Quantum Computing Glossary — Part 5 — R-S

The glossary is too large for a single document (over 3,000 entries), so it is divided into six parts, plus the introduction:

  1. Quantum Computing Glossary — Introduction.
  2. Quantum Computing Glossary — Part 1 — A-C.
  3. Quantum Computing Glossary — Part 2 — D-G.
  4. Quantum Computing Glossary — Part 3 — H-P.
  5. Quantum Computing Glossary — Part 4 — Q.
  6. Quantum Computing Glossary — Part 5 — R-S. This part.
  7. Quantum Computing Glossary — Part 6 — T-Z.

R-S

  1. R-pi. Abbreviation for Pauli-Z gate. Quantum logic gate which rotates a qubit about the Z-axis by pi radians. Synonym for Z and Z gate.
  2. Rabi interaction. TBD.
  3. radiation. Short for electromagnetic radiation (EMR). Technically, radiation means all forms of EMR, as well as some particles, but in some contexts it refers to X-ray radiation and gamma radiation, excluding light, radio waves, and microwaves. And in some contexts it reviews to only X-rays and radioactive decay, or even only radioactive decay alone. There are other forms of radiation, which may or may not be included in a particular context, including neutrons, positrons, ultraviolet light, and infrared light. May come from natural sources, such as with radioactive decay, or artificial sources, such as X-rays from electrons in a cathode ray tube.
  4. radiative relaxation. TBD. Referenced in the Universal holonomic quantum gates over geometric spin qubits with polarised microwaves paper by Nagata, Kuramitani, Sekiguchi, and Kosaka.
  5. radio frequency. The frequency characteristic of radio waves. Alternatively, synonym for radio waves. Depending on context, microwaves may or may not be considered as radio waves — if not clear from context, microwaves should be considered to be radio waves. Abbreviated as RF. see the Wikipedia Radio Frequency article.
  6. radio frequency interference. See radio-frequency interference.
  7. radio-frequency interference. Electromagnetic radiation (EMR) which is not desired within a quantum computer, such as commercial radio waves and cell phone signals. Some EMR, such as microwaves, is used to control qubit state, but any other EMR is unwelcome and runs the risk of disturbing the fragile quantum state of qubits. Abbreviated as RFI. See also: stray electromagnetic radiation.
  8. radio waves. The lowest frequency, longest wavelength of electromagnetic radiation. Depending on the context, may or may not Include microwaves, which are a lower frequency and longer wavelength than infrared and visible light but higher frequency and shorter wavelength than other radio waves. Typically used for communication, especially over long distances. Includes cell phone signals and all other forms of wireless communication (other than infrared and visible light) — unless microwaves are excluded. Unless clear from context, microwaves should be considered as radio waves. See the Wikipedia Radio wave article. See also: radio frequency and RF.
  9. radioactive decay. Radiation which results from a breakdown or transition within an atom. The common forms being alpha particles, beta particles, and gamma radiation. Such radiation can occur in natural materials, including those used to fabricate electronic devices, and can affect electronics and quantum systems. Radioactive decay can also be artificially induced, such as in a nuclear reactor, nuclear weapon, or particle accelerator/collider. Shielding can help to some degree, but ultimately radioactive decay is simply a reality of the physical world, whose effects must be mitigated.
  10. RAM. Initialism for random access memory.
  11. Ramsey experiment. Method used to measure the T2* time (dephasing time) for a qubit. See also: Hahn echo experiment.
  12. random access memory. Large-capacity memory for general-purpose computing, commonly on a classical computer, but can be modeled on a quantum computer — see quantum random access memory.
  13. random quantum circuit. TBD.
  14. random quantum dynamics. TBD.
  15. randomized low‐depth quantum circuits. A method for constructing quantum supremacy tests. See the The complexity of quantum sampling problems presentation by Michael Bremner, et al. Also referred to as low-depth quantum circuit sampling. See also: simulation of low-depth quantum circuits.
  16. range. See range of a function. See also: domain and interval.
  17. range of a function. The full set of possible output values for a function. See the Wikipedia Range (mathematics) article. See also: domain of a function.
  18. range of function. Encompassing a relatively wide spectrum or relatively large number of functions, in contrast to a single function or an extremely narrow or small cluster of functions.
  19. range of problems. Encompassing a relatively wide spectrum or relatively large number of problems, in contrast to a single problem or a narrow niche of problems.
  20. rapid single flux quantum. A superconducting device capable of representing a qubit as a magnetic quanta. For example, a Josephson function. [TBD: refine]. See the Wikipedia Rapid single flux quantum article. Abbreviated as RSFQ. See also: single-flux-quantum.
  21. rational number. A real number which can be expressed as a numerator and denominator which are integer values. Whether a rational number should be considered a numeric value or a non-numeric value in the context of computation, data formats, and data storage is unclear and debatable — it works both ways.
  22. raw bits. Data which is simply a sequence of bits, with no other intended interpretation, although at some stage, some software probably will associate some interpretation to the organization of the raw bits, but in the interim the data has no interpretation. See also: binary data.
  23. raw bytes. Data which is simply a sequence of bytes, with no other intended interpretation, although at some stage, some software probably will associate some interpretation to the organization of the raw bytes, but in the interim the data has no interpretation. See also: binary data.
  24. raw text. Data which is simply text, such as the text of an article or book. Or a data file while is simply lines of text. See also: log file. May either be natural language text, a sequence of symbols, or simply a sequence of characters.
  25. RDM. Initialism for reduced density matrix.
  26. reaction. Response or change in state of a system in response to some external stimulus or inputs. Alternatively, interaction between two or more systems. Alternatively, chemical reaction.
  27. readout. Synonym for measurement. See quantum measurement.
  28. readout assignment fidelity. TBD. Referenced in The Quantum Processing Unit (QPU) doc from Rigetti Computing.
  29. readout device attached to a qubit. An electronic component or electronic device, such as a resonator (cavity), which permits the quantum state of a qubit to be communicated to a digital circuit. This causes the wave function of the qubit to collapse to a single basis state, |0> or 1>. See also: readout of a qubit and quantum measurement.
  30. readout devices attached to each qubit. See readout device attached to a qubit.
  31. readout error. See qubit readout error.
  32. readout of a qubit. See quantum measurement. See also: dispersive readout of a qubit, readout resonator, and quasi-lumped element resonator.
  33. readout resonator. A waveguide (resonator) used to measure the quantum state of a qubit using a photon, such as a microwave pulse, trapped in a cavity. See also: superconducting transmission line resonator.
  34. real. The traditional mathematical meaning — a number capable of representing the quantity of any continuous phenomenon of the real world or even imaginary worlds, such as measuring distance. A number which may have a fraction. Between any two consecutive integers there are an infinity of real numbers. The integers are considered real as well. See real number. See also: non-real, integer, complex number. Alternatively, that an entity exists in the real world. See also: realized and theorized. Alternatively, relating to the real world.
  35. real classical computer. A physical classical computer, in contrast to a simulated classical computer or a virtual machine. Alternatively, a classical computer which has actually been built, in contrast to a theoretical design for a classical computer which has never been built.
  36. real classical system. See real classical computer.
  37. real computer. A physical computer, in contrast to a simulated computer or a virtual machine. Alternatively, a computer which has actually been built, in contrast to a theoretical design for a computer which has never been built.
  38. real eigenvalue. The eigenvalue for an eigenvector. This term is redundant since by definition all eigenvalues are real. Simply used to emphasize that the value is real.
  39. real number. A number which is continuous and can represent a real quantity such as a distance or magnitude, in contrast to an integer or an imaginary number. Integers are real numbers as well. See also: complex number and integer number. See the Wikipedia Real number article. See also: real and floating-point number.
  40. real organization. An actual organization which exists in the real world, in contrast to one which is only theorized, imagined, or contemplated.
  41. real part. The real portion of a complex number. The non-imaginary part. See also: imaginary part.
  42. real physical system. See real quantum system.
  43. real product. An actual product as intended for delivery to customers, in contrast to a prototype.
  44. real quantum computer. An actual, operational quantum computer, with qubits obeying the principles of quantum mechanics. See actual quantum computer and physical quantum computer, in contrast to a quantum computer simulator running on a classical computer, or a speculative or merely planned but not yet built design for a quantum computer. Alternatively, a quantum computer that is a universal quantum computer, capable of all computation of a classical computer, and not a fixed-function quantum computer.
  45. real quantity. A quantity of a real system, a physical system.
  46. real quantum device. TBD.
  47. real quantum system. An arbitrary quantum system from the real world, in contrast to the quantum system within a qubit or a quantum system. The context is using a quantum computer to model physical systems from the real world, not computers per se. Alternatively, may refer to an existing quantum computer.
  48. real value. A value which is a real number. See also: integer value and complex value. See also: floating-point value.
  49. real-time processing. All processing for execution of a quantum circuit on a quantum computer, from preparation through measurement. Alternatively, any processing on a computer which is in response to events in the real world at very close to the time when those events actually occur.
  50. real-world. Related to the real world.
  51. real world. The physical world. Alternatively, practical applications.
  52. real-world application. An application which has practical use in the everyday operations of real organizations, in contrast to a toy application or a contrived application more suitable for the research stage or experimental stage. Synonym for practical application. Alternatively, a synonym for real-world problem.
  53. real-world problem. A problem present in the everyday operations of real organizations.
  54. real-world use case. TBD.
  55. realize. To make real, such as in a product or at least a working prototype. To create an entity in the real-world based on a theory or conceptual approach. The design for an advanced quantum computer might be theorized but may not yet have been realized.
  56. realized. Has been made real, such as in a product or at least a working prototype.
  57. recalibration. See physical qubit calibration, with emphasis on the need to do this calibration of qubits on a fairly frequent and fairly regular basis.
  58. reduced density matrix. TBD. Abbreviated as RDM.
  59. reduced density operator. TBD.
  60. reduced Planck constant. Planck’s constant divided by two times pi for applications which are using angular velocity rather than frequency. See Wikipedia Planck constant article. Denoted by h bar. See also: Planck’s constant.
  61. reduced Planck’s constant. See reduced Planck constant.
  62. reduced state. TBD.
  63. redundancy. The use of extra data or extra components to compensate for errors and component failures. See redundant component and redundant data. See also: quantum error correction (QEC).
  64. redundant component. The use of an extra component to compensate for component failure and possibly for errors as well. See also: quantum error correction (QEC).
  65. redundant data. The use of extra data to compensate for errors. See also: quantum error correction (QEC).
  66. reference basis. TBD.
  67. refrigeration unit. Synonym for cryostat.
  68. regex. Short for regular expression. See also: regexp.
  69. regexp. Short for regular expression. See also: regex.
  70. register. A device capable of representing a value. Either a classical register, which can represent only a single value at any moment, or a quantum register, which can represent all possible values at every moment.
  71. regular. Spaced evenly, at an equal distance, either in time or space. See also: grid, lattice, crystal.
  72. regular expression. An expression formed according to the rules of a specialized language, not sophisticated enough for expressing and parsing a programming language, but sufficient for expressing of patterns for decoding formatted text, symbols, and short strings. Abbreviated as regex and regexp. See the Wikipedia Regular expression article.
  73. regular quantum Fourier transform. Synonym for full quantum Fourier transform and exact quantum Fourier transform.
  74. relational operator. An operator which performs a comparison between two values and returns a boolean value indicating whether the values are related as specified — equal, not equal, less than, less than or equal, greater, or greater than or equal. The values are normally numeric expressions or possibly some non-numeric expressions, such as character strings or rational numbers. Relational operators are typically used within boolean expressions, particularly in high-level programming languages.
  75. relationship. The logical or abstract meaning of an association between two or more entities. Association here does not necessarily imply an actual connection, but possibly simply that a relationship exists between the entities.
  76. relative phase. TBD.
  77. relaxation time. See energy relaxation time (T1).
  78. reliable quantum computer. See robust quantum computer. A quantum computer which can be depended on, relied on, to consistently give expected results.
  79. remote login. The ability to access a remote computer as if you were directly in front of the computer entering commands on a keyboard and using a mouse or other pointing device. Generally discouraged or reserved for elite computer professionals who have a special and approved need.
  80. remote quantum device. See remote quantum computer.
  81. remote quantum computer. A quantum computer which is accessed remotely, over the Internet, such as a quantum cloud service.
  82. remote quantum simulator. A remote classical computer configured to execute a quantum simulator as a cloud service. See also: local quantum simulator.
  83. render a graphical image for display. The generation of a graphical image by a computer using graphical elements, combining them into one integrated image. See graphical image generation.
  84. render graphical images for display. See render a graphical image for display.
  85. rendering a graphical image for display. See render a graphical image for display.
  86. requirement. A function, feature, or quality which is deemed necessary for a system. An expectation by a user or customer of a system as to what the system must do for them. Not so much how the expectation might be met, but the fact that it must be met. Some requirements may be optional while most are deemed mandatory. An individual requirement as part of a the full set of requirements. Detailed in a requirements specification. See also: optional requirement, mandatory requirement, and constraint.
  87. requirement spec. See requirements specification.
  88. requirement specification. See requirements specification.
  89. requirements. The full set of requirements for a system, detail on each individual requirement.
  90. requirements spec. See requirements specification.
  91. requirements specification. A document which records the result of capturing the requirements for a system, the expectations of users and sponsors of the system as to what it must do for them. See also: detailed specification, architecture specification, functional specification, API specification, design specification, and software requirements specification. See the Wikipedia Software requirements specification article. Shortened as requirement specification or requirement spec.
  92. research. Rigorous, focused, systematic, and even experimental inquiry and investigation into some phenomenon, both its actuality and its potential. Research can both precede and follow theoryresearch can develop ideas which can lead to theory, and theory can suggest avenues for research, and so on, ad infinitum. See also: quantum computing research.
  93. research problem. A problem which is of research interest to an organization or individual, in contrast to a theoretical problem, an experimental problem, or a practical problem.
  94. research stage. The stage in the development of a technology where either the theory is still being developed, or the developed theory is being implemented in prototype form, and there are still significant questions about practicality, in contrast to the experimental stage, product development stage, and commercial availability stage.
  95. researcher. An individual, commonly a scientist or other professional, endeavoring to gain data and insight, and to prove or disprove theories through research, including experiments. See also: quantum researcher, quantum information researcher, and quantum information theorist.
  96. resonant frequency. The frequency at which a waveguide (resonator) or cavity traps a photon, such as a microwave pulse. May be a fixed frequency or a tunable frequency.
  97. resonant microwave drive. TBD.
  98. resonator. A waveguide used as a cavity to contain a photon of a designated frequency, such as for control or entanglement of qubits on a quantum computer. Alternatively, an electronic circuit with a capacitor and inductor which has a resonant frequency. See the Wikipedia Resonator article. See also: coplanar waveguide, coupling resonator, readout resonator, and superconducting transmission line resonator.
  99. resonator frequency. TBD. Referenced in The Quantum Processing Unit (QPU) doc from Rigetti Computing.
  100. resonator port. TBD. Referenced in The Quantum Processing Unit (QPU) doc from Rigetti Computing.
  101. resource. Any capability which can be utilized by a user, machine, or computer program, including memory, registers, synchronization locks and queues, input and output devices, files, and resources available over a network, subject to availability and authorization. An entire quantum computer is a resource, allocated to users on a demand basis. See also: access, authorization, and access control.
  102. resource management. The organization and control of resources. Facilitating the acquisition, scheduling, and access to resources. See also: authorization.
  103. resource theory of quantum coherence. TBD.
  104. REST API. A standardized style of API for communicating with a software service which is available on the Internet. Each software service will have its own REST API, but they all are based on common principles, making it easier for software developers to adapt to any new software service which comes along or with which they have no prior experience. See the Wikipedia Representational state transfer (REST) article.
  105. result. The measured state of a qubit of a quantum computer at the end of execution of a quantum program. See also: results and final results. Alternatively, an output of a computer program.
  106. results. The measured state of the qubits of a quantum computer at the end of execution of a quantum program. See final results. Alternatively, the output of a computer program.
  107. reverse annealing. See reverse quantum annealing.
  108. reverse quantum annealing. The use of quantum annealing for local refinement. [TBD: add detail, benefits] See the Reverse Quantum Annealing for Local Refinement of Solutions whitepaper from D-Wave Systems.
  109. reversible logic gate. Any logic gate, quantum or classical, is reversible if no information is lost, such that the input values can be deduced solely from the output values of the gate. Reversible logic gates are rare in classical logic, but all quantum logic gates (with the exception of gates for preparation and measurement) are by definition reversible logic gates.
  110. reversible quantum logic gate. By definition, all quantum logic gates (with the exception of gates for preparation and measurement) are reversible logic gates. This is a requirement for quantum computation, which is based on the science of quantum mechanics, which presumes that every operation is time-invertible, meaning that the information that resulted from an operation can be used to determine the information that was fed into that operation.
  111. RF. Initialism for radio frequency.
  112. RF drive. TBD. Use of radio frequency (RF) signals to control a qubit, such as for execution of a quantum logic gate. See also: flux bias line and microwave drive. Referenced in The Quantum Processing Unit (QPU) doc from Rigetti Computing.
  113. RFI. See radio-frequency interference.
  114. robust quantum computer. A quantum computer which has a very substantial and reliable quantum coherence due to quantum error correction (QEC), better qubit technology, or other technical means.
  115. robust and reliable quantum computer. See robust quantum computer. Redundant since robustness implies reliability, but emphasizing that the user can rely on the quantum computer to deliver expected results.
  116. robust. See fault-tolerant.
  117. robust quantum information science and technology industry. TBD. Referenced in National Quantum Initiative Act bill.
  118. robustness. See robust. Emphasis on degree of fault tolerance — either not robust, minimally robust, reasonably robust, or extremely robust. Unless context indicates otherwise, extremely robust is presumed as the intended meaning.
  119. row. The vertical dimension of a table or matrix. Data or information is organized horizontally as columns in a row. See also: column.
  120. row matrix. See row vector.
  121. row vector. A vector which is a 1 x n matrix, n columns wide but only 1 row vertically. A row vector can be transposed to form a column vector, and vice versa. See the Wikipedia Row and column vectors article. See also column vector and bra. Synonym for row matrix.
  122. root. See root node.
  123. root node. In graph theory, a node or a directed graph which has no incoming edges. A tree has a single root node. See also: branch node and leaf node.
  124. roots of unity. TBD. x^k = 1 (mod n)
  125. RSA. Initialism for Rivest–Shamir–Adleman, the names of the inventors of an approach to cryptography, specifically public-key cryptography. See the Wikipedia RSA (cryptosystem) article.
  126. RSA key. The common type of key used for public-key encryption, in July 2018. See also: traditional modern cryptographic method.
  127. RSA key size. The number of binary bits in an RSA key for public-key encryption. Common value as of July 2018 are 1024, 2048, and 4096 bits. See also: traditional modern cryptographic method.
  128. RSFQ. Initialism for rapid single flux quantum.
  129. RX. See RX gate.
  130. RX gate. A quantum logic gate which rotates a qubit about the X-axis by a specified angle, in radians. Abbreviated as RX. See also: RY gate and RZ gate.
  131. RY. See RY gate.
  132. RY gate. A quantum logic gate which rotates a qubit about the Y-axis by a specified angle, in radians. Abbreviated as RY. See also: RX gate and RZ gate.
  133. Rydberg state. Swedish physicist Johannes Rydberg discovered the formula for calculating the the wavelengths for the spectral lines of chemical elements. These states allow trapped ions (trapped Rydberg ions) to be used to construct qubitstrapped Rydberg ion qubits. See the Wikipedia Rydberg state article.
  134. RZ. See RZ gate.
  135. RZ gate. A quantum logic gate which rotates a qubit about the Z-axis by a specified angle, in radians. Abbreviated as RZ. See also: RX gate, RY gate, S gate, and T gate.
  136. S. See S gate.
  137. S gate. A quantum logic gate which rotates a qubit about the Z-axis by a fixed angle of pi divided by two radians (90 degrees.) Abbreviated as S. Equivalent to the RZ gate with an angle of pi divided by two. [TBD: what does S stand for?].
  138. safe prime. A prime number which is one greater than twice another prime number — p2 = 2 * p1 + 1. This formula is a necessary but not sufficient condition — one greater than twice any prime number is not necessarily still a prime number, such as 17 * 2 + 1 = 35, which is not prime (5 * 7), although 35 happens to be a semiprime and in fact a safe semiprime since 5 = 2 * 2 + 1 and 7 = 2 * 3 + 1. And 17 itself is not a safe prime since (17–1) / 2 = 8, which is not a prime (2 * 2 * 2.) See also: safe semiprime.
  139. safe semiprime. An integer which is a semiprime whose two factors are safe primes — they are prime numbers which are one greater than twice two other prime numbers. For example, 35 is a safe semiprime since 35 = 5 * 7, 5 = 2 * 2 + 1, and 7 = 2 * 3 + 1.
  140. scalability. See scalable, emphasizing the degree or ease of scaling.
  141. scalable. A design and architecture for hardware or software which can accommodate a linear increase in capacity with a linear increase in required resources. See also: scaling.
  142. scalable photonic quantum information processing architecture. TBD. Referenced in the Continuous-Variable Quantum Computing in Optical Time-Frequency Modes using Quantum Memories paper by Humphreys, Kolthammer, Nunn, Barbieri, Datta, and Walmsley.
  143. scalable QD quantum computing. See scalable quantum dot quantum computing.
  144. scalable quantum dot quantum computing. See scalable quantum dot quantum computer.
  145. scalable quantum dot quantum computer. A quantum computer based on quantum dots (QD), which permits significantly better scalability compared to non-QD approaches.
  146. scalable qubit array. The ability to fabricate a significant number of qubits in an array or lattice arrangement on a chip. Required for efficient quantum error correction (QEC).
  147. scale. See scaling.
  148. scaling. Growing the capacity and performance of a system to accommodate greater use, including more users and more data. See also: scalable.
  149. schedule. Align a request to access a resource with availability of that resource. If the resource is busy with another user, the requested access may have to be placed in a queue and the user must wait.
  150. scheduling. The process of maintaining a queue of users who are requesting access to a resource which is currently or frequently busy processing the requests of other users. See also: schedule and resource management.
  151. Schmidt bases. TBD.
  152. Schmidt coefficient. TBD. See the Wikipedia Schmidt decomposition article.
  153. Schmidt decomposition. TBD. See the Wikipedia Schmidt decomposition article.
  154. Schmidt number. TBD.
  155. Schmidt rank. TBD. See the Wikipedia Schmidt decomposition article.
  156. Schrödinger’s cat. Metaphor for quantum superposition — said cat is simultaneously alive and dead. See the Wikipedia Schrödinger’s cat article. See also: cat state.
  157. Schrödinger equation. Describes the changes over time of a physical system according to the principles of quantum mechanics. See the Wikipedia Schrödinger equation article. The equation has two forms: the time-dependent Schrödinger equation (TDSE) and the time-independent Schrödinger equation (TISE).
  158. Schrödinger kitten state. Cat state using a single particle or atom.
  159. science. The systematic study and development of knowledge of all aspects of the world and universe, both natural and manmade, partitioned into branches or fields, enabling specialization by those who study those fields, scientists. See the Wikipedia Science article.
  160. scientist. A highly-educated professional focused on a particular field of science, who studies phenomena of that field, creating and sharing knowledge gained from research.
  161. script. A program written in a scripting language.
  162. scripting language. A specialized programming language designed to manipulate resources on a computer system, such as files, databases, computer programs, system commands, and system utilities.
  163. SDE. Initialism for software development engineer. A software developer.
  164. search. The process of locating an instance of a pattern. Alternatively, the process of finding a solution to a problem by evaluating alternative solutions, using either heuristics or brute force.
  165. search engine. A software system which specializes in search, especially text search. In theory, hardware could be used to accelerate search, but software is the standard approach at present. Usually involves indexing a large number of documents to accelerate keyword search.
  166. secondary processor. Any processor of a multiprocessor computer system other than the main processor or any parallel processors. This includes coprocessors, adjunct processors, auxiliary processors, or graphics processors.
  167. secure communication networks. TBD. Referenced in the Universal holonomic quantum gates over geometric spin qubits with polarised microwaves paper by Nagata, Kuramitani, Sekiguchi, and Kosaka. See also: quantum communication.
  168. security. Protecting data and systems from unauthorized access.
  169. security measure. A method utilized to assure the security of data and systems. Such as a password or cryptographic key. Or access control.
  170. security method. See security measure.
  171. self-adjoint operator. A mathematical concept a bit too esoteric for discussion here, but needed for the foundation of quantum mechanics. See Hermitian operator.See the Wolfram Hermitian operator page or the Wikipedia Self-adjoint operator article.
  172. semi-structured information. Information (data) which has a limited degree of structure, such as the XML data format, but not as structured as records or rows in a table. See also: structured information, unstructured information, knowledge, and insight.
  173. semiclassical. See semiclassical physics.
  174. semiclassical physics. TBD.
  175. semiconductor. A material which is normally electrically neutral, an insulator, but whose conductivity can be controlled by an electric field, a magnetic field, light, heat, or mechanical force, making it very useful both for logic circuits and as a sensor. See also: semiconductor device. See the Wikipedia Semiconductor article. See also: silicon and silicon semiconductor.
  176. semiconductor component. See semiconductor device.
  177. semiconductor device. An electronic device based on semiconductors. Alternatively, synonym for an individual semiconductor component.
  178. semiconductor particle. A particle which is a semiconductor — composed of the same material as a semiconductor device, simply even smaller.
  179. semiconductor-based qubit. See silicon-based qubit.
  180. semiprime. An integer which is the product of two prime numbers, its two factors. Commonly used as the key value for public-key encryption. See the Wikipedia Semiprime article. See also: safe semiprime.
  181. sensor. An electronic device (or electronic component) whose conductivity varies based on the presence of an electric field, a magnetic field, light, heat, or mechanical force. See also: semiconductor.
  182. separable state. Quantum state which is not entangled with another quantum state. A quantum system, such as a qubit, which is not entangled with another quantum system, such as another qubit. In contrast to quantum entanglement. See the Wikipedia Separable state article.
  183. sequence. A collection of steps or stages which must be executed sequentially, in the order specified, in contrast to in parallel. Alternatively, a series of items of some type.
  184. sequence of characters. A series of any number of characters. See also: text and string. Depending on the context, may be no characters, an empty string.
  185. sequence of gates. See sequence of quantum logic gates.
  186. sequence of inputs. A series of input values, which arrive in the order specified, such as those which drive a state machine.
  187. sequence of instructions. A series of instructions to be executed in order on a classical computer, which is loosely equivalent to the concept of a quantum circuit, which is a series of quantum logic gates or quantum operations to be executed in order on a quantum computer. See also: sequence of operations, sequence of quantum logic gates, and sequence of statements.
  188. sequence of logic gates. See sequence of quantum logic gates.
  189. sequence of logic steps. See sequence of operations.
  190. sequence of operations. One or more steps to be performed as part of either an algorithm or code. See also: sequence of instructions, sequence of quantum logic gates, and sequence of statements.
  191. sequence of quantum logic gates. A series of quantum logic gates to be executed in the order they are written. May be a complete quantum logic circuit or a subset of a larger quantum logic circuit. See also: sequence of instructions, sequence of operations, and quantum logic subcircuit.
  192. sequence of statements. One or more steps (statements) to be performed as part of either an algorithm or code. See also: sequence of instructions and sequence of operations.
  193. sequence of steps. One or more steps (quantum logic gates, operations, or statements) to be performed as part of either an algorithm or code. See also: sequence of quantum logic gates, sequence of instructions, sequence of operations, and sequence of statements.
  194. sequence of quantum circuit executions. One or more quantum logic circuits which are executed in succession, such as under the control of a classical program interacting with the quantum computer in a hybrid mode of operation. Alternatively, repeatedly executing the same quantum circuit, to assure that a correct result can be obtained, weeding out results where quantum errors occurred due to decoherence.
  195. sequence of symbols. One or more symbols, marks or identifiers, and possibly words as well. See also: text and sequence of characters.
  196. server. A computer on the Internet or other network which can be accessed remotely by users, typically to provide users with a service which they cannot execute conveniently on their own computer.
  197. service. Software on a server which provides remote access to features or computation to users. Alternatively, providing assistance to a customer, usually for a fee.
  198. SFA. Initialism for Shor’s factoring algorithm.
  199. SFQ. Initialism for single-flux-quantum.
  200. SFQ computer. See single-flux-quantum computer.
  201. SFQ microprocessor. A microprocessor based on single-flux quantum (SFQ). [TBD: For the qubits only?].
  202. shallow circuit. A quantum circuit with only a relatively small gate count. See also short-depth quantum circuit. [TBD: a number, what’s typical?]
  203. shared classical/quantum memory model. See shared memory architecture.
  204. shared memory architecture. The ability of two or more processes to share memory to permit immediate and direct access to data of common interest. An approach to the architecture of software which permits access to the quantum state of a simulated quantum computer by a software tool while a quantum program or quantum logic circuit is executing, such as to monitor the quantum state of qubits as execution is progressing.
  205. shared quantum classical memory. See shared memory architecture.
  206. shield. See shielding.
  207. shielded enclosure. See shielding.
  208. shielding. Metallic barriers which prevent stray electromagnetic radiation (EMR) from affecting the fragile state of the qubits in a quantum computer. This can include magnetic shielding and placing the entire quantum computer in a Faraday cage and some subsystems in a Faraday shield.
  209. shielding from stray electromagnetic radiation. See shielding. Redundant since EMR is the primary reason for shielding.
  210. Shor’s algorithm. A quantum algorithm for factoring very large numbers, designed to exploit the power of a quantum computer for numbers so large that a classical computer would take too long. Useful for cracking encryption keys which are based on two large prime numbers. See the Wikipedia Shor’s algorithm article.
  211. Shor’s factoring algorithm. See Shor’s algorithm. Abbreviated as SFA.
  212. short-depth quantum circuit. A quantum circuit with only a relatively small gate count. See also shallow circuit.
  213. shortest vector problem. TBD. Abbreviated as SVP. See the Wikipedia Shortest vector problem article.
  214. shuttling. TBD. [controlled movement of trapped ions (qubits) — entangled qubits retain their quantum state (e.g., entanglement) while being moved spatially, potentially over extended distances]
  215. sign. Whether a number is positive, negative, or zero. Alternatively, a symbol.
  216. signal. A level or flow of information or energy (charge), such as bits or current. See also: analog signal and digital signal.
  217. silicon quantum integrated circuit. An integrated circuit containing one or more silicon-based qubits.
  218. silicon. A chemical element which is a material particularly well-suited as a semiconductor. See the Wikipedia Silicon article. Also suitable for a type of qubitsilicon spin qubit.
  219. silicon-based quantum computer. TBD.
  220. silicon-based qubit. See silicon spin qubit.
  221. silicon quantum computing. TBD.
  222. silicon quantum computing industry. TBD.
  223. silicon quantum photonics. TBD.
  224. silicon semiconductor. Semiconductor based on silicon. Most semiconductors are.
  225. silicon semiconductor technology. The methods, tools, equipment, and software needed for design and fabrication of chips (integrated circuits) based on silicon semiconductors.
  226. silicon spin qubit. A qubit based on the spin property of an electron on a silicon atom. The main advantage being fabrication of chips using standard silicon semiconductor processes. See Intel Intel Sees Promise of Silicon Spin Qubits for Quantum Computing press release.
  227. simulate. Use a computer program to model and imitate the behavior of another computer program, another computer system, a machine or device other than a computer, or a physical system. See also: simulator, simulation, simulate on a classical computer, simulate on a quantum computer, and simulate a physical system.
  228. simulate on a classical computer. Execution of a quantum program or circuit on a quantum computer simulator running on a classical computer.
  229. simulate on a quantum computer. Use a quantum computer to simulate a process, device, or physical system. See also: quantum physics simulator.
  230. simulate a physical system. See simulate quantum physics.
  231. simulate quantum physics. Execute a quantum physics simulator with a description of a physical system as its input. Simulates the quantum physics of that physical system.
  232. simulated annealing. An algorithmic approach to finding the global optimum for a function. See the Wikipedia Simulated annealing article. See also quantum annealing and reverse quantum annealing.
  233. simulated classical computer. A simulated computer which is a classical computer. One classical computer simulating another classical computer.
  234. simulated computer. Software which enables a computer to mimic the execution of computer programs written for another computer, typically of a different computer architecture. May be a simulated classical computer or a simulated quantum computer. See also: virtual machine.
  235. simulated noise. Introduction of variability into the results of simulating a quantum program on a quantum simulator on a classical computer to more closely approximate the probabilistic nature of a real quantum computer, in contrast to the deterministic nature of a classical computer, on which the quantum simulator is being executed.
  236. simulated quantum computer. See quantum computer simulator.
  237. simulating a classical computer. See classical computer simulator.
  238. simulating noise. The generation of simulated noise to make a quantum simulation more realistic, to reflect the probabilistic nature of a real quantum computer, in contrast to the deterministic nature of a classical computer, on which a quantum simulation is being executed.
  239. simulating a quantum computer. See quantum computer simulator.
  240. simulation of low-depth quantum circuits. A method for constructing quantum supremacy tests. See the Simulation of low-depth quantum circuits as complex undirected graphical models paper by Boixo, Isakov, Smelyanskiy, and Neven. See also randomized low‐depth quantum circuits.
  241. simulation. Simulate the behavior of another computer program, another computer system, a machine or device other than a computer, or a physical system. Alternatively, execute a simulator. Alternatively, the process of executing a simulator.
  242. simulator. See simulated computer. See also: interpreter. Alternatively, a computer program which models the behavior of another computer program, another computer system, a machine or device other than a computer, or a physical system. See also: simulate and simulation.
  243. simultaneous perturbation stochastic approximation. TBD. Abbreviated as SPSA.
  244. single circuit step. A single quantum logic gate or instruction or operation, either the logic of the gate or its execution.
  245. single faulty quantum gate. TBD.
  246. single-flux-quantum. A method for reading a superconducting qubit. [TBD: expand]. See the NIST Flux Quantum Electronics web page. Abbreviated as SFQ. See also: flux quantum electronics and rapid single flux quantum.
  247. single-flux-quantum circuit. Circuit based on single-flux quantum technology.
  248. single-flux-quantum computer. A quantum computer constructed with single-flux-quantum qubits. Also known as an SFQ computer.
  249. single-flux-quantum electronics. See single-flux-quantum circuit.
  250. single-flux-quantum microprocessor. A complete microprocessor based on single-flux quantum technology. [TBD: Is this a complete quantum computer?].
  251. single-flux quantum technology. See single-flux-quantum.
  252. single-qubit gate. Short for single-qubit quantum logic gate.
  253. single-qubit logic gate. Short for single-qubit quantum logic gate.
  254. single-qubit measurement. TBD.
  255. single-qubit quantum logic gate. A quantum logic gate which operates on only a single qubit. Synonym for one-qubit quantum logic gate. Abbreviated as 1Q gate or 1Q. Shortened as single-qubit logic gate or single-qubit gate.
  256. single qubit resistant to errors. TBD.
  257. single-precision floating point. Representation of a real value in 32 bits on a classical computer. Covers values of magnitude from approximately 1.1755 times 10 to the minus 38 to approximately 3.403 times 10 to the 38. See the Wikipedia Single-precision floating-point format article. See also: double-precision floating point and extended-precision floating point.
  258. single-qubit control. The use of hardware, such as microwave pulses in a resonator, driven by execution of a quantum logic gate, to directly control the quantum state of a qubit, in contrast to two-qubit interaction (coupling or entanglement.)
  259. single-qubit gate fidelity. TBD. Referenced in The Quantum Processing Unit (QPU) doc from Rigetti Computing.
  260. single-qubit gate performance. See 1-qubit gate performance.
  261. single-qubit operation. An operation or quantum logic gate which references only a single qubit, in contrast to a two-qubit operation which references two qubits.
  262. single-qubit states. The two possible quantum states of a qubit, |0> and |1>, either individually or superimposed.
  263. single-Slater determinant wavefunction. TBD.
  264. single step. Incrementally execute a computer program, typically to debug it or to learn something about how its state changes incrementally during execution. Generally only possible on a classical computer but not on a quantum computer.
  265. single step execution of a quantum program. Single step a quantum program. Incrementally execute a quantum logic circuit or quantum program so that the quantum state of the qubits can be examined after or before each circuit step (quantum logic gate or operation), typically to debug a quantum program. Only possible on a quantum simulator since the state of a quantum system cannot be examined, observed, or measured directly without causing the quantum state (wave function) to collapse.
  266. situation. Some specified pattern of properties in some location or over some area which is of interest for some reason. May or may not constitute a problem. May be an opportunity rather than a problem per se.
  267. Slater determinant. TBD.
  268. Slater determinant wavefunction ansatz. TBD.
  269. small-angle XX gate. TBD.
  270. small-depth quantum circuit. See low‐depth quantum circuit.
  271. small quantum computer. Vague term which may refer to either a small number of qubits or a small physical size. At present, the latter does not exist. Synonym for small-sized quantum computer. See also: modest-sized quantum computer and medium-sized quantum computer.
  272. small-scale quantum computer. A quantum computer with a relatively modest number of qubits, say 5 to 8 qubits.
  273. small-scale quantum computing. Computing on a small-scale quantum computer..
  274. small-scale quantum computing device. See small-scale quantum computer.
  275. small-scale universal quantum computer. A quantum computer which is full-featured and capable of solving a wide range of problems, but with only a limited capacity, such as a relatively modest qubit count.
  276. small-scale universal quantum computing system. See small-scale universal quantum computer.
  277. small-sized quantum computer. Vague definition of the usability of a quantum computer in terms of its qubit count. Currently, less than 8 qubits would be considered a small-sized quantum computer. More than that would be a modest-sized quantum computer or a medium-sized quantum computer. Different individuals and organizations might quibble over these numbers and characterizations. These numbers will rise each year as more qubits become available. In two years, 16 to 20 qubits will likely be considered a small-sized quantum computer. In five years, the number for small-sized might be 64, 72, 128, 192, or even 256, depending on the pace of hardware advances. See also: large-sized quantum computer.
  278. software. May be a reference to code, computer program, application software, software code, software system, software subsystem, software library, or software component, in contrast to the hardware on which that software can be used.
  279. software application. See application software.
  280. software component. A component comprised of software code and any associated data needed by that component. Software components may be composed so that one software component is comprised of some number of other software components. A collection of related software components may be organized for reuse in a software library. A software system or a software subsystem is composed of software components. See also: subsystem.
  281. software code. The collection of instructions or statements which comprise a software component, computer program, software library, software application, software subsystem, or software system. Shortened as code.
  282. software-defined trapped-ion quantum computer. A trapped-ion quantum computer in which the quantum computer architecture — including both the number of qubits and their physical arrangement — can be reconfigured on demand — for each quantum program to be executed.
  283. software developer. An individual who engages in development of computer software. A computer programmer who engages in design and coding of software. May or may not design algorithms. See also: programmer and software development engineer.
  284. software development. The process of development of computer software, primarily the function of software developers. See also: quantum development.
  285. software development engineer. See software developer. Abbreviated as SDE. see also: programmer and software engineer.
  286. software engineer. See software developer.
  287. software engineering. See software development. See the Wikipedia Software engineering article.
  288. software framework. A software library which provides an overall structure for a significant portion of a software application. The application developer then fills in the gaps with the code which is specific to their application.
  289. software library. A collection of related software components which are designed to be reused and shared by any number of software systems or software applications.
  290. software to operate quantum computers. Any software needed to support the functioning of a quantum computer, including configuration, control of the physical machine, calibration, monitoring, scheduling access, reporting usage, and user submission of programs to be executed.
  291. software professional. Any individual whose profession, job, or function is primarily related to some aspect of software development or the delivery of software, including but not limited to software developers. For example, software test engineers, tech writers, technical management, sales engineers, and solution architects.
  292. software requirements specification. See requirements specification.
  293. software service. Middleware software or application software which provides an API permitting application software or other software services to use these software services to accomplish needed tasks. Includes database software. See also REST API.
  294. software subsystem. A collection of software components which collectively serve as a portion of a software system. Shortened as subsystem.
  295. software system. A collection of software components and software subsystems which collectively serve some significant purpose, such as application software or a software service.
  296. software-tailored architecture for quantum. See Software-Tailored Architecture for Quantum.
  297. Software-Tailored Architecture for Quantum. See Software-Tailored Architecture for Quantum co-design (STAQ) project.
  298. Software-Tailored Architecture for Quantum co-design (STAQ) project. An NSF research project to produce a practical fully-connected quantum computer using trapped-ion technology for qubits.
  299. software tool. Software which performs one or more relatively narrow functions which can be used in a variety of situations, typically by a software developer or other software professional. Excludes programs and applications which are intended to act as solutions to problems or opportunities and used by end-users. The focus is on performing relatively narrow functions needed by software developers and other software professionals. Includes compilers, source code control, and other software for working with programming languages.
  300. solid. See solid-state.
  301. solid matter. See solid-state matter.
  302. solid medium. A medium which is solid, such as wiring, metal, or a crystal, in contrast with liquid medium, gaseous medium, or plasma medium. See also: solid matter.
  303. solid-state. May be simply a reference to solid matter or a reference to solid-state electronics.
  304. solid-state device. Either an individual semiconductor device or a larger device which utilizes semiconductor devices, such as a solid-state drive for mass storage.
  305. solid-state drive. Mass storage which is implemented using flash memory. Synonym for solid-state storage.
  306. solid-state electronics. Electronic circuits based on semiconductor devices, in contrast to mechanical or vacuum-based devices (relays and tubes.) See the Wikipedia Solid-state electronics article.
  307. solid-state matter. Matter in which the atoms and molecules are closely packed and relatively stationary relative to each other, in contrast to liquid, gas, and plasma. See the Wikipedia Solid article. By definition, a single atom or a single molecule isolated from other matter would not constitute solid state matter.
  308. solid-state QIP. Short for solid-state quantum information processor.
  309. solid-state quantum computation. Computation using a solid-state quantum computer. May be used as a synonym for solid-state quantum computer.
  310. solid-state quantum computer. A quantum computer constructed using solid-state qubits, in contrast to atomic qubits. See the Theory of solid state quantum information processing paper by Guido Burkard of IBM.
  311. solid-state quantum information processor. TBD. In contrast to a trapped-ion quantum information processor, for example. Abbreviated as solid-state QIP.
  312. solid-state qubit. A qubit which is fabricated in solid-state form, meaning more than one atom, in contrast to an atomic qubit consisting of a single atom, such as an ion trap.
  313. solid-state storage. See solid-state drive.
  314. solution. A transformation of a situation which is considered a problem or an opportunity, and in which there is some need or desire to transform some pattern of properties to some new pattern of properties which are considered better than the original arrangement. Such a transformation is considered to be a solution to the problem or opportunity. See also: approximate solution, optimal solution, and practical solution.
  315. sound. Transmission of energy through a medium in the form of mechanical waves, in contrast to the waves of electromagnetic radiation. See the Wikipedia Sound article.
  316. source code. The textual representation for a computer program or code fragment which can be easily written by a human developer and easily read by both human developers and a programming language compiler. Can be compiled into an executable program.
  317. source format. The initial data format for data, information, or code before any transformation has been performed, in contrast to an intermediate format or final format. In the case of code, this would be source codecode or logic expressed as text in a programming language.
  318. space. TBD. see also: time.
  319. SPAM. Initialism for state preparation and measurement.
  320. SPAM error. Short for state preparation and measurement error.
  321. spatial. The quality of being arranged in space, based on position, and with direction, distance, and velocity. See also: visual and temporal.
  322. special value. Values which have some special significance in mathematics or a field which uses mathematics, such ae e, i, and pi. Typically have an associated name or symbol.
  323. specialized application. An application which is focused on a particular niche or for which there are few potential customers.
  324. specialized computer. A computer which was designed for a special, particular, or narrow purpose, in contrast to a general-purpose computer.
  325. specialized programming language. A programming language which is especially tailored to niche applications, such as data science or statistics, in contrast to a general-purpose programming language which applies to all applications. Will generally be a high-level programming language and quite likely a higher-level programming language.
  326. specialized language. A language designed for some special purpose, in contrast to nature language or a general-purpose programming language.
  327. specialized notation. An abbreviated form of language designed to concisely express concepts or information.
  328. specialized software. Code other than a typical computer program or application software, which executes only on a secondary processor rather than on the main processor of a computer, in contrast to a typical computer program which was developed by a typical software developer. Alternatively, from the perspective of a classical software developer, a quantum program would be specialized software, although technically it actually executes on the main processor of a quantum computer.
  329. speculative. Anything of interest which is only imagined and neither real nor even necessarily fully theorized yet. It may or may not be possible. All that is known is that it is interesting.
  330. speculative concept. A concept which has been imagined but not realized, and possibly not even theorized. It may or may not be possible. All that is known is that it is interesting.
  331. speed. Magnitude of the velocity of an object or other entity in space, independent of the direction of motion. See also: position, direction, distance, and velocity.
  332. spin. Angular momentum of a particle, such as an electron. Useful for encoding quantum information for a qubit. see the Wikipedia Spin (physics) article.
  333. spin lattice time. TBD.
  334. spin orbit coupling. TBD.
  335. spin qubit. A qubit which relies on the spin or angular momentum of a particle to encode quantum information. See also silicon spin qubit. Other types of qubit include charge qubit, flux qubit, and phase qubit.
  336. spin qubit array. Linear arrangement of a significant number of qubits. Required for efficient quantum error correction (QEC).
  337. spin qubit chip. Fabrication of a significant number of spin qubits on a single integrated circuit (chip).
  338. spin qubit error correcting code. An arrangement of spin qubits sufficient to support efficient and effective quantum error correction (QEC).
  339. spin-­spin relaxation time. TBD.
  340. spin state. The quantized angular momentum of a particle. See the Wikipedia Spin quantum number article.
  341. spontaneous emission time. TBD.
  342. SPSA. Initialism for simultaneous perturbation stochastic approximation.
  343. SQ gate. TBD.
  344. square matrix. A matrix with the same number of rows as columns.
  345. SQRT NOT. See square root of NOT gate.
  346. square root of NOT gate. A quantum logic gate which TBD. Abbreviated SQRT NOT. See Wikipedia Quantum logic gate article.
  347. SQRT SWAP. See square root of SWAP gate.
  348. square root of SWAP gate. A quantum logic gate which TBD. Abbreviated SQRT SWAP. See Wikipedia Quantum logic gate article.
  349. SQUID. Initialism for superconducting quantum interference device.
  350. stabilizer. TBD.
  351. stabilizer circuit. TBD. Referenced in the Wikipedia Gottesman-Knill theorem article.
  352. stabilizer code. TBD. See the Wikipedia Stabilizer code article.
  353. standard basis. TBD.
  354. standard basis state. TBD. [qubits are in basis state rather than a superposition or basis states.]
  355. standard basis vector. TBD.
  356. standard KAK form. TBD.
  357. standard mathematical function. Any of the functions commonly used in mathematics, including trigonometric functions, square root, exponential functions, logarithms, and statistical functions. Arguments to functions can be arbitrary algebraic expressions, which evaluate to real values, complex values, or integer values. The result returned by the function can be a real value, complex value, or an integer value.
  358. standard silicon semiconductor integrated circuit technology. Existing silicon semiconductor technology for producing chips. Nothing exotic.
  359. standard silicon semiconductor processes. See standard silicon semiconductor integrated circuit technology.
  360. standards for quantum information science and technology. TBD. Referenced in National Quantum Initiative Act bill.
  361. standards for quantum information science and technology security. TBD. Referenced in National Quantum Initiative Act bill.
  362. STAQ. Initialism for Software-Tailored Architecture for Quantum. See Software-Tailored Architecture for Quantum co-design (STAQ) project.
  363. state. Either quantum state or classical state. Alternatively, the state of mattersolid, liquid, gas (gaseous), or plasma.
  364. state change. A difference in state as a result of some action, activity, or external control.
  365. state machine. Hardware or software which is constructed to recognize a sequence of inputs, maintaining its state while it awaits the next input value, which will in turn cause the state machine to advance to a potentially new state based on the particular input value. See also: automata.
  366. state of matter. The form of mattersolid, liquid, gas (gaseous), or plasma.
  367. state preparation. See quantum state preparation. See also: state preparation and measurement (SPAM).
  368. state preparation and measurement error. TBD. Referenced in the Universal holonomic quantum gates over geometric spin qubits with polarised microwaves paper by Nagata, Kuramitani, Sekiguchi, and Kosaka.
  369. state preparation technique. TBD.
  370. state space. TBD.
  371. state tomography. TBD. See quantum state tomography and output state tomography. See also: quantum process tomography.
  372. static system. A system whose behavior does not change as a function of time, in contrast to a dynamical system which does change over time.
  373. stationary qubit. A qubit which is immobile, in contrast to a flying qubit which is mobile. Referenced in the Universal holonomic quantum gates over geometric spin qubits with polarised microwaves paper by Nagata, Kuramitani, Sekiguchi, and Kosaka.
  374. statistical algorithm. An algorithm which is based on a statistical analysis of the problem rather than seeking an absolutely precise solution, such as based on a fixed formula with fixed inputs.
  375. statement. An instruction in a higher-level programming language. Either a non-executable statement such as a declaration or an executable statement. A program in a high-level language consists of a sequence of statements, each of which may contain one or more expressions and one or more operations, each of which may be compiled into any number of machine language instructions, in contrast with an assembly language program which is composed of a sequence of instructions, directly written in machine language. Alternatively, a statement may be a declaration, such as declaring a variable or a data structure. Some programing languages may consider declarations to be distinct from executable statements.
  376. Steane ancillas. TBD. See the Optimizing the Frequency of Quantum Error Correction using the [[7,1,3]] Steane Code paper by Abu-Nada, Fortescue, and Byrd.
  377. Steane code. TBD. See the Optimizing the Frequency of Quantum Error Correction using the [[7,1,3]] Steane Code paper by Abu-Nada, Fortescue, and Byrd.
  378. Steane code with Steane ancillas. TBD. See the Optimizing the Frequency of Quantum Error Correction using the [[7,1,3]] Steane Code paper by Abu-Nada, Fortescue, and Byrd.
  379. step. A single operation to be performed in a sequence of operations or sequence of instructions, either in an algorithm or in code. Alternatively, a single executable statement in a program written in a high-level language or in an algorithm.
  380. storage. Place where items, values, data, or information can be stored. Storage is comprised of some number of storage locations, which may or may not be contiguous. See also: storage location, memory, register, and mass storage.
  381. storage location. Place where an individual item or value is stored in storage.
  382. stored program. The code for a computer program, in the form of machine language, stored in memory, ready to be executed. The processor fetches instructions of the stored program from memory. Instructions may branch or loop within the stored program. The memory used for code is the same as the memory used for data, although in some computers there may be separate memories for code and data. The former is known as a Von Neumann architecture, and the latter a Harvard architecture. This is the standard model for execution of programs on a classical computer, but there is no equivalent at this stage for quantum computers, where individual quantum logic gates of a quantum circuit from an external source are presented to the quantum processor one at a time, with any decisions about what quantum logic gate to execute next performed outside of the quantum processor. [TBD: is there hardware to hold the multiple gates of a quantum circuit? How large?] The quantum computer itself has no ability to branch or loop — a quantum circuit is a simple linear sequence of quantum logic gates, with no branching or looping, although the classical computer which feeds quantum logic gates to the quantum processor may in fact support a variety of classical control structures and even classical data structures for what is known as the hybrid mode of operation, but the core quantum processor knows nothing about such classical structures, and which are completely distinct from the quantum information stored in the qubits of the quantum processor. Future quantum computers are likely to evolve more sophisticated structures for both code and data, with hybrids for both.
  383. stored quantum information. The quantum information in a qubit as represented by the quantum state or wave function of the qubit.
  384. strategy. General and broad approach to address an issue or approach a problem, in contrast to a narrower tactic or technique.
  385. stray electromagnetic radiation. Electromagnetic radiation (EMR) which is not desired within a quantum computer, such as commercial radio waves and cell phone signals. Some EMR, such as microwaves, is used to control the quantum state of a qubit, but any other EMR is unwelcome and runs the risk of disturbing the fragile quantum state of the qubits. See also: radio frequency interference (RFI).
  386. string. See character string. See also: text.
  387. strong adjustable coupling. TBD.
  388. strong coherent state. TBD.
  389. strong flux tunable coupling. TBD.
  390. strong spin-orbit coupling. TBD.
  391. strong spin-orbit coupling materials. TBD.
  392. strong spin-orbit interaction. TBD.
  393. strong spin-orbit materials. TBD.
  394. strongly correlated fermion systems. TBD.
  395. strongly correlated fermionic systems. TBD.
  396. structure. Arrangement of objects or other entities, according to some coherent and consistent criteria, such as a grid, tree,or based on function. See also: organization.
  397. structured information. Any form of information (data) other than a single value or a linear sequence of bytes or bits, such as an object, a list, a record, a row, a table, or a database. See also: semi-structured information, unstructured information, knowledge, and insight.
  398. subatomic particle. The smaller particles which are composed to form an atom. Synonym for elementary particle.
  399. subcircuit. See quantum logic subcircuit.
  400. subclass. An OOP class which is defined as being derived from another OOP class. That latter class is the parent class of the subclass. Code in the functions of a subclass can access the data items of the parent class or any superclass of the parent class. See also: object-oriented programming.
  401. Subcommittee on Quantum Information Science. See Subcommittee on Quantum Information Science of the National Science and Technology Council.
  402. Subcommittee on Quantum Information Science of the National Science and Technology Council. TBD. Referenced in National Quantum Initiative Act bill.
  403. subsystem. Relatively self-contained portion of a system. May be either hardware or software. See also: system component, hardware component, and software component. Alternatively, in quantum mechanics, one of the two or more quantum systems which make up a quantum system and may or may not be entangled, such as individual qubits or entangled qubits. See also: subsystem decomposition.
  404. subsystem decomposition. In quantum mechanics, the partitioning of a quantum system into subsystems. See the Subsystems and time in quantum mechanics paper by Foreman.
  405. subsystem of a quantum computer. Any of the major components of a quantum computer or of the entire quantum computer system.
  406. superclass. An OOP class from which other OOP classes are derived. A superclass is the parent class of all classes which are derived from it. Code in the functions of a subclass can access the data items of the parent class or any superclass of the parent class. See also: object-oriented programming.
  407. supercomputer. The highest performance and highest capacity of computers. They outperform the vast majority of computers at even the most sophisticated organizations. Very few organizations have supercomputers. Even most large technology companies do not have supercomputers, preferring large distributed networks of computers with a more moderate performance and capacity. Currently, all supercomputers are classical computers. This will continue to be true even as quantum computers may finally begin to outperform classical computers for some niche applications in the coming years. [TBD: criteria for when a quantum computer could be considered a supercomputer]. A radical departure in architecture will be required for quantum computers to overtake supercomputers for general-purpose applications. See the Wikipedia Supercomputer article. See also: high performance computing (HPC).
  408. superconducting. See superconductivity.
  409. superconducting charge qubit. A qubit which is a charge qubit, based on Cooper pairs and a Josephson junction, requiring superconductivity. All charge qubits are superconducting charge qubits, by definition, at least at this time. Also known as a transmon or superconducting transmon qubit. See the Wikipedia Transmon and Charge qubit articles. See also: fixed-frequency superconducting transmon qubit.
  410. superconducting electronic circuit. An electronic circuit whose components and interconnections require superconductivity.
  411. superconducting loop. Maintains a flow of current without resistance or heat loss. Used to construct a superconducting quantum interference device or SQUID. Used in the construction of a superconducting qubit with a Josephson junction. See the Wikipedia Superconducting quantum computing and Magnetic flux quantum articles.
  412. superconducting quantum computer. A quantum computer based on superconducting electronic circuits, such as those based on Josephson junctions. See the Wikipedia Superconducting quantum computing article.
  413. superconducting quantum computing. Computing using a superconducting quantum computer.
  414. superconducting quantum interference device. Used to measure very weak magnetic fields. Abbreviated as SQUID. Sometimes loosely referred to as a quantum transistor, but more as a marketing term. See the Wikipedia SQUID article.
  415. superconducting qubit. A qubit which requires superconductivity, which is all of them in current quantum computers, and for the foreseeable future.
  416. superconducting qubit architecture. An architecture for a quantum computer which requires superconducting qubits.
  417. superconducting qubit chip. An integrated circuit which implements one or more superconducting qubits.
  418. superconducting transmission line resonator. A resonator which has an embedded superconducting device (a qubit), to measure, manipulate, or couple (entangle) a qubit, such as using a trapped microwave pulse (photon.) See the Normal modes of a superconducting transmission-line resonator with embedded lumped element circuit components paper by Mortensen, Mølmer, and Andersen. See also: readout resonator and coupling resonator.
  419. superconducting transmon qubit. See superconducting charge qubit. See also: fixed-frequency superconducting transmon qubit.
  420. superconductivity. Conduction of electricity without any resistance or heat loss. Requires very cold temperature, limiting its utility. Currently required for the operation of the qubits of a quantum computer. [TBD: explain why] See the Wikipedia Superconductivity article.
  421. superimposed. The quality of two or more quantum states being present at the same time in the same quantum system. See also: superimposed quantum state.
  422. superimposed quantum state. The ability of a quantum system to be in a superposition of more than a single quantum state simultaneously. The ability of a quantum bit (qubit) to be both a 0 and 1 at the same time.
  423. superimposed state. Each of the individual quantum states which are superimposed to collectively comprise the quantum state of a qubit or quantum system.
  424. superoperator. TBD.
  425. superpolynomially. TBD. Such as an algorithm whose performance scales exponentially with input size. In contrast to polynomially.
  426. superposition. See quantum superposition.
  427. superposition principle. See quantum superposition principle.
  428. supervised pattern recognition. TBD. See the Implementing a distance-based classifier with a quantum interference circuit paper by Schuld, Fingerhuth, and Petruccione.
  429. supervised pattern recognition task. TBD. See supervised pattern recognition.
  430. supra-classical quantum simulation. Quantum simulation on a quantum computer which exceeds the capabilities of a classical computer. Term has so far apparently only been used in the title of a grant proposal, Supra-classical quantum simulation in physically restricted models of quantum computation, by Michael Bremner.
  431. supremacy. See quantum supremacy.
  432. supremacy regime. TBD.
  433. surface code. TBD. See topological quantum error correcting code. See also: surface code quantum error correction.
  434. surface code error correction. See surface code quantum error correction.
  435. surface code QEC. See surface code quantum error correction.
  436. surface code quantum error correction. TBD. See the Surface code quantum error correction incorporating accurate error propagation paper by Fowler, Wang, and Hollenberg.
  437. surrounding environment. Environment is close proximity to a system, close enough to have an immediate impact on the system.
  438. SVP. Initialism for shortest vector problem.
  439. SWAP. See SWAP gate.
  440. SWAP gate. A quantum logic gate which swaps the quantum states of two qubits. Abbreviated as SWAP. See the Wikipedia Quantum logic gate article.
  441. swap network. TBD.
  442. swap test. See SWAP test.
  443. SWAP test. A quantum circuit which determines the degree of overlap between the quantum states of two qubits. See the Wikipedia Swap test article.
  444. symbol. A mark (symbolic mark) or name (symbolic name) which represents a reference to an entity or some meaning.
  445. symbolic. The quality of symbols, in contrast to textual, numerical, or graphical.
  446. symbolic constant. See symbolic value, emphasizing that the value never changes.
  447. symbolic mark. A mark which serves as a symbol, to represent a reference to some entity or meaning.
  448. symbolic name. A name or identifier used to reference some entity, concept, meaning, or value, such as a mathematical constant. See also: e, h, i, and pi. Not quite the same as a variable, whose value can and is expected to change, while the value for a mathematical constant associated with a symbolic name would never change.
  449. symbolic value. Symbolic name for a value, such as a symbolic constant or a mathematical constant, such as e, h, and pi.
  450. synchronized. See synchronous.
  451. synchronous. The requirement that an operation or process be executed in sequence or lockstep with other operations and processes, in contrast to asynchronous.
  452. synchronous operation. Two or more operations must be executed either at the same time, separately, or in a required order, in contrast to asynchronous operation.
  453. synchronous processes. Two or more processes must coordinate their execution to assure that they both operate at exactly the same time or sequentially in a required order, in contrast to asynchronous process.
  454. syntax. The pattern which describes the structure of a textual expression. The pattern is detailed using a grammar with syntax rules. Or, in simpler cases, a regular expression.
  455. syntax rule. A pattern with an associated name which describes the ordering and structure of the words, terms, values, tokens, punctuation, and references to other named syntax rules for linguistic elements in a language, particularly programming languages and other specialized languages designed to be executed or interpreted by a computer. A set of syntax rules define the grammar for a language. See the Wikipedia Backus–Naur form article.
  456. system. A man-made or natural physical system. May be a static system or a dynamical system. Alternatively, a computer system. Alternatively, a software system.
  457. sysadmin. See system administrator.
  458. system administrator. An individual who is an administrator for a particular computer system or collection of systems. Controls who has access to the system and performs or arranges for any needed maintenance for the system.
  459. system command. An instruction to the operating system of a computer system to utilize, control, or monitor system resources, as well as to request the execution of computer programs, scripts, and application software. See also: scripting language.
  460. system component. Subsystem or software component. Alternatively, a device or hardware component.
  461. system resource. A capability of a computer system, such as files, computer programs, processes, memory, processors, and devices. See also: system command and system component.
  462. system utility. Software which executes directly on the bare operating system of a computer system to make the system easier to use, to access, control, and monitor all system resources, and to perform maintenance tasks for the system.
  463. system software. Lower-level software which is needed to operate a computer system, including the operating system, as well as system utilities needed to maintain the system and to make the system easier to use, in contrast to application software, middleware, and software tools.
  464. system transfer function. TBD.

To browse other parts of the glossary:

  1. Quantum Computing Glossary — Introduction.
  2. Quantum Computing Glossary — Part 1 — A-C.
  3. Quantum Computing Glossary — Part 2 — D-G.
  4. Quantum Computing Glossary — Part 3 — H-P.
  5. Quantum Computing Glossary — Part 4 — Q.
  6. Quantum Computing Glossary — Part 5 — R-S. This part.
  7. Quantum Computing Glossary — Part 6 — T-Z.

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