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Jiuzhang (quantum Computer)
Jiuzhang ( zh, 九章) is the first photonic quantum computer to claim quantum supremacy. Previously quantum supremacy has been achieved only once in 2019 by Google’s Sycamore processor, Sycamore, however Google's computer was based on superconducting materials, and not photons. Jiuzhang was developed by a team from University of Science and Technology of China (USTC) led by Pan Jianwei and Lu Chaoyang. The computer is named after ''Jiuzhang suanshu'', an ancient Chinese mathematical classic. On 3 December 2020, USTC announced in ''Science (journal), Science'' that Jiuzhang successfully performed Gaussian boson sampling in 200 seconds, with a maximum of 76 detected photons. The USTC group estimated that it would take 2.5 billion years for the Sunway TaihuLight supercomputer to perform the same calculation. In addition to a quantum computational advantage, Jiuzhang has a Hilbert space 10 billion times larger than Google's superconductor-based Sycamore processor, and as such, is har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Computer
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 quantum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hilbert Space
In mathematics, Hilbert spaces (named after David Hilbert) allow generalizing the methods of linear algebra and calculus from (finite-dimensional) Euclidean vector spaces to spaces that may be infinite-dimensional. Hilbert spaces arise naturally and frequently in mathematics and physics, typically as function spaces. Formally, a Hilbert space is a vector space equipped with an inner product that defines a distance function for which the space is a complete metric space. The earliest Hilbert spaces were studied from this point of view in the first decade of the 20th century by David Hilbert, Erhard Schmidt, and Frigyes Riesz. They are indispensable tools in the theories of partial differential equations, quantum mechanics, Fourier analysis (which includes applications to signal processing and heat transfer), and ergodic theory (which forms the mathematical underpinning of thermodynamics). John von Neumann coined the term ''Hilbert space'' for the abstract concept that under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2020 In Science
A number of significant scientific events occurred in 2020. Events January February March April May June July August September October * 1 October ** Researchers report the discovery of a novel overlapping gene (OLG) (a gene partially overlapping with a sequence of another gene), named ''ORF3d'', in the SARS-CoV-2 genome, that may be a factor in the SARS-CoV-2 pandemic. They found the gene has been identified before, but only in a variant of coronavirus that infects pangolins. Available undeCC BY 4.0 **Astronomers announce spectroscopic confirmation of a web-like structure containing galaxies and dark matter around, and likely fueling, a quasar at an age of the Universe of 0.9 bn years, which contributes to an explanation of how such supermassive black holes could have grown rapidly so early. * 2 October – A rippling graphene-based Brownian ratchet-related energy-harvesting circuit with the potential to deliver "clean, limitless, low-voltage power fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-photon Detector
Photon counting is a technique in which individual photons are counted using a single-photon detector (SPD). A single-photon detector emits a pulse of signal for each detected photon, in contrast to a normal photodetector, which generates an analog signal proportional to the photon flux. The number of pulses (but not their amplitude) is counted, giving an integer number of photons detected per measurement interval. The counting efficiency is determined by the quantum efficiency and the system's electronic losses. Many photodetector Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation. There is a wide variety of photodetectors which may be classified by mechanism of detection, such as Photoelectric effect, photoelectric or photoc ...s can be configured to detect individual photons, each with relative advantages and disadvantages. Common types include photomultipliers, geiger counters, single-photon avalanche diodes, superconducting na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band-pass Filter
A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. Description In electronics and signal processing, a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its ''passband'' but blocks components with frequencies above or below this band. This contrasts with a high-pass filter, which allows through components with frequencies above a specific frequency, and a low-pass filter, which allows through components with frequencies below a specific frequency. In digital signal processing, in which signals represented by digital numbers are processed by computer programs, a band-pass filter is a computer algorithm that performs the same function. The term band-pass filter is also used for optical filters, sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squeezed Coherent State
In physics, a squeezed coherent state is a quantum state that is usually described by two non-commuting observables having continuous spectra of eigenvalues. Examples are position x and momentum p of a particle, and the (dimension-less) electric field in the amplitude X (phase 0) and in the mode Y (phase 90°) of a light wave (the wave's quadratures). The product of the standard deviations of two such operators obeys the uncertainty principle: :\Delta x \Delta p \geq \frac2\; and \;\Delta X \Delta Y \geq \frac4 , respectively. Trivial examples, which are in fact not squeezed, are the ground state , 0\rangle of the quantum harmonic oscillator and the family of coherent states , \alpha\rangle. These states saturate the uncertainty above and have a symmetric distribution of the operator uncertainties with \Delta x_g = \Delta p_g in "natural oscillator units" and \Delta X_g = \Delta Y_g = 1/2. (In literature different normalizations for the quadrature amplitudes are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Titanyl Phosphate
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac- colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sapphire Laser
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide () with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. The name sapphire is derived via the Latin "sapphirus" from the Greek "sappheiros", which referred to lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires 9 on the Mohs scale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) sapphires are also u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Pumping
Optical pumping is a process in which light is used to raise (or "pump") electrons from a lower energy level in an atom or molecule to a higher one. It is commonly used in laser construction to pump the active laser medium so as to achieve population inversion. The technique was developed by the 1966 Nobel Prize winner Alfred Kastler in the early 1950s. Page 56. Optical pumping is also used to cyclically pump electrons bound within an atom or molecule to a well-defined quantum state. For the simplest case of coherent two-level optical pumping of an atomic species containing a single outer-shell electron, this means that the electron is coherently pumped to a single hyperfine sublevel (labeled m_F\!), which is defined by the polarization of the pump laser along with the quantum selection rules. Upon optical pumping, the atom is said to be ''oriented'' in a specific m_F\! sublevel, however, due to the cyclic nature of optical pumping, the bound electron will actually be undergoin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunway TaihuLight
The Sunway TaihuLight ( ''Shénwēi·tàihú zhī guāng'') is a Chinese supercomputer which, , is ranked fourth in the TOP500 list, with a LINPACK benchmark rating of 93 petaflops. The name is translated as ''divine power, the light of Taihu Lake''. This is nearly three times as fast as the previous Tianhe-2, which ran at 34 petaflops. , it is ranked as the 16th most energy-efficient supercomputer in the Green500, with an efficiency of 6.051 GFlops/watt. It was designed by the National Research Center of Parallel Computer Engineering & Technology (NRCPC) and is located at the National Supercomputing Center in Wuxi in the city of Wuxi, in Jiangsu province, China. The Sunway TaihuLight was the world's fastest supercomputer for two years, from June 2016 to June 2018, according to the TOP500 lists. The record was surpassed in June 2018 by IBM's Summit. Architecture The Sunway TaihuLight uses a total of 40,960 Chinese-designed SW26010 manycore 64-bit RISC processors based on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Supremacy
In quantum computing, quantum supremacy or quantum advantage is the goal of demonstrating that a programmable quantum device can solve a problem that no classical computer can solve in any feasible amount of time (irrespective of the usefulness of the problem). Conceptually, quantum supremacy involves both the engineering task of building a powerful quantum computer and the computational-complexity-theoretic task of finding a problem that can be solved by that quantum computer and has a superpolynomial speedup over the best known or possible classical algorithm for that task. The term was coined by John Preskill in 2012, but the concept of a quantum computational advantage, specifically for simulating quantum systems, dates back to Yuri Manin's (1980) and Richard Feynman's (1981) proposals of quantum computing. Examples of proposals to demonstrate quantum supremacy include the boson sampling proposal of Aaronson and Arkhipov, D-Wave's specialized frustrated cluster loop problems, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaussian Boson Sampling
Boson sampling is a restricted model of non-universal quantum computation introduced by Scott Aaronson and Alex Arkhipov after the original work of Lidror Troyansky and Naftali Tishby, that explored possible usage of boson scattering to evaluate expectation values of permanents of matrices. The model consists of sampling from the probability distribution of identical bosons scattered by a linear interferometer. Although the problem is well defined for any bosonic particles, its photonic version is currently considered as the most promising platform for a scalable implementation of a boson sampling device, which makes it a non-universal approach to linear optical quantum computing. Moreover, while not universal, the boson sampling scheme is strongly believed to implement computing tasks which are hard to implement with classical computers by using far fewer physical resources than a full linear-optical quantum computing setup. This advantage makes it an ideal candidate for demons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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