Quantum Glossary

151 short definitions of the terms used across this site.

A B C D E F G H I K L M N O P Q R S T U V W

Airdrop: A distribution of free tokens to wallets. Scammers imitate it. Read more
AMM: Automated market maker, a trading system that uses a pool of two tokens and a formula to set prices instead of matching buyers with sellers.
Amplitude amplification: A technique that boosts the probability of the right answer by repeatedly nudging amplitudes. Grover's algorithm is its best-known use.
Associated token account: The standard token account tied to one wallet and one token on Solana, found by a fixed formula. It is why a first-time token receipt can cost a small amount of rent.
Atomic clock: A clock that keeps time by counting the very regular vibrations of atoms. Read more
Bell pair: Two qubits prepared in a maximally entangled state, often the first circuit people try. Read more
Block explorer: A website that lets you look up addresses, tokens and transactions on a blockchain. Read more
Bonding curve: A formula that sets a token's price from how much has been bought, used by pump.fun at launch. Read more
Burn: Permanently destroying tokens to reduce supply. Read more
Calibration: Regularly tuning the control signals for each qubit and gate so the machine stays accurate. Drift in hardware means calibration is never finished.
Cat qubit: A qubit stored in a special state of a microwave resonator that naturally resists one kind of error (bit flips). It can cut the number of physical qubits needed for error correction. Read more
Circulating supply: The number of tokens currently available to trade, not locked or unreleased.
CNOT gate: A two-qubit gate that flips the second qubit only if the first is 1. It is a common way to create entanglement. Read more
CNSA 2.0: The Commercial National Security Algorithm Suite 2.0, guidance from the US National Security Agency listing the quantum-resistant algorithms national security systems must adopt, with timelines running through the 2030s.
Code distance: A measure of how many errors a quantum error-correcting code can tolerate. Larger distance means better protection but more physical qubits.
Coherence time: The length of time a qubit keeps its quantum behavior before noise ruins it. T1 and T2 are the usual ways to measure it.
Compute unit: A measure of how much processing a Solana transaction uses. Transactions have a compute limit, and priority fees are priced per compute unit.
Contract address (CA): The unique address of a token on a blockchain. Always verify it before buying. Read more
Crosstalk: Unwanted interference where controlling one qubit accidentally disturbs its neighbors. It is a major source of error in tightly packed chips.
Cryostat: A super-cold container that houses quantum hardware. A dilution refrigerator is the usual type for superconducting chips.
Crypto agility: Designing systems so cryptographic algorithms can be swapped out without rebuilding everything. It makes the move to post-quantum methods easier. Read more
DARPA QBI: The Quantum Benchmarking Initiative from the US defense research agency DARPA. It evaluates whether companies can show a path to a useful, utility-scale quantum computer. Read more
Decimals: How many places a token can be divided into smaller units.
Decoder: The classical software or hardware that reads syndromes and works out which correction to apply. It must run fast enough to keep up with the quantum computer. Read more
Decoherence: The loss of quantum behavior when a qubit is disturbed by its environment.
Dev wallet: The wallet that created a token or holds the team's share. Readers often check how much supply it holds and whether it has sold.
DEX: A decentralized exchange where you swap tokens from your own wallet using smart contracts. Read more
Digital signature: A cryptographic proof that a message was approved by the owner of a private key. Read more
Dilution refrigerator: A multi-stage fridge that cools superconducting qubits to a tiny fraction of a degree above absolute zero. Read more
Dual-rail qubit: A qubit encoded in which of two paths or resonators holds a single quantum of energy. Its main error shows up as a detectable loss, which is easier to fix than a silent error.
Elliptic curve cryptography (ECC): Public key cryptography based on math about points on a curve, used by many blockchains. Read more
Entanglement: A link between qubits so their states must be described together. Read more
Error mitigation: Techniques that reduce the effect of noise on results without full error correction. Read more
Error threshold: The physical error rate below which adding more qubits to a code makes the logical error rate fall instead of rise. Hardware must beat the threshold for error correction to pay off.
Falcon: A lattice-based signature scheme with small signatures, selected by NIST and being standardized as FN-DSA. It is tricky to implement safely because it uses floating-point math.
Fault tolerance: The ability of a quantum computer to keep computing correctly even when its parts make errors. Read more
FDV: Fully diluted valuation: price multiplied by total or maximum supply. Read more
Fidelity: A score from 0 to 1 (or 0 to 100 percent) for how close an operation or state is to what was intended. A two-qubit gate fidelity of 99.9 percent means about one error per thousand gates.
Fluxonium: A superconducting qubit design that can hold its quantum state for longer than a typical transmon. It is harder to control, so it is still less common.
Freeze authority: The permission to freeze token accounts. When revoked, nobody can freeze holders. Read more
Gate model: The approach to quantum computing that runs programs made of quantum gates. Read more
Gate time: How long a single quantum gate takes to run. Superconducting qubits are generally faster than trapped ions, which typically trade speed for higher fidelity.
Graduation: When a pump.fun token's bonding curve completes and liquidity moves to a decentralized exchange pool. Read more
Grover's algorithm: A quantum search algorithm that gives a quadratic speed-up for unstructured search.
Hadamard gate: A single-qubit gate that turns a definite 0 or 1 into an even blend of both. Read more
Hardware wallet: A dedicated device that keeps your private keys offline. Read more
Harvest now, decrypt later: An attack plan where someone records encrypted data today and stores it until a quantum computer can break the encryption. It is why long-lived secrets need protection early.
Hash function: A function that turns any input into a fixed-length fingerprint that cannot be reversed. Read more
Hash-based signature: A quantum-resistant digital signature built mainly from hash functions. Read more
HHL algorithm: A 2009 quantum method for solving certain systems of linear equations, named for Harrow, Hassidim and Lloyd. Its speedup depends on strict conditions about the data and how the answer is read out.
Holder concentration: How much of a token's supply sits in a few wallets. High concentration means a few holders can move the price when they trade.
Honeypot: A scam token that lets you buy but blocks you from selling. Read more
Hybrid key exchange: Combining a classical key exchange with a post-quantum one so the connection stays safe if either is broken. Many browsers and servers already use this approach.
Interference: Adding quantum amplitudes so wrong answers cancel and right answers grow. It is how algorithms steer results.
KEM: Key encapsulation mechanism, a method for two parties to agree on a shared secret key using public-key cryptography. ML-KEM is the NIST standard version.
Lattice problem: A hard math problem about finding special points in a high-dimensional grid. The best known classical and quantum attacks are slow, which is why many post-quantum schemes rely on them.
Lattice surgery: A way of doing operations between logical qubits in the surface code by merging and splitting patches of qubits on the chip.
Lattice-based cryptography: A family of quantum-resistant methods built on hard problems about points in a grid. Read more
Liquidity: The value in a trading pool, which decides how easily you can buy or sell. Read more
Liquidity lock: Locking LP tokens for a set time so the project cannot pull the pool's funds out during that period. It lowers one risk but does not remove all risks.
Liquidity pool: A smart contract holding two tokens that traders swap against. Read more
Liquidity provider: Someone who deposits tokens into a pool so others can trade, often earning a share of fees.
Logical error rate: How often an encoded, error-corrected qubit still gets a wrong result. Cutting it is the goal of error correction.
Logical qubit: A reliable qubit built from many physical qubits using error correction. Read more
LP token: A receipt token given to someone who adds funds to a liquidity pool. It represents their share of the pool and is used to withdraw it later.
Magic state: A specially prepared quantum state used to perform gates that cannot be done directly in many error-correcting codes. Producing enough of them is a big part of the cost of a fault-tolerant machine.
Magic state distillation: A process that turns many noisy magic states into fewer, cleaner ones. It is expensive in qubits and time.
Market cap: Price multiplied by circulating supply. Read more
Measurement: Reading a qubit, which turns its quantum state into an ordinary 0 or 1.
Memecoin: A cryptocurrency driven mainly by community and culture rather than utility. Read more
Merkle tree: A tree of hashes where each parent hashes its children, so one top hash (the root) can vouch for a large set of data. It is used in many blockchains and in hash-based signatures.
Metadata: The name, symbol, image and links attached to a token. On Solana it can be set by a metadata program, and it may or may not be changeable later.
Mint: The account that defines a token, including its supply and decimals. Read more
Mint authority: The permission to create new tokens. When revoked, supply can never increase. Read more
ML-DSA: The lattice-based digital signature standard from NIST (FIPS 204), derived from CRYSTALS-Dilithium.
ML-KEM: The lattice-based key encapsulation standard from NIST (FIPS 203), derived from CRYSTALS-Kyber. It is meant to replace key exchange methods that quantum computers could break.
Neutral atom qubit: A qubit made from an individual uncharged atom held in place by focused laser beams called optical tweezers. These arrays can reach hundreds or thousands of atoms.
NISQ: Noisy intermediate-scale quantum: today's small, error-prone quantum computers.
NIST PQC standards: The first post-quantum cryptography standards published by the US National Institute of Standards and Technology in August 2024: ML-KEM, ML-DSA and SLH-DSA.
No-cloning theorem: A rule of quantum physics that an unknown quantum state cannot be perfectly copied. Read more
One-time signature: A signature scheme where each key pair can safely sign only one message. Hash-based schemes often build many one-time keys into a larger structure.
Photonic qubit: A qubit carried by a particle of light, useful for quantum communication. Read more
Physical qubit: A real hardware qubit, such as a superconducting circuit or a trapped ion. Read more
Post-quantum cryptography: Cryptography designed to resist attacks by both normal and quantum computers. Read more
Price impact: How much your own trade moves the price in a pool.
Priority fee: An optional extra payment on Solana that helps a transaction get processed sooner. Read more
Private key: The secret that signs transactions for an account. Anyone with it controls the funds. Read more
Program (Solana): What Solana calls a smart contract: code deployed on the chain that accounts and transactions interact with.
Public address: The shareable address others use to send tokens to your wallet.
Pump.fun graduation: When a token launched on Pump.fun sells enough on its bonding curve, its liquidity moves to a regular trading pool. Graduation does not make a token safe or valuable.
PumpSwap: The automated market maker built by Pump.fun where graduated tokens trade. It works like other pool-based exchanges.
Q-Day: A nickname for the day a quantum computer can break widely used public-key encryption. Nobody knows when, or if, it will arrive.
QAOA: Quantum approximate optimization algorithm, a hybrid method that tries to find good answers to optimization problems using a short quantum circuit with settings tuned by a classical computer.
qLDPC code: Quantum low-density parity-check code, a family of error-correcting codes that could protect the same number of logical qubits with fewer physical qubits than the surface code. They usually need longer-range connections between qubits.
Quantum advantage: A quantum computer beating classical methods on a task that matters. Read more
Quantum annealing: A method for finding low-energy solutions to optimization problems, used by D-Wave. Read more
Quantum circuit: An ordered series of quantum gates applied to qubits, ending in measurement. Read more
Quantum cloud access: Renting time on a quantum computer over the internet instead of owning one. Several vendors and cloud providers offer it.
Quantum Fourier transform: The quantum version of the Fourier transform, which finds repeating patterns in data. It is a key step in Shor's algorithm.
Quantum gate: An operation that changes the state of one or more qubits, like a logic gate in a normal computer.
Quantum kernel: A method that uses quantum states to measure how similar data points are. Read more
Quantum key distribution: A way to share encryption keys using the physics of quantum light, where eavesdropping is detectable. It needs special hardware and is different from post-quantum cryptography.
Quantum phase estimation: An algorithm that reads out a hidden number (a phase) from a quantum operation. It underlies Shor's algorithm and many chemistry methods, but needs error-corrected hardware.
Quantum repeater: A proposed device that extends quantum links over long distances by passing on entanglement. Read more
Quantum roadmap: A company's public plan for future hardware, with targets such as qubit counts, error rates or logical qubits by given years. Roadmaps are goals, not guarantees.
Quantum sensing: Using quantum effects to measure time, motion, gravity or magnetic fields very precisely. Read more
Quantum simulation: Using a quantum computer to model another quantum system, such as a molecule or material. It was the original idea that motivated building quantum computers.
Quantum supremacy: A quantum computer doing a task no classical computer could do in reasonable time, even if useless. Read more
Quantum volume: A single-number benchmark from IBM that reflects how large and how accurate a circuit a device can run successfully. It captures qubit count, error rates and connectivity together.
Quantum walk: The quantum version of a random walk, where a particle spreads out in superposition. It is used as a building block for some search algorithms.
Qubit: The basic unit of quantum information. It can be in a blend of 0 and 1 until measured. Read more
Qubit connectivity: Which qubits on a device can interact directly with each other. Better connectivity means fewer extra operations to move information around.
Randomized benchmarking: A way to measure average gate errors by running long random gate sequences and seeing how quickly accuracy falls.
Readout error: A mistake made when measuring a qubit, such as reporting 0 when it was 1. It is tracked separately from gate errors.
Recovery phrase: The words that restore your wallet. Never share them. Read more
Rent (Solana): A refundable deposit paid in SOL to keep an account's data stored on Solana. Accounts holding the minimum amount are rent-exempt and stay open; closing an account returns the deposit.
RSA: A public key system whose security depends on the difficulty of factoring large numbers. Read more
Rug pull: When insiders sell or remove liquidity so other holders cannot sell fairly. Read more
Sandwich attack: A trick where a bot buys just before your trade and sells right after, profiting from the price move your trade causes. Lower slippage tolerance can reduce the damage.
Seed phrase: A list of words that can restore a wallet. Never share it. Read more
Self-custody: Holding your own keys so you, not a company, control your crypto.
Shor's algorithm: A 1994 quantum algorithm that could break RSA and elliptic curve cryptography on a large quantum computer. Read more
SLH-DSA: The hash-based digital signature standard from NIST (FIPS 205), derived from SPHINCS+. It relies only on hash functions, with fairly large signatures.
Slippage: The difference between the price you expect and the price you get, caused by price movement or low liquidity.
Slippage tolerance: The largest price change you accept between clicking swap and the trade finishing. If the price moves further, the trade fails instead of filling at a worse price.
SOL: The native currency of the Solana blockchain, used to pay network fees.
Spin qubit: A qubit that uses the spin of an electron or nucleus, often in silicon. It is attractive because it can borrow chip-making methods from the semiconductor industry.
SPL token: A token created with Solana's original token program. Read more
Stabilizer code: A type of quantum error-correcting code defined by a set of measurements that reveal errors without disturbing the stored data. The surface code is one example.
Superconducting qubit: A qubit built from a tiny electrical circuit that has no resistance when very cold. Read more
Superposition: A quantum system holding a combination of states at once, with probabilities set by the blend. Read more
Surface code: A popular error-correcting code that arranges qubits on a 2D grid and only needs neighbor-to-neighbor interactions. It has a relatively high error threshold but uses many qubits.
Symmetric encryption: Encryption where the same secret key locks and unlocks data, such as AES. Quantum computers weaken it only modestly, so larger keys are usually enough.
Syndrome: The pattern of check measurements in error correction that hints where an error happened without revealing the stored data.
T1 time: How long a qubit takes to lose its energy and fall from the 1 state to the 0 state. Longer T1 means the qubit keeps its information longer.
T2 time: How long a qubit keeps its phase, the timing that makes superposition useful. T2 is usually shorter than or equal to twice T1.
Token account: An account in your wallet that holds a balance of one specific token.
Token-2022: Solana's newer token program that supports optional extensions such as built-in metadata. Read more
Tokenomics: The design of a token's supply, distribution and rules. Read more
Topological qubit: A proposed qubit that stores information in a global property of a material so local noise cannot easily damage it. Building a reliable one has been a long-running research challenge.
Transaction signature: The unique ID of a blockchain transaction, used to look it up on an explorer.
Transmon: The most common type of superconducting qubit, a small circuit built to be less sensitive to electrical noise than earlier designs. Google and IBM both use transmon-style qubits.
Transversal gate: A logical gate done by applying the same simple gate to each physical qubit separately, which keeps errors from spreading. No code can do every needed gate this way.
Trapped ion qubit: A qubit stored in the energy levels of an individual charged atom held in place by electric fields. Read more
Utility scale: A quantum computer big and reliable enough to do useful work that is worth more than it costs to run. The term is used by DARPA and several vendors.
Variational algorithm: A method that pairs a short quantum circuit with a normal computer that tunes its settings. Read more
Verified source: Published code that a block explorer or tool has matched to what is actually deployed, so people can check what a contract does.
VQE: Variational quantum eigensolver, a hybrid algorithm that estimates the lowest energy of a molecule by tuning a quantum circuit with a classical optimizer.
Wallet drainer: Malicious code or a site that tricks you into approvals that empty your wallet. Read more
Winternitz signature: A one-time hash-based signature trick that shortens signatures by signing chunks of the message using chains of hashes. Each key must only be used once.
Wrapped SOL: SOL packaged as an SPL token (wSOL) so it can be used in token swaps and pools the same way as other tokens.