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This book traces scientists and their discoveries about electricity from 271 CE to 2007.

Professor Emanuel uses clear presentation to compare and facilitate understanding of two seminal standards, The IEEE Std. 1459 and The DIN 40110-2:2002-11. Through critical analysis of the most important and recent theories and review of basic concepts, a highly accessible guide to the essence of the standards is presented. <p><b>Key features:</b></p> <ul> <li>Explains the physical mechanism of energy flow under different conditions: single- and three-phase, sinusoidal and nonsinusoidal, balanced and unbalanced systems</li> <li>Starts at an elementary level and becomes more complex, with six core chapters and six appendices to clarify the mathematical aspects</li> <li>Discusses and recommends power definitions that played a significant historical role in paving the road for the two standards</li> <li>Provides a number of original unsolved problems at the end of each chapter</li> <li>Introduces a new nonactive power; the Randomness power.</li> </ul> <p><i>Power Definitions and the Physical Mechanism of Power Flow</i> is useful for electrical engineers and consultants involved in energy and power quality. It is also helpful to engineers dealing with energy flow quantification, design and manufacturing of metering instrumentation; consultants working with regulations related to renewable energy courses and the smart grid; and electric utility planning and operation engineers dealing with energy bill structure. The text is also relevant to university researchers, professors, and advanced students in power systems, power quality and energy related courses.</p>

Elastic electron–proton scattering (e–p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r p . In 2010, a new method using muonic hydrogen atoms 1 found a substantial discrepancy compared with previous results 2 , which became known as the ‘proton radius puzzle’. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen 3 , 4 . Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e–p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e–p experiments and enabled measurements at very small forward-scattering angles. Our result, r p  = 0.831 ± 0.007 stat  ± 0.012 syst  femtometres, is smaller than the most recent high-precision e–p measurement 5 and 2.7 standard deviations smaller than the average of all e–p experimental results 6 . The smaller r p we have now measured supports the value found by two previous muonic hydrogen experiments 1 , 7 . In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant 8 —one of the most accurately evaluated fundamental constants in physics. A magnetic-spectrometer-free method for electron–proton scattering data reveals a proton charge radius 2.7 standard deviations smaller than the currently accepted value from electron–proton scattering, yet consistent with other recent experiments.

Topological crystalline insulators (TCIs) can exhibit unusual, quantized electric phenomena such as fractional electric polarization and boundary-localized fractional charge 1 – 6 . This quantized fractional charge is the generic observable for identification of TCIs that lack clear spectral features 5 – 7 , including ones with higher-order topology 8 – 11 . It has been predicted that fractional charges can also manifest where crystallographic defects disrupt the lattice structure of TCIs, potentially providing a bulk probe of crystalline topology 10 , 12 – 14 . However, this capability has not yet been confirmed in experiments, given that measurements of charge distributions in TCIs have not been accessible until recently 11 . Here we experimentally demonstrate that disclination defects can robustly trap fractional charges in TCI metamaterials, and show that this trapped charge can indicate non-trivial, higher-order crystalline topology even in the absence of any spectral signatures. Furthermore, we uncover a connection between the trapped charge and the existence of topological bound states localized at these defects. We test the robustness of these topological features when the protective crystalline symmetry is broken, and find that a single robust bound state can be localized at each disclination alongside the fractional charge. Our results conclusively show that disclination defects in TCIs can strongly trap fractional charges as well as topological bound states, and demonstrate the primacy of fractional charge as a probe of crystalline topology. It is experimentally shown that crystallographic defects may trap fractional charges, as well as topological states, in the bulk of topological crystalline insulators.

Low-temperature measurements of the Hall effect in cuprate materials in which superconductivity is suppressed by high magnetic fields show that the pseudogap is not related to the charge ordering that has been seen at intermediate doping levels, but is instead linked to the antiferromagnetic Mott insulator at low doping. Bridging the pseudogap phase The possible origin of the enigmatic 'pseudogap' phase in the high-temperature superconductors comes into sharper focus in light of some new low-temperature Hall measurements at magnetic fields high enough to suppress the confounding effects of superconductivity. Louis Taillefer and colleagues are able to show that the psudogap is not, as some have suspected, related to the charge-ordering that has been seen at intermediate doping levels, but is instead linked to the Mott insulator state at low doping. The pseudogap is a partial gap in the electronic density of states that opens in the normal (non-superconducting) state of cuprate superconductors and whose origin is a long-standing puzzle. Its connection to the Mott insulator phase at low doping (hole concentration, p ) remains ambiguous 1 and its relation to the charge order 2 , 3 , 4 that reconstructs the Fermi surface 5 , 6 at intermediate doping is still unclear 7 , 8 , 9 , 10 . Here we use measurements of the Hall coefficient in magnetic fields up to 88 tesla to show that Fermi-surface reconstruction by charge order in the cuprate YBa 2 Cu 3 O y ends sharply at a critical doping p  = 0.16 that is distinctly lower than the pseudogap critical point p * = 0.19 (ref. 11 ). This shows that the pseudogap and charge order are separate phenomena. We find that the change in carrier density n from n  = 1 +  p in the conventional metal at high doping (ref. 12 ) to n  =  p at low doping (ref. 13 ) starts at the pseudogap critical point. This shows that the pseudogap and the antiferromagnetic Mott insulator are linked.

A conceptually new type of transistor, based on a strongly correlated material, allows external control of a macroscopic electronic phase transition, and gives rise to a non-volatile memory effect. A promising vanadium dioxide transistor The principle behind the classic transistor is the use of an external voltage to control the electrical conductivity of a nanometre-sized conducting channel near the surface of the device material. This paper reports the development of a conceptually new type of transistor in which an electric field controls the electronic properties of the whole of the device. This is made possible by using, instead of silicon, the strongly correlated material vanadium dioxide. The application of just one volt, at room temperature, switches the material from being an insulator to having a metallic ground state on a macroscopic scale and gives rise to a non-volatile memory effect, making it of great practical interest for applications including the remote transmission of electrical signals and voltage-tunable optical switching. In the classic transistor, the number of electric charge carriers—and thus the electrical conductivity—is precisely controlled by external voltage, providing electrical switching capability. This simple but powerful feature is essential for information processing technology, and also provides a platform for fundamental physics research 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 . As the number of charges essentially determines the electronic phase of a condensed-matter system, transistor operation enables reversible and isothermal changes in the system’s state, as successfully demonstrated in electric-field-induced ferromagnetism 2 , 3 , 4 and superconductivity 5 , 6 , 7 , 8 , 9 , 10 . However, this effect of the electric field is limited to a channel thickness of nanometres or less, owing to the presence of Thomas–Fermi screening. Here we show that this conventional picture does not apply to a class of materials characterized by inherent collective interactions between electrons and the crystal lattice. We prepared metal–insulator–semiconductor field-effect transistors based on vanadium dioxide—a strongly correlated material with a thermally driven, first-order metal–insulator transition well above room temperature 17 , 18 , 19 , 20 , 21 , 22 , 23 —and found that electrostatic charging at a surface drives all the previously localized charge carriers in the bulk material into motion, leading to the emergence of a three-dimensional metallic ground state. This non-local switching of the electronic state is achieved by applying a voltage of only about one volt. In a voltage-sweep measurement, the first-order nature of the metal–insulator transition provides a non-volatile memory effect, which is operable at room temperature. Our results demonstrate a conceptually new field-effect device, extending the concept of electric-field control to macroscopic phase control.

Elastic electron-proton scattering (e-p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r.sub.p. In 2010, a new method using muonic hydrogen atoms.sup.1 found a substantial discrepancy compared with previous results.sup.2, which became known as the 'proton radius puzzle'. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen.sup.3,4. Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e-p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e-p experiments and enabled measurements at very small forward-scattering angles. Our result, r.sub.p = 0.831 [plus or minus] 0.007.sub.stat [plus or minus] 0.012.sub.syst femtometres, is smaller than the most recent high-precision e-p measurement.sup.5 and 2.7 standard deviations smaller than the average of all e-p experimental results.sup.6. The smaller r.sub.p we have now measured supports the value found by two previous muonic hydrogen experiments.sup.1,7. In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant.sup.8--one of the most accurately evaluated fundamental constants in physics.

Elastic electron-proton scattering (e-p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r.sub.p. In 2010, a new method using muonic hydrogen atoms.sup.1 found a substantial discrepancy compared with previous results.sup.2, which became known as the 'proton radius puzzle'. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen.sup.3,4. Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e-p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e-p experiments and enabled measurements at very small forward-scattering angles. Our result, r.sub.p = 0.831 [plus or minus] 0.007.sub.stat [plus or minus] 0.012.sub.syst femtometres, is smaller than the most recent high-precision e-p measurement.sup.5 and 2.7 standard deviations smaller than the average of all e-p experimental results.sup.6. The smaller r.sub.p we have now measured supports the value found by two previous muonic hydrogen experiments.sup.1,7. In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant.sup.8--one of the most accurately evaluated fundamental constants in physics.

Watching particles wobble helps pin down shape of their electric field.

Watching particles wobble helps pin down shape of their electric field.