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Quantum Machine
A quantum machine is a human-made device whose collective motion follows the laws of quantum mechanics. The idea that macroscopic objects may follow the laws of quantum mechanics dates back to the advent of quantum mechanics in the early 20th century. However, as highlighted by the Schrödinger's cat thought experiment, quantum effects are not readily observable in large-scale objects. Consequently, quantum states of motion have only been observed in special circumstances at extremely low temperatures. The fragility of quantum effects in macroscopic objects may arise from rapid quantum decoherence. Researchers created the first quantum machine in 2009, and the achievement was named the "Breakthrough of the Year" by ''Science'' in 2010. History The first quantum machine was created on August 4, 2009 by Aaron D. O'Connell while pursuing his Ph.D. under the direction of Andrew N. Cleland and John M. Martinis at the University of California, Santa Barbara. O'Connell and his co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association For The Advancement Of Science
The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the betterment of all humanity. It is the world's largest general scientific society, with over 120,000 members, and is the publisher of the well-known scientific journal ''Science''. History Creation The American Association for the Advancement of Science was created on September 20, 1848, at the Academy of Natural Sciences in Philadelphia, Pennsylvania. It was a reformation of the Association of American Geologists and Naturalists. The society chose William Charles Redfield as their first president because he had proposed the most comprehensive plans for the organization. According to the first constitution which was agreed to at the September 20 meeting, the goal of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonons
In physics, a phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids. A type of quasiparticle, a phonon is an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles. Phonons can be thought of as quantized sound waves, similar to photons as quantized light waves. The study of phonons is an important part of condensed matter physics. They play a major role in many of the physical properties of condensed matter systems, such as thermal conductivity and electrical conductivity, as well as in models of neutron scattering and related effects. The concept of phonons was introduced in 1932 by Soviet physicist Igor Tamm. The name ''phonon'' comes from the Greek word (), which translates to ''sound'' or ''voice'', because long-wavelength phonons give rise to sound. The name is analogous to the word ''photon''. Definiti ... [...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 quantum s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Qubit
In quantum computing, and more specifically in superconducting quantum computing, the phase qubit is a superconducting device based on the superconductor–insulator–superconductor (SIS) Josephson junction, designed to operate as a quantum bit, or qubit. The phase qubit is closely related, yet distinct from, the flux qubit and the charge qubit, which are also quantum bits implemented by superconducting devices. The major distinction among the three is the ratio of Josephson energy vs charging energy (the necessary energy for one Cooper pair to ''charge'' the total capacitance in the circuit): * For phase qubit, this ratio is on the order of 106, which allows for macroscopic bias current through the junction; * For flux qubit it's on the order of 10, which allows for mesoscopic supercurrents (typically ~300 nAUniversity of De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectric Material
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''piezoelectricity'' means electricity resulting from pressure and latent heat. It is derived from the Greek word ; ''piezein'', which means to squeeze or press, and ''ēlektron'', which means amber, an ancient source of electric charge. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electrical field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilution Refrigerator
A 3He/4He dilution refrigerator is a cryogenics, cryogenic device that provides continuous cooling to temperatures as low as 2 Kelvin, mK, with no moving parts in the low-temperature region. The cooling power is provided by the heat of mixing of the Helium-3 and Helium-4 isotopes. The dilution refrigerator was first proposed by Heinz London in the early 1950s, and was experimentally realized in 1964 in the Kamerlingh Onnes Laboratorium at Leiden University. The field of dilution refrigeration is reviewed by Zu et al. Theory of operation The refrigeration process uses a mixture of two isotopes of helium: helium-3 and helium-4. When cooled below approximately Orders of magnitude (temperature), 870 Kelvin, millikelvins, the mixture undergoes spontaneous phase separation to form a 3He-rich phase (the concentrated phase) and a 3He-poor phase (the dilute phase). As shown in the phase diagram, at very low temperatures the concentrated phase is essentially pure 3He, whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thin Film Bulk Acoustic Resonator
A thin-film bulk acoustic resonator (FBAR or TFBAR) is a device consisting of a piezoelectric material manufactured by thin film methods between two conductive – typically metallic – electrodes and acoustically isolated from the surrounding medium. The operation is based on the piezoelectricity of the piezolayer between the electrodes. FBAR devices using piezoelectric films with thicknesses ranging from several micrometres down to tens of micrometres resonate in the frequency range of 100 MHz to 20 GHz. FBAR or TFBAR resonators fall in the category of bulk acoustic resonators (BAW) and piezoelectric resonators and they are used in applications where high frequency, small size and weight is needed. Piezoelectricity in thin films The crystallographic orientation of a thin film depends on the piezomaterial selected and many other items like the surface on which the film is grown and various manufacturing - thin film growth - conditions (temperatures selected, pressure, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boltzmann Constant
The Boltzmann constant ( or ) is the proportionality factor that relates the average relative kinetic energy of particles in a gas with the thermodynamic temperature of the gas. It occurs in the definitions of the kelvin and the gas constant, and in Planck's law of black-body radiation and Boltzmann's entropy formula, and is used in calculating thermal noise in resistors. The Boltzmann constant has dimensions of energy divided by temperature, the same as entropy. It is named after the Austrian scientist Ludwig Boltzmann. As part of the 2019 redefinition of SI base units, the Boltzmann constant is one of the seven " defining constants" that have been given exact definitions. They are used in various combinations to define the seven SI base units. The Boltzmann constant is defined to be exactly . Roles of the Boltzmann constant Macroscopically, the ideal gas law states that, for an ideal gas, the product of pressure and volume is proportional to the product of amount of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planck Constant
The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivalence, the relationship between mass and frequency. Specifically, a photon's energy is equal to its frequency multiplied by the Planck constant. The constant is generally denoted by h. The reduced Planck constant, or Dirac constant, equal to the constant divided by 2 \pi, is denoted by \hbar. In metrology it is used, together with other constants, to define the kilogram, the SI unit of mass. The SI units are defined in such a way that, when the Planck constant is expressed in SI units, it has the exact value The constant was first postulated by Max Planck in 1900 as part of a solution to the ultraviolet catastrophe. At the end of the 19th century, accurate measurements of the spectrum of black body radiation existed, but the distribut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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