure it.
BeginnerqubitsDuration pendingPublication date pending
How Qubits Store Data
A closer look at how information is actually encoded in a qubit — amplitudes, phase, and why a quantum state holds more than a simple 0 or 1.
BeginnerqubitsDuration pendingPublication date pending
How Quantum Superposition Works
What superposition really means: how a qubit holds amplitudes for both 0 and 1, why interference matters, and what happens the moment you measure.
BeginnersuperpositionDuration pendingPublication date pending
Thumbnail pending
What Is Quantum Information?
A plain-language introduction to how information can be stored in quantum systems, and why that changes what computers and networks can do.
Beginnerquantum informationDuration pendingPublication date pending
Thumbnail pending
What Is a Qubit?
How a qubit differs from a classical bit, and what it really means for a quantum system to hold a combination of 0 and 1.
BeginnerqubitsDuration pendingPublication date pending
Thumbnail pending
Superposition Explained
Why superposition is about combined amplitudes rather than an object being in two places at once, shown with simple diagrams.
BeginnersuperpositionDuration pendingPublication date pending
What is quantum information?
Quantum information is information represented and processed using quantum systems. Its basic unit is the qubit, which can behave differently from an ordinary binary bit because of properties such as superposition, interference, and entanglement. These properties create new possibilities for computing, communication, sensing, and scientific discovery.
Information is always stored in something physical, and the rules that system obeys set the limits of what you can do with it. Ordinary computers use components large enough that quantum effects wash out. Quantum information science asks what becomes possible when information lives in systems small and isolated enough for quantum rules to apply directly.
The practical consequences are already visible. Atomic clocks — quantum sensors — define the second and keep satellite navigation accurate. Quantum key distribution runs over deployed fibre links. Small quantum processors are used for research. Large error-corrected quantum computers, by contrast, remain a goal rather than a product.
| Property | Classical bit | Qubit |
|---|---|---|
| State | Exactly 0 or 1 | Amplitudes for both 0 and 1 |
| Reading it | Non-destructive | Generally disturbs the state |
| Copying | Trivial | Impossible for unknown states |
| Combining | Values add logically | Amplitudes can interfere and cancel |
Frequently asked questions
- What is quantum information?
- Quantum information is information represented and processed using quantum systems. Its basic unit is the qubit, which can behave differently from an ordinary binary bit because of properties such as superposition, interference, and entanglement.
- What is a qubit?
- A qubit is a two-level quantum system used as the basic unit of quantum information. Its state assigns amplitudes to the outcomes 0 and 1.
- How is a qubit different from a bit?
- A bit is definitely 0 or 1. A qubit holds amplitudes for both outcomes that can interfere, and measuring it returns one outcome with a probability set by those amplitudes.
- What is quantum superposition?
- A quantum state formed by combining other states, each with an amplitude. It is not an object being in two places at once.
- What is quantum entanglement?
- A link between quantum systems in which the whole has a definite description while the parts do not, producing correlations stronger than any classical model allows.
- How does quantum computing work?
- Qubits are prepared in a known state, transformed by a sequence of gates, and measured, with interference arranged so the useful outcome is likely to appear.
- Can quantum computers replace ordinary computers?
- No. They are specialised accelerators expected to work alongside classical machines on a narrow set of problems.
- What is quantum teleportation?
- A protocol that transfers a quantum state using shared entanglement and two classical bits. Nothing material travels and nothing outruns light.
- Is quantum communication secure?
- Quantum key distribution can detect eavesdropping, but real-world security depends on hardware assumptions and it secures key exchange only.
- Why is quantum error correction necessary?
- Because qubits decohere and gates are imperfect, so errors accumulate faster than a long computation can complete.
Get new lessons and videos
A short note when a new lesson or video is published. No tracking pixels, no spam.