GLOSSARY

Boson Sampling is a specialized model of quantum computation that involves sampling from the probability distribution of identical bosons (typically photons) scattered through a linear optical network. This quantum approach […]

Computational complexity studies the resources (mostly, time and space) required to solve a problem on a computer. It classifies problems based on how difficult they are to solve for different […]

What are the DiVicenzo criteria?  The DiVincenzo Criteria (find the paper here) are a set of fundamental requirements formulated by physicist David DiVincenzo in 2000 that define the necessary conditions […]

An error-corrected qubit is a logical qubit that is protected from errors using quantum [error correction] (QEC) techniques. More precisely, error-corrected qubits are highly-entangled quantum states where one or several […]

FTQC, which stands for Fault-Tolerant Quantum Computing, refers to the ability of a quantum computer to continue operating correctly in the presence of errors and faults. It involves sophisticated techniques […]

  The term “logical qubit” can be used in two contexts, with slightly different meanings. It can be meant as a mathematical concept that represents a perfect quantum bit, i.e. […]

NISQ, which stands for Noisy Intermediate-Scale Quantum, refers to the current generation of quantum computers. These devices have several tens to a few hundred qubits and are characterized by their […]

Early electronic computers, such as ENIAC in the 1950s, were built using bulky components that required a significant amount of space. Over time, advancements in semiconductor technology led to compact, […]

What is a Photonic Qubit? A Photonic Qubit is a quantum bit encoded in the quantum states of light. At the quantum level light is made up of individual particles […]

A physical qubit can be any physical system able to encode a qubit degree of freedom, i.e. well defined and manipulable |0> and |1> states. Two-level physical systems are ideal […]

Quantum as a Service (QaaS) refers to cloud-based platforms that provide access to quantum computing resources over the internet. This model allows users to run quantum algorithms and experiments on […]

Artificial intelligence (AI) is a field of research in computer science that refers to the capability of computers to perform tasks typically associated with human intelligence, such as learning, reasoning, […]

A benchmark is a condition against which we can judge that a quantum device is “good enough” in some sense – usually many different benchmarking metrics are required. Benchmarking is […]

They are analogous to classical logic circuits but operate on qubits according to the principles of quantum mechanics.  A quantum circuit consists of a series of initializations , quantum gates […]

Classical computers (laptops, mobiles phones, gaming consoles…) are built around the concept of “bits”. Bits are binary units of information, meaning that a bit can take the values “0” or […]

Quantum Computing is a revolutionary approach to computation that harnesses the principles of quantum mechanics to process information. Unlike classical computers that use bits (0s and 1s), quantum computers use […]

Decoherence is a phenomenon where a quantum system loses its coherence, or quantum behavior, due to interactions with its environment. It’s the process by which the quantum nature of a […]

A quantum dot (QD) is a nanoscale semiconductor structure that exhibits unique optical and electronic properties due to quantum mechanical effects. These structures are typically a few nanometers in size […]

Quantum entanglement is a fundamental quantum phenomenon where two or more particles become correlated in such a way that the quantum state of each particle cannot be described independently, even […]

Machine learning (ML) is a subfield of artificial intelligence where algorithms are not explicitly programmed, but rather learn directly from the data, or from experience, i.e. interacting with an environment.  […]

Quantum Mechanics is a fundamental theory in physics that describes the behavior of light and matter at the molecular, atomic, nuclear, and even smaller microscopic levels. It provides a mathematical […]

Superposition is a phenomenon where a quantum system can exist in multiple states simultaneously. Unlike classical systems that must be in one definite state at any given time, a quantum […]

Quantum volume is a benchmark used for assessing generic quantum circuit performance. The benchmark consists of applying sequences of random gates and checking whether, at a certain number of qubits […]

A qubit is the fundamental unit of quantum information, existing in a superposition of two basis states simultaneously. Unlike classical bits, qubits can represent a continuum of states between 0 and 1, enabling the unique computational capabilities of quantum systems.

A Single Photon Source (SPS) is a specialized device or system that can emit exactly one photon at a time, either on demand or with high probability. These sources are […]

A quantum gate is a single operation performed in a [Quantum circuit], which modifies the logical state of the qubits involved in the computation according to some predetermined rules.  Depending […]

A two-qubit gate is an operation that acts on two qubits throughout a quantum computation. Depending on the operation, the qubits, after the application of the two-qubit gate, can be […]