📖 Quantum Computing Glossary
Learn the language of quantum computing
A step-by-step procedure for solving a problem or performing a computation.
A complex number associated with each possible state in a quantum superposition, whose squared magnitude gives the probability of measuring that state.
A quantum technique that increases the probability of measuring desired states while decreasing others.
The fundamental states that form a complete description of a quantum system, typically |0⟩ and |1⟩ for a single qubit.
An optical device that splits an incoming light beam into two separate beams, creating superposition in photonic quantum computing.
A maximally entangled quantum state of two qubits, forming the simplest example of entanglement.
A geometric representation of a single qubit state as a point on or inside a unit sphere.
A two-qubit quantum gate that flips the target qubit if and only if the control qubit is in state |1⟩.
The property that allows quantum systems to maintain superposition and entanglement over time.
The process by which a quantum system loses its quantum properties through interaction with its environment.
A quantum phenomenon where two or more qubits become correlated such that the quantum state of each cannot be described independently.
Techniques for detecting and correcting errors in quantum computation without destroying quantum information.
A quantum computing approach where errors can be detected and corrected faster than they accumulate.
A measure of how accurately a quantum operation or state matches the intended ideal, expressed as a percentage.
A basic operation on qubits that transforms their quantum state, analogous to logic gates in classical computing.
A quantum algorithm that searches an unstructured database quadratically faster than classical algorithms.
A single-qubit gate that creates an equal superposition of |0⟩ and |1⟩ from a basis state.
Educational approach using real quantum hardware rather than just simulators.
Computing approaches that combine quantum and classical processors, with each handling tasks suited to its strengths.
The phenomenon where quantum probability amplitudes combine, either reinforcing (constructive) or cancelling (destructive).
An error-corrected qubit encoded across multiple physical qubits for fault-tolerant computation.
An optical device that splits light, sends it along two paths, and recombines it to create interference patterns.
The process of extracting classical information from a quantum system, causing the superposition to collapse to a definite state.
Noisy Intermediate-Scale Quantum: the current era of quantum computers with 50-1000 qubits but significant noise and no error correction.
A fundamental principle stating that it is impossible to create an exact copy of an unknown quantum state.
A set of three single-qubit gates (X, Y, Z) that perform fundamental rotations on the Bloch sphere.
An optical component that changes the phase of light passing through it, essential for photonic quantum gates.
A particle of light that can carry quantum information in photonic quantum computers.
A quantum computing approach that uses photons (particles of light) as qubits.
The orientation of the electric field oscillation of a photon, used to encode qubit states in photonic systems.
Demonstration that a quantum computer can solve a specific problem faster than any classical computer.
A communication pathway that can transmit quantum information, such as fiber optic cables carrying photons.
A sequence of quantum gates applied to qubits, representing a quantum computation.
Security protocols based on quantum mechanical principles, offering theoretically unbreakable encryption.
The quantum analogue of the discrete Fourier transform, exponentially faster than classical FFT.
Understanding of quantum computing concepts sufficient to participate in quantum technology discussions and decisions.
The intersection of quantum computing and machine learning, potentially offering speedups for certain ML tasks.
A collection of qubits that together store quantum information for computation.
Using a controllable quantum system to simulate another quantum system that is difficult to study directly.
The complete mathematical description of a quantum system at a given moment.
The milestone where a quantum computer performs a calculation practically impossible for any classical computer.
A protocol to transfer a quantum state from one location to another using entanglement and classical communication.
A metric that measures the overall capability of a quantum computer, accounting for qubits, connectivity, and error rates.
The fundamental unit of quantum information, analogous to a classical bit but able to exist in superposition.
Quantum computing systems that operate at normal ambient temperatures without cryogenic cooling.
A quantum algorithm that can factor large integers exponentially faster than known classical algorithms.
A quantum computing approach using circuits made from superconducting materials, requiring near-absolute-zero temperatures.
A quantum state where a qubit exists in multiple basis states simultaneously until measured.
A single-qubit gate that applies a π/4 phase rotation, essential for universal quantum computation.
A qubit implementation using individual ions suspended by electromagnetic fields and manipulated with lasers.
A set of quantum gates sufficient to approximate any quantum operation to arbitrary precision.
Variational Quantum Eigensolver: a hybrid algorithm for finding ground state energies of molecules.