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Quantum Volume
Quantum volume is a metric that measures the capabilities and error rates of a quantum computer. It expresses the maximum size of square quantum circuits that can be implemented successfully by the computer. The form of the circuits is independent from the quantum computer architecture, but compiler can transform and optimize it to take advantage of the computer's features. Thus, quantum volumes for different architectures can be compared. The current world record for highest quantum volume as of February 2023 is 32,768 (215), accomplished by Quantinuum's H1 Ion trap quantum computer. Introduction Quantum computers are difficult to compare. Quantum volume is a single number designed to show all around performance. It is a measurement and not a calculation, and takes into account several features of a quantum computer, starting with its number of qubits—other measures used are gate and measurement errors, crosstalk and connectivity. IBM defined its Quantum Volume metric because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Computing
Quantum computing is a type of computation whose operations can harness the phenomena of quantum mechanics, such as superposition, interference, and entanglement. Devices that perform quantum computations are known as quantum computers. Though current quantum computers may be too small to outperform usual (classical) computers for practical applications, larger realizations are believed to be capable of solving certain computational problems, such as integer factorization (which underlies RSA encryption), substantially faster than classical computers. The study of quantum computing is a subfield of quantum information science. There are several models of quantum computation with the most widely used being quantum circuits. Other models include the quantum Turing machine, quantum annealing, and adiabatic quantum computation. Most models are based on the quantum bit, or "qubit", which is somewhat analogous to the bit in classical computation. A qubit can be in a 1 or 0 quantu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Circuit
In quantum information theory, a quantum circuit is a model for quantum computation, similar to classical circuits, in which a computation is a sequence of quantum gates, measurements, initializations of qubits to known values, and possibly other actions. The minimum set of actions that a circuit needs to be able to perform on the qubits to enable quantum computation is known as DiVincenzo's criteria. Circuits are written such that the horizontal axis is time, starting at the left hand side and ending at the right. Horizontal lines are qubits, doubled lines represent classical bits. The items that are connected by these lines are operations performed on the qubits, such as measurements or gates. These lines define the sequence of events, and are usually not physical cables. The graphical depiction of quantum circuit elements is described using a variant of the Penrose graphical notation. Richard Feynman used an early version of the quantum circuit notation in 1986. Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qubit
In quantum computing, a qubit () or quantum bit is a basic unit of quantum information—the quantum version of the classic binary bit physically realized with a two-state device. A qubit is a two-state (or two-level) quantum-mechanical system, one of the simplest quantum systems displaying the peculiarity of quantum mechanics. Examples include the spin of the electron in which the two levels can be taken as spin up and spin down; or the polarization of a single photon in which the two states can be taken to be the vertical polarization and the horizontal polarization. In a classical system, a bit would have to be in one state or the other. However, quantum mechanics allows the qubit to be in a coherent superposition of both states simultaneously, a property that is fundamental to quantum mechanics and quantum computing. Etymology The coining of the term ''qubit'' is attributed to Benjamin Schumacher. In the acknowledgments of his 1995 paper, Schumacher states that the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-entropy Benchmarking
Cross-entropy benchmarking (also referred to as XEB) is a quantum benchmarking protocol which can be used to demonstrate quantum supremacy. In XEB, a random quantum circuit is executed on a quantum computer multiple times in order to collect a set of k samples in the form of bitstrings \. The bitstrings are then used to calculate the cross-entropy benchmark fidelity (F_) via a classical computer, given by :F_= 2^ \langle P(x_) \rangle_ - 1 = \frac \left(\sum_^, \langle 0^, C, x_\rangle, ^\right) - 1, where n is the number of qubits in the circuit and P(x_) is the probability of a bitstring for an ideal quantum circuit C. If F_ = 1, the samples were collected from a noiseless quantum computer. If F_ = 0, then the samples could have been obtained via random guessing. This means that if a quantum computer did generate those samples, then the quantum computer is too noisy and thus has no chance of performing beyond-classical computations. Since it takes an exponential amoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IonQ
IonQ is a quantum computing hardware and software company based in College Park, Maryland. They are developing a general-purpose trapped ion quantum computer and software to generate, optimize, and execute quantum circuits. History IonQ was co-founded by Christopher Monroe and Jungsang Kim, professors at the University of Maryland and Duke University, respectively, in 2015, with the help of Harry Weller and Andrew Schoen, partners at venture firm New Enterprise Associates. The company is an offshoot of the co-founders’ 25 years of academic research in quantum information science. Monroe's quantum computing research began as a Staff Researcher at the National Institute of Standards and Technology (NIST) with Nobel-laureate physicist David Wineland where he led a team using trapped ions to produce the first controllable qubits and the first controllable quantum logic gate, culminating in a proposed architecture for a large-scale trapped ion computer. Kim and Monroe began col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum (journal) ''Quantum'' is an online-only, open-access, peer-reviewed scientific journal for quantum science and related fields. The journal was established in 2017. ''Quantum'' is an arXiv overlay journal, meaning the journal's content is hosted on the arXiv. ''Quantum'' is listed in the Directory of Open Access Journals and the Emerging Sources Citation Index, and it is recognized by the European Physical Society as maintaining a high standard of peer review. See also * ''Discrete Analysis ''Discrete Analysis'' is a mathematics journal covering the applications of analysis to discrete structures. ''Discrete Analysis'' is an arXiv overlay journal, meaning the journal's content is hosted on the arXiv. History ''Discrete Analysis' ...'' References External links * Open access journals Physics journals Publications established in 2017 English-language journals Online-only journals {{physics-journal-stub ... |
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