Please remember that the field of quantum computing is rapidly evolving, and new terms and concepts
are continually being developed.
Alpha
Advanced Encryption Standard (AES)
Symmetric encryption algorithm widely used for secure data
transmission. Quantum computers
could potentially break AES with large enough qubit counts, driving research into
quantum-resistant cryptography
Algorithm
Algorithms are step-by-step procedures designed to solve specific
problems using quantum
mechanical principles
Algorithmic Qubit (AQ)
AQ is an application-based benchmark that measures performance
across 6 quantum algorithms for near-term use cases:
Optimization, Quantum Simulation, and Quantum Machine Learning. It evaluates a quantum
processor's capability to execute
these algorithms
Analog Quantum Computing
Type of quantum computing that uses continuous physical variables
to represent quantum states,
as opposed to discrete digital states. This approach can be useful for simulating
certain quantum systems
Ansatz
In the context of variational quantum algorithms, an ansatz is a
parameterized quantum circuit
used as a starting point for optimization. The structure of the ansatz is typically
chosen based on the problem
being solved
Atom
The basic unit of matter, consisting of a nucleus surrounded by
electrons. Certain atoms, like
neutral atoms or ions, can be used as qubits in quantum computing systems
Atom Traps
Atom traps isolate atoms from their environment to then manipulate
the atom and use it to
process quantum information. Common types include optical traps and ion traps
Atomic Clock
Precise timekeeping device that uses the oscillations (change of
energy levels) of atoms, often
cesium, to measure time
Attenuator (Superconducting QC)
Attenuators are used to reduce the power of control signals sent to
qubits, helping to minimize
noise and improve qubit control
Auxiliary Qubit
Qubits used in quantum circuits to assist with computations or
error correction, but not
directly part of the final measurement or result (also referred to as an ancilla)
Bravo
Barren Plateaus
Phenomenon in training variational quantum circuits where the
gradient of the objective
function becomes exponentially small, making optimization difficult
Bell Inequality
Mathematical inequality that distinguishes between quantum
mechanical and classical theories of
reality. Violations of Bell's inequality demonstrate the non-classical nature of quantum
entanglement
Bell States
Bell states are quantum states of two qubits that represent simple
examples of quantum
entanglement
Bell's Theorem
Fundamental concept in quantum physics that relates to the
measurement of entangled particles.
It states that the predictions of quantum mechanics cannot be explained by any local
hidden variable theory, meaning
that particles can influence each other's states instantaneously, regardless of the
distance between them
Bit
The fundamental unit of classical information, representing either
0 or 1
Bit-flips
Errors that cause a qubit to change its state unexpectedly. These
errors can occur due to
environmental interference or imperfect control of the qubit, and they pose a
significant challenge in maintaining
the stability and reliability of quantum computations.
Bloch Sphere
Geometrical representation of the pure state space of a qubit. It
provides a useful
visualization of single-qubit operations and quantum states
Charlie
Cat Qubits
Type of logical qubit encoded in superpositions of coherent states
in a quantum harmonic
oscillator. Named after Schrödinger's cat thought experiment, these qubits can be more
robust against certain types
of errors
ChaCha
A symmetric encryption algorithm that, like AES
Circuit Ansatz
Specific structure or pattern of quantum gates used as a starting
point in variational quantum
algorithms. The choice of circuit ansatz can significantly affect the algorithm's
performance
Circuit Depth
The number of layers in a quantum circuit
Circulator (Superconducting QC)
Device used in superconducting quantum computing systems to control
the direction of signal
flow, often used to separate input and output signals
Classical Cryptography
Traditional encryption methods that rely on the computational
difficulty of certain
mathematical problems
Classical Noise
Random fluctuations in classical control systems that can lead to
errors in quantum operations.
It can be caused by physical factors such as, temperature fluctuations, or imperfections
in the materials used
within the device itself
Clifford Gates
Set of quantum gates that can be efficiently simulated on classical
computers. They play a
crucial role in quantum error correction and fault-tolerant quantum computing
CLOPS
A measure of how many layers of a quantum volume circuit a QPU can
execute per unite of time. Its unit is thousands (K)
Cluster State
Entangled multi-qubit state that can serve as a universal resource
for measurement-based
quantum computation
Coherence / Decoherence
Coherence describes the stability of a quantum system. A coherent
qubit can maintain its state
as 0, 1, or any superposition
Collapse
The process by which a quantum system in superposition resolves to
a single observable state
upon measurement
Combinatorial Optimization
Class of problems involving finding the best solution from a finite
set of possibilities
Complementary Metal-Oxide-Semiconductor (CMOS)
Technology used in manufacturing integrated circuits, including
computer processors. It's known
for its low power consumption and high noise immunity, making it the dominant technology
in modern digital
electronics
Controlled Gate
A multi-qubit gate where the operation on one qubit (target)
depends on the state of another
qubit (control)
Cooper Pair
Pair of electrons bound together in superconducting materials
Coupling Resonator (Superconducting QC)
Device used to mediate interactions between qubits that are not
physically adjacent
Central Processing Unit (CPU)
Primary component of a classical computer that performs
computations
Crosstalk
Unintended interactions between qubits, or between qubits and
control or readout signals,
leading to errors in quantum operations
Cryo-CMOS
CMOS electronics designed to operate at cryogenic temperatures,
used for control and readout of
quantum systems that require very low temperatures
Cryogenic Cooling
The process of cooling quantum computing systems to very low
temperatures, often near absolute
zero, to minimize thermal noise and maintain quantum coherence
Cryostat
Device used to maintain very low temperatures for quantum computing
systems, typically using
liquid helium or dilution refrigeration techniques
CRYSTAL-Kyber
Key encapsulation mechanism (KEM) based on the hardness of the
module learning with errors
(MLWE) problem
CRYSTALS-Dilithium
Digital signature scheme based on the hardness of lattice problems,
specifically the module
learning with errors (MLWE) and module short integer solution (MSIS) problems
CUDA-Q
Library and compiler toolchain for programming hybrid quantum
programs on both GPU's and QPU's
Delta
Data Qubit
Qubits used to store and process quantum information in a quantum
computation, as opposed to
auxiliary or ancilla qubits used for other purposes like error correction
Decoherence
Decoherence occurs when the interaction with the environment around
a quantum system causes it
to collapse and lose all information
Deep Shielding
Advanced techniques for isolating quantum systems from
environmental noise and interference
Diamond Vacancy Centers
Defects in diamond crystal structures that can be used as qubits,
known for their ability to
operate at room temperature
Diffie-Hellman key exchange
A method for securely exchanging cryptographic keys over a public
channel
Digital Signature
Cryptographic method for verifying the authenticity and integrity
of digital messages or
documents
Dilution Refrigerator
Specialized refrigeration system capable of reaching temperatures
close to absolute zero, used
in many superconducting and spin qubit quantum computing systems
Dirac Notation
Symbolic representation of quantum states via linear algebra, also
called bra-ket notation. The
bra portion represents a row vector and the ket portion represents a column vector.
DiVincenzo Criteria
Set of requirements proposed by David DiVincenzo for the physical
implementation of a quantum
computer, including scalable qubits, the ability to initialize qubits, long coherence
times, a universal set of
quantum gates, and the ability to measure specific qubits
Drive (Superconducting QC)
Microwave signals used to control and manipulate the states of
qubits
Dynamical Decoupling
Cancels out noise by inserting gates whose net effect is to perform
the identity operation
Echo
Eccosorb Filter (Superconducting QC)
Material used in superconducting quantum computing systems to
absorb unwanted electromagnetic
radiation, helping to reduce noise and improve qubit performance
Electron
Subatomic particle found in all atoms. It acts as the primary
carrier of electricity, has a
spin of "up" or "down", and has a negative charge
Electron Microscopes
High-resolution microscopes that use beams of electrons instead of
light
Entanglement
Phenomenon where two or more particles become correlated in such a
way that the quantum state
of each particle cannot be described independently
Entropy
Measure of the amount of uncertainty or randomness in a quantum
state
Error-Corrected Qubit
Logical qubit implemented using multiple physical qubits and error
correction techniques to
achieve higher fidelity and longer coherence times than individual physical qubits
Estimator Primitive
Returns expectation values of observables corresponding to physical
quantities or cost
functions
Excited State
The highest energy state of a quantum system, the exited state
represents the |1⟩ state
Foxtrot
FALCON
Fast-Fourier Lattice-based Compact Signatures over NTRU is a
lattice-based digital signature
scheme. It offers compact signatures and fast signing operations, based on the hardness
of the NTRU lattice problem
Fault-Tolerant Quantum Computing (FTGC)
Paradigm in quantum computing where quantum error correction and
fault-tolerant protocols are
used to perform reliable quantum computations even in the presence of noise and errors
Feed line (Superconducting QC)
Transmission line used to deliver control signals to qubits
Fiber Quantum Channel
Optical fiber used to transmit quantum information, often in the
form of single photons, for
applications in quantum communication and quantum key distribution
FIPS 203 (ML-KEM)
Part of the NIST Post-Quantum Cryptography Standardization process.
Module-Lattice-Based
Key-Encapsulation Mechanism Standard. In order of increasing security strength and
decreasing performance, these are
ML-KEM-512, ML-KEM-768, and ML-KEM-1024
FIPS 204 (ML-DSA)
Part of the NIST Post-Quantum Cryptography Standardization process.
Module-Lattice-Based
Digital Signature Standard
FIPS 205 (SLH-DSA)
Part of the NIST Post-Quantum Cryptography Standardization process.
Stateless Hash-Based
Digital Signature Standard, SLH-DSA is based on SPHINCS+
Flux (Superconducting QC)
Control line used to adjust the magnetic flux through a
superconducting loop, allowing for the
tuning of qubit properties
Fluxonium
Type of superconducting qubit that uses a combination of Josephson
junctions and a
superinductor to achieve improved coherence times
Fock state
Quantum state that describes a definite number of non-interacting
identical particles. For
instance, in quantum optics, a single-photon state is a Fock state of one photon
Golf
Gate
Reversible operation that manipulates the state of one or more
qubits
Gate All-Around Field-Effect Transistor (GAAFET)
Advanced transistor design used in classical computing
Gate Speed
The rate at which quantum gate operations can be performed. Faster
gate speeds allow for more
operations to be completed within the coherence time of the qubits
GHZ State
Type of maximally entangled state involving three or more qubits,
named after Greenberger,
Horne, and Zeilinger
Graphical Processing Unit (GPU)
Originally designed for rendering graphics, GPUs are now used for
various parallel computing
tasks. In quantum computing, GPUs are often used for classical simulation of quantum
systems and for control and
readout processing
Ground State
The lowest energy state of a quantum system, the ground state
represents the |0⟩ state
Grover's Algorithm
Quantum algorithm for searching an unsorted database, providing a
quadratic speedup over
classical algorithms
Hotel
Hadamard Gate
Single-qubit quantum gate that creates an equal superposition of
the |0⟩ and |1⟩ states. It's a
fundamental operation in many quantum algorithms.
Hamiltonian
The operator corresponding to the total energy of a system
Hashing
Process of mapping data of arbitrary size to fixed-size values
Hollow-Core Fiber (HCF))
Type of optical fiber with a hollow core, which can be used for
low-loss transmission of light
or for containing atoms for quantum information processing.
Heisenberg Uncertainty
Fundamental principle in quantum mechanics stating that certain
pairs of physical properties,
such as position and momentum, cannot be simultaneously measured with arbitrary
precision
HHL Algorithm
Harrow-Hassidim-Lloyd algorithm, a quantum algorithm for solving
systems of linear equations
that, under certain conditions, can provide an exponential speedup over classical
methods.
High Electron Mobility Transistor (HEMT)
Transistor used in low-noise amplifiers for readout in
superconducting quantum computing
systems
High Performing Computer (HPC)
The use of supercomputers and parallel processing techniques to
solve complex computational
problems
Extension of the QUBO problem formulation that allows for
higher-order terms in the objective
function. Some quantum annealing devices are designed to solve HUBO problems
Housing
Refers to the physical packaging that encloses and supports quantum
processing units. It is
designed to protect delicate quantum components from environmental disturbances and to
maintain optimal conditions
for quantum coherence
Hybrid Computation
An approach that combines classical and quantum computing resources
to solve problems,
leveraging the strengths of both paradigms
India
Identity Gate
Quantum gate that leaves the state of a qubit unchanged. While it
doesn't perform any
operation, it's often used in circuit design and quantum error correction
Interference
Phenomenon where the probability amplitudes of different paths in a
quantum system combine,
leading to constructive or destructive interference. This is a key principle underlying
many quantum algorithms
Intrinsic Randomness
The fundamental unpredictability in quantum mechanics, which can be
harnessed for applications
like quantum random number generation
Juliet
Jitter
Random fluctuations in the timing of signals or operations in
quantum systems. Minimizing
jitter is crucial for maintaining precise control over qubits and achieving
high-fidelity quantum operations
Josephson Junction (JJ)
Quantum mechanical device consisting of two superconductors
separated by a thin insulating
barrier. Josephson junctions are key components in many superconducting qubit designs
Josephson Parametric Amplifier (JPA)
Low-noise amplifier based on Josephson junctions, used for
high-fidelity readout of
superconducting qubits
Kilo
Key Generation
The process of creating cryptographic keys
Key-Encapsulation Mechanism (KEM)
Set of algorithms that, under certain conditions, can be used by
two parties to establish a
shared secret key over a public channel. A shared secret key that is securely
established using a KEM can then be
used with symmetric-key cryptographic algorithms to perform basic tasks in secure
communications, such as encryption
and authentication
Lima
Lasers
Device that emit coherent beams of light generated by the quantum
process of stimulated
emission
Leakage Removal Qubit
Technique used to remove unwanted population from higher energy
states in multi-level quantum
systems, helping to maintain the qubit subspace.
Lifetime
The duration over which a quantum state can be maintained before it
decoheres or relaxes to its
ground state. Longer lifetimes are crucial for performing complex quantum computations.
Linear Algebra
Branch of mathematics dealing with linear equations and linear
transformations, fundamental to
the mathematical formalism of quantum mechanics and quantum computing.
Logical Qubit
Qubit encoded using multiple physical qubits and quantum error
correction techniques to achieve
higher fidelity and longer coherence times than individual physical qubits.
Mike
Magic State
Special quantum states that, when combined with Clifford gates,
enable universal quantum
computation. Preparing high-fidelity magic states is a key challenge in fault-tolerant
quantum computing
Magnetic Resonance Imaging (MRI)
A medical imaging technique that uses strong magnetic fields and
radio waves for creating
non-invasively 3D images of an object
Majorana Fermions
Exotic quantum particles that are their own antiparticles.
Theorized to be useful for
topological quantum computing due to their potential resistance to decoherence
Maximum Independent Set
In graph theory, a maximal independent set is a set of vertices in
a graph where no two
vertices are adjacent, and no more vertices can be added without violating this
condition
Measure Qubit
Qubit specifically designated for measurement in a quantum circuit,
often used in error
correction schemes or to read out the results of a computation
Measurement
The process of observing a quantum system, which collapses the
system's wavefunction and yields
a classical result. Understanding and optimizing measurement is crucial for quantum
error correction and algorithm
implementation
Mid-circuit Measurement
Ability to measure some qubits during the execution of a quantum
circuit without disturbing
other qubits
Mixing Chamber
Coldest part of a dilution refrigerator, where quantum processors
are typically housed in
superconducting qubit systems
Molecule
Group of atoms bonded together
Multi-Product Formulas (MPF)
Technique used in quantum simulation algorithms to improve the
accuracy of simulating quantum
dynamics. Reduces algorithmic errors aka Trotter errors through a weighted
combination of several circuit
executions
November
Native Gates
Specific set of quantum gates that a particular quantum processor
can execute directly without requiring any
transformation or compilation
Neutral Atom Quantum Computing
Quantum computing architecture that uses neutral atoms (often
alkali metals) trapped in optical
lattices as qubits
Neutral Atoms
Atoms with no net electric charge, used as qubits in some quantum
computing architectures due
to their long coherence times and ability to be manipulated with lasers
Neutron
Neutron is a subatomic particle found in the nuclei of almost all
atoms. It does not have an
electrical charge and remains neutral
NIST Post-Quantum Cryptography Standardization
Process led by the National Institute of Standards and Technology
to develop and standardize
cryptographic systems that are resistant to attacks by quantum computers
Nitrogen Vacancy Center (NVC)
A defect in a diamond consisting of a nitrogen atom substituting
for a carbon atom in a lattice
next to a lattice vacancy
No-Cloning Theorem
Fundamental principle of quantum mechanics stating that it is
impossible to create an identical
copy of an arbitrary unknown quantum state
Noise
Unwanted disturbances in a quantum system that can lead to errors
in quantum operations
Noise Temperature
Measure of the amount of noise in a quantum system, often expressed
as an equivalent
temperature
Noisy Intermediate-Scale Quantum (NISQ)
The current era of quantum computing, characterized by quantum
processors with 50-100 qubits
that are still subject to significant noise and errors, coined by John Preskill in 2017
Non-Classical (Quantum) Light
Light that exhibits properties that cannot be explained by
classical electromagnetic theory,
such as squeezed states or entangled photons
Non-Clifford Gates
Quantum gates that cannot be efficiently simulated on classical
computers and are necessary for
universal quantum computation
Non-Deterministic
Processes or algorithms that may produce different outcomes given
the same initial conditions.
Many quantum algorithms are inherently non-deterministic due to the probabilistic nature
of quantum mechanics
NOT Gate
Quantum gate that flips the state of a qubit, analogous to the
classical NOT operation. It's
also known as the Pauli-X gate
Nuclear Magnetic Resonance (NMR)
Technique that uses pulses of electromagnetic radiation to control,
manipulate and read out the
spin of a nucleus within a molecule
Oscar
Operator Backpropagation (OBP)
Technique used in variational quantum algorithms to efficiently
compute gradients of quantum
circuits
Optical Tweezers
Scientific instrument that uses a highly focused laser beam to hold
and move microscopic
objects, are used to trap and manipulate individual atoms for use as qubits
Oracle
An oracle is a black-box function that can be queried to solve a
specific problem
Output (Superconducting QC)
Signals measured from the qubits after a computation, typically
requiring amplification and
signal processing
Papa
Parameter-shift Rule
Technique used in quantum machine learning to compute gradients of
parameterized quantum
circuits
Pauli Twirling
Inserting random gates to simplify the average noise
Photonic Crystal Fiber (PCF))
Type of optical fiber with a periodic structure that can be used
for low-loss transmission of
light in quantum communication applications
Phase Flip
Type of quantum error where the phase of a qubit is reversed
Photon
Photon is the smallest amount of electromagnetic energy a single
particle of light at a certain
wavelength can carry
Photon Number Statistics
Statistical distribution of the number of photons in a light field
Photonic Qubits
Qubits that use different properties of photons (such as
polarization or path) to encode
quantum information
Physical Qubit
Basic unit of quantum information in a quantum computer,
implemented using a physical system
such as a superconducting circuit, trapped ion, or photon
Public Key Encryption (PKE)
Type of encryption that uses a pair of keys: a public key for
encryption and a private key for
decryption
Post-Quantum Cryptography (PQC)
Cryptographic systems that are believed to be secure against
attacks by both classical and
quantum computers
Probabilistic Error Cancellation
Quantum error mitigation technique that aims to counteract noise by
applying additional
operations to the quantum circuit. It works by characterizing the noise in the system,
then designing and
implementing a set of operations that statistically cancel out the effects of that noise
when averaged over many
runs
Process Design Kit (PDK)
Set of files and documentation used to model and design quantum
circuits
Pseudo Random Number Generator (PRNG)
Algorithm that generates a sequence of numbers that approximates
the properties of random
numbers
Pump (Superconducting QC)
Microwave signal used to drive parametric processes, often used in
amplifiers for qubit readout
Purcell Filters (Superconducting QC)
Devices used in superconducting quantum computing to protect qubits
from spontaneous emission
while allowing for fast readout
Quebec
Q1 Individual (Gate Fidelity)
It refers to the fidelity of a single-qubit gate operation when
measured individually. It quantifies how accurately a
single-qubit gate performs its intended operation without interference from other qubits
or the environment.
Q1 Parallel (Gate Fidelity)
It refers to the fidelity of single-qubit gate operations when
multiple gates are executed in parallel on different
qubits. It tells how well these gates perform simultaneously without introducing
additional errors due to interactions
between separate qubits.
Q2 Fidelity (Gate Fidelity)
It refers to the likelihood in percentage that a two-qubit gate
operation is executed correctly without introducing
errors. It is crucial for ensuring that quantum algorithms that rely on entanglement and
interactions between qubits
function as it is supposed to do.
Qinu Fridge
Type of cryogenic system used to cool quantum computing hardware to
very low temperatures
Qiskit Functions Catalog
Collection of pre-built quantum functions and algorithms provided
as part of the Qiskit
framework
Qiskit Primitives
Basic building blocks in the Qiskit framework that represent
fundamental quantum operations or
algorithms
Qiskit Runtime
Quantum computing service and programming model that allows users
to optimize workloads and
efficiently execute them on quantum systems at scale
Qiskit SDK
An open-source framework for quantum computing developed by IBM,
allowing users to create and
manipulate quantum circuits and run them on simulators or real quantum hardware
QPU Topology
The physical layout and connectivity of qubits in a quantum
processing unit. The topology can
significantly impact the efficiency of quantum algorithms and error correction schemes
QRNG (Quantum Random Number Generator)
Device that generates random numbers based on inherently random
quantum processes, providing
true randomness as opposed to the pseudo-randomness of classical generators
Type of optimization problem where the objective function is
quadratic and the variables are
binary. Many quantum annealing devices are designed to solve QUBO problems
Quantization
The process by which certain physical quantities in quantum systems
can only take on discrete
values, rather than varying continuously
Quantum Advantage
The point at which a quantum computer can solve a problem
significantly faster than the best
known classical algorithm on the most powerful classical supercomputer
Quantum Algorithm
Step-by-step procedure designed to be run on a quantum computer,
often aiming to solve problems
more efficiently than classical algorithms
Quantum Annealer
Type of quantum computer specialized for solving optimization
problems by finding the lowest
energy state of a system.
Quantum Approximate Optimization Algorithm (QAOA)
Hybrid quantum-classical algorithm designed to find approximate
solutions to combinatorial
optimization problems
Quantum Chemistry
Research area focused on addressing classically intractable
chemistry problems with quantum
computing
Quantum Circuit
Sequence of quantum logic gates applied to a set of qubits to
perform a computation.
Quantum Cloud
Cloud-based services that provide access to quantum computing
resources, allowing users to run
quantum algorithms without owning physical quantum hardware
Quantum Communication
Quantum communication research develops ultra-secure communication
channels and global networks
by leveraging the phenomena of quantum information
Quantum Computing as a Service (QCaaS)
Cloud-based platforms that provide access to quantum computing
resources and associated
software tools on a pay-as-you-go basis
Quantum Convolutional Codes
Class of quantum error-correcting codes inspired by classical
convolutional codes, designed to
protect quantum information from errors
Quantum Convolutional Neural Network
Quantum neural network inspired by classical convolutional neural
networks, designed to process
quantum data with a structure similar to image data
Quantum Cryptography
The use of quantum mechanical principles to perform cryptographic
tasks. This includes quantum
key distribution and post-quantum cryptography
Quantum Datasets
Collections of data generated by or designed for quantum computers,
used in the development and
testing of quantum algorithms and applications
Quantum Development Kit (QDK)
Set of tools and libraries for quantum programming, often provided
by quantum hardware
companies or software developers
Quantum Differentiable Programming
Paradigm that combines quantum computing with automatic
differentiation techniques, useful for
optimizing variational quantum algorithms and quantum machine learning
Quantum Dot
Nanocrystals of semiconductor wherein an electron-hole pair can be
trapped. The nanometer size
is comparable to the wavelength of light and so, just like in an atom, the electron can
occupy discrete energy
levels. The dots can be confined in a photonic crystal cavity, where they can be probed
with laser light
Quantum Electrodynamics (QED)
Quantum field theory of electromagnetism. Cavity QED, which studies
the interaction between
atoms and photons in cavities, is particularly relevant to some quantum computing
architectures
Quantum Embedding
Technique used in quantum machine learning to map classical data
into quantum states, allowing
classical problems to be solved on quantum hardware
Quantum Error Correction (QEC)
Techniques used to detect and correct errors in quantum systems,
crucial for building
large-scale, fault-tolerant quantum computers
Quantum Feature Map
Mathematical map that embeds classical data into a quantum state.
Usually executed by a
variational quantum circuit whose parameters depend on the input data
Quantum Firmware
Low-level software that directly controls quantum hardware,
managing tasks like pulse
generation and qubit calibration
Quantum Games
Games that leverage quantum mechanical principles, either in their
design or in strategies for
playing them
Quantum Gate
Quantum gate can transform a sequence of quantum bits. Quantum
gates are mathematically
represented by matrices
Quantum Generative Adversarial Network (GANs)
Quantum version of the classical generative adversarial network,
using quantum circuits for the
generator and/or discriminator to produce and classify data
Quantum Gradient
The gradient of a quantum circuit with respect to its parameters,
used in the optimization of
variational quantum algorithms
Quantum Indeterminacy
Principle in quantum mechanics that certain properties of quantum
systems do not have definite
values until they are measured
Quantum Information Science (QIS)
Interdisciplinary field that combines quantum physics, computer
science, and information theory
to study how quantum systems can be used to store, process, and transmit information
Quantum Information science and technology (QIST)
Quantum Information Science and Technology (QIST) is a
multidisciplinary field bringing
together quantum mechanics and information technology
Quantum Internet
Proposed network that would distribute quantum information and
entanglement between distant
quantum devices, enabling new forms of secure communication and distributed quantum
computing
Quantum Just-in-time (QJIT)
Technique for compiling quantum circuits at runtime, optimizing
them based on the specific
quantum hardware they will run on.
Quantum Key Distribution (QKD)
Method of securely exchanging cryptographic keys using quantum
mechanical principles,
theoretically secure against any eavesdropping attempts.
Quantum Locking
Phenomenon where a superconductor can be locked in position above a
magnet due to quantum
effects
Quantum Logic Gate(s)
Operation that manipulates the state of one or more qubits,
analogous to classical logic gates.
Quantum Machine Learning
Intersection of quantum computing and machine learning, exploring
how quantum algorithms can
enhance or speed up machine learning tasks
Quantum Mechanics
The fundamental theory describing the behavior of matter and energy
at the atomic and subatomic
scales, forming the basis for quantum computing
Quantum Memory
Device capable of storing quantum information for extended periods,
crucial for quantum
communication and large-scale quantum computing
Quantum Network
A system of interconnected quantum devices that can share quantum
information, crucial for
distributed quantum computing and quantum communication
Quantum Neural Network
Machine learning model that uses quantum circuits to process
information, analogous to
classical neural networks.
Quantum Node
Point in a quantum network capable of processing and routing
quantum information
Quantum Open Architecture (QOA)
Open framework for designing and implementing quantum computing
systems, allowing for
interoperability and collaboration in quantum hardware and software development
Quantum Parallelism
Ability of a quantum computer to perform multiple computations
simultaneously by leveraging
superposition, a key advantage over classical computers for certain problems
Quantum Phase Estimation
Quantum algorithm used to estimate the eigenvalues of a unitary
operator, with applications in
many other quantum algorithms
Quantum Processing Unit (QPU)
Core component of a quantum computer that contains the qubits and
performs quantum operations
Quantum Random Number Generation (QRNG)
The use of quantum mechanical phenomena to generate truly random
numbers, as opposed to the
pseudo-random numbers generated by classical algorithms
Quantum Readiness Index
Measure of an organization's preparedness to adopt and utilize
quantum technologies
Quantum Repeater
Device designed to extend the range of quantum communication by
overcoming the effects of
signal loss in quantum channels. Quantum repeaters are crucial for building
long-distance quantum networks
Quantum Research
Scientific investigation into quantum phenomena and their
applications, including quantum
computing, quantum communication, and quantum sensing
Quantum Reservoir Computing
Quantum version of classical reservoir computing, using quantum
systems as the reservoir to
process temporal data
Quantum Safe Cryptography
Quantum-safe cryptography is the study of information security
protocols that are designed to
be secure against attacks by both classical and quantum computers
Quantum Sensing
The use of quantum systems to measure physical quantities with
greater precision or sensitivity
than classical sensors
Quantum Sensor
Device that uses quantum mechanical effects to measure physical
quantities, often achieving
higher precision than classical sensors
Quantum Simulation
Use of quantum computers to model and study quantum systems that
are difficult or impossible to
simulate efficiently on classical computers
Quantum State
Complete description of a quantum system, typically represented as
a vector in a complex
Hilbert space
Quantum Superposition
Fundamental principle of quantum mechanics where a quantum system
can exist in multiple states
simultaneously until measured
Quantum Teleportation
Quantum communication protocol that transfers the quantum state of
one qubit to another qubit
at a distant location, using entanglement and classical communication.
Quantum Transducer
Device that converts quantum information from one form to another,
such as from optical qubits
to solid-state qubits.
Quantum Tunnelling
Quantum mechanical phenomenon where a particle passes through a
potential barrier that it
classically could not surmount.
Quantum Utillity
The practical value or usefulness of a quantum computer for solving
real-world problems.
Quantum Volume (QV)
Metric developed by IBM to measure the overall performance of a
quantum computer, taking into
account both the number of qubits and their quality
Quanvolutional Neural Network
Hybrid classical-quantum model in which classical CNNs are
augmented by layers of variational
quantum circuits.
Qubit
Fundamental unit of quantum information, analogous to a classical
bit but capable of existing
in superposition states.
Qubit Chip
Chip with qubits and supporting circuitry. These chips serve as the
foundational building
blocks of quantum processors, enabling the physical realisation of quantum circuits and
operations
Qubit Count
Number of qubits in a quantum processor, one measure of its
computational power.
Qubit Lifetime
The duration over which a qubit can maintain its quantum state
before decoherence occurs
Qubit Ring
Circular arrangement of qubits, often used in certain quantum
computing architectures to
facilitate interactions between qubits
Qubit Shuttling
Technique used in some quantum computing architectures to move
qubits physically within the
quantum processor
Qumodes
Qumodes are like qubits but for photonic quantum computers
Romeo
Random Number Generator (RNG)
Device or algorithm that produces a sequence of numbers that lack
any predictable pattern
Readout Bus
Communication channel used to read the state of qubits after a
computation
Readout Fidelity
Accuracy with which the state of a qubit can be determined through
measurement
Readout Resonator (Superconducting QC)
Device used to measure the state of a qubit by probing its resonant
frequency
Rivest-Shamir-Adelstein (RSA)
Cryptographic system that secures communication and data
transmission. It employs a pair of
keys, public and private, to encrypt and decrypt information. The public key is used to
encrypt data, while the
private key is kept secret and used for decryption. Its security is based on the
difficulty of factoring large
integers
Rubidium
Alkali metal often used in atomic clocks and some quantum computing
implementations
Rydberg atom
Atom whose electron(s) is (are) excited to a high quantum state
Rydberg Blockade
Phenomenon where the presence of one highly excited Rydberg atom
prevents nearby atoms from
also being excited to Rydberg states, used for implementing quantum gates in some
neutral atom quantum computers.
Sierra
Sampler Primitive
Returns the quasi-probability distributions representing the
likelihood of measuring certain
bit-strings
Sampling-based Quantum Diagonalisation (SQD)
Quantum algorithm for estimating the eigenvalues and eigenvectors
of a Hermitian matrix.
Schrodinger's Cat
Famous thought experiment in quantum mechanics illustrating the
concept of quantum
superposition and the role of measurement in quantum systems.
Seed
In the context of random number generation, an initial value used
to start the generation
process
Shielding
Physical barriers or techniques used to protect quantum systems
from external interference,
crucial for maintaining qubit coherence
Shor's Algorithm
Quantum algorithm for integer factorization that can break many
public-key cryptography systems
like RSA encryption, one of the main drivers for the development of post-quantum
cryptography
Silicon Spin Qubits
Qubits based on the spin states of electrons or nuclei in silicon
Single-photon Detector
Device capable of detecting individual photons
Single-photon Source
Device that can reliably produce individual photons on demand
SPHINCS+
Stateless hash-based signature scheme that derives its security
from the security of
cryptographic hash functions
Spin
Intrinsic form of angular momentum carried by elementary particles
Spintronics
Field of study focused on the manipulation and utilization of
electron spin for information
processing
Stabilizer Codes
Class of quantum error-correcting codes that are particularly
efficient to implement and
analyze
State Preparation and Measurement (SPAM) Error
Errors that occur during the initialization of qubits into a
desired state or during the
measurement of qubit states
Steane's Code
Quantum error-correcting code that encodes one logical qubit into
seven physical qubits,
capable of correcting arbitrary single-qubit errors
Store-Now Decrypt-Later (SNDL)
Potential threat where an adversary stores encrypted data now with
the intention of decrypting
it later when sufficiently powerful quantum computers become available
Superconducting Circuits
Electrical circuits made from superconducting materials, used in
one of the leading
architectures for building quantum computers
Superconducting Qubit
Type of qubit implemented using superconducting circuits, typically
operated at very low
temperatures
Surface Codes
Class of quantum error-correcting codes well-suited for
implementation on two-dimensional
arrays of qubits
SWAP Gate
Quantum gate that exchanges the states of two qubits
Tango
T1 Amplitude Decoherence time
T1 is the relaxation time, the amount of time it takes for the
qubit to go back from the excited state to
the ground state. Its unit is microseconds (μs)
T2 Echo Phase Decoherence time
The time after which an initial state will evolve into an equal
classical probabilistic mixture of states, so that you can no longer confidently predict
the state. Its unit is microseconds (μs)
T3 Ramsey time
It's the duration between two operations on a quantum system: one
that prepares the system, and another that measures
it. During this time, you don't disturb the system, allowing certain quantum properties
to evolve undisturbed. Its unit is microseconds (μs)
Tensor Networks
Mathematical and graphical approach for representing and
manipulating quantum states and
operations, particularly useful for simulating quantum systems
The [[8,3,2]] Code
Quantum error detecting code that encodes 3 logical qubits into 8
physical qubits and can
detect arbitrary single-qubit errors
The Double-slit Experiment
Fundamental experiment in quantum mechanics that demonstrates the
wave-particle duality of
quantum entities
Time Crystal
Phase of matter that breaks time-translation symmetry, potentially
useful for creating more
robust qubits.
Toffoli Gate
Three-qubit gate that performs a controlled-controlled-NOT
operation
Topological Quantum Computing
Proposed form of quantum computing that uses topological states of
matter to encode and process
quantum information, potentially more resistant to errors than other approaches.
Transmon Qubit
Type of superconducting qubit designed to be less sensitive to
charge noise, widely used in
current superconducting quantum computers.
Transpilled Circuits
Quantum circuits that have been translated and optimized to run on
specific quantum hardware
Trapped Ion Quantum Computing
Quantum computing architecture that uses individual ions trapped in
electromagnetic fields as
qubits.
Trapped Ions
Individual ions held in place by electromagnetic fields, used as
qubits in one of the leading
quantum computing architectures
Travelling Salesman Problem (TSP)
Famous optimization problem that quantum computers may be able to
solve more efficiently than
classical computers for certain problem sizes
Travelling Wave Parametric Amplifier (TWPA)
Type of low-noise amplifier used in the readout of superconducting
qubits.
True Random Number Generator (TRNG)
Device that generates random numbers based on unpredictable
physical processes, often
leveraging quantum phenomena
Tunable Coupler
Device used in quantum circuits to dynamically control the
interaction strength between qubits,
allowing for adjustable coupling that can be turned on or off as needed
Twirled Readout Error Extinction (TREX)
Remove bias from expectation values that result from readout noise
Uniform
Uncertainty Principle
Fundamental principle in quantum mechanics stating that certain
pairs of physical properties,
such as position and momentum, cannot be simultaneously measured with arbitrary
precision
Universal Gate Set
Set of quantum gates that can be used to approximate any quantum
operation to arbitrary
precision
Universal Quantum Computer
Quantum computer capable of implementing any quantum algorithm, as
opposed to specialized
devices like quantum annealers
Victor
Variational Quantum Algorithm
Algorithm that depend on tunable parameters, and can therefore be
optimized
Variational Quantum Classifier (VQC)
Supervised learning algorithm in which variational circuits QNNs
are trained to perform
classification tasks
Variational Quantum Eigensolver (VQE)
Hybrid quantum-classical algorithm for finding the ground state
energy of molecules and other
quantum systems
Variational Quantum Linear Solver (VQLS)
Hybrid quantum-classical algorithm for solving systems of linear
equations
Variational Quantum Thermalizer (VQT)
Quantum algorithm for preparing thermal states of quantum systems
VBG Quantum Channel
Optical component used in some quantum communication systems to
filter and route photons
Virtual Qubits
Logical qubits that are mapped onto physical qubits
Von Neumann Entropy
Measure of quantum information that generalizes classical
information entropy to quantum
systems
Whiskey
Wavefunction
Mathematical model of the quantum state of a quantum system. It
describes the characteristics
of a particle, such as its position, momentum, time and/or spin.
Wave-Particle Duality
Concept of quantum mechanics stating that all particles exhibit
both wave and particle
properties.
Wigner Function
Quasi-probability distribution that describes the state of a
quantum system in phase space
X-ray
X-basis Measurement
Measurement of a qubit in the basis formed by the eigenstates of
the Pauli-X operator
Yankee
Y2Q
Years to Quantum, a term used to estimate the time until
large-scale quantum computers become a
reality and potentially threaten current cryptographic systems
Yao's Millionaires' problem
Cryptographic protocol that can be used to compare two numbers
without revealing any
information about the numbers themselves. The protocol is based on the use of quantum
random numbers to generate
secret keys that are used to encrypt and decrypt the numbers being compared
Zulu
Zeno Effect
Phenomenon where frequent observation of a system inhibits
transitions between quantum states
Zero Noise Extrapolation (ZNE)
Quantum error mitigation technique that involves running a quantum
circuit multiple times with
varying levels of intentionally added noise, then extrapolating the results to estimate
the outcome in the absence
of noise