Maxwell's Daemon: information versus particle statistics.
Plesch, Martin; Dahlsten, Oscar; Goold, John; Vedral, Vlatko
2014-01-01
Maxwell's daemon is a popular personification of a principle connecting information gain and extractable work in thermodynamics. A Szilard Engine is a particular hypothetical realization of Maxwell's daemon, which is able to extract work from a single thermal reservoir by measuring the position of particle(s) within the system. Here we investigate the role of particle statistics in the whole process; namely, how the extractable work changes if instead of classical particles fermions or bosons are used as the working medium. We give a unifying argument for the optimal work in the different cases: the extractable work is determined solely by the information gain of the initial measurement, as measured by the mutual information, regardless of the number and type of particles which constitute the working substance. PMID:25385291
Maxwell's Daemon: Information versus Particle Statistics
Plesch, Martin; Dahlsten, Oscar; Goold, John; Vedral, Vlatko
2014-01-01
Maxwell's daemon is a popular personification of a principle connecting information gain and extractable work in thermodynamics. A Szilard Engine is a particular hypothetical realization of Maxwell's daemon, which is able to extract work from a single thermal reservoir by measuring the position of particle(s) within the system. Here we investigate the role of particle statistics in the whole process; namely, how the extractable work changes if instead of classical particles fermions or bosons are used as the working medium. We give a unifying argument for the optimal work in the different cases: the extractable work is determined solely by the information gain of the initial measurement, as measured by the mutual information, regardless of the number and type of particles which constitute the working substance. PMID:25385291
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
The highest mountain range on Venus, situated in the upland region Ishtar Terra, and centered at 65.2 °N, 3.3 °E. It extends for 797 km, and contains the highest point on the planet, nearly 12 km above Venus's average surface level (comparable in this respect to Earth's Mount Everest). It is the only Venusian feature to bear a male name, honoring James Clerk Maxwell. The range showed up prominent...
Abdoul-Carime, Hassan; Berthias, Francis; Feketeová, Linda; Marciante, Mathieu; Calvo, Florent; Forquet, Valérian; Chermette, Henry; Farizon, Bernadette; Farizon, Michel; Märk, Tilmann D
2015-12-01
The velocity of a molecule evaporated from a mass-selected protonated water nanodroplet is measured by velocity map imaging in combination with a recently developed mass spectrometry technique. The measured velocity distributions allow probing statistical energy redistribution in ultimately small water nanodroplets after ultrafast electronic excitation. As the droplet size increases, the velocity distribution rapidly approaches the behavior expected for macroscopic droplets. However, a distinct high-velocity contribution provides evidence of molecular evaporation before complete energy redistribution, corresponding to non-ergodic events. PMID:26473406
Davidson, R.C.; Lee, W.W.; Stoltz, P.
1997-08-01
This paper presents a detailed formulation and analysis of the rate equations for statistically-averaged quantities for an intense nonneutral beam propagating through a periodic solenoidal focusing field B{sup sol}(x). The analysis is based on the nonlinear Vlasov-Maxwell equations in the electrostatic approximation, assuming a thin beam with characteristic beam radius r{sub b} {much_lt} S. The results are applied to investigate the nonlinear evolution of the generalized entropy, mean canonical angular momentum {l_angle}P{sub {theta}}{r_angle}, center-of-mass motion for {l_angle}X{r_angle} and {l_angle}Y{r_angle}, mean kinetic energy (1/2) {l_angle}X{sup {prime}2} + Y{sup {prime}2}{r_angle}, mean-square beam radius {l_angle}X{sup 2} + Y{sup 2}{r_angle}, and coupled rate equations for the unnormalized transverse emittance {epsilon}(s) and root-mean-square beam radius R{sub b}(s) = {l_angle}X{sup 2} + Y{sup 2}{r_angle}{sup 1/2}. Global energy balance is discussed, and the coupled rate equations for {epsilon}(s) and R{sub b}(s) are examined for the class of axisymmetric beam distributions F{sub b}.
NASA Astrophysics Data System (ADS)
Siegel, Z.; Siegel, Edward Carl-Ludwig
2011-03-01
RANDOMNESS of Numbers cognitive-semantics DEFINITION VIA Cognition QUERY: WHAT???, NOT HOW?) VS. computer-``science" mindLESS number-crunching (Harrel-Sipser-...) algorithmics Goldreich "PSEUDO-randomness"[Not.AMS(02)] mea-culpa is ONLY via MAXWELL-BOLTZMANN CLASSICAL-STATISTICS(NOT FDQS!!!) "hot-plasma" REPULSION VERSUS Newcomb(1881)-Weyl(1914;1916)-Benford(1938) "NeWBe" logarithmic-law digit-CLUMPING/ CLUSTERING NON-Randomness simple Siegel[AMS Joint.Mtg.(02)-Abs. # 973-60-124] algebraic-inversion to THE QUANTUM and ONLY BEQS preferentially SEQUENTIALLY lower-DIGITS CLUMPING/CLUSTERING with d = 0 BEC, is ONLY VIA Siegel-Baez FUZZYICS=CATEGORYICS (SON OF TRIZ)/"Category-Semantics"(C-S), latter intersection/union of Lawvere(1964)-Siegel(1964)] category-theory (matrix: MORPHISMS V FUNCTORS) "+" cognitive-semantics'' (matrix: ANTONYMS V SYNONYMS) yields Siegel-Baez FUZZYICS=CATEGORYICS/C-S tabular list-format matrix truth-table analytics: MBCS RANDOMNESS TRUTH/EMET!!!
Cold Atoms and Maxwell's Demon
NASA Astrophysics Data System (ADS)
Steck, Daniel A.
2013-12-01
Recent experiments have focused on realizing and studying asymmetric potential barriers for ultracold atoms. Practically speaking, asymmetric barriers, or "atomtronic diodes", open up newmethods for controlling cold atoms, and possibly methods for laser cooling atoms and molecules that are not amenable to present laser-cooling techniques. More fundamentally, asymmetric barriers are interesting as realizations of the textbook statistical-mechanics scenario of Maxwell's demon. This chapter reviews experimental progress in this area, as well as some related practical and theoretical issues.
NASA Astrophysics Data System (ADS)
O'Brien, Sheila
2012-12-01
I found Nicole Yunger-Halpern's Lateral Thoughts on "Fiddling around with physics" (September p60) quite amusing, but I am sure James Clerk Maxwell would have preferred to play the theramin instead of the electric guitar.
NASA Astrophysics Data System (ADS)
Nieuwenhuizen, Theo M.; Allahverdyan, Armen E.
2002-11-01
Maxwell's demon is a tiny but fine-fingered being, capable to extract work from a system at instantaneous equilibrium, without needing energy input or information erasure. In the 20'th century many workers have claimed that the demon cannot operate. Here the point of view is taken that this exorcism of the demon never applied, since one did not consider Maxwell's original invention. For a Brownian particle coupled to a quantum bath it was shown by us that quantum entanglement can allow extraction of work from a non-equilibrium system coupled to a single bath. And mesoscopic work sources may establish work extraction cycles even when they are coupled to equilibrium mesoscopic systems immersed in a macroscopic thermal bath. Quantum entanglement and mesocopicity are now identified with (true) Maxwell demons.
Obtaining Maxwell's equations heuristically
NASA Astrophysics Data System (ADS)
Diener, Gerhard; Weissbarth, Jürgen; Grossmann, Frank; Schmidt, Rüdiger
2013-02-01
Starting from the experimental fact that a moving charge experiences the Lorentz force and applying the fundamental principles of simplicity (first order derivatives only) and linearity (superposition principle), we show that the structure of the microscopic Maxwell equations for the electromagnetic fields can be deduced heuristically by using the transformation properties of the fields under space inversion and time reversal. Using the experimental facts of charge conservation and that electromagnetic waves propagate with the speed of light, together with Galilean invariance of the Lorentz force, allows us to finalize Maxwell's equations and to introduce arbitrary electrodynamics units naturally.
Maxwell's Demon and the Second Law
NASA Astrophysics Data System (ADS)
Leff, Harvey S.; Rex, Andrew F.
2002-11-01
Maxwell's demon emanates from a thought experiment proposed by James Clerk Maxwell in 1867 to illustrate the statistical nature of the second law of thermodynamics. Subsequently researchers wondered whether such a demon could in fact violate the second law. Leon Brillouin argued that the entropy produced during the demon's measurement precluded such a violation. Years later Oliver Penrose and Charles Bennett observed (independently) that a Maxwell's demon gathers information and stores it in a memory. Penrose showed that erasure of such a memory sends sufficient entropy to the environment to preclude violation of the second law. Notably this is so even when measurement produces arbitrarily little entropy. Bennett obtained the same result using Rolf Landauer's seminal research on the thermodynamics of computation. The stunning shift in focus from measurement to erasure provided the impetus to better understand the role of information in quantum mechanics and thermodynamics. Indeed the linkage of information with physics is the principal legacy of Maxwell's demon. Szilard's one-particle classical "gas" model and its quantum mechanical extension, together with postulated connections between entropy and algorithmic information, have provided useful insights. We review the long history of Maxwell's demon and assess the current status of the second law in the context of the demon's operations.
Vidrighin, Mihai D; Dahlsten, Oscar; Barbieri, Marco; Kim, M S; Vedral, Vlatko; Walmsley, Ian A
2016-02-01
We report an experimental realization of Maxwell's demon in a photonic setup. We show that a measurement at the few-photons level followed by a feed-forward operation allows the extraction of work from intense thermal light into an electric circuit. The interpretation of the experiment stimulates the derivation of an equality relating work extraction to information acquired by measurement. We derive a bound using this relation and show that it is in agreement with the experimental results. Our work puts forward photonic systems as a platform for experiments related to information in thermodynamics. PMID:26894692
NASA Astrophysics Data System (ADS)
Vidrighin, Mihai D.; Dahlsten, Oscar; Barbieri, Marco; Kim, M. S.; Vedral, Vlatko; Walmsley, Ian A.
2016-02-01
We report an experimental realization of Maxwell's demon in a photonic setup. We show that a measurement at the few-photons level followed by a feed-forward operation allows the extraction of work from intense thermal light into an electric circuit. The interpretation of the experiment stimulates the derivation of an equality relating work extraction to information acquired by measurement. We derive a bound using this relation and show that it is in agreement with the experimental results. Our work puts forward photonic systems as a platform for experiments related to information in thermodynamics.
NASA Astrophysics Data System (ADS)
Lu, Zhiyue; Mandal, Dibyendu; Jarzynski, Christopher
2015-03-01
We describe a hypothetical machine, with moving, mechanical components, that acts as an autonomous Maxwell's demon. The machine operates in two useful modes. It can act as an information engine by rectifying the thermal motions of surrounding gas particles to lift a mass against gravity, while writing information to a stream of bits. Alternatively, it can act as an eraser, harnessing the energy of a falling mass to erase information from a stream of bits. We solve for the phase diagram and compute the efficiency of our model, both analytically and numerically. Our model provides a simple example of a mechanical machine that is driven by the information entropy of a stream of bits, rather than a difference in temperatures or chemical potentials. This research is supported by the U.S. Army Research Office under Contract Number W911NF-13-1-0390.
Quantum Behavior of an Autonomous Maxwell Demon
NASA Astrophysics Data System (ADS)
Chapman, Adrian; Miyake, Akimasa
2015-03-01
A Maxwell Demon is an agent that can exploit knowledge of a system's microstate to perform useful work. The second law of thermodynamics is only recovered upon taking into account the work required to irreversibly update the demon's memory, bringing information theoretic concepts into a thermodynamic framework. Recently, there has been interest in modeling a classical Maxwell demon as an autonomous physical system to study this information-work tradeoff explicitly. Motivated by the idea that states with non-local entanglement structure can be used as a computational resource, we ask whether these states have thermodynamic resource quality as well by generalizing a particular classical autonomous Maxwell demon to the quantum regime. We treat the full quantum description using a matrix product operator formalism, which allows us to handle quantum and classical correlations in a unified framework. Applying this, together with techniques from statistical mechanics, we are able to approximate nonlocal quantities such as the erasure performed on the demon's memory register when correlations are present. Finally, we examine how the demon may use these correlations as a resource to outperform its classical counterpart.
James Clerk Maxwell and the Kinetic Theory of Gases: A Review Based on Recent Historical Studies
ERIC Educational Resources Information Center
Brush, Stephen G.
1971-01-01
Maxwell's four major papers and some shorter publications relating to kinetic theory and statistical mechanics are discussed in the light of subsequent research. Reviews Maxwell's ideas on such topics as velocity, distribution law, the theory of heat conduction, the mechanism of the radiometer effect, the ergodic hypothesis, and his views on the…
Quantum discord and Maxwell's demons
Zurek, Wojciech Hubert
2003-01-01
Quantum discord was proposed as an information-theoretic measure of the 'quantumness' of correlations. I show that discord determines the difference between the efficiency of quantum and classical Maxwell's demons - that is, entities that can or cannot measure nonlocal observables or carry out conditional quantum operations - in extracting work from collections of correlated quantum systems.
Links to sources of cancer-related statistics, including the Surveillance, Epidemiology and End Results (SEER) Program, SEER-Medicare datasets, cancer survivor prevalence data, and the Cancer Trends Progress Report.
James Clerk Maxwell: Life and science
NASA Astrophysics Data System (ADS)
Marston, Philip L.
2016-07-01
Maxwell's life and science are presented with an account of the progression of Maxwell's research on electromagnetic theory. This is appropriate for the International Year of Light and Light-based Technologies, 2015. Maxwell's own confidence in his 1865 electromagnetic theory of light is examined, along with some of the difficulties he faced and the difficulties faced by some of his followers. Maxwell's interest in radiation pressure and electromagnetic stress is addressed, as well as subsequent developments. Some of Maxwell's other contributions to physics are discussed with an emphasis on the kinetic and molecular theory of gases. Maxwell's theistic perspective on science is illustrated, accompanied by examples of perspectives on Maxwell and his science provided by his peers and accounts of his interactions with those peers. Appendices examine the peer review of Maxwell's 1865 electromagnetic theory paper and the naming of the Maxwell Garnett effective media approximation and provide various supplemental perspectives. From Maxwell's publications and correspondence there is evidence he had a high regard for Michael Faraday. Examples of Maxwell's contributions to electromagnetic terminology are noted.
Helices of fractionalized Maxwell fluid
NASA Astrophysics Data System (ADS)
Jamil, Muhammad; Abro, Kashif Ali; Khan, Najeeb Alam
2015-12-01
In this paper the helical flows of fractionalized Maxwell fluid model, through a circular cylinder, is studied. The motion is produced by the cylinder that at the initial moment begins to rotate around its axis with an angular velocity Omegatp, and to slide along the same axis with linear velocity Utp. The solutions that have been obtained using Laplace and finite Hankel transforms and presented in series form in terms of the newly defined special function M(z), satisfy all imposed initial and boundary conditions. Moreover, the corresponding solutions for ordinary Maxwell and Newtonian fluid obtained as special cases of the present general solution. Finally, the influence of various pertinent parameters on fluid motion as well as the comparison among different fluids models is analyzed by graphical illustrations.
Structural mapping of Maxwell Montes
NASA Technical Reports Server (NTRS)
Keep, Myra; Hansen, Vicki L.
1993-01-01
Four sets of structures were mapped in the western and southern portions of Maxwell Montes. An early north-trending set of penetrative lineaments is cut by dominant, spaced ridges and paired valleys that trend northwest. To the south the ridges and valleys splay and graben form in the valleys. The spaced ridges and graben are cut by northeast-trending graben. The northwest-trending graben formed synchronously with or slightly later than the spaced ridges. Formation of the northeast-trending graben may have overlapped with that of the northwest-trending graben, but occurred in a spatially distinct area (regions of 2 deg slope). Graben formation, with northwest-southeast extension, may be related to gravity-sliding. Individually and collectively these structures are too small to support the immense topography of Maxwell, and are interpreted as parasitic features above a larger mass that supports the mountain belt.
Joseph Maxwell on mediumistic personifications.
Alvarado, Carlos S
2016-09-01
The study of mediumship received much impetus from the work of psychical researchers. This included ideas about the phenomena of personation, or changes in attitudes, dispositions and behaviours shown by some mediums that supposedly indicated discarnate action. The aim of this Classic Text is to reprint passages about this topic from the writings of French psychical researcher Joseph Maxwell (1858-1938), which were part of the contributions of some psychical researchers to reconceptualize the manifestations in psychological terms. Maxwell suggested these changes in mediums were a production of their subconscious mind. His ideas are a reflection of previous theorization about secondary personalities and a particular example of the contributions of psychical researchers to understand the psychology of mediumship. PMID:27473729
Introducing polarization and magnetization into Maxwell's equations: A modified approach
NASA Astrophysics Data System (ADS)
Jakoby, Bernhard
2014-01-01
The introduction of electric polarization and magnetization—the density of electric and magnetic dipole moments respectively—into Maxwell's equations requires establishing their respective relation to polarization charges and magnetization currents. Using a method introduced by Feynman in his famous lectures on physics and considering statistically distributed dipoles on the microscopic scale, the desired relations can be established in a manner that may be more intuitive to undergraduate students.
New family of Maxwell like algebras
NASA Astrophysics Data System (ADS)
Concha, P. K.; Durka, R.; Merino, N.; Rodríguez, E. K.
2016-08-01
We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
Vortex shedding and Maxwell's problem
NASA Astrophysics Data System (ADS)
Michelin, Sebastien; Smith, Stefan Llewellyn
2006-11-01
The coupled problem of a flow around a solid body has applications from the fall of objects in a fluid to the computation of forces on wind-exposed structures. A simplified 2D model is proposed here for the interaction between solid bodies and potential flows. Potential flows over sharp edges generate singular velocities at the edges. To satisfy the Kutta condition, vorticity sheets must be shed from the edges to remove these singularities. Here 2D vorticity sheets are represented as discrete point-vortices with monotically varying intensity. From the fluid momentum conservation, an equation of motion for these vortices, the Brown and Michael equation, is derived and mechanical efforts applied by the fluid on the body are computed. The set of dynamical equations obtained for the fluid-body system is closed and is applied to Maxwell's problem of the 2D fall of a plate in an inviscid fluid initially at rest.
NASA Astrophysics Data System (ADS)
Parrondo, J. M. R.; Granger, L.
2015-07-01
Although there is not a complete "proof" of the second law of thermodynamics based on microscopic dynamics, two properties of Hamiltonian systems have been used to prove the impossibility of work extraction from a single thermal reservoir: Liouville's theorem and the adiabatic invariance of the volume enclosed by an energy shell. In this paper we analyze these two properties in the Szilard engine and other systems related with the Maxwell demon. In particular, we recall that the enclosed volume is no longer an adiabatic invariant in non ergodic systems and explore the consequences of this on the second law. This article is supplemented with comments by H. Ouerdane and Lawrence S. Schulman and a final reply by the authors.
The Proell Effect: A Macroscopic Maxwell's Demon
NASA Astrophysics Data System (ADS)
Rauen, Kenneth M.
2011-12-01
Maxwell's Demon is a legitimate challenge to the Second Law of Thermodynamics when the "demon" is executed via the Proell effect. Thermal energy transfer according to the Kinetic Theory of Heat and Statistical Mechanics that takes place over distances greater than the mean free path of a gas circumvents the microscopic randomness that leads to macroscopic irreversibility. No information is required to sort the particles as no sorting occurs; the entire volume of gas undergoes the same transition. The Proell effect achieves quasi-spontaneous thermal separation without sorting by the perturbation of a heterogeneous constant volume system with displacement and regeneration. The classical analysis of the constant volume process, such as found in the Stirling Cycle, is incomplete and therefore incorrect. There are extra energy flows that classical thermo does not recognize. When a working fluid is displaced across a regenerator with a temperature gradient in a constant volume system, complimentary compression and expansion work takes place that transfers energy between the regenerator and the bulk gas volumes of the hot and cold sides of the constant volume system. Heat capacity at constant pressure applies instead of heat capacity at constant volume. The resultant increase in calculated, recyclable energy allows the Carnot Limit to be exceeded in certain cycles. Super-Carnot heat engines and heat pumps have been designed and a US patent has been awarded.
Green`s function of Maxwell`s equations and corresponding implications for iterative methods
Singer, B.S.; Fainberg, E.B.
1996-12-31
Energy conservation law imposes constraints on the norm and direction of the Hilbert space vector representing a solution of Maxwell`s equations. In this paper, we derive these constrains and discuss the corresponding implications for the Green`s function of Maxwell`s equations in a dissipative medium. It is shown that Maxwell`s equations can be reduced to an integral equation with a contracting kernel. The equation can be solved using simple iterations. Software based on this algorithm have successfully been applied to a wide range of problems dealing with high contrast models. The matrix corresponding to the integral equation has a well defined spectrum. The equation can be symmetrized and solved using different approaches, for instance one of the conjugate gradient methods.
Maxwell Duality, Lorentz Invariance, and Topological Phase
NASA Technical Reports Server (NTRS)
Dowling, J.; Williams, C.; Franson, J.
1999-01-01
We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena.
How Maxwell's equations came to light
NASA Astrophysics Data System (ADS)
Mahon, Basil
2015-01-01
The nineteenth-century Scottish physicist James Clerk Maxwell made groundbreaking contributions to many areas of science including thermodynamics and colour vision. However, he is best known for his equations that unified electricity, magnetism and light.
Shock waves: The Maxwell-Cattaneo case.
Uribe, F J
2016-03-01
Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27≈M_{1}
Maxwellians and the Remaking of Maxwell's Equations
NASA Astrophysics Data System (ADS)
Hunt, Bruce
2012-02-01
Although James Clerk Maxwell first formulated his theory of the electromagnetic field in the early 1860s, it went through important changes before it gained general acceptance in the 1890s. Those changes were largely the work of a group of younger physicists, the Maxwellians, led by G. F. FitzGerald in Ireland, Oliver Lodge and Oliver Heaviside in England, and Heinrich Hertz in Germany. Together, they extended, refined, tested, and confirmed Maxwell's theory, and recast it into the set of four vector equations known ever since as ``Maxwell's equations.'' By tracing how the Maxwellians remade and disseminated Maxwell's theory between the late 1870s and the mid-1890s, we can gain a clearer understanding not just of how the electromagnetic field was understood at the end of the 19th century, but of the collaborative nature of work at the frontiers of physics.
Axially Symmetric Brans-Dicke-Maxwell Solutions
NASA Astrophysics Data System (ADS)
Chatterjee, S.
1981-05-01
Following a method of John and Goswami new solutions of coupled Brans-Dicke-Maxwell theory are generated from Zipoy's solutions in oblate and prolate spheroidal coordinates for source-free gravitational field. All these solutions become Euclidean at infinity. The asymptotic behavior and the singularity of the solutions are discussed and a comparative study made with the corresponding Einstein-Maxwell solutions. The possibility of a very large red shift from the boundary of the spheroids is also discussed.
Magnetic monopoles, Galilean invariance, and Maxwell's equations
NASA Astrophysics Data System (ADS)
Crawford, Frank S.
1992-02-01
Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ``as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant-i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v<
Operational derivation of Boltzmann distribution with Maxwell's demon model.
Hosoya, Akio; Maruyama, Koji; Shikano, Yutaka
2015-01-01
The resolution of the Maxwell's demon paradox linked thermodynamics with information theory through information erasure principle. By considering a demon endowed with a Turing-machine consisting of a memory tape and a processor, we attempt to explore the link towards the foundations of statistical mechanics and to derive results therein in an operational manner. Here, we present a derivation of the Boltzmann distribution in equilibrium as an example, without hypothesizing the principle of maximum entropy. Further, since the model can be applied to non-equilibrium processes, in principle, we demonstrate the dissipation-fluctuation relation to show the possibility in this direction. PMID:26598363
Maxwell's demon. (I) A thermodynamic exorcism
NASA Astrophysics Data System (ADS)
Gyftopoulos, Elias P.
2002-05-01
It is shown that Maxwell's demon is unable to accomplish his task not because of considerations related to irreversibility, acquisition of information, and computers and erasure of information but because of limitations imposed by the properties of the system on which he is asked to perform his demonic manipulations. The limitations emerge from two recent but related developments of which Maxwell was completely unaware. One is an exposition of thermodynamics as a nonstatistical theory, valid for all systems, both large and small, including a system with only one degree of (translational) freedom, and for all states, both thermodynamic or stable equilibrium states and states that are not thermodynamic equilibrium, including states encountered in mechanics. In this theory, entropy is proven to be a nondestructible, nonstatistical property of any state in the same sense that inertial mass is a nonstatistical property of any state. In Part I, the demon is shown to be incapable of accomplishing his task because this would be equivalent either to reducing the nondestructible and nonstatistical entropy of air in a container without compensation by any other system, including himself, or to extracting only energy from the air under conditions that require the extraction of both energy and entropy. The second development is a unified, quantum-theoretic interpretation of mechanics and the thermodynamics just cited. In this theory: (a) the quantum-theoretic probabilities of measurement results are represented by a density operator ρ that corresponds to a homogeneous ensemble of identical systems, identically prepared; homogeneous is an ensemble in which every member is described by the same density operator ρ as any other member, that is, the ensemble is not a statistical mixture of projectors (wave functions); said differently, experimentally (as opposed to algebraically) the homogeneous ensemble cannot be decomposed into mixtures either of pure states or other mixtures
Venus - Maxwell Montes and Cleopatra Crater
NASA Technical Reports Server (NTRS)
1991-01-01
This Magellan full-resolution image shows Maxwell Montes, and is centered at 65 degrees north latitude and 6 degrees east longitude. Maxwell is the highest mountain on Venus, rising almost 11 kilometers (6.8 miles) above mean planetary radius. The western slopes (on the left) are very steep, whereas the eastern slopes descend gradually into Fortuna Tessera. The broad ridges and valleys making up Maxwell and Fortuna suggest that the topography resulted from compression. Most of Maxwell Montes has a very bright radar return; such bright returns are common on Venus at high altitudes. This phenomenon is thought to result from the presence of a radar reflective mineral such as pyrite. Interestingly, the highest area on Maxwell is less bright than the surrounding slopes, suggesting that the phenomenon is limited to a particular elevation range. The pressure, temperature, and chemistry of the atmosphere vary with altitude; the material responsible for the bright return probably is only stable in a particular range of atmospheric conditions and therefore a particular elevation range. The prominent circular feature in eastern Maxwell is Cleopatra. Cleopatra is a double-ring impact basin about 100 kilometers (62 miles) in diameter and 2.5 kilometers (1.5 miles) deep. A steep-walled, winding channel a few kilometers wide breaks through the rough terrain surrounding the crater rim. A large amount of lava originating in Cleopatra flowed through this channel and filled valleys in Fortuna Tessera. Cleopatra is superimposed on the structures of Maxwell Montes and appears to be undeformed, indicating that Cleopatra is relatively young.
Euclideanization of Maxwell-Chern-Simons theory
NASA Astrophysics Data System (ADS)
Bowman, Daniel Alan
We quantize the theory of electromagnetism in 2 + 1-spacetime dimensions with the addition of the topological Chern-Simons term using an indefinite metric formalism. In the process, we also quantize the Proca and pure Maxwell theories, which are shown to be related to the Maxwell-Chern-Simons theory. Next, we Euclideanize these three theories, obtaining path space formulae and investigating Osterwalder-Schrader positivity in each case. Finally, we obtain a characterization of those Euclidean states that correspond to physical states in the relativistic theories.
A Modification to Maxwell's Needle Apparatus
ERIC Educational Resources Information Center
Soorya, Tribhuvan N.
2015-01-01
Maxwell's needle apparatus is used to determine the shear modulus (?) of the material of a wire of uniform cylindrical cross section. Conventionally, a single observation is taken for each observable, and the value of ? is calculated in a single shot. A modification to the above apparatus is made by varying one of the observables, namely the mass…
Maxwell's electromagnetic theory and special relativity.
Hall, Graham
2008-05-28
This paper presents a brief history of electromagnetic theory from ancient times up to the work of Maxwell and the advent of Einstein's special theory of relativity. It is divided into five convenient periods and the intention is to describe these developments for the benefit of a lay scientific audience and with the minimum of technical detail. PMID:18218598
Maxwell Equations for Slow-Moving Media
NASA Astrophysics Data System (ADS)
Rozov, Andrey
2015-12-01
In the present work, the Minkowski equations obtained on the basis of theory of relativity are used to describe electromagnetic fields in moving media. But important electromagnetic processes run under non-relativistic conditions of slow-moving media. Therefore, one should carry out its description in terms of classical mechanics. Hertz derived electrodynamic equations for moving media within the frame of classical mechanics on the basis of the Maxwell theory. His equations disagree with the experimental data concerned with the moving dielectrics. In the paper, a way of description of electromagnetic fields in slow-moving media on the basis of the Maxwell theory within the frame of classical mechanics is offered by combining the Hertz approach and the experimental data concerned with the movement of dielectrics in electromagnetic fields. Received Maxwell equations lack asymmetry in the description of the reciprocal electrodynamic action of a magnet and a conductor and conform to known experimental data. Comparative analysis of the Minkowski and Maxwell models is carried out.
21 CFR 886.1435 - Maxwell spot.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Maxwell spot. 886.1435 Section 886.1435 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES...-powered device that is a light source with a red and blue filter intended to test macular function....
Shock waves: The Maxwell-Cattaneo case
NASA Astrophysics Data System (ADS)
Uribe, F. J.
2016-03-01
Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M ) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈M1
Fractional statistics and confinement
NASA Astrophysics Data System (ADS)
Gaete, P.; Wotzasek, C.
2005-02-01
It is shown that a pointlike composite having charge and magnetic moment displays a confining potential for the static interaction while simultaneously obeying fractional statistics in a pure gauge theory in three dimensions, without a Chern-Simons term. This result is distinct from the Maxwell-Chern-Simons theory that shows a screening nature for the potential.
What physics is encoded in Maxwell's equations?
NASA Astrophysics Data System (ADS)
Kosyakov, B. P.
2005-08-01
We reconstruct Maxwell's equations showing that a major part of the information encoded in them is taken from topological properties of spacetime, and the residual information, divorced from geometry, which represents the physical contents of electrodynamics, %these equations, translates into four assumptions:(i) locality; (ii) linearity; %of the dynamical law; (iii) identity of the charge-source and the charge-coupling; and (iv) lack of magnetic monopoles. However, a closer inspection of symmetries peculiar to electrodynamics shows that these assumptions may have much to do with geometry. Maxwell's equations tell us that we live in a three-dimensional space with trivial (Euclidean) topology; time is a one-dimensional unidirectional and noncompact continuum; and spacetime is endowed with a light cone structure readable in the conformal invariance of electrodynamics. Our geometric feelings relate to the fact that Maxwell's equations are built in our brain, hence our space and time orientation, our visualization and imagination capabilities are ensured by perpetual instinctive processes of solving Maxwell's equations. People are usually agree in their observations of angle relations, for example, a right angle is never confused with an angle slightly different from right. By contrast, we may disagree in metric issues, say, a colour-blind person finds the light wave lengths quite different from those found by a man with normal vision. This lends support to the view that conformal invariance of Maxwell's equations is responsible for producing our notion of space. Assuming that our geometric intuition is guided by our innate realization of electrodynamical laws, some abnormal mental phenomena, such as clairvoyance, may have a rational explanation.
Altered Maxwell equations in the length gauge
NASA Astrophysics Data System (ADS)
Reiss, H. R.
2013-09-01
The length gauge uses a scalar potential to describe a laser field, thus treating it as a longitudinal field rather than as a transverse field. This distinction is manifested by the fact that the Maxwell equations that relate to the length gauge are not the same as those for transverse fields. In particular, a source term is necessary in the length-gauge Maxwell equations, whereas the Coulomb-gauge description of plane waves possesses the basic property of transverse fields that they propagate with no source terms at all. This difference is shown to be importantly consequential in some previously unremarked circumstances; and it explains why the Göppert-Mayer gauge transformation does not provide the security that might be expected of full gauge equivalence.
Maxwell's demons in multipartite quantum correlated systems
NASA Astrophysics Data System (ADS)
Braga, Helena C.; Rulli, Clodoaldo C.; de Oliveira, Thiago R.; Sarandy, Marcelo S.
2014-10-01
We investigate the extraction of thermodynamic work by a Maxwell's demon in a multipartite quantum correlated system. We begin by adopting the standard model of a Maxwell's demon as a Turing machine, either in a classical or quantum setup depending on its ability to implement classical or quantum conditional dynamics. Then, for an n -partite system (A1,A2,⋯,An) , we introduce a protocol of work extraction that bounds the advantage of the quantum demon over its classical counterpart through the amount of multipartite quantum correlation present in the system, as measured by a thermal version of the global quantum discord. This result is illustrated for an arbitrary n -partite pure state of qubits with Schmidt decomposition, where it is shown that the thermal global quantum discord exactly quantifies the quantum advantage. Moreover, we also consider the work extraction via mixed multipartite states, where examples of tight upper bounds can be obtained.
Maxwell electrodynamics subjected to quantum vacuum fluctuations
Gevorkyan, A. S.; Gevorkyan, A. A.
2011-06-15
The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) equations. For a model of 'white noise' fluctuations, using ML equations, a second order partial differential equation is found which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the 'ground state' energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of the vacuum quantum field fluctuations may be constructed on a 6D space-time continuum with a 2D compactified subspace. Their influence on the refraction indexes of vacuum is studied.
Venus - Detailed mapping of Maxwell Montes region
NASA Astrophysics Data System (ADS)
Alexandrov, Yu. N.; Crymov, A. A.; Kotelnikov, V. A.; Petrov, G. M.; Rzhiga, O. N.; Sidorenko, A. I.; Sinilo, V. P.; Zakharov, A. I.; Akim, E. L.; Basilevski, A. T.; Kadnichanski, S. A.; Tjuflin, Yu. S.
1986-03-01
From October 1983 to July 1984, the north hemisphere of Venus, from latitude 30° to latitude 90°, was mapped by means of the radar imagers and altimeters of the spacecraft Venera 15 and Venera 16. This report presents the results of the radar mapping of the Maxwell Montes region, one of the most interesting features of Venus' surface. A radar mosaic map and contour map have been compiled.
Venus: detailed mapping of maxwell montes region.
Alexandrov, Y N; Crymov, A A; Kotelnikov, V A; Petrov, G M; Rzhiga, O N; Sidorenko, A I; Sinilo, V P; Zakharov, A I; Akim, E L; Basilevski, A T; Kadnichanski, S A; Tjuflin, Y S
1986-03-14
From October 1983 to July 1984, the north hemisphere of Venus, from latitude 30 degrees to latitude 90 degrees , was mapped by means of the radar imagers and altimeters of the spacecraft Venera 15 and Venera 16. This report presents the results of the radar mapping of the Maxwell Montes region, one of the most interesting features of Venus' surface. A radar mosaic map and contour map have been compiled. PMID:17839563
Loading relativistic Maxwell distributions in particle simulations
Zenitani, Seiji
2015-04-15
Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ≈50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.
Multipartite information flow for multiple Maxwell demons
NASA Astrophysics Data System (ADS)
Horowitz, Jordan M.
2015-03-01
The second law of thermodynamics dictates the fundamental limits to the amount of energy and information that can be exchanged between physical systems. In this work, we extend a thermodynamic formalism describing this flow of energy and information developed for a pair of bipartite systems to many multipartite systems. We identify a natural thermodynamic quantity that describes the information exchanged among these systems. We then introduce and discuss a refined version. Our results are illustrated with a model of two, competing Maxwell demons.
Loading relativistic Maxwell distributions in particle simulations
NASA Astrophysics Data System (ADS)
Zenitani, Seiji
2015-04-01
Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ≈50 % for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.
Maxwell: A new vision of the world
NASA Astrophysics Data System (ADS)
Maystre, Daniel
2014-05-01
The paper outlines the crucial contributions of James Clerk Maxwell to Physics and more generally to our vision of the world. He achieved 150 years ago a synthesis of the pioneering works in magnetostatics, electrostatics, induction and, by introducing the notion of displacement current, gave birth to Electromagnetics. Then, he deduced the existence of electromagnetic waves and identified light as one of them. Maxwell equations deeply changed a Newtonian conception of the world based on particle interactions by pointing out the vital role of waves in physics. This new conception had a strong influence on the development of quantum physics. Finally, the invariance of light velocity in Galilean frames led to Lorentz transformations, a key step toward the theory of relativity. Par ailleurs, les équations de Maxwell ont profondément changé une conception du monde newtonienne basée sur l'interaction entre particules en révélant le rôle essentiel des ondes en physique, ce qui eut une influence déterminante sur le développement de la physique quantique. Enfin, l'invariance de la vitesse de la lumière dans les repères galiléens a entraîné la découverte des transformations de Lorentz, une étape capitale vers la théorie de la relativité.
The Pseudo-Maxwell Equations Revisited
NASA Astrophysics Data System (ADS)
Stavroudis, Orestes N.
1982-02-01
The so-called pseudo-Maxwell are a set of partial differential eauations that strongly resemble the Maxwell equations, yet are based only on Fermat's principle, the idea of an orthotomic system of rays, and certain theorems from differential gecmetry. From Fermat's principle, applying the Euler equation from the variational calculus, one obtains the ray equation whose solutions describe ray paths in an inhomogeneous medium. We define an aggregate of such rays as an orthotomic system if it is possible to find a sur-face orthogonal to all rays in the aggregate. Making use of the Frenet equations from differential geometry, one may derive relationships between certain geometrical vectors and their derivatives. These are the pseudo-Maxwell equations. Their existence is' paradoxical. Are they merely a mathematical artifact, an accidental quirk of the notation we are accustomed to use? Or do they indicate that there is more geometry lurking in the physics of electricity and magnetism than we ever dreamed of in our philosophies?
Deforming the Maxwell-Sim algebra
Gibbons, G. W.; Gomis, Joaquim; Pope, C. N.
2010-09-15
The Maxwell algebra is a noncentral extension of the Poincare algebra, in which the momentum generators no longer commute, but satisfy [P{sub {mu}},P{sub {nu}}]=Z{sub {mu}{nu}}. The charges Z{sub {mu}{nu}} commute with the momenta, and transform tensorially under the action of the angular momentum generators. If one constructs an action for a massive particle, invariant under these symmetries, one finds that it satisfies the equations of motion of a charged particle interacting with a constant electromagnetic field via the Lorentz force. In this paper, we explore the analogous constructions where one starts instead with the ISim subalgebra of Poincare, this being the symmetry algebra of very special relativity. It admits an analogous noncentral extension, and we find that a particle action invariant under this Maxwell-Sim algebra again describes a particle subject to the ordinary Lorentz force. One can also deform the ISim algebra to DISim{sub b}, where b is a nontrivial dimensionless parameter. We find that the motion described by an action invariant under the corresponding Maxwell-DISim algebra is that of a particle interacting via a Finslerian modification of the Lorentz force. In an appendix is it shown that the DISim{sub b} algebra is isomorphic to the extended Schroedinger algebra with its standard deformation parameter z, when b=(1/1-z).
Infinite Maxwell fisheye inside a finite circle
NASA Astrophysics Data System (ADS)
Liu, Yangjié; Chen, Huanyang
2015-12-01
This manuscript proposes a two-dimensional heterogeneous imaging medium composed of an isotropic refractive index. We exploit conformal-mapping to transfer the full Maxwell fisheye into a finite circle. Unlike our previous design that requires a mirror of Zhukovski airfoil shape, this approach can work without a mirror, while offering a comparable imaging resolution. This medium may also be used as an isotropic gradient index lens to transform a light source inside it into two identical sources of null interference. A merit of this approach is reduction of the near-zero-index area from an infinite zone into a finite one, which shall ease its realization.
Maxwell's demon based on a single qubit
NASA Astrophysics Data System (ADS)
Pekola, J. P.; Golubev, D. S.; Averin, D. V.
2016-01-01
We propose and analyze Maxwell's demon based on a single qubit with avoided level crossing. Its operation cycle consists of adiabatic drive to the point of minimum energy separation, measurement of the qubit state, and conditional feedback. We show that the heat extracted from the bath at temperature T can ideally approach the Landauer limit of kBT ln2 per cycle even in the quantum regime. Practical demon efficiency is limited by the interplay of Landau-Zener transitions and coupling to the bath. We suggest that an experimental demonstration of the demon is fully feasible using one of the standard superconducting qubits.
Maxwell's demon. (II) A quantum-theoretic exorcism
NASA Astrophysics Data System (ADS)
Gyftopoulos, Elias P.
2002-05-01
In Part II of this two-part paper we prove that Maxwell's demon is unable to accomplish his task of sorting air molecules into swift and slow because in air in a thermodynamic equilibrium state there are no such molecules. The proof is based on the principles of a unified quantum theory of mechanics and thermodynamics. The key idea of the unified theory is that von Neumann's concept of a homogeneous ensemble of identical systems, identically prepared, is valid not only for a density operator ρ equal to a projector (every member of the ensemble is assigned the same projector, ρi=| ψi> < ψi|= ρi2, or the same wave function ψ i as any other member) but also for a density operator that is not a projector (every member of the ensemble is assigned the same density operator, ρ>ρ 2, as any other member). So, the latter ensemble is not a statistical mixture of projectors. The broadening of the validity of the homogeneous ensemble is consistent with the quantum-theoretic postulates about observables, measurement results, and value of any observable. In the context of the unified theory, among the many novel results is the theorem that each molecule of a system in a thermodynamic equilibrium state has zero value of momentum, that is, each molecule is at a standstill and, therefore, there are no molecules to be sorted as swift and slow. Said differently, if Maxwell were cognizant of quantum theory, he would not have conceived of the idea of the demon. It is noteworthy that the zero value of momentum is not the result of averaging over different momenta of many molecules. Under the specified conditions, it is the quantum-theoretic value of the momentum of any one molecule, and the same result is valid even if the system consists of only one molecule.
Comparing Teaching Approaches About Maxwell's Displacement Current
NASA Astrophysics Data System (ADS)
Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício
2014-08-01
Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.
Maxwell Equations and the Redundant Gauge Degree of Freedom
ERIC Educational Resources Information Center
Wong, Chun Wa
2009-01-01
On transformation to the Fourier space (k,[omega]), the partial differential Maxwell equations simplify to algebraic equations, and the Helmholtz theorem of vector calculus reduces to vector algebraic projections. Maxwell equations and their solutions can then be separated readily into longitudinal and transverse components relative to the…
Maxwell and creation: Acceptance, criticism, and his anonymous publication
NASA Astrophysics Data System (ADS)
Marston, Philip L.
2007-08-01
Although James Clerk Maxwell's religious views and discussions on atoms having the properties of ``manufactured articles'' have been discussed, some aspects of the responses by his contemporaries to his remarks on creation have been neglected. Various responses quoted here include a book from 1878 by ``Physicus'' (George John Romanes) attributing ``arrogance'' to Maxwell for his inferences. Relevant aspects of the evolution of the perspective of Romanes are noted. A response by B. F. Westcott indicated that Maxwell was the author of a related anonymous publication concerned with what eventually became known as the heat death of the universe. In his teaching to theology students, Westcott, a friend of Maxwell, emphasized Maxwell's reasoning based on the dissipation of energy. There are similarities between Maxwell's perspective on creation and Biblical commentaries by fellow Eranus Club members Westcott and J. B. Lightfoot. Interest in Maxwell's remarks extended into the twentieth century. The principal Baptist chapel attended by Maxwell and his wife when in London in the 1860s is identified and some relevant attributes of the chapel and of its pastor are described.
Chaotic magnetic fields in Vlasov-Maxwell equilibria
Ghosh, Abhijit; Janaki, M. S.; Dasgupta, Brahmananda; Bandyopadhyay, Alak
2014-03-15
Stationary solutions of Vlasov-Maxwell equations are obtained by exploiting the invariants of single particle motion leading to linear or nonlinear functional relations between current and vector potential. For a specific combination of invariants, it is shown that Vlasov-Maxwell equilibria have an associated Hamiltonian that exhibits chaos.
Post-Newtonian approximation in Maxwell-like form
Kaplan, Jeffrey D.; Nichols, David A.; Thorne, Kip S.
2009-12-15
The equations of the linearized first post-Newtonian approximation to general relativity are often written in 'gravitoelectromagnetic' Maxwell-like form, since that facilitates physical intuition. Damour, Soffel, and Xu (DSX) (as a side issue in their complex but elegant papers on relativistic celestial mechanics) have expressed the first post-Newtonian approximation, including all nonlinearities, in Maxwell-like form. This paper summarizes that DSX Maxwell-like formalism (which is not easily extracted from their celestial mechanics papers), and then extends it to include the post-Newtonian (Landau-Lifshitz-based) gravitational momentum density, momentum flux (i.e. gravitational stress tensor), and law of momentum conservation in Maxwell-like form. The authors and their colleagues have found these Maxwell-like momentum tools useful for developing physical intuition into numerical-relativity simulations of compact binaries with spin.
Relativistic Entanglement From Maxwell's Classical Equations
NASA Astrophysics Data System (ADS)
Carroll, John E.; Quarterman, Adrian H.
2013-09-01
With the help of light cone coordinates and light cone field representations of Maxwell's classical equations, quantum polarization entanglement is explained using the relativistic results of a companion paper that shows how conventional or reference waves can have an adjoint wave, travelling in phase with the reference wave, but in a proper relativistic frame that travels in the opposing direction to the proper frame of the reference wave. This subsequently allows waves, travelling in opposite directions, to have the same proper frame and consequently such waves can be regarded as relativistically local. The light cone coordinates offer a classical form of a quantum wave function and demonstrate a classical equivalent of a mixed quantum state.
Mechanical Weyl Modes in Topological Maxwell Lattices
NASA Astrophysics Data System (ADS)
Rocklin, D. Zeb; Chen, Bryan Gin-ge; Falk, Martin; Vitelli, Vincenzo; Lubensky, T. C.
2016-04-01
We show that two-dimensional mechanical lattices can generically display topologically protected bulk zero-energy phonon modes at isolated points in the Brillouin zone, analogs of massless fermion modes of Weyl semimetals. We focus on deformed square lattices as the simplest Maxwell lattices, characterized by equal numbers of constraints and degrees of freedom, with this property. The Weyl points appear at the origin of the Brillouin zone along directions with vanishing sound speed and move away to the zone edge (or return to the origin) where they annihilate. Our results suggest a design strategy for topological metamaterials with bulk low-frequency acoustic modes and elastic instabilities at a particular, tunable finite wave vector.
Nondiffracting accelerating wave packets of Maxwell's equations.
Kaminer, Ido; Bekenstein, Rivka; Nemirovsky, Jonathan; Segev, Mordechai
2012-04-20
We present the nondiffracting spatially accelerating solutions of the Maxwell equations. Such beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams to the full domain of the wave equation. For both TE and TM polarizations, the beams exhibit shape-preserving bending which can have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90°. We show that these accelerating beams are self-healing, analyze their properties, and find the new class of accelerating breathers: self-bending beams of periodically oscillating shapes. Finally, we emphasize that in their scalar form, these beams are the exact solutions for nondispersive accelerating wave packets of the most common wave equation describing time-harmonic waves. As such, this work has profound implications to many linear wave systems in nature, ranging from acoustic and elastic waves to surface waves in fluids and membranes. PMID:22680719
The Life of James Clerk Maxwell
NASA Astrophysics Data System (ADS)
Campbell, Lewis; Garnett, William
2010-06-01
Preface; Part I. Biographical Outline: 1. Birth and parentage; 2. Glenlair - childhood, 1831-1841; 3. Boyhood, 1841-1844; 4. Adolescence, 1844-1847; 5. Opening manhood, 1847-1850; 6. Undergraduate life at Cambridge, 1850-1854; 7. Bachelor-scholar and fellow of Trinity, 1854-1856; 8. Essays at Cambridge, 1853-1856; 9. Death of his father. Professorship at Aberdeen, 1856-1857; 10. Aberdeen. Marriage, 1857-1860; 11. King's College, London. Glenair, 1860-1870; 12. Cambridge, 1871-1879; 13. Illness and death, 1879; 14. Last essays at Cambridge; Part II. Contributions to Science: 1. Experiments on colour vision, and other contributions to optics; 2. Investigations respecting elastic solids; 3. Pure geometry; 4. Mechanics; 5. Saturn's rings; 6. Faraday's lines of force, and Maxwell's theory of the electromagnetic field; 7. Molecular physics; Part III. Poems: 1. Juvenile verses and translations; 2. Occasional pieces; 3. Serio-comic verse; Index.
Fractional vector calculus and fractional Maxwell's equations
Tarasov, Vasily E.
2008-11-15
The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.
Anomalous Maxwell equations for inhomogeneous chiral plasma
NASA Astrophysics Data System (ADS)
Gorbar, E. V.; Shovkovy, I. A.; Vilchinskii, S.; Rudenok, I.; Boyarsky, A.; Ruchayskiy, O.
2016-05-01
Using the chiral kinetic theory we derive the electric and chiral current densities in inhomogeneous relativistic plasma. We also derive equations for the electric and chiral chemical potentials that close the Maxwell equations in such a plasma. The analysis is done in the regimes with and without a drift of the plasma as a whole. In addition to the currents present in the homogeneous plasma (Hall current, chiral magnetic, chiral separation, and chiral electric separation effects, as well as Ohm's current) we derive several new terms associated with inhomogeneities of the plasma. Apart from various diffusionlike terms, we find also new dissipationless terms that are independent of relaxation time. Their origin can be traced to the Berry curvature modifications of the kinetic theory.
Mechanical Weyl Modes in Topological Maxwell Lattices.
Rocklin, D Zeb; Chen, Bryan Gin-Ge; Falk, Martin; Vitelli, Vincenzo; Lubensky, T C
2016-04-01
We show that two-dimensional mechanical lattices can generically display topologically protected bulk zero-energy phonon modes at isolated points in the Brillouin zone, analogs of massless fermion modes of Weyl semimetals. We focus on deformed square lattices as the simplest Maxwell lattices, characterized by equal numbers of constraints and degrees of freedom, with this property. The Weyl points appear at the origin of the Brillouin zone along directions with vanishing sound speed and move away to the zone edge (or return to the origin) where they annihilate. Our results suggest a design strategy for topological metamaterials with bulk low-frequency acoustic modes and elastic instabilities at a particular, tunable finite wave vector. PMID:27081989
Thermodynamics with information flow: Applications to Maxwell demons and biochemical sensing
NASA Astrophysics Data System (ADS)
Horowitz, Jordan
2015-03-01
Information is often perceived as an immaterial entity. However, since the birth of statistical physics, it has been argued, based on thought experiments by the likes of Maxwell, that there are physical thermodynamic implications to information manipulation. In this talk, I will discuss a unified framework for the information transfers between continuously interacting systems, describing how information generated in an auxiliary system can be utilized by another as a fuel for an otherwise impossible process. Indeed, while the joint system satisfies the second law, the entropy balance of each system is modified by an information term related to the mutual information between the pair of systems. I will then show how this result incorporates the traditional analysis of Maxwell's demon. In addition, I will use this framework to analyze the thermodynamics and energetics of biological sensory adaptation, employing the biochemical sensing network of E. Coli chemotaxis as a representative example.
Adaptive node techniques for Maxwell's equations
Hewett, D W
2000-04-01
The computational mesh in numerical simulation provides a framework on which to monitor the spatial dependence of function and their derivatives. Spatial mesh is therefore essential to the ability to integrate systems in time without loss of fidelity. Several philosophies have emerged to provide such fidelity (Eulerian, Lagrangian, Arbitrary Lagrangian Eulerian ALE, Adaptive Mesh Refinement AMR, and adaptive node generation/deletion). Regardless of the type of mesh, a major difficulty is in setting up the initial mesh. Clearly a high density of grid points is essential in regions of high geometric complexity and/or regions of intense, energetic activity. For some problems, mesh generation is such a crucial part of the problem that it can take as much computational effort as the run itself, and these tasks are now taking weeks of massively parallel CPU time. Mesh generation is no less crucial to electromagnetic calculations. In fact EM problem set up can be even more challenging without the clues given by fluid motion in hydrodynamic systems. When the mesh is advected with the fluid (Lagrangian), mesh points naturally congregate in regions of high activity. Similarly in AMR algorithms, strong gradients in the fluid flow are one of the triggers for mesh refinement. In the hyperbolic Maxwell's equations without advection, mesh point placement/motion is not so intuitive. In fixed geometry systems, it at least feasible to finely mesh high leverage, geometrically challenged areas. For other systems, where the action takes place far from the boundaries and, likely, changes position in time, the options are limited to either using a high resolution (expensive) mesh in all regions that could require such resolution or adaptively generating nodes to resolve the physics as it evolves. The authors have developed a new time of adaptive node technique for Maxwell's equations to deal with this set of issues.
Electromagnetic mirrors in the sky: Accessible applications of Maxwell's equations
NASA Astrophysics Data System (ADS)
Withers, Paul
2015-06-01
All too often, Maxwell's equations are taught as mathematical abstractions without any connections to students' personal experiences. However, the interaction of radio waves with Earth's ionosphere provides an opportunity to apply Maxwell's equations in scenarios that have some connections to students' daily lives. A description of how electromagnetic waves propagate through a plasma is derived from Maxwell's equations. This description is used to show how the reflection of radio waves by the ionosphere can be used to enable long range radio communications, to establish that the Sun's emission varies over the solar cycle, and to measure physical properties of the ionosphere.
Generalized gravitational entropy of interacting scalar field and Maxwell field
NASA Astrophysics Data System (ADS)
Huang, Wung-Hong
2014-12-01
The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.
Reconstruction of symmetric Dirac-Maxwell equations using nonassociative algebra
NASA Astrophysics Data System (ADS)
Kalauni, Pushpa; Barata, J. C. A.
2015-01-01
In the presence of sources, the usual Maxwell equations are neither symmetric nor invariant with respect to the duality transformation between electric and magnetic fields. Dirac proposed the existence of magnetic monopoles for symmetrizing the Maxwell equations. In the present work, we obtain the fully symmetric Dirac-Maxwell's equations (i.e. with electric and magnetic charges and currents) as a single equation by using 4 × 4 matrix presentation of fields and derivative operators. This matrix representation has been derived with the help of the algebraic properties of quaternions and octonions. Such description gives a compact representation of electric and magnetic counterparts of the field in a single equation.
A Maxwell formulation for the equations of a plasma
Thompson, Richard J.; Moeller, Trevor M.
2012-01-15
In light of the analogy between the structure of electrodynamics and fluid dynamics, the fluid equations of motion may be reformulated as a set of Maxwell equations. This analogy has been explored in the literature for incompressible turbulent flow and compressible flow but has not been widely explored in relation to plasmas. This letter introduces the analogous fluid Maxwell equations and formulates a set of Maxwell equations for a plasma in terms of the species canonical vorticity and its cross product with the species velocity. The form of the source terms is presented and the magnetohydrodynamic (MHD) limit restores the typical variety of MHD waves.
Quantum Maxwell's demon in thermodynamic cycles.
Dong, H; Xu, D Z; Cai, C Y; Sun, C P
2011-06-01
We study the physical mechanism of Maxwell's demon (MD), which helps do extra work in thermodynamic cycles with the heat engine. This is exemplified with one molecule confined in an infinitely deep square potential with a movable solid wall. The MD is modeled as a two-level system (TLS) for measuring and controlling the motion of the molecule. The processes in the cycle are described in a quantum fashion. It is discovered that a MD with quantum coherence or one at a temperature lower than the molecule's heat bath can enhance the ability of the whole working substance, formed by the heat engine plus the MD, to do work outside. This observation reveals that the essential role of the MD is to drive the whole working substance off equilibrium, or equivalently, to work between two heat baths with different effective temperatures. The elaborate studies with this model explicitly reveal the effect of finite size off the classical limit or thermodynamic limit, which contradicts common sense on a Szilard heat engine (SHE). The quantum SHE's efficiency is evaluated in detail to prove the validity of the second law of thermodynamics. PMID:21797303
Deformed Maxwell Algebras and their Realizations
Gomis, Joaquim; Kamimura, Kiyoshi; Lukierski, Jerzy
2009-12-15
We study all possible deformations of the Maxwell algebra. In D = d+1not =3 dimensions there is only one-parameter deformation. The deformed algebra is isomorphic to so(d+1, 1)+so(d, 1) or to so(d, 2)+so(d, 1) depending on the signs of the deformation parameter. We construct in the dS(AdS) space a model of massive particle interacting with Abelian vector field via nonlocal Lorentz force. In D = 2+1 the deformations depend on two parameters b and k. We construct a phase diagram, with two parts of the (b, k) plane with so(3, 1)+so(2, 1) and so( 2, 2)+so(2, 1) algebras separated by a critical curve along which the algebra is isomorphic to Iso(2, 1)+so(2, 1). We introduce in D = 2+1 the Volkov-Akulov type model for a Abelian Goldstone-Nambu vector field described by a non-linear action containing as its bilinear term the free Chern-Simons Lagrangean.
Weyl, Dirac and Maxwell Quantum Cellular Automata
NASA Astrophysics Data System (ADS)
Bisio, Alessandro; D'Ariano, Giacomo Mauro; Perinotti, Paolo; Tosini, Alessandro
2015-10-01
Recent advances on quantum foundations achieved the derivation of free quantum field theory from general principles, without referring to mechanical notions and relativistic invariance. From the aforementioned principles a quantum cellular automata (QCA) theory follows, whose relativistic limit of small wave-vector provides the free dynamics of quantum field theory. The QCA theory can be regarded as an extended quantum field theory that describes in a unified way all scales ranging from an hypothetical discrete Planck scale up to the usual Fermi scale. The present paper reviews the automaton theory for the Weyl field, and the composite automata for Dirac and Maxwell fields. We then give a simple analysis of the dynamics in the momentum space in terms of a dispersive differential equation for narrowband wave-packets. We then review the phenomenology of the free-field automaton and consider possible visible effects arising from the discreteness of the framework. We conclude introducing the consequences of the automaton dispersion relation, leading to a deformed Lorentz covariance and to possible effects on the thermodynamics of ideal gases.
Construction of Three Dimensional Solutions for the Maxwell Equations
NASA Technical Reports Server (NTRS)
Yefet, A.; Turkel, E.
1998-01-01
We consider numerical solutions for the three dimensional time dependent Maxwell equations. We construct a fourth order accurate compact implicit scheme and compare it to the Yee scheme for free space in a box.
Propagation of ultra-short solitons in stochastic Maxwell's equations
Kurt, Levent; Schäfer, Tobias
2014-01-15
We study the propagation of ultra-short short solitons in a cubic nonlinear medium modeled by nonlinear Maxwell's equations with stochastic variations of media. We consider three cases: variations of (a) the dispersion, (b) the phase velocity, (c) the nonlinear coefficient. Using a modified multi-scale expansion for stochastic systems, we derive new stochastic generalizations of the short pulse equation that approximate the solutions of stochastic nonlinear Maxwell's equations. Numerical simulations show that soliton solutions of the short pulse equation propagate stably in stochastic nonlinear Maxwell's equations and that the generalized stochastic short pulse equations approximate the solutions to the stochastic Maxwell's equations over the distances under consideration. This holds for both a pathwise comparison of the stochastic equations as well as for a comparison of the resulting probability densities.
Holographic superconductors for the Power-Maxwell field with backreactions
NASA Astrophysics Data System (ADS)
Jing, Jiliang; Jiang, Li; Pan, Qiyuan
2016-01-01
We investigate the properties of holographic superconductors for the Power-Maxwell field with backreactions in the background of a d-dimensional AdS black hole. Studying the marginally stable modes of the system numerically, we find that stronger backreaction, larger power parameter of the Power-Maxwell field and lower dimension of the spacetime make it harder for the scalar hair to form. We improve the Sturm-Liouville method to confirm the numerical findings and argue that this analytical method is still powerful to study holographic superconductors for the Power-Maxwell field even if we consider the backreactions. Moreover, we observe that the critical exponent for condensation operators always takes the mean-field value, which is independent of the backreactions and Power-Maxwell field.
Complete Vector Spherical Harmonic Expansion for Maxwell's Equations
ERIC Educational Resources Information Center
Lambert, R. H.
1978-01-01
Conventional expansions of solutions to Maxwell's equations in vector spherical harmonics apply only outside the sources. The complete solution, applying both inside and outside the sources, is given here. Harmonic time dependence is assumed. (Author/GA)
Variational formulations of guiding-center Vlasov-Maxwell theory
NASA Astrophysics Data System (ADS)
Brizard, Alain J.; Tronci, Cesare
2016-06-01
The variational formulations of guiding-center Vlasov-Maxwell theory based on Lagrange, Euler, and Euler-Poincaré variational principles are presented. Each variational principle yields a different approach to deriving guiding-center polarization and magnetization effects into the guiding-center Maxwell equations. The conservation laws of energy, momentum, and angular momentum are also derived by Noether method, where the guiding-center stress tensor is now shown to be explicitly symmetric.
Maxwell-Garnett effective medium theory: Quantum nonlocal effects
Moradi, Afshin
2015-04-15
We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.
Compressible Navier-Stokes Equations with Revised Maxwell's Law
NASA Astrophysics Data System (ADS)
Hu, Yuxi; Racke, Reinhard
2016-05-01
We investigate the compressible Navier-Stokes equations where the constitutive law for the stress tensor given by Maxwell's law is revised to a system of relaxation equations for two parts of the tensor. The global well-posedness is proved as well as the compatibility with the classical compressible Navier-Stokes system in the sense that, for vanishing relaxation parameters, the solutions to the Maxwell system are shown to converge to solutions of the classical system.
Effects of slip on oscillating fractionalized Maxwell fluid
NASA Astrophysics Data System (ADS)
Jamil, Muhammad
2016-03-01
The flow of an incompressible fractionalized Maxwell fluid induced by an oscillating plate has been studied, where the no-slip assumption between the wall and the fluid is no longer valid. The solutions obtained for the velocity field and the associated shear stress, written in terms of H-functions, using discrete Laplace transform, satisfy all imposed initial and boundary conditions. The no-slip contributions, that appeared in the general solutions, as expected, tend to zero when slip parameter θ → 0. Furthermore, the solutions for ordinary Maxwell and Newtonian fluids, performing the same motion, are obtained as limiting cases of general solutions. The solutions for fractionalized and ordinary Maxwell fluids for noslip condition also obtained as a special cases and they are similar to the solutions of classical Stokes' first problem of fractionalized and ordinary Maxwell fluid, if oscillating parameter ω = 0. Finally, the influence of the material, slip and the fractional parameters on the fluid motion, as well as a comparison among fractionalized Maxwell, ordinary Maxwell and Newtonian fluids is also analyzed by graphical illustrations.
Complex and biofluids: From Maxwell to nowadays
NASA Astrophysics Data System (ADS)
Misbah, Chaouqi
2009-11-01
Complex fluids are the rule in biology and in many industrial applications. Typical examples are blood, cartilage, and polymer solutions. Unlike water (as well as domestic oils, soft clear drinks, and so on), the law(s) describing the behavior of complex fluids are not yet fully established. The complexity arises from strong coupling between microscopic scales (like the motion of a red blood cell in the case of blood, or a polymer molecule for a polymer solution) and the global scale of the flow (say at the scale of a blood artery, or a channel in laboratory experiments). In this issue entitled Complex and Biofluids a large panel of experimental and theoretical problems of complex fluids is exposed. The topics range from dilute polymer solutions, food products, to biology (blood flow, cell and tissue mechanics). One of the earliest model put forward as an attempt to describe a complex fluid was suggested a long time ago by James Clerk Maxwell (in 1867). Other famous scientists, like Einstein (in 1906), and Taylor (in 1932) have made important contributions to the field, but the topic of complex fluids still continues to pose a formidable challenge to science. This field has known during the past decade an unbelievable upsurge of interest in many branches of science (physics, mechanics, chemistry, biology, medical science, mathematics, and so on). Understanding complex fluids is viewed as one of the biggest challenge of the present century. This synthesis will provide a simple introduction to the topic, summarize the main contribution of this issue, and list major open questions in this field. To cite this article: C. Misbah, C. R. Physique 10 (2009).
CSR Fields: Direct Numerical Solution of the Maxwell___s Equation
Novokhatski, A.; /SLAC
2011-06-22
We discuss the properties of the coherent electromagnetic fields of a very short, ultra-relativistic bunch in a rectangular vacuum chamber inside a bending magnet. The analysis is based on the results of a direct numerical solution of Maxwell's equations together with Newton's equations. We use a new dispersion-free time-domain algorithm which employs a more efficient use of finite element mesh techniques and hence produces self-consistent and stable solutions for very short bunches. We investigate the fine structure of the CSR fields including coherent edge radiation. This approach should be useful in the study of existing and future concepts of particle accelerators and ultrafast coherent light sources. The coherent synchrotron radiation (CSR) fields have a strong action on the beam dynamics of very short bunches, which are moving in the bends of all kinds of magnetic elements. They are responsible for additional energy loss and energy spread; micro bunching and beam emittance growth. These fields may bound the efficiency of damping rings, electron-positron colliders and ultrafast coherent light sources, where high peak currents and very short bunches are envisioned. This is relevant to most high-brightness beam applications. On the other hand these fields together with transition radiation fields can be used for beam diagnostics or even as a powerful resource of THz radiation. A history of the study of CSR and a good collection of references can be found in [1]. Electromagnetic theory suggests several methods on how to calculate CSR fields. The most popular method is to use Lienard-Wiechert potentials. Other approach is to solve numerically the approximate equations, which are a Schrodinger type equation. These numerical methods are described in [2]. We suggest that a direct solution of Maxwell's equations together with Newton's equations can describe the detailed structure of the CSR fields [3].
On the Correct Analysis of the Maxwell Distribution
NASA Astrophysics Data System (ADS)
Kalanov, Temur Z.
2006-04-01
The critical analysis of the Maxwell distribution is proposed. The main results of the analysis are as follows. (1) As is known, an experimental device for studying the Maxwell distribution consists of the following basic physical subsystems: (a) ideal molecular gas enclosed in a vessel (gas is in the equilibrium state); (b) molecule beam which is emitted from the small aperture of the vessel (the small aperture is a stochastic source of quantum particles). (2) The energy of the molecule of the beam does not represent random quantity, since molecules does not collide with each other. In this case, only the set of the monoenergetic molecules emitted by the stochastic source is a random quantity. This set is called a quantum gas. The probability pk that the quantum gas has the energy Enk is given by the Gibbs quantum canonical distribution: pk=p0,,-Enk / Enk T) . - T), k=0,;1,; where k is the number of molecules with energy En; T is temperature of the molecule in the vessel. (3) The average number of the molecules with energyEn represents the Planck distribution function: f=∑k=0^∞kpk ≡f(Planck). (4) In classical case, the expression Enf(Planck) represents the Maxwell distribution function: f(Maxwell)˜En,(Planck)˜v^2,;(-mv^2 / mv^2 2T) . - 2T). Consequently, the generally accepted statement that the Maxwell distribution function describes gas enclosed in a vessel is a logical error.
TWO-GRID METHODS FOR MAXWELL EIGENVALUE PROBLEMS
ZHOU, J.; HU, X.; ZHONG, L.; SHU, S.; CHEN, L.
2015-01-01
Two new two-grid algorithms are proposed for solving the Maxwell eigenvalue problem. The new methods are based on the two-grid methodology recently proposed by Xu and Zhou [Math. Comp., 70 (2001), pp. 17–25] and further developed by Hu and Cheng [Math. Comp., 80 (2011), pp. 1287–1301] for elliptic eigenvalue problems. The new two-grid schemes reduce the solution of the Maxwell eigenvalue problem on a fine grid to one linear indefinite Maxwell equation on the same fine grid and an original eigenvalue problem on a much coarser grid. The new schemes, therefore, save total computational cost. The error estimates reveals that the two-grid methods maintain asymptotically optimal accuracy, and the numerical experiments presented confirm the theoretical results. PMID:26190866
Maxwell-Chern-Simons theory with a boundary
NASA Astrophysics Data System (ADS)
Blasi, A.; Maggiore, N.; Magnoli, N.; Storace, S.
2010-08-01
The Maxwell-Chern-Simons (MCS) theory with a planar boundary is considered. The boundary is introduced according to Symanzik's basic principles of locality and separability. A method of investigation is proposed, which, avoiding the straight computation of correlators, is appealing for situations where the computation of propagators, modified by the boundary, becomes quite complex. For the MCS theory, the outcome is that a unique solution exists, in the form of chiral conserved currents, satisfying a Kač-Moody algebra, whose central charge does not depend on the Maxwell term.
Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations.
Bruckner, Florian; Vogler, Christoph; Bergmair, Bernhard; Huber, Thomas; Fuger, Markus; Suess, Dieter; Feischl, Michael; Fuehrer, Thomas; Page, Marcus; Praetorius, Dirk
2013-10-01
Magnetostatic Maxwell equations and the Landau-Lifshitz-Gilbert (LLG) equation are combined to a multiscale method, which allows to extend the problem size of traditional micromagnetic simulations. By means of magnetostatic Maxwell equations macroscopic regions can be handled in an averaged and stationary sense, whereas the LLG allows to accurately describe domain formation as well as magnetization dynamics in some microscopic subregions. The two regions are coupled by means of their strayfield and the combined system is solved by an optimized time integration scheme. PMID:24092951
Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations☆
Bruckner, Florian; Vogler, Christoph; Bergmair, Bernhard; Huber, Thomas; Fuger, Markus; Suess, Dieter; Feischl, Michael; Fuehrer, Thomas; Page, Marcus; Praetorius, Dirk
2013-01-01
Magnetostatic Maxwell equations and the Landau–Lifshitz–Gilbert (LLG) equation are combined to a multiscale method, which allows to extend the problem size of traditional micromagnetic simulations. By means of magnetostatic Maxwell equations macroscopic regions can be handled in an averaged and stationary sense, whereas the LLG allows to accurately describe domain formation as well as magnetization dynamics in some microscopic subregions. The two regions are coupled by means of their strayfield and the combined system is solved by an optimized time integration scheme. PMID:24092951
Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations
NASA Astrophysics Data System (ADS)
Bruckner, Florian; Vogler, Christoph; Bergmair, Bernhard; Huber, Thomas; Fuger, Markus; Suess, Dieter; Feischl, Michael; Fuehrer, Thomas; Page, Marcus; Praetorius, Dirk
2013-10-01
Magnetostatic Maxwell equations and the Landau-Lifshitz-Gilbert (LLG) equation are combined to a multiscale method, which allows to extend the problem size of traditional micromagnetic simulations. By means of magnetostatic Maxwell equations macroscopic regions can be handled in an averaged and stationary sense, whereas the LLG allows to accurately describe domain formation as well as magnetization dynamics in some microscopic subregions. The two regions are coupled by means of their strayfield and the combined system is solved by an optimized time integration scheme.
Maxwell boundary condition and velocity dependent accommodation coefficient
Struchtrup, Henning
2013-11-15
A modification of Maxwell's boundary condition for the Boltzmann equation is developed that allows to incorporate velocity dependent accommodation coefficients into the microscopic description. As a first example, it is suggested to consider the wall-particle interaction as a thermally activated process with three parameters. A simplified averaging procedure leads to jump and slip boundary conditions for hydrodynamics. Coefficients for velocity slip, temperature jump, and thermal transpiration flow are identified and compared with those resulting from the original Maxwell model and the Cercignani-Lampis model. An extension of the model leads to temperature dependent slip and jump coefficients.
Hamiltonian time integrators for Vlasov-Maxwell equations
He, Yang; Xiao, Jianyuan; Zhang, Ruili; Liu, Jian; Qin, Hong; Sun, Yajuan
2015-12-15
Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature.
Generalized dilaton-Maxwell cosmic string and wall solutions
NASA Astrophysics Data System (ADS)
Morris, John R.
2006-09-01
The class of static solutions found by Gibbons and Wells for dilaton-electrodynamics in flat spacetime, which describe nontopological strings and walls that trap magnetic flux, is extended to a class of dynamical solutions supporting arbitrarily large, nondissipative traveling waves, using techniques previously applied to global and local topological defects. These solutions can then be used in conjunction with S-duality to obtain more general solitonic solutions for various axidilaton-Maxwell theories. As an example, a set of dynamical solutions is found for axion, dilaton, and Maxwell fields in low energy heterotic string theory using the SL(2,R) invariance of the equations of motion.
A spinor representation of Maxwell equations and Dirac equation
Vaz, J. Jr.; Rodrigues, W.A. Jr.
1993-02-01
Using the Clifford bundle formalism and starting from the free Maxwell equations dF = {delta}F = 0 we show by writing F = b{psi}{gamma}{sup 1}{gamma}{sup 2}{psi}{sup *}, where {psi} is a Dirac-Hestenes spinor field, that the Dirac-Hestenes equation (which is the representative of the standard Dirac equation in the Clifford bundle over Minkowski spacetime) is equivalent under general assumptions to those free Maxwell equations. We briefly discuss the implications of our findings for the interpretation of quantum mechanics. 15 refs.
Multiparticle quantum Szilard engine with optimal cycles assisted by a Maxwell's demon.
Cai, C Y; Dong, H; Sun, C P
2012-03-01
We present a complete-quantum description of a multiparticle Szilard engine that consists of a working substance and a Maxwell's demon. The demon is modeled as a multilevel quantum system with specific quantum control, and the working substance consists of identical particles obeying Bose-Einstein or Fermi-Dirac statistics. In this description, a reversible scheme to erase the demon's memory by a lower-temperature heat bath is used. We demonstrate that (1) the quantum control of the demon can be optimized for a single-particle Szilard engine so that the efficiency of the demon-assisted thermodynamic cycle could reach the Carnot cycle's efficiency and (2) the low-temperature behavior of the working substance is very sensitive to the quantum statistics of the particles and the insertion position of the partition. PMID:22587045
NASA Astrophysics Data System (ADS)
Faliagas, A. C.
2016-03-01
Maxwell's theory of multicomponent diffusion and subsequent extensions are based on systems of mass and momentum conservation equations. The partial stress tensor, which is involved in these equations, is expressed in terms of the gradients of velocity fields by statistical and continuum mechanical methods. We propose a method for the solution of Maxwell's equations of diffusion coupled with Müller's expression for the partial stress tensor. The proposed method consists in a singular perturbation process, followed by a weak (finite element) analysis of the resulting PDE systems. The singularity involved in the obtained equations was treated by a special technique, by which lower-order systems were supplemented by proper combinations of higher-order equations. The method proved particularly efficient for the solution of the Maxwell-Müller system, eventually reducing the number of unknown fields to that of the classical Navier-Stokes/Fick system. It was applied to the classical Stefan tube problem and the Hagen-Poiseuille flow in a hollow-fiber membrane tube. Numerical results for these problems are presented, and compared with the Navier-Stokes/Fick approximation. It is shown that the 0-th order term of the Maxwell-Müller equations differs from a properly formulated Navier-Stokes/Fick system, by a numerically insignificant amount. Numerical results for 1st-order terms indicate a good agreement of the classical approximation (with properly formulated Navier-Stokes and Fick's equations) with the Maxwell-Müller system, in the studied cases.
Colliding superposed waves in the Einstein-Maxwell theory
Halilsoy, M.
1989-04-15
We reformulate the initial data on the characteristic surface for colliding waves in the Einstein-Maxwell theory. This approach takes into account the superposition principle for gravitational and electromagnetic waves. Finding exact solutions for colliding superposed waves happens to be a rather challenging problem.
Exact Faraday rotation in the cylindrical Einstein-Maxwell waves
Arafah, M.R.; Fakioglu, S.; Halilsoy, M. )
1990-07-15
We obtain the exact behavior of the cross-polarized cylindrical Einstein-Maxwell waves that generalizes the well-known Einstein-Rosen waves. In the presence of the second mode of polarization the outgoing waves interact with the incoming ones to exhibit an analogous effect of the Faraday rotation.
Comparing Teaching Approaches about Maxwell's Displacement Current
ERIC Educational Resources Information Center
Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício
2014-01-01
Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment…
Maxwell-Higgs equation on higher dimensional static curved spacetimes
Mulyanto; Akbar, Fiki Taufik Gunara, Bobby Eka
2015-09-30
In this paper we consider a class of solutions of Maxwell-Higgs equation in higher dimensional static curved spacetimes called Schwarzchild de-Sitter spacetimes. We obtain the general form of the electric fields and magnetic fields in background Schwarzchild de-Sitter spacetimes. However, determining the interaction between photons with the Higgs scalar fields is needed further studies.
Radiation and Maxwell Stress Stabilization of Liquid Bridges
NASA Technical Reports Server (NTRS)
Marr-Lyon, M. J.; Thiessen, D. B.; Blonigen, F. J.; Marston, P. L.
1999-01-01
The use of both acoustic radiation stress and the Maxwell stress to stabilize liquid bridges is reported. Acoustic radiation stress arises from the time-averaged acoustic pressure at the surface of an object immersed in a sound field. Both passive and active acoustic stabilization schemes as well as an active electrostatic method are examined.
A geometric description of Maxwell field in a Kerr spacetime
NASA Astrophysics Data System (ADS)
Jezierski, Jacek; Smołka, Tomasz
2016-06-01
We consider the Maxwell field in the exterior of a Kerr black hole. For this system, we propose a geometric construction of generalized Klein–Gordon equation called Fackerell–Ipser equation. Our model is based on conformal Yano–Killing tensor (CYK tensor). We present non-standard properties of CYK tensors in the Kerr spacetime which are useful in electrodynamics.
Soliton solutions of coupled Maxwell-Bloch equations
NASA Astrophysics Data System (ADS)
Chakravarty, S.
2016-03-01
In this paper we study the soliton solutions of the coupled Maxwell-Bloch equations which describe pulse propagation in an active optical medium with coherent three-level atomic transitions and inhomogeneous broadening. The soliton solutions and polarization shifts due to soliton interactions are investigated. An infinite set of conservation laws as well as the soliton trace formulae are derived.
Galilean symmetry of Maxwell's equations in classical electrodynamics
NASA Astrophysics Data System (ADS)
Kotel'Nikov, G. A.
1985-08-01
It is shown that the Galilean group, like the Lorentz group, is a group of exact symmetry of Maxwell's equation. The Galilean group differs in that, while the field transformations are linear and global in the relativistic case, they are nonlinear in the Galilean and, generally speaking, depend on the coordinates of the event through some weight functions.
Entanglement entropy of a Maxwell field on the sphere
NASA Astrophysics Data System (ADS)
Casini, Horacio; Huerta, Marina
2016-05-01
We compute the logarithmic coefficient of the entanglement entropy on a sphere for a Maxwell field in d =3 +1 dimensions. In spherical coordinates the problem decomposes into one-dimensional ones along the radial coordinate for each angular momentum. We show that the entanglement entropy of a Maxwell field is equivalent to one of two identical massless scalars from which the mode of l =0 has been removed. This shows the relation clogM=2 (clogS-clogSl =0) between the logarithmic coefficient in the entropy for a Maxwell field clogM , the one for a d =3 +1 massless scalar clogS , and the logarithmic coefficient clogSl =0 for a d =1 +1 scalar with a Dirichlet boundary condition at the origin. Using the accepted values for these coefficients clogS=-1 /90 and clogSl =0=1 /6 , we get clogM=-16 /45 , which coincides with Dowker's calculation, but does not match the coefficient -31/45 in the trace anomaly for a Maxwell field. We have numerically evaluated these three numbers clogM , clogS and clogSl =0, verifying the relation, as well as checked that they coincide with the corresponding logarithmic term in mutual information of two concentric spheres.
Maxwell-Vlasov equations as a continuous Hamiltonian system
Morrison, P.J.
1980-11-01
The well-known Maxwell-Vlasov equations that describe a collisionless plasma are cast into Hamiltonian form. The dynamical variables are the physical although noncanonical variables E, B, and f. We present a Poisson bracket which acts on these variables and the energy functional to produce the equations of motion.
Maxwell-Vlasov equations as a continuous Hamiltonian system
Morrison, P.J.
1980-09-01
The well-known Maxwell-Vlasov equations that describe a collisionless plasma are cast into Hamiltonian form. The dynamical variables are the physical although noncanonical variables E, B and f. We present a Poisson bracket which acts on these variables and the energy functional to produce the equations of motion.
Mechanic-Like Resonance in the Maxwell-Bloch Equations
ERIC Educational Resources Information Center
Meziane, Belkacem
2008-01-01
We show that, in their unstable regime of operation, the "Maxwell-Bloch" equations that describe light-matter interactions inside a bad-cavity-configured laser carry the same resonance properties as any externally driven mechanic or electric oscillator. This finding demonstrates that the nonlinearly coupled laser equations belong to the same…
How to Obtain the Covariant Form of Maxwell's Equations from the Continuity Equation
ERIC Educational Resources Information Center
Heras, Jose A.
2009-01-01
The covariant Maxwell equations are derived from the continuity equation for the electric charge. This result provides an axiomatic approach to Maxwell's equations in which charge conservation is emphasized as the fundamental axiom underlying these equations.
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-02
... Archaeology, Maxwell Museum of Anthropology, MSC01 1050, University of New Mexico, Albuquerque, NM 87131... should contact David Phillips, Curator of Archaeology, Maxwell Museum of Anthropology, MSC01...
Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory
ERIC Educational Resources Information Center
Tweney, Ryan D.
2011-01-01
James Clerk Maxwell "translated" Michael Faraday's experimentally-based field theory into the mathematical representation now known as "Maxwell's Equations." Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other results in the physics of…
Federal Register 2010, 2011, 2012, 2013, 2014
2012-10-26
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... to be culturally affiliated with the human remains may contact the Maxwell Museum of Anthropology.... Heather Edgar, Maxwell Museum of Anthropology, MSC01 1050, University of New Mexico, Albuquerque, NM...
Maxwell, electromagnetism, and fluid flow in resistive media
NASA Astrophysics Data System (ADS)
Narasimhan, T. N.
Common wisdom has it that Darcy [1856] founded the modern field of fluid flow through porous media with his celebrated 1856 experiment on the steady flow of water through a sand column. For considerable time, Darcy's empirical observation, in conjunction with Fourier's [1807] heat equation, was used to analyze fluid flow in porous media simply by mathematical analogy. Hubbert [1940] is credited with placing Darcy's work on sound hydrodynamic foundations. Among other things, he defined an energy potential, interpreted permeability in the context of balancing impelling and resistive forces, and derived an expression for the refraction of flow lines. In 1856, James Clerk Maxwell constructed a theory for the flow of an incompressible fluid in a resistive medium as a metaphor for comprehending the emerging field of electromagnetism [Maxwell, 1890].
Computational modeling of femtosecond optical solitons from Maxwell's equations
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Taflove, Allen; Joseph, Rose M.; Hagness, Susan C.
1992-01-01
An algorithm is developed that permits the direct time integration of full-vector nonlinear Maxwell's equations. This capability permits the modeling of both linear and nonlinear instantaneous and dispersive effects in the electric polarization in material media. The modeling of the optical carrier is retained. The fundamental innovation is to notice that it is possible to treat the linear and nonlinear convolution integrals, which describe the dispersion, as new dependent variables. A coupled system of nonlinear second-order ordinary differential equations can then be derived for the linear and nonlinear convolution integrals, by differentiating them in the time domain. These equations, together with Maxwell's equations, are solved to determine the electromagnetic fields in nonlinear dispersive media. Results are presented of calculations in one dimension of the propagation and collision of femtosecond electromagnetic solitons that retain the optical carrier, taking into account as the Kerr and Raman interactions.
Experimental violation of Tsirelson's bound by Maxwell fields
NASA Astrophysics Data System (ADS)
Sandeau, N.; Akhouayri, H.; Matzkin, A.; Durt, T.
2016-05-01
In analogy with quantum optics it is possible to impose nonseparability between different degrees of freedom of an optical beam. The resulting correlations between these degrees of freedom can be investigated with correlations functions traditionally employed in quantum mechanics, such as the well-known Clauser-Horne-Shimony-Holt (CHSH) correlation function. In this paper we present results achieving a maximal violation of Tsirelson's bound on CHSH correlations between spatial and polarization degrees of freedom of classical (Maxwell) fields. We describe the theoretical method, based on the realization of a nonunitary gate, and then proceed to its experimental implementation carried out with classical optical techniques. Our approach relies on the realization at the level of classical Maxwell fields of a so-called POVM (positive operator valued measure) which is traditionally discussed in the realm of quantum physics.
Class of Einstein-Maxwell-dilaton-axion space-times
Matos, Tonatiuh; Miranda, Galaxia; Sanchez-Sanchez, Ruben; Wiederhold, Petra
2009-06-15
We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-dilaton-axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions Sp(4,R){approx}O(5). We find solutions of the EMDA field equations for the one- and two-dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalize the Schwarzschild solution with dilaton, axion, and electromagnetic fields.
Algorithm development for Maxwell's equations for computational electromagnetism
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.
1990-01-01
A new algorithm has been developed for solving Maxwell's equations for the electromagnetic field. It solves the equations in the time domain with central, finite differences. The time advancement is performed implicitly, using an alternating direction implicit procedure. The space discretization is performed with finite volumes, using curvilinear coordinates with electromagnetic components along those directions. Sample calculations are presented of scattering from a metal pin, a square and a circle to demonstrate the capabilities of the new algorithm.
MAXWELL-LORENTZ EQUATIONS IN GENERAL FRENET-SERRET COORDINATES
Kabel, A
2004-09-17
We consider the trajectory of a charged particle in an arbitrary external magnetic field. A local orthogonal coordinate system is given by the tangential, curvature, and torsion vectors. We write down Maxwell's equations in this coordinate system. The resulting partial differential equations for the magnetic fields fix conditions among its local multipole components, which can be viewed as a generalization of the usual multipole expansion of the fields of magnetic elements.
Charged Particle Tunnels from the Einstein-Maxwell Black Hole
NASA Astrophysics Data System (ADS)
Chen, Deyou; Yang, Shuzheng
Considering the self-gravitation interaction and the unfixed background space-time, we study the Hawking radiation of the Einstein-Maxwell-Dilaton-Axion (EMDA) black hole by the radial geodesic method and the Hamilton-Jacobi method. Both sets of results agree with Parikh and Wilczek's and show that the actual radiation spectrum deviates from the purely thermal one and the tunneling probability is related to the change of Bekenstein-Hawking entropy, which satisfies an underlying unitary theory.
Transient growth in stable linearized Vlasov-Maxwell plasmas
NASA Astrophysics Data System (ADS)
Podesta, J. J.
2010-12-01
Large amplitude transient growth of kinetic scale perturbations in stable collisionless magnetized plasmas has recently been demonstrated using a linearized Landau fluid model. Initial perturbations with lengthscales of the order of the ion gyroradius were shown to have transient timescales that in some cases were long compared to the ion gyroperiod, Ωit≫1. Moreover, it was suggested that such perturbations are not rare but instead form a large class within the set of all possible initial conditions. For collisionless plasmas, the Vlasov-Maxwell equations provide a more complete description of kinetic physics and the existence of transient growth of solutions for the linearized Vlasov-Maxwell system is an interesting question. The existence of transient growth of solutions is demonstrated here for a special case of the Vlasov-Maxwell equations, namely, the one dimensional Vlasov-Poisson system. The analysis is different from the standard approach of nonmodal analysis since the initial value problem is described by a Volterra integral equation of the second kind, reflecting the fact that the time evolution of the system depends on the memory of the state from time zero through time t. For the case of a thermal equilibrium plasma, it is shown how initial conditions may be constructed to obtain solutions that grow linearly in time; the duration of this growth is the time required for a thermal electron to traverse the wavelength of the initial perturbation, a timescale that can last for many plasma periods 2π/ωpe, thus demonstrating the existence of transient growth of solutions for the linearized Vlasov-Poisson system. The results suggest that the phenomenon of transient growth may be a common feature of the linearized Vlasov-Maxwell system as well as for Landau fluid models.
Maxwell electromagnetism as an emergent phenomenon in condensed matter.
Rehn, J; Moessner, R
2016-08-28
The formulation of a complete theory of classical electromagnetism by Maxwell is one of the milestones of science. The capacity of many-body systems to provide emergent mini-universes with vacua quite distinct from the one we inhabit was only recognized much later. Here, we provide an account of how simple systems of localized spins manage to emulate Maxwell electromagnetism in their low-energy behaviour. They are much less constrained by symmetry considerations than the relativistically invariant electromagnetic vacuum, as their substrate provides a non-relativistic background with even translational invariance broken. They can exhibit rich behaviour not encountered in conventional electromagnetism. This includes the existence of magnetic monopole excitations arising from fractionalization of magnetic dipoles; as well as the capacity of disorder, by generating defects on the lattice scale, to produce novel physics, as exemplified by topological spin glassiness or random Coulomb magnetism.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. PMID:27458263
An analysis of peristaltic motion of compressible convected Maxwell fluid
NASA Astrophysics Data System (ADS)
Abbasi, A.; Ahmad, I.; Ali, N.; Hayat, T.
2016-01-01
This paper presents a theoretical study for peristaltic flow of a non-Newtonian compressible Maxwell fluid through a tube of small radius. Constitutive equation of upper convected Maxwell model is used for the non-Newtonian rheology. The governing equations are modeled for axisymmetric flow. A regular perturbation method is used for the radial and axial velocity components up to second order in dimensionless amplitude. Exact expressions for the first-order radial and axial velocity components are readily obtained while second-order mean axial velocity component is obtained numerically due to presence of complicated non-homogenous term in the corresponding equation. Based on the mean axial velocity component, the net flow rate is calculated through numerical integration. Effects of various emerging parameters on the net flow rate are discussed through graphical illustrations. It is observed that the net flow rate is positive for larger values of dimensionless relaxation time λ1. This result is contrary to that of reported by [D. Tsiklauri and I. Beresnev, "Non-Newtonian effects in the peristaltic flow of a Maxwell fluid," Phys. Rev. E. 64 (2001) 036303]." i.e. in the extreme non-Newtonian regime, there is a possibility of reverse flow.
The Maxwell-Stefan description of binary diffusion
NASA Astrophysics Data System (ADS)
Bringuier, E.
2013-09-01
The paper deals with interdiffusion in a two-component fluid (also called binary or mutual diffusion) near isothermal equilibrium. The historical approach of Maxwell and Stefan, developed in an ideal gaseous mixture, is updated by introducing the chemical potentials of the components subsequently devised by Gibbs, which enable one to implement the Maxwell-Stefan picture of interdiffusion in an arbitrary fluid mixture. The pattern of the interdiffusion law reduces to Fick's in the high-dilution limit, but care should be taken of the reference frame in which the laws of diffusion are written. For a third-year university student, the assets of the modern Maxwell-Stefan description, besides its simplicity and inborn connection with thermodynamics, are (i) manifest Galilean invariance (the principle of relativity of motion); (ii) straightforward compatibility with fluid dynamics; and (iii) simple generalization to a multicomponent fluid in future, graduate-level studies. The value of the mutual-diffusion coefficient, which is not given by the macroscopic description, was calculated by Stefan in an ideal gaseous mixture and found to be independent of the composition. That independence is often observed in real mixtures and is taken as evidence against the mean-free-path account of diffusion. Yet a mixture of components of disparate masses shows a dependence of the mutual-diffusion coefficient on its composition, and we examine why Stefan's calculation can be invalid for this mixture.
Druskin, V.; Knizhnerman, L.
1994-12-31
The authors solve the Cauchy problem for an ODE system Au + {partial_derivative}u/{partial_derivative}t = 0, u{vert_bar}{sub t=0} = {var_phi}, where A is a square real nonnegative definite symmetric matrix of the order N, {var_phi} is a vector from R{sup N}. The stiffness matrix A is obtained due to semi-discretization of a parabolic equation or system with time-independent coefficients. The authors are particularly interested in large stiff 3-D problems for the scalar diffusion and vectorial Maxwell`s equations. First they consider an explicit method in which the solution on a whole time interval is projected on a Krylov subspace originated by A. Then they suggest another Krylov subspace with better approximating properties using powers of an implicit transition operator. These Krylov subspace methods generate optimal in a spectral sense polynomial approximations for the solution of the ODE, similar to CG for SLE.
Algorithmic information content, Church-Turing thesis, physical entropy, and Maxwell's demon
Zurek, W.H.
1990-01-01
Measurements convert alternative possibilities of its potential outcomes into the definiteness of the record'' -- data describing the actual outcome. The resulting decrease of statistical entropy has been, since the inception of the Maxwell's demon, regarded as a threat to the second law of thermodynamics. For, when the statistical entropy is employed as the measure of the useful work which can be extracted from the system, its decrease by the information gathering actions of the observer would lead one to believe that, at least from the observer's viewpoint, the second law can be violated. I show that the decrease of ignorance does not necessarily lead to the lowering of disorder of the measured physical system. Measurements can only convert uncertainty (quantified by the statistical entropy) into randomness of the outcome (given by the algorithmic information content of the data). The ability to extract useful work is measured by physical entropy, which is equal to the sum of these two measures of disorder. So defined physical entropy is, on the average, constant in course of the measurements carried out by the observer on an equilibrium system. 27 refs., 6 figs.
Three-dimensional asymptotically flat Einstein-Maxwell theory
NASA Astrophysics Data System (ADS)
Barnich, Glenn; Lambert, Pierre-Henry; Mao, Pujian
2015-12-01
Three-dimensional Einstein-Maxwell theory with non-trivial asymptotics at null infinity is solved. The symmetry algebra is a Virasoro-Kac-Moody type algebra that extends the bms3 algebra of the purely gravitational case. Solution space involves logarithms and provides a tractable example of a polyhomogeneous solution space. The associated surface charges are non-integrable and non-conserved due to the presence of electromagnetic news. As in the four-dimensional purely gravitational case, their algebra involves a field-dependent central charge.
Consequences of Moduli Stabilization in the Einstein-Maxwell Landscape
NASA Astrophysics Data System (ADS)
Asensio, César; Seguí, Antonio
2013-01-01
A toy landscape sector is introduced as a compactification of the Einstein-Maxwell model on a product of two spheres. Features of the model include moduli stabilization, a distribution of the effective cosmological constant of the dimensionally reduced 1+1 spacetime, which is different from the analogous distribution of the Bousso-Polchinski landscape, and the absence of the so-called α* problem. This problem arises when the Kachru-Kallosh-Linde-Trivedi stabilization mechanism is naively applied to the states of the Bousso-Polchinski landscape. The model also contains anthropic states, which can be readily constructed without needing any fine-tuning.
Perturbative charged rotating 5D Einstein-Maxwell black holes
NASA Astrophysics Data System (ADS)
Navarro-Lérida, Francisco
2010-12-01
We present perturbative charged rotating 5D Einstein-Maxwell black holes with spherical horizon topology. The electric charge Q is the perturbative parameter, the perturbations being performed up to 4th order. The expressions for the relevant physical properties of these black holes are given. The gyromagnetic ratio g, in particular, is explicitly shown to be non-constant in higher order, and thus to deviate from its lowest order value, g = 3. Comparison of the perturbative analytical solutions with their non-perturbative numerical counterparts shows remarkable agreement.
A Maxwell Demon Model Connecting Information and Thermodynamics
NASA Astrophysics Data System (ADS)
Peng, Pei-Yan; Duan, Chang-Kui
2016-08-01
In the past decade several theoretical Maxwell's demon models have been proposed exhibiting effects such as refrigerating, doing work at the cost of information, and some experiments have been done to realise these effects. Here we propose a model with a two level demon, information represented by a sequence of bits, and two heat reservoirs. Which reservoir the demon interact with depends on the bit. If information is pure, one reservoir will be refrigerated, on the other hand, information can be erased if temperature difference is large. Genuine examples of such a system are discussed.
SCUBA: A Camera for the James Clerk Maxwell Telescope
NASA Astrophysics Data System (ADS)
Gear, W. K.; Cunningham, C. R.
We briefly describe the Submillimetre Common User Bolometer Array which has been built and is currently being tested at Edinburgh for the James Clerk Maxwell Telescope in Hawaii. This instrument will define the state-of-the-art in submillimetre continuum astronomical instrumentation. SCUBA has 2 arrays covering a field of two and a half arcminutes simultaneously in 2 submillimetre bands, plus 3 longer wavelength individual pixels for photometry. The detectors are germanium bolometers cooled to 0.1K with a dilution fridge and all pixels are background-limited.
Demons: Maxwell's demon, Szilard's engine and Landauer's erasure-dissipation
NASA Astrophysics Data System (ADS)
Kish, Laszlo B.; Granqvist, Claes G.; Khatri, Sunil P.; Wen, He
2014-09-01
This talk addressed the following questions in the public debate at HoTPI: (i) energy dissipation limits of switches, memories and control; (ii) whether reversible computers are possible, or does their concept violate thermodynamics; (iii) Szilard's engine, Maxwell's demon and Landauer's principle: corrections to their exposition in the literature; (iv) whether Landauer's erasure-dissipation principle is valid, if the same energy dissipation holds for writing information, or if it is invalid; and (v) whether (non-secure) erasure of memories, or the writing of the same amount of information, dissipates most heat.
Climate Controlled Sedimentation in Maxwell Bay, King George Island, Antarctica
NASA Astrophysics Data System (ADS)
Hass, H.; Kuhn, G.; Wittenberg, N.; Woelfl, A.; Betzler, C.
2012-12-01
Climatic change in Antarctica is strongest over the Antarctic Peninsula where in places the annual mean temperatures increased by 0.5 K per decade through the past 60 years. The impact of this warming trend is clearly visible in the form of retreating glaciers and melting ice sheets, loss of sea ice and strong meltwater discharge into the coastal zone. While it is generally accepted that the rapidity of the present climate change bears a significant anthropogenic aspect, it is not clear whether the effects caused by the warming trend are exceptional and unprecedented or whether the reaction of the environment is similar to that of earlier climate phases such as the Medieval Warm Period (MWP) about 1,000 years ago. One of the major goals of the joint international research project IMCOAST is to investigate the strength of the recent warming trend and its impact on the marine environment of the West Antarctic Peninsula (WAP). The study we present here reveals the Upper Holocene climatic history based on high-resolution sediment cores from Maxwell Bay (King George Island, WAP) and information on the actual processes triggered or altered by the recent warming trend based on sedimentologic and hydroacoustic investigations in Potter Cove, a tributary fjord to Maxwell Bay. Long sediment cores from Maxwell Bay reveal grain-size changes that can be linked to cold and warm phases such as the Little Ice Age (LIA) and the MWP. Generally, warm phases are finer grained than cold phases as a result of longer and stronger melting processes during the warm phases. It is suggested that meltwater plumes carry fine-grained sediment out of the surrounding fjords into Maxwell Bay where it settles in suitable areas to produce sediments that have a modal value around 16 μm. This mode is largely absent in sediments deposited during e.g. the LIA. However, post LIA sediments are depleted in the 16 μm-mode sediment suggesting slightly different conditions during the last century. One reason
Derivation of special relativity from Maxwell and Newton.
Dunstan, D J
2008-05-28
Special relativity derives directly from the principle of relativity and from Newton's laws of motion with a single undetermined parameter, which is found from Faraday's and Ampère's experimental work and from Maxwell's own introduction of the displacement current to be the -c(-2) term in the Lorentz transformations. The axiom of the constancy of the speed of light is quite unnecessary. The behaviour and the mechanism of the propagation of light are not at the foundations of special relativity. PMID:18218595
SIM(1)-VSR Maxwell-Chern-Simons electrodynamics
NASA Astrophysics Data System (ADS)
Bufalo, R.
2016-06-01
In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM (1)-VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and healthy departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges is derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.
Time-harmonic Maxwell equations with asymptotically linear polarization
NASA Astrophysics Data System (ADS)
Qin, Dongdong; Tang, Xianhua
2016-06-01
This paper is concerned with the following time-harmonic semilinear Maxwell equation: nabla× (nabla× u)+λ u=f(x,u), &in Ω ν × u=0, &on partialΩ, where {Ωsubset {R}3} is a bounded, convex domain and {ν : partial Ωto {R}3} is the exterior normal. Motivated by recent work of Bartsch and Mederski and based on some observations and new techniques, we study above equation by developing the generalized Nehari manifold method. Particularly, existence of ground-state solutions of Nehari-Pankov type for the equation is established with asymptotically linear nonlinearity.
The Remote Maxwell Demon as Energy Down-Converter
NASA Astrophysics Data System (ADS)
Hossenfelder, S.
2016-04-01
It is demonstrated that Maxwell's demon can be used to allow a machine to extract energy from a heat bath by use of information that is processed by the demon at a remote location. The model proposed here effectively replaces transmission of energy by transmission of information. For that we use a feedback protocol that enables a net gain by stimulating emission in selected fluctuations around thermal equilibrium. We estimate the down conversion rate and the efficiency of energy extraction from the heat bath.
Role of measurement-feedback separation in autonomous Maxwell's demons
NASA Astrophysics Data System (ADS)
Shiraishi, Naoto; Ito, Sosuke; Kawaguchi, Kyogo; Sagawa, Takahiro
2015-04-01
We introduce an information heat engine that is autonomous (i.e., without any time-dependent parameter) but has separated measurement and feedback processes. This model serves as a bridge between different types of information heat engines inspired by Maxwell's demon; from the original Szilard-engine type systems to the autonomous demonic setups. By analyzing our model on the basis of a general framework introduced in our previous paper (Shiraishi and Sagawa 2015 Phys. Rev. E 91 012130), we clarify the role of the separation of measurement and feedback in the integral fluctuation theorems.
How an autonomous quantum Maxwell demon can harness correlated information
NASA Astrophysics Data System (ADS)
Chapman, Adrian; Miyake, Akimasa
2015-12-01
We study an autonomous quantum system which exhibits refrigeration under an information-work trade-off like a Maxwell demon. The system becomes correlated as a single "demon" qubit interacts sequentially with memory qubits while in contact with two heat reservoirs of different temperatures. Using strong subadditivity of the von Neumann entropy, we derive a global Clausius inequality to show thermodynamic advantages from access to correlated information. It is demonstrated, in a matrix product density operator formalism, that our demon can simultaneously realize refrigeration against a thermal gradient and erasure of information from its memory, which is impossible without correlations. The phenomenon can be even enhanced by the presence of quantum coherence.
Light wave propagation through a dilaton-Maxwell domain wall
NASA Astrophysics Data System (ADS)
Morris, J. R.; Schulze-Halberg, A.
2015-10-01
We consider the propagation of electromagnetic waves through a dilaton-Maxwell domain wall of the type introduced by Gibbons and Wells [G. W. Gibbons and C. G. Wells, Classical and Quantum Gravity 11, 2499 (1994)]. It is found that if such a wall exists within our observable Universe, it would be absurdly thick, or else have a magnetic field in its core which is much stronger than observed intergalactic fields. We conclude that it is highly improbable that any such wall is physically realized.
By design: James Clerk Maxwell and the evangelical unification of science.
Stanley, Matthew
2012-03-01
James Clerk Maxwell's electromagnetic theory famously unified many of the Victorian laws of physics. This essay argues that Maxwell saw a deep theological significance in the unification of physical laws. He postulated a variation on the design argument that focused on the unity of phenomena rather than Paley's emphasis on complexity. This argument of Maxwell's is shown to be connected to his particular evangelical religious views. His evangelical perspective provided encouragement for him to pursue a unified physics that supplemented his other philosophical, technical and social influences. Maxwell's version of the argument from design is also contrasted with modern 'intelligent-design' theory. PMID:22702031
Einstein-Maxwell-Anti-de-Sitter spinning solitons
NASA Astrophysics Data System (ADS)
Herdeiro, Carlos; Radu, Eugen
2016-06-01
Electrostatics on global Anti-de-Sitter (AdS) spacetime is sharply different from that on global Minkowski spacetime. It admits a multipolar expansion with everywhere regular, finite energy solutions, for every multipole moment except the monopole [1]. A similar statement holds for global AdS magnetostatics. We show that everywhere regular, finite energy, electric plus magnetic fields exist on AdS in three distinct classes: (I) with non-vanishing total angular momentum J; (II) with vanishing J but non-zero angular momentum density, Tφt ; (III) with vanishing J and Tφt . Considering backreaction, these configurations remain everywhere smooth and finite energy, and we find, for example, Einstein-Maxwell-AdS solitons that are globally - Type I - or locally (but not globally) - Type II - spinning. This backreaction is considered first perturbatively, using analytical methods and then non-perturbatively, by constructing numerical solutions of the fully non-linear Einstein-Maxwell-AdS system. The variation of the energy and total angular momentum with the boundary data is explicitly exhibited for one example of a spinning soliton.
Application of Block Krylov Subspace Spectral Methods to Maxwell's Equations
Lambers, James V.
2009-10-08
Ever since its introduction by Kane Yee over forty years ago, the finite-difference time-domain (FDTD) method has been a widely-used technique for solving the time-dependent Maxwell's equations. This paper presents an alternative approach to these equations in the case of spatially-varying electric permittivity and/or magnetic permeability, based on Krylov subspace spectral (KSS) methods. These methods have previously been applied to the variable-coefficient heat equation and wave equation, and have demonstrated high-order accuracy, as well as stability characteristic of implicit time-stepping schemes, even though KSS methods are explicit. KSS methods for scalar equations compute each Fourier coefficient of the solution using techniques developed by Gene Golub and Gerard Meurant for approximating elements of functions of matrices by Gaussian quadrature in the spectral, rather than physical, domain. We show how they can be generalized to coupled systems of equations, such as Maxwell's equations, by choosing appropriate basis functions that, while induced by this coupling, still allow efficient and robust computation of the Fourier coefficients of each spatial component of the electric and magnetic fields. We also discuss the implementation of appropriate boundary conditions for simulation on infinite computational domains, and how discontinuous coefficients can be handled.
Fundamental Physical Basis for Maxwell-Heaviside Gravitomagnetism
NASA Astrophysics Data System (ADS)
Nyambuya, Golden Gadzirayi
2015-08-01
Gravitomagnetism is universally and formally recognised in contemporary physics as being the linear first-order approximation of Einstein's field equations emerging from the General Theory of Relativity (GTR). Herein, we argue that, as has been done by others in the past, gravitomagnetism can be viewed as a fully-fledged independent theory of gravitomagnetism that can be divorced from Professor Einstein's GTR. The gravitomagnetic theory whose exposition we give herein is exactly envisioned by Professor Maxwell and Dr. Heaviside. The once speculative Maxwell-Heaviside Gravitomagnetic theory now finds full justification as a fully fledged theory from Professor José Hera's Existence Theorem which states that all that is needed for there to exist the four Max-well-type field equations is that a mass-current conservation law be obeyed. Our contribution in the present work, if any, is that we demonstrate conclusively that like electromagnetism, the gravitomagnetic phenomenon leads to the prediction of gravitomagnetic waves that travel at the speed of light. Further, we argue that for the gravitational phenomenon, apart from the Newtonian gravitational potential, there are four more potentials and these operate concurrently with the Newtonian potential. At the end of it, it is seen that the present work sets the stage for a very interesting investigation of several gravitational anomalies such as the ponderous Pioneer Anomaly, the vexing Flyby Anomalies, the mysterious Anomalous Rotation Curves of Spiral Galaxies and as well, the possibility of the generation of stellar magnetic fields by rotating gravitational masses.
A Maxwell elasto-brittle rheology for sea ice modelling
NASA Astrophysics Data System (ADS)
Dansereau, Véronique; Weiss, Jérôme; Saramito, Pierre; Lattes, Philippe
2016-07-01
A new rheological model is developed that builds on an elasto-brittle (EB) framework used for sea ice and rock mechanics, with the intent of representing both the small elastic deformations associated with fracturing processes and the larger deformations occurring along the faults/leads once the material is highly damaged and fragmented. A viscous-like relaxation term is added to the linear-elastic constitutive law together with an effective viscosity that evolves according to the local level of damage of the material, like its elastic modulus. The coupling between the level of damage and both mechanical parameters is such that within an undamaged ice cover the viscosity is infinitely large and deformations are strictly elastic, while along highly damaged zones the elastic modulus vanishes and most of the stress is dissipated through permanent deformations. A healing mechanism is also introduced, counterbalancing the effects of damaging over large timescales. In this new model, named Maxwell-EB after the Maxwell rheology, the irreversible and reversible deformations are solved for simultaneously; hence drift velocities are defined naturally. First idealized simulations without advection show that the model reproduces the main characteristics of sea ice mechanics and deformation: strain localization, anisotropy, intermittency and associated scaling laws.
A multigrid method for variable coefficient Maxwell's equations
Jones, J E; Lee, B
2004-05-13
This paper presents a multigrid method for solving variable coefficient Maxwell's equations. The novelty in this method is the use of interpolation operators that do not produce multilevel commutativity complexes that lead to multilevel exactness. Rather, the effects of multilevel exactness are built into the level equations themselves--on the finest level using a discrete T-V formulation, and on the coarser grids through the Galerkin coarsening procedure of a T-V formulation. These built-in structures permit the levelwise use of an effective hybrid smoother on the curl-free near-nullspace components, and these structures permit the development of interpolation operators for handling the curl-free and divergence-free error components separately, with the resulting block diagonal interpolation operator not satisfying multilevel commutativity but having good approximation properties for both of these error components. Applying operator-dependent interpolation for each of these error components leads to an effective multigrid scheme for variable coefficient Maxwell's equations, where multilevel commutativity-based methods can degrade. Numerical results are presented to verify the effectiveness of this new scheme.
Einstein-aether theory with a Maxwell field: General formalism
Balakin, Alexander B.; Lemos, José P.S.
2014-11-15
We extend the Einstein-aether theory to include the Maxwell field in a nontrivial manner by taking into account its interaction with the time-like unit vector field characterizing the aether. We also include a generic matter term. We present a model with a Lagrangian that includes cross-terms linear and quadratic in the Maxwell tensor, linear and quadratic in the covariant derivative of the aether velocity four-vector, linear in its second covariant derivative and in the Riemann tensor. We decompose these terms with respect to the irreducible parts of the covariant derivative of the aether velocity, namely, the acceleration four-vector, the shear and vorticity tensors, and the expansion scalar. Furthermore, we discuss the influence of an aether non-uniform motion on the polarization and magnetization of the matter in such an aether environment, as well as on its dielectric and magnetic properties. The total self-consistent system of equations for the electromagnetic and the gravitational fields, and the dynamic equations for the unit vector aether field are obtained. Possible applications of this system are discussed. Based on the principles of effective field theories, we display in an appendix all the terms up to fourth order in derivative operators that can be considered in a Lagrangian that includes the metric, the electromagnetic and the aether fields.
Maxwell's demon and the management of ignorance in stochastic thermodynamics
NASA Astrophysics Data System (ADS)
Ford, Ian J.
2016-07-01
It is nearly 150 years since Maxwell challenged the validity of the second law of thermodynamics by imagining a tiny creature who could sort the molecules of a gas in such a way that would decrease entropy without exerting any work. The demon has been discussed largely using thought experiments, but it has recently become possible to exert control over nanoscale systems, just as Maxwell imagined, and the status of the second law has become a more practical matter, raising the issue of how measurements manage our ignorance in a way that can be exploited. The framework of stochastic thermodynamics extends macroscopic concepts such as heat, work, entropy and irreversibility to small systems and allows us explore the matter. Some arguments against a successful demon imply a second law that can be suspended indefinitely until we dissipate energy in order to remove the records of his operations. In contrast, under stochastic thermodynamics, the demon fails because on average, more work is performed upfront in making a measurement than can be extracted by exploiting the outcome. This requires us to exclude systems and a demon that evolve under what might be termed self-sorting dynamics, and we reflect on the constraints on control that this implies while still working within a thermodynamic framework.
Holography and hydrodynamics for EMD theory with two Maxwell fields
NASA Astrophysics Data System (ADS)
Smolic, Milena
2013-03-01
We use `generalized dimensional reduction' to relate a specific Einstein-Max-well-Dilaton (EMD) theory, including two gauge fields, three neutral scalars and an axion, to higher-dimensional AdS gravity (with no higher-dimensional Maxwell field). In general, this is a dimensional reduction over compact Einstein spaces in which the dimension of the compact space is continued to non-integral values. Specifically, we perform a non-diagonal Kaluza-Klein (KK) reduction over a torus, involving two KK gauge fields. Our aim is to determine the holographic dictionary and hydrodynamic behaviour of the lower-dimensional theory by performing the generalized dimensional reduction on AdS. We study a specific example of a black brane carrying a wave, whose universal sector is described by gravity coupled to two Maxwell fields, three neutral scalars and an axion, and compute the first order transport coefficients of the dual theory. In these theories {{widehat{ζ}}_s}/widehat{η}<2( {1/( {d-1} )-widehat{c}_s^2} ) , where {{widehat{c}}_s} is the speed of sound, violating a conjectured bound, but an alternative bound is satisfied.
Impact of the integration of a Maxwell-elastic-brittle rheology in NEMO-LIM3
NASA Astrophysics Data System (ADS)
Raulier, Jonathan; Fichefet, Thierry; Legat, Vincent; Weiss, Jérôme; Dansereau, Véronique
2015-04-01
Satellite observations of the Arctic sea ice show the existence of a dense mesh of leads constantly opening and closing over short time scales. Those leads are highly linked to the presence of linear kinematic features which are quasi linear patterns present in the strain field that stretch all across the Arctic basin. Current sea ice models fail to reproduce those linear kinematic features and the observed statistical distribution of deformation rate. In order to refine the physical representation of sea ice dynamics into sea ice models, a new approach has been adopted for the rheology of sea ice. This approach, based on a Maxwell elasto-brittle rheology, is being integrated in the NEMO-LIM3 global ocean-sea ice model (\\url{www.nemo-ocean.eu} ; \\url{www.elic.ucl.ac.be/lim}). In the present study, we examine the influence of the new rheology on the statistical characteristics of the simulated deformation rate and on the ability of the model to reproduce the existence of leads within the ice pack. We will also address the impact of the representation of leads on the fluxes between atmosphere and ocean.
The Covariant Formulation of Maxwell's Equations Expressed in a Form Independent of Specific Units
ERIC Educational Resources Information Center
Heras, Jose A.; Baez, G.
2009-01-01
The covariant formulation of Maxwell's equations can be expressed in a form independent of the usual systems of units by introducing the constants alpha, beta and gamma into these equations. Maxwell's equations involving these constants are then specialized to the most commonly used systems of units: Gaussian, SI and Heaviside-Lorentz by giving…
Federal Register 2010, 2011, 2012, 2013, 2014
2011-09-13
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Museum of Anthropology, University of New Mexico has completed an inventory of human remains, in... itself to be culturally affiliated with the human remains may contact the Maxwell Museum of...
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-02
... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Museum of Anthropology has completed an inventory of human remains in consultation with the appropriate... Maxwell Museum of Anthropology at the address below by September 4, 2012. ADDRESSES: Heather...
NASA Astrophysics Data System (ADS)
Tod, Paul
2007-07-01
Following the technique of Müller zum Hagen (Proc. Camb. Phil. Soc. 67: 415-421, 1970) we show that strictly static and strictly stationary solutions of the Einstein-Maxwell equations are analytic in harmonic coordinates. This holds whether or not the Maxwell field inherits the symmetry.
Maxwell's contrived analogy: An early version of the methodology of modeling
NASA Astrophysics Data System (ADS)
Hon, Giora; Goldstein, Bernard R.
2012-11-01
The term "analogy" stands for a variety of methodological practices all related in one way or another to the idea of proportionality. We claim that in his first substantial contribution to electromagnetism James Clerk Maxwell developed a methodology of analogy which was completely new at the time or, to borrow John North's expression, Maxwell's methodology was a "newly contrived analogue". In his initial response to Michael Faraday's experimental researches in electromagnetism, Maxwell did not seek an analogy with some physical system in a domain different from electromagnetism as advocated by William Thomson; rather, he constructed an entirely artificial one to suit his needs. Following North, we claim that the modification which Maxwell introduced to the methodology of analogy has not been properly appreciated. In view of our examination of the evidence, we argue that Maxwell gave a new meaning to analogy; in fact, it comes close to modeling in current usage.
Marginal and irrelevant disorder in Einstein-Maxwell backgrounds
NASA Astrophysics Data System (ADS)
García-García, Antonio M.; Loureiro, Bruno
2016-03-01
We study analytically the effect of a weak random chemical potential of zero average in an Einstein-Maxwell background. For uncorrelated disorder this perturbation is relevant; however we show that it can become marginal or even irrelevant by tuning disorder correlations. At zero temperature we find that, to leading order in the disorder strength, the correction to the conductivity for irrelevant perturbations vanishes. In the marginal case, in order to renormalize a logarithmic divergence, we carry out a resummation of the perturbative expansion of the metric that leads to a Lifshitz-like geometry in the infrared. Disorder in this case also induces a positive correction to the conductivity. At finite temperature the black hole acquires an effective charge and the thermal conductivity has the expected Drude peak that signals the breaking of translational invariance. However the electric conductivity is not affected by the random chemical potential to leading order in the disorder strength.
Skyrme-Maxwell solitons in 2+1 dimensions
Gladikowski, J.; Piette, B.M.; Schroers, B.J.
1996-01-01
A gauged (2+1)-dimensional version of the Skyrme model is investigated. The gauge group is U(1) and the dynamics of the associated gauge potential is governed by a Maxwell term. In this model there are topologically stable soliton solutions carrying magnetic flux which is not topologically quantized. The properties of static, rotationally symmetric solitons of degree one and two are discussed in detail. It is shown that the electric field of such solutions is necessarily zero. The solitons{close_quote} shape, mass, and magnetic flux depend on the U(1) coupling constant, and this dependence is studied numerically from very weak to very strong coupling. {copyright} {ital 1996 The American Physical Society.}
Structures of general relativity in dilaton-Maxwell electrodynamics
NASA Astrophysics Data System (ADS)
Kechkin, O. V.; Mosharev, P. A.
2016-08-01
It is shown that electro (magneto) static sector of Maxwell’s electrodynamics coupled to the dilaton field in a string theory form possesses the symmetry group of the stationary General Relativity in vacuum. Performing the Ernst formalism, we develope a technique for generation of exact solutions in this modified electrodynamics on the base of the normalized Ehlers symmetry transformation. In the electrostatic case, we construct and study a general class of spherically symmetric solutions that describes a pointlike source of the Coulomb type. It is demonstrated that this source is characterized by finite and singularity-free interaction at short distances. Also it is established that the total electrostatic energy of this source is finite and inversely proportional to the dilaton-Maxwell coupling constant.
Maxwell's Demons Everywhere: Evolving Design as the Arrow of Time
Bejan, Adrian
2014-01-01
Science holds that the arrow of time in nature is imprinted on one-way (irreversible) phenomena, and is accounted for by the second law of thermodynamics. Here I show that the arrow of time is painted much more visibly on another self-standing phenomenon: the occurrence and change (evolution in time) of flow organization throughout nature, animate and inanimate. This other time arrow has been present in science but not recognized as such since the birth of thermodynamics. It is Maxwell's demon. Translated in macroscopic terms, this is the physics of the phenomenon of design, which is the universal natural tendency of flow systems to evolve into configurations that provide progressively greater access over time, and is summarized as the constructal law of design and evolution in nature. Knowledge is the ability to effect design changes that facilitate human flows on the landscape. Knowledge too flows. PMID:24510201
How an autonomous quantum Maxwell demon can harness correlated information.
Chapman, Adrian; Miyake, Akimasa
2015-12-01
We study an autonomous quantum system which exhibits refrigeration under an information-work trade-off like a Maxwell demon. The system becomes correlated as a single "demon" qubit interacts sequentially with memory qubits while in contact with two heat reservoirs of different temperatures. Using strong subadditivity of the von Neumann entropy, we derive a global Clausius inequality to show thermodynamic advantages from access to correlated information. It is demonstrated, in a matrix product density operator formalism, that our demon can simultaneously realize refrigeration against a thermal gradient and erasure of information from its memory, which is impossible without correlations. The phenomenon can be even enhanced by the presence of quantum coherence. PMID:26764650
Maxwell's demon in biochemical signal transduction with feedback loop.
Ito, Sosuke; Sagawa, Takahiro
2015-01-01
Signal transduction in living cells is vital to maintain life itself, where information transfer in noisy environment plays a significant role. In a rather different context, the recent intensive research on 'Maxwell's demon'-a feedback controller that utilizes information of individual molecules-have led to a unified theory of information and thermodynamics. Here we combine these two streams of research, and show that the second law of thermodynamics with information reveals the fundamental limit of the robustness of signal transduction against environmental fluctuations. Especially, we find that the degree of robustness is quantitatively characterized by an informational quantity called transfer entropy. Our information-thermodynamic approach is applicable to biological communication inside cells, in which there is no explicit channel coding in contrast to artificial communication. Our result could open up a novel biophysical approach to understand information processing in living systems on the basis of the fundamental information-thermodynamics link. PMID:26099556
On the locally rotationally symmetric Einstein-Maxwell perfect fluid
NASA Astrophysics Data System (ADS)
Pugliese, D.; Valiente Kroon, J. A.
2016-06-01
We examine the stability of Einstein-Maxwell perfect fluid configurations with a privileged radial direction by means of a 1+1+2-tetrad formalism. We use this formalism to cast in a quasilinear symmetric hyperbolic form the equations describing the evolution of the system. This hyperbolic reduction is used to discuss the stability of linear perturbations in some special cases. By restricting the analysis to isotropic fluid configurations, we assume a constant electrical conductivity coefficient for the fluid. As a result of this analysis we provide a complete classification and characterization of various stable and unstable configurations. We find, in particular, that in many cases the stability conditions are strongly determined by the constitutive equations and the electric conductivity. A threshold for the emergence of the instability appears in both contracting and expanding systems.
Foxboro, Bradley gear combined at Maxwell House plant
Maggs, J.
1986-02-03
In what is described as an unusual installation, industrial process control equipment from the Foxboro Co., Foxboro, Mass., and Allen Bradley Co., Milwaukee, was combined at General Foods' Maxwell House plant in Houston, and is working together with a Hewlett-Packard 1000 computer to improve product quality and cut energy costs, according to Kevin McCormick, decaffeination business manager. As a result, the process controls are expected to reduce energy costs at the facility by 5 to 10%, he said. Four Foxboro model 300 systems were installed to provide monitoring and analog control of four processes - coffee bean decaffeination, instant coffee preparation, Minute Rice preparation, and separate Foxboro system to control the plant's two boilers, which are fired with natural gas and with waste coffee grounds.
A Generalization of the Einstein-Maxwell Equations
NASA Astrophysics Data System (ADS)
Cotton, Fredrick
2016-03-01
The proposed modifications of the Einstein-Maxwell equations include: (1) the addition of a scalar term to the electromagnetic side of the equation rather than to the gravitational side, (2) the introduction of a 4-dimensional, nonlinear electromagnetic constitutive tensor and (3) the addition of curvature terms arising from the non-metric components of a general symmetric connection. The scalar term is defined by the condition that a spherically symmetric particle be force-free and mathematically well-behaved everywhere. The constitutive tensor introduces two auxiliary fields which describe the particle structure. The additional curvature terms couple both to particle solutions and to electromagnetic and gravitational wave solutions. http://sites.google.com/site/fwcotton/em-30.pdf
Conformally invariant thermodynamics of a Maxwell-Dilaton black hole
NASA Astrophysics Data System (ADS)
Lopez-Monsalvo, C. S.; Nettel, F.; Quevedo, H.
2013-12-01
The thermodynamics of Maxwell-Dilaton black holes has been extensively studied. It has served as a fertile ground to test ideas about temperature through various definitions of surface gravity. In this paper, we make an independent analysis of this black hole solution in both, Einstein and Jordan, frames. We explore a set of definitions for the surface gravity and observe the different predictions they make for the near extremal configuration of this black hole. Finally, motivated by the singularity structure in the interior of the event horizon, we use a holographic argument to remove the micro-states from the disconnected region of this solution. In this manner, we construct a frame independent entropy from which we obtain a temperature which agrees with the standard results in the non-extremal regime, and has a desirable behaviour around the extremal configurations according to the third law of black hole mechanics.
How can an autonomous quantum Maxwell demon harness correlated information?
NASA Astrophysics Data System (ADS)
Chapman, Adrian; Miyake, Akimasa; CQuIC Thermodynamics Team
We study an autonomous quantum system, which exhibits refrigeration under an information-work tradeoff like a Maxwell demon. The system becomes correlated as a single ``demon'' qubit interacts sequentially with memory qubits while in contact with two heat reservoirs of different temperatures. Using strong subadditivity of the von Neumann entropy, we derive a global Clausius inequality to show thermodynamical advantages from access to correlated information. It is demonstrated, in a matrix product density operator formalism, that our demon can simultaneously realize refrigeration against a thermal gradient and erasure of information from its memory, which is impossible without correlations. The phenomenon can be even enhanced by the presence of quantum coherence. The work was supported in part by National Science Foundation Grants PHY-1212445 and PHY-1521016.
Maxwell's demon in biochemical signal transduction with feedback loop
NASA Astrophysics Data System (ADS)
Ito, Sosuke; Sagawa, Takahiro
2015-06-01
Signal transduction in living cells is vital to maintain life itself, where information transfer in noisy environment plays a significant role. In a rather different context, the recent intensive research on `Maxwell's demon'--a feedback controller that utilizes information of individual molecules--have led to a unified theory of information and thermodynamics. Here we combine these two streams of research, and show that the second law of thermodynamics with information reveals the fundamental limit of the robustness of signal transduction against environmental fluctuations. Especially, we find that the degree of robustness is quantitatively characterized by an informational quantity called transfer entropy. Our information-thermodynamic approach is applicable to biological communication inside cells, in which there is no explicit channel coding in contrast to artificial communication. Our result could open up a novel biophysical approach to understand information processing in living systems on the basis of the fundamental information-thermodynamics link.
Experiments on Maxwell's fish-eye dynamics in elastic plates
NASA Astrophysics Data System (ADS)
Lefebvre, Gautier; Dubois, Marc; Beauvais, Romain; Achaoui, Younes; Ing, Ros Kiri; Guenneau, Sébastien; Sebbah, Patrick
2015-01-01
We experimentally demonstrate that a Duraluminium thin plate with a thickness profile varying radially in a piecewise constant fashion as h ( r ) = h ( 0 ) ( 1 + (r / R max ) 2 ) 2 , with h(0) = 0.5 mm, h(Rmax) = 2 mm, and Rmax = 10 cm, behaves in many ways as Maxwell's fish-eye lens in optics. Its imaging properties for a Gaussian pulse with central frequencies 30 kHz and 60 kHz are very similar to those predicted by ray trajectories (great circles) on a virtual sphere (rays emanating from the North pole meet at the South pole). However, the refocusing time depends on the carrier frequency as a direct consequence of the dispersive nature of flexural waves in thin plates. Importantly, experimental results are in good agreement with finite-difference-time-domain simulations.
Tidal dissipation in heterogeneous bodies: Maxwell vs Andrade rheology
NASA Astrophysics Data System (ADS)
Behounkova, M.; Cadek, O.
2014-04-01
The tremendous volcanism on Jupiter's moon Io as well as the huge activity at the south pole of Saturn's moon Enceladus show that tidal dissipation is a very strong source of energy for some bodies in the Solar System. Outside the Solar System, tidal heating in short-period exoplanets may cause Io-like volcanism, large-scale melting and even thermal runaways [1-4]. Here we further develop the method to compute tidal heating in heterogeneous bodies [5]. Especially, we concentrate on the Andrade rheology implementation. We study the impact of the improved model on bodies with large lateral viscosity variation such as Enceladus and tidally locked exoEarth with a large surface temperature contrast due to uneven insolation [6]. We discuss the influence of empirical parameters describing the Andrade rheology and compare the tidal heating and tidal stress obtained for the Andrade rheology with frequently used Maxwell models for different forcing frequencies.
Using Maxwell's Equations in the late 1800s
NASA Astrophysics Data System (ADS)
Buchwald, Jed
2012-02-01
Between the publication of Maxwell's Treatise on Electricity and Magnetism in 1873 and the early 1900s his field equations were not considered to be fundamental by many Cambridge-trained physicists Instead, they were thought to derive from Hamilton's principle given an appropriate energy expression. Such an expression usually assigned a velocity or a position function to field quantities, though this was not invariably done. Precisely because the Hamiltonian, and not the derivative field equations, was taken to be basic, new effects could be generated by adding terms to the energy expression. This was how the Faraday and Kerr magneto-optic effects were handled. The program however never did generate a method for incorporating dissipative phenomena, as Oliver Heaviside (who disliked the use of Hamilton's principle) demonstrated. The procedure was in the end decisively abandoned when J. G. Leathem, a student of Joseph Larmor a Cambridge, demonstrated that it could not handle a particularly subtle magneto-optic process.
Black Holes and Quasiblack Holes in Einstein-Maxwell Theory
NASA Astrophysics Data System (ADS)
Meinel, Reinhard; Breithaupt, Martin; Liu, Yu-Chun
2015-01-01
Continuous sequences of asymptotically flat solutions to the Einstein-Maxwell equations describing regular equilibrium configurations of ordinary matter can reach a black hole limit. For a distant observer, the spacetime becomes more and more indistinguishable from the metric of an extreme Kerr-Newman black hole outside the horizon when approaching the limit. From an internal perspective, a still regular but non-asymptotically flat spacetime with the extreme Kerr-Newman near-horizon geometry at spatial infinity forms at the limit. Interesting special cases are sequences of Papapetrou-Majumdar distributions of electrically counterpoised dust leading to extreme Reissner-Nordström black holes and sequences of rotating uncharged fluid bodies leading to extreme Kerr black holes.
Development and Application of Compatible Discretizations of Maxwell's Equations
White, D; Koning, J; Rieben, R
2005-05-27
We present the development and application of compatible finite element discretizations of electromagnetics problems derived from the time dependent, full wave Maxwell equations. We review the H(curl)-conforming finite element method, using the concepts and notations of differential forms as a theoretical framework. We chose this approach because it can handle complex geometries, it is free of spurious modes, it is numerically stable without the need for filtering or artificial diffusion, it correctly models the discontinuity of fields across material boundaries, and it can be very high order. Higher-order H(curl) and H(div) conforming basis functions are not unique and we have designed an extensible C++ framework that supports a variety of specific instantiations of these such as standard interpolatory bases, spectral bases, hierarchical bases, and semi-orthogonal bases. Virtually any electromagnetics problem that can be cast in the language of differential forms can be solved using our framework. For time dependent problems a method-of-lines scheme is used where the Galerkin method reduces the PDE to a semi-discrete system of ODE's, which are then integrated in time using finite difference methods. For time integration of wave equations we employ the unconditionally stable implicit Newmark-Beta method, as well as the high order energy conserving explicit Maxwell Symplectic method; for diffusion equations, we employ a generalized Crank-Nicholson method. We conclude with computational examples from resonant cavity problems, time-dependent wave propagation problems, and transient eddy current problems, all obtained using the authors massively parallel computational electromagnetics code EMSolve.
Federal Register 2010, 2011, 2012, 2013, 2014
2013-07-30
... National Park Service Notice of Intent to Repatriate Cultural Item: Maxwell Museum of Anthropology...: The Maxwell Museum of Anthropology, in consultation with the appropriate Indian tribes or Native... the Maxwell Museum of Anthropology. If no additional claimants come forward, transfer of control...
NASA Astrophysics Data System (ADS)
Zhang, Ning
This thesis presents the parasitic extraction and magnetic analysis for transformers, inductors, and IGBT bridge busbars with Maxwell 2D and Maxwell 3D simulation. In the first chapter, the magnetic field of a transformer in Maxwell 2D is analyzed. The parasitic capacitance between each winding of the transformer are extracted by Maxwell 2D. According to the actual dimensions, the parasitic capacitances are calculated. The results are verified by comparing with the measurement results from 4395A impedance analyzer. In the second chapter, two CM inductors are simulated in Maxwell 3D. One is the conventional winding inductor, the other one is the proposed one. The magnetic field distributions of different winding directions are analyzed. The analysis is verified by the simulation result. The last chapter introduces a technique to analyze, extract, and measure the parasitic inductance of planar busbars. With this technique, the relationship between self-inductance and mutual-inductance is analyzed. Secondly, a total inductance is calculated based on the developed technique. Thirdly, the current paths and the inductance on a planar busbar are investigated with DC-link capacitors. Furthermore, the analysis of the inductance is addressed. Ansys Q3D simulation and analysis are presented. Finally, the experimental verification is shown by the S-parameter measurement.
Cosmic statistics of statistics
NASA Astrophysics Data System (ADS)
Szapudi, István; Colombi, Stéphane; Bernardeau, Francis
1999-12-01
The errors on statistics measured in finite galaxy catalogues are exhaustively investigated. The theory of errors on factorial moments by Szapudi & Colombi is applied to cumulants via a series expansion method. All results are subsequently extended to the weakly non-linear regime. Together with previous investigations this yields an analytic theory of the errors for moments and connected moments of counts in cells from highly non-linear to weakly non-linear scales. For non-linear functions of unbiased estimators, such as the cumulants, the phenomenon of cosmic bias is identified and computed. Since it is subdued by the cosmic errors in the range of applicability of the theory, correction for it is inconsequential. In addition, the method of Colombi, Szapudi & Szalay concerning sampling effects is generalized, adapting the theory for inhomogeneous galaxy catalogues. While previous work focused on the variance only, the present article calculates the cross-correlations between moments and connected moments as well for a statistically complete description. The final analytic formulae representing the full theory are explicit but somewhat complicated. Therefore we have made available a fortran program capable of calculating the described quantities numerically (for further details e-mail SC at colombi@iap.fr). An important special case is the evaluation of the errors on the two-point correlation function, for which this should be more accurate than any method put forward previously. This tool will be immensely useful in the future for assessing the precision of measurements from existing catalogues, as well as aiding the design of new galaxy surveys. To illustrate the applicability of the results and to explore the numerical aspects of the theory qualitatively and quantitatively, the errors and cross-correlations are predicted under a wide range of assumptions for the future Sloan Digital Sky Survey. The principal results concerning the cumulants ξ, Q3 and Q4 is that
NASA Technical Reports Server (NTRS)
Barth, Timothy
2005-01-01
The role of involutions in energy stability of the discontinuous Galerkin (DG) discretization of Maxwell and magnetohydrodynamic (MHD) systems is examined. Important differences are identified in the symmetrization of the Maxwell and MHD systems that impact the construction of energy stable discretizations using the DG method. Specifically, general sufficient conditions to be imposed on the DG numerical flux and approximation space are given so that energy stability is retained These sufficient conditions reveal the favorable energy consequence of imposing continuity in the normal component of the magnetic induction field at interelement boundaries for MHD discretizations. Counterintuitively, this condition is not required for stability of Maxwell discretizations using the discontinuous Galerkin method.
The nonlinear stability of the trivial solution to the Maxwell-Born-Infeld system
NASA Astrophysics Data System (ADS)
Speck, Jared
2012-08-01
In this article, we use an electromagnetic gauge-free framework to establish the existence of small-data global solutions to the Maxwell-Born-Infeld (MBI) system on the Minkowski spacetime background in 1+3 dimensions. Because the nonlinearities in the system have a special null structure, we are also able to show that these solutions decay at least as fast as solutions to the linear Maxwell-Maxwell system. In addition, we show that on any Lorentzian manifold, the MBI system is hyperbolic in the interior of the field-strength regime in which its Lagrangian is real-valued.
Self-dual Maxwell field in 3D gravity with torsion
Blagojevic, M.; Cvetkovic, B.
2008-08-15
We study the system of a self-dual Maxwell field coupled to 3D gravity with torsion, with the Maxwell field modified by a topological mass term. General structure of the field equations reveals a new, dynamical role of the classical central charges, and gives a simple correspondence between self-dual solutions with torsion and their Riemannian counterparts. We construct two exact self-dual solutions, corresponding to the sectors with a massless and massive Maxwell field, and calculate their conserved charges.
James Clerk Maxwell, a precursor of system identification and control science
NASA Astrophysics Data System (ADS)
Bittanti, Sergio
2015-12-01
One hundred and fifty years ago James Clerk Maxwell published his celebrated paper 'Dynamical theory of electromagnetic field', where the interaction between electricity and magnetism eventually found an explanation. However, Maxwell was also a precursor of model identification and control ideas. Indeed, with the paper 'On Governors' of 1869, he introduced the concept of feedback control system; and moreover, with his essay on Saturn's rings of 1856 he set the basic principle of system identification. This paper is a tutorial exposition having the aim to enlighten these latter aspects of Maxwell's work.
Mathematical analysis of plasmonic resonances for nanoparticles: The full Maxwell equations
NASA Astrophysics Data System (ADS)
Ammari, Habib; Ruiz, Matias; Yu, Sanghyeon; Zhang, Hai
2016-09-01
In this paper we use the full Maxwell equations for light propagation in order to analyze plasmonic resonances for nanoparticles. We mathematically define the notion of plasmonic resonance and analyze its shift and broadening with respect to changes in size, shape, and arrangement of the nanoparticles, using the layer potential techniques associated with the full Maxwell equations. We present an effective medium theory for resonant plasmonic systems and derive a condition on the volume fraction under which the Maxwell-Garnett theory is valid at plasmonic resonances.
Maxwell stress induced optical torque upon gold prolate nanospheroid
NASA Astrophysics Data System (ADS)
Liaw, Jiunn-Woei; Chen, Ying-Syuan; Kuo, Mao-Kuen
2016-03-01
This study theoretically analyzes the surface traction on an elongated Au prolate nanospheroid to examine the resultant optical torque exerted by an optical tweezers. The multiple multipole method is applied to evaluate quantitatively the electromagnetic field induced by a linearly polarized plane wave illuminating a nanospheroid, then obtaining the surface traction in terms of Maxwell stress tensor. The optical torque is calculated by the surface integral of the cross product of position vector and traction over the nanospheroid's surface. Our results show that two pairs of positive and negative traction zones at the two apexes of the nanospheroid play a critical role. Furthermore, the resultant optical torque is wavelength-dependent. If the wavelength is shorter than the longitudinal surface plasmon resonance (LSPR) of the nanospheroid, the optical torque rotates the long axis of nanospheroid perpendicular to the polarization direction of the incident wave. In contrast, if the wavelength is longer than the LSPR the long axis is pushed parallel to the polarization direction. The turning point with a null torque, between the perpendicular and parallel modes, is at the LSPR. The optical performance of Au nanospheroid is equivalent to that of Au NR with the same volume and aspect ratio, but the LSPR of Au NR is little red-shifted from that of an equivalent prolate spheroid.
Relation of magnetism and electricity beyond Faraday-Maxwell electrodynamics
NASA Astrophysics Data System (ADS)
Kurkin, M. I.; Orlova, N. B.
2014-11-01
A comparison has been performed between the Landau-Dzyaloshinskii-Astrov magnetoelectric effects and the electromagnetic effects caused by the electromagnetic Faraday induction and Maxwell displacement currents. The requirement for the spontaneous violation of symmetry relative to space inversion and time reversion is formulated as the condition for the existence of magnetoelectric effects. An analysis is performed of some results obtained by E.A. Turov both personally and in association with colleagues, which made a significant contribution to the development of the science of magnetoelectricity. These results include the development of the scheme of a simplified symmetry analysis for describing collinear spin structures; the use of this scheme for the invariant expansion of thermodynamic potentials for the magnetic materials with different types of magnetic ordering; the formulation of the microscopic model of magnetoelectricity with the use of the relation between spins and electroactive optical phonons; the study of the phenomena of the enhancement of magnetoelectric effects upon the magnetic resonance; the analysis of the opportunities of electrodipole excitation and of the detection of different signals of magnetic resonance; and the study of the manifestations of magnetoelectric effects in magnetoacoustics and optics.
Rectifying thermal fluctuations: Minimal pumping and Maxwell's demon
NASA Astrophysics Data System (ADS)
Mandal, Dibyendu
Molecular complexes with movable components form the basis of nanoscale machines. Their inherent stochastic nature makes it a challenge to generate any controllable movement. Rather than fighting these fluctuations, one can utilize them by the periodic modulation of system parameters, or stochastic pumping. For the no-pumping theorem (NPT), which establishes minimal conditions for directed pumping, we present a simplified proof using an elementary graph theoretical construction. Motivated by recent experiments, we propose a new class of "hybrid" models combining elements of both the purely discrete and purely continuous descriptions prevalent in the field. We formulate the NPT in this hybrid framework to give a detailed justification of the original experiment observation. We also present an extension of the NPT to open stochastic systems. Next we consider the paradox of "Maxwell's demon," an imaginary intelligent being that rectifies thermal fluctuations in a manner that seems to violate the second law of thermodynamics. We present two exactly solvable, autonomous models that can reproduce the actions of the demon. Of necessity, both of these models write information on a memory device as part of their operation. By exposing their explicit, transparent mechanisms, our models offer simple paradigms to investigate the autonomous rectification of thermal fluctuations and the thermodynamics of information processing.
Maxwell's conjecture on three point charges with equal magnitudes
NASA Astrophysics Data System (ADS)
Tsai, Ya-Lun
2015-08-01
Maxwell's conjecture on three point charges states that the number of non-degenerate equilibrium points of the electrostatic field generated by them in R3 is at most four. We prove the conjecture in the cases when three point charges have equal magnitudes and show the number of isolated equilibrium points can only be zero, two, three, or four. Specifically, fixing positions of two positive charges in R3, we know exactly where to place the third positive charge to have two, three, or four equilibrium points. All equilibrium points are isolated and there are no other possibilities for the number of isolated equilibrium points. On the other hand, if both two of the fixed charges have negative charge values, there are always two equilibrium points except when the third positive charge lies in the line segment connecting the two negative charges. The exception cases are when the field contains only a curve of equilibrium points. In this paper, computations assisted by computer involve symbolic and exact integer computations. Therefore, all the results are proved rigorously.
From Maxwell's Electrodynamics to Relativity, a Geometric Journey
NASA Astrophysics Data System (ADS)
Smith, Felix T.
2015-05-01
Since Poincaré and Minkowski recognized ict as a fourth coordinate in a four-space associated with the Lorentz transformation, the occurrence of that imaginary participant in the relativistic four-vector has been a mystery of relativistic dynamics. A reexamination of Maxwell's equations (ME) shows that one of their necessary implications is to bring to light a constraint that distorts the 3-space of our experience from strict Euclidean zero curvature by a time-varying, spatially isotropic term creating a minute curvature Kcurv(t) and therefore a radius of curvature rcurv(t) =Kcurv- 1 / 2 (t). In the light of Michelson-Morley and the Lorentz transformation, this radius must be imaginary, and the geometric curvature K must be negative. From the time dependence of the ME the rate of change of the curvature radius is shown to be drcurv / dt = ic , agreeing exactly with the Hubble expansion. The imaginary magnitude is the radius of curvature; the time itself is not imaginary. Minkowski's space-time is unjustified. Important consequences for the foundations of special relativity follow.
Relativistic plasma expansion with Maxwell-Juettner distribution
Huang, Yongsheng; Wang, Naiyan; Tang, Xiuzhang; Shi, Yijin
2013-11-15
A self-similar analytical solution is proposed to describe the relativistic ion acceleration with the local Maxwell-Juettner relativistic distribution electrons. It is an alternative to the existing static model [M. Passoni and M. Lontano, Phys. Rev. Lett. 101, 115001 (2008)], which exploits a limited solution for the acceleration potential. With our model, the potential is finite naturally and has an upper limitation proportional to the square root of the electron temperature. The divergent potential in the non-relativistic case is the linear items of the Taylor expansion of that obtained relativistic one here. The energy distribution of ions and the dependence of the ion momentum on the acceleration time are obtained analytically. Maximum ion energy has an upper limitation decided by the finite potential difference. In the ultra-relativistic region, the ion energy at the ion front is proportional to t{sup 4/5} and the energy of the ions behind the ion front is proportional to t{sup 2/3} since the field there is shielded by the ions beyond them and the field at the ion front is the most intense.
From Maxwell's Equations to Polarimetric SAR Images: A Simulation Approach
Sant'Anna, Sidnei J. S.; da S. Lacava, J. C.; Fernandes, David
2008-01-01
A new electromagnetic approach for the simulation of polarimetric SAR images is proposed. It starts from Maxwell's equations, employs the spectral domain full-wave technique, the moment method, and the stationary phase method to compute the far electromagnetic fields scattered by multilayer structures. A multilayer structure is located at each selected position of a regular rectangular grid of coordinates, which defines the scene area under imaging. The grid is determined taking into account the elementary scatter size and SAR operational parameters, such as spatial resolution, pixel spacing, look angle and platform altitude. A two-dimensional separable “sinc” function to represent the SAR spread point function is also considered. Multifrequency sets of single-look polarimetric SAR images are generated, in L-, C- and X-bands and the images are evaluated using several measurements commonly employed in SAR data analysis. The evaluation shows that the proposed simulation process is working properly, since the obtained results are in accordance with those presented in the literature. Therefore, this new approach becomes suitable for carrying out theoretical and practical studies using polarimetric SAR images.
Gravitational spreading of Danu, Freyja and Maxwell Montes, Venus
NASA Technical Reports Server (NTRS)
Smrekar, Suzanne E.; Solomon, Sean C.
1991-01-01
The potential energy of elevated terrain tends to drive the collapse of the topography. This process of gravitational spreading is likely to be more important on Venus than on Earth because the higher surface temperature weakens the crust. The highest topography on Venus is Ishtar Terra. The high plateau of Lakshmi Planum has an average elevation of 3 km above mean planetary radius, and is surrounded by mountain belts. Freyja, Danu, and Maxwell Montes rise, on average, an additional 3, 0.5, and 5 km above the plateau, respectively. Recent high resolution Magellan radar images of this area, east of approx. 330 deg E, reveal widespread evidence for gravity spreading. Some observational evidence is described for gravity spreading and the implications are discussed in terms of simple mechanical models. Several simple models predict that gravity spreading should be an important process on Venus. One difficulty in using remote observations to infer interior properties is that the observed features may not have formed in response to stresses which are still active. Several causes of surface topography are briefly examined.
Maxwell's mixing equation revisited: characteristic impedance equations for ellipsoidal cells.
Stubbe, Marco; Gimsa, Jan
2015-07-21
We derived a series of, to our knowledge, new analytic expressions for the characteristic features of the impedance spectra of suspensions of homogeneous and single-shell spherical, spheroidal, and ellipsoidal objects, e.g., biological cells of the general ellipsoidal shape. In the derivation, we combined the Maxwell-Wagner mixing equation with our expression for the Clausius-Mossotti factor that had been originally derived to describe AC-electrokinetic effects such as dielectrophoresis, electrorotation, and electroorientation. The influential radius model was employed because it allows for a separation of the geometric and electric problems. For shelled objects, a special axial longitudinal element approach leads to a resistor-capacitor model, which can be used to simplify the mixing equation. Characteristic equations were derived for the plateau levels, peak heights, and characteristic frequencies of the impedance as well as the complex specific conductivities and permittivities of suspensions of axially and randomly oriented homogeneous and single-shell ellipsoidal objects. For membrane-covered spherical objects, most of the limiting cases are identical to-or improved with respect to-the known solutions given by researchers in the field. The characteristic equations were found to be quite precise (largest deviations typically <5% with respect to the full model) when tested with parameters relevant to biological cells. They can be used for the differentiation of orientation and the electric properties of cell suspensions or in the analysis of single cells in microfluidic systems. PMID:26200856
Presliding friction identification based upon the Maxwell Slip model structure.
Rizos, Demosthenis D; Fassois, Spilios D
2004-06-01
The problem of presliding friction identification based upon the Maxwell Slip model structure, which is capable of accounting for the presliding hysteresis with nonlocal memory, is considered. The model structure's basic properties are examined, based upon which a priori identifiability is established, the role of initial conditions on identification is investigated, and the necessary and sufficient conditions for a posteriori identifiability are derived. Using them, guidelines for excitation signal design are also formulated. Building upon these results, two new methods, referred to as Dynamic Linear Regression (DLR) and NonLinear Regression (NLR), are postulated for presliding friction identification. Both may be thought of as different extensions of the conventional Linear Regression (LR) method that uses threshold preassignment: The DLR by introducing extra dynamics in the form of a vector finite impulse response filter, and the NLR by relaxing threshold preassignment through a special nonlinear regression procedure. The effectiveness of both methods is assessed via Monte Carlo experiments and identification based upon laboratory signals. The results indicate that both methods achieve significant improvements over the LR. The DLR offers the highest accuracy, with the NLR striking a very good balance between accuracy and parametric complexity. PMID:15189071
Characterization of thunderstorm induced Maxwell current densities in the middle atmosphere
NASA Technical Reports Server (NTRS)
Baginski, Michael Edward
1989-01-01
Middle atmospheric transient Maxwell current densities generated by lightning induced charge perturbations are investigated via a simulation of Maxwell's equations. A time domain finite element analysis is employed for the simulations. The atmosphere is modeled as a region contained within a right circular cylinder with a height of 110 km and radius of 80 km. A composite conductivity profile based on measured data is used when charge perturbations are centered about the vertical axis at altitudes of 6 and 10 km. The simulations indicate that the temporal structure of the Maxwell current density is relatively insensitive to altitude variation within the region considered. It is also shown that the electric field and Maxwell current density are not generally aligned.
5D Einstein-Maxwell solitons and concentric rotating dipole black rings
Yazadjiev, Stoytcho S.
2008-09-15
We discuss the application of the solitonic techniques to the 5D Einstein-Maxwell gravity. As an illustration we construct a new exact solution describing two concentric rotating dipole black rings. The properties of the solution are investigated.
NASA Astrophysics Data System (ADS)
Yazadjiev, Stoytcho; Lazov, Boian
2016-04-01
We consider the problem for the classification of static and asymptotically flat Einstein-Maxwell-dilaton spacetimes with a photon sphere. It is first proven that the photon spheres in Einstein-Maxwell-dilaton gravity have constant mean and constant scalar curvature. Then we derive some relations between the mean curvature and the physical characteristics of the photon spheres. Using further the symmetries of the dimensionally reduced Einstein-Maxwell-dilaton field equations we show that the lapse function, the electrostatic potential, and the dilaton field are functionally dependent in the presence of a photon sphere. Using all this we prove the main classification theorem by explicitly constructing all Einstein-Maxwell-dilaton solutions possessing a nonextremal photon sphere.
Maxwell solvers for the simulations of the laser-matter interaction
NASA Astrophysics Data System (ADS)
Nuter, Rachel; Grech, Mickael; Gonzalez de Alaiza Martinez, Pedro; Bonnaud, Guy; d'Humières, Emmanuel
2014-06-01
With the advent of high intensity laser beams, solving the Maxwell equations with a free-dispersive algorithm is becoming essential. Several Maxwell solvers, implemented in Particle-In-Cell codes, have been proposed. We present here some of them by describing their computational stencil in two-dimensional geometry and defining their stability area as well as their numerical dispersion relation. Numerical simulations of Backward Raman amplification and laser wake-field are presented to compare these different solvers.
Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory
NASA Astrophysics Data System (ADS)
Tweney, Ryan D.
2011-07-01
James Clerk Maxwell `translated' Michael Faraday's experimentally-based field theory into the mathematical representation now known as `Maxwell's Equations.' Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other results in the physics of electricity and magnetism. Examination of Maxwell's procedures opens many issues about the role of mathematical representation in physics and the learning background required for its success. Specifically, Maxwell's training in `Cambridge University' mathematical physics emphasized the use of analogous equations across fields of physics and the repeated solving of extremely difficult problems in physics. Such training develops an array of overlearned mathematical representations supported by highly sophisticated cognitive mechanisms for the retrieval of relevant information from long term memory. For Maxwell, mathematics constituted a new form of representation in physics, enhancing the formal derivational and calculational role of mathematics and opening a cognitive means for the conduct of `experiments in the mind' and for sophisticated representations of theory.
Thermodynamics of higher dimensional topological dilation black holes with a power-law Maxwell field
NASA Astrophysics Data System (ADS)
Zangeneh, M. Kord; Sheykhi, A.; Dehghani, M. H.
2015-02-01
In this paper, we extend the study on the nonlinear power-law Maxwell field to dilaton gravity. We introduce the (n +1 ) -dimensional action in which gravity is coupled to a dilaton and power-law nonlinear Maxwell field, and we obtain the field equations by varying the action. We construct a new class of higher dimensional topological black hole solutions of Einstein-dilaton theory coupled to a power-law nonlinear Maxwell field and investigate the effects of the nonlinearity of the Maxwell source as well as the dilaton field on the properties of the spacetime. Interestingly enough, we find that the solutions exist provided one assumes three Liouville-type potentials for the dilaton field, and in the case of the Maxwell field, one of the Liouville potentials vanishes. After studying the physical properties of the solutions, we compute the mass, charge, electric potential and temperature of the topological dilaton black holes. We also study the thermodynamics and thermal stability of the solutions and disclose the effects of the dilaton field and the power-law Maxwell field on the thermodynamics of these black holes. Finally, we comment on the dynamical stability of the obtained solutions in four dimensions.
2+1 dimensional magnetically charged solutions in Einstein-power-Maxwell theory
NASA Astrophysics Data System (ADS)
Mazharimousavi, S. Habib; Gurtug, O.; Halilsoy, M.; Unver, O.
2011-12-01
We obtain a class of magnetically charged solutions in 2+1 dimensional Einstein-Power-Maxwell theory. In the linear Maxwell limit, such horizonless solutions are known to exist. We show that in 3D geometry, black hole solutions with magnetic charge do not exist even if it is sourced by the power-Maxwell field. Physical properties of the solution with particular power k of the Maxwell field is investigated. The true timelike naked curvature singularity develops when k>1 which constitutes one of the striking effects of the power-Maxwell field. For specific power parameter k, the occurrence of a timelike naked singularity is analyzed in the quantum mechanical point of view. Quantum test fields obeying the Klein-Gordon and the Dirac equations are used to probe the singularity. It is shown that the class of static pure magnetic spacetime in the power-Maxwell theory is quantum-mechanically singular when it is probed with fields obeying Klein-Gordon and Dirac equations in the generic case.
Global smooth flows for compressible Navier-Stokes-Maxwell equations
NASA Astrophysics Data System (ADS)
Xu, Jiang; Cao, Hongmei
2016-08-01
Umeda et al. (Jpn J Appl Math 1:435-457, 1984) considered a rather general class of symmetric hyperbolic-parabolic systems: A0zt+sum_{j=1}nAjz_{xj}+Lz=sum_{j,k=1}nB^{jk}z_{xjxk} and showed optimal decay rates with certain dissipative assumptions. In their results, the dissipation matrices {L} and {B^{jk}(j,k=1,ldots,n)} are both assumed to be real symmetric. So far there are no general results in case that {L} and {B^{jk}} are not necessarily symmetric, which is left open now. In this paper, we investigate compressible Navier-Stokes-Maxwell (N-S-M) equations arising in plasmas physics, which is a concrete example of hyperbolic-parabolic composite systems with non-symmetric dissipation. It is observed that the Cauchy problem for N-S-M equations admits the dissipative mechanism of regularity-loss type. Consequently, extra higher regularity is usually needed to obtain the optimal decay rate of {L1({mathbb{R}}^3)}-{L^2({mathbb{R}}^3)} type, in comparison with that for the global-in-time existence of smooth solutions. In this paper, we obtain the minimal decay regularity of global smooth solutions to N-S-M equations, with aid of {L^p({mathbb{R}}^n)}-{Lq({mathbb{R}}^n)}-{Lr({mathbb{R}}^n)} estimates. It is worth noting that the relation between decay derivative orders and the regularity index of initial data is firstly found in the optimal decay estimates.
Generalized transport coefficients for inelastic Maxwell mixtures under shear flow.
Garzó, Vicente; Trizac, Emmanuel
2015-11-01
The Boltzmann equation framework for inelastic Maxwell models is considered to determine the transport coefficients associated with the mass, momentum, and heat fluxes of a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. The Boltzmann equation is solved by means of a Chapman-Enskog-type expansion around the (local) shear flow distributions f(r)(0) for each species that retain all the hydrodynamic orders in the shear rate. Due to the anisotropy induced by the shear flow, tensorial quantities are required to describe the transport processes instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled equations, which can be analytically solved as functions of the shear rate a, the coefficients of restitution α(rs), and the parameters of the mixture (masses, diameters, and composition). Since the reference distribution functions f(r)(0) apply for arbitrary values of the shear rate and are not restricted to weak dissipation, the corresponding generalized coefficients turn out to be nonlinear functions of both a and α(rs). The dependence of the relevant elements of the three diffusion tensors on both the shear rate and dissipation is illustrated in the tracer limit case, the results showing that the deviation of the generalized transport coefficients from their forms for vanishing shear rates is in general significant. A comparison with the previous results obtained analytically for inelastic hard spheres by using Grad's moment method is carried out, showing a good agreement over a wide range of values for the coefficients of restitution. Finally, as an application of the theoretical expressions derived here for the transport coefficients, thermal diffusion segregation of an intruder immersed in a granular gas is also studied. PMID:26651684
Generalized transport coefficients for inelastic Maxwell mixtures under shear flow
NASA Astrophysics Data System (ADS)
Garzó, Vicente; Trizac, Emmanuel
2015-11-01
The Boltzmann equation framework for inelastic Maxwell models is considered to determine the transport coefficients associated with the mass, momentum, and heat fluxes of a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. The Boltzmann equation is solved by means of a Chapman-Enskog-type expansion around the (local) shear flow distributions fr(0 ) for each species that retain all the hydrodynamic orders in the shear rate. Due to the anisotropy induced by the shear flow, tensorial quantities are required to describe the transport processes instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled equations, which can be analytically solved as functions of the shear rate a , the coefficients of restitution αr s, and the parameters of the mixture (masses, diameters, and composition). Since the reference distribution functions fr(0 ) apply for arbitrary values of the shear rate and are not restricted to weak dissipation, the corresponding generalized coefficients turn out to be nonlinear functions of both a and αr s. The dependence of the relevant elements of the three diffusion tensors on both the shear rate and dissipation is illustrated in the tracer limit case, the results showing that the deviation of the generalized transport coefficients from their forms for vanishing shear rates is in general significant. A comparison with the previous results obtained analytically for inelastic hard spheres by using Grad's moment method is carried out, showing a good agreement over a wide range of values for the coefficients of restitution. Finally, as an application of the theoretical expressions derived here for the transport coefficients, thermal diffusion segregation of an intruder immersed in a granular gas is also studied.
Language Individuation and Marker Words: Shakespeare and His Maxwell's Demon
Marsden, John; Budden, David; Craig, Hugh; Moscato, Pablo
2013-01-01
Background Within the structural and grammatical bounds of a common language, all authors develop their own distinctive writing styles. Whether the relative occurrence of common words can be measured to produce accurate models of authorship is of particular interest. This work introduces a new score that helps to highlight such variations in word occurrence, and is applied to produce models of authorship of a large group of plays from the Shakespearean era. Methodology A text corpus containing 55,055 unique words was generated from 168 plays from the Shakespearean era (16th and 17th centuries) of undisputed authorship. A new score, CM1, is introduced to measure variation patterns based on the frequency of occurrence of each word for the authors John Fletcher, Ben Jonson, Thomas Middleton and William Shakespeare, compared to the rest of the authors in the study (which provides a reference of relative word usage at that time). A total of 50 WEKA methods were applied for Fletcher, Jonson and Middleton, to identify those which were able to produce models yielding over 90% classification accuracy. This ensemble of WEKA methods was then applied to model Shakespearean authorship across all 168 plays, yielding a Matthews' correlation coefficient (MCC) performance of over 90%. Furthermore, the best model yielded an MCC of 99%. Conclusions Our results suggest that different authors, while adhering to the structural and grammatical bounds of a common language, develop measurably distinct styles by the tendency to over-utilise or avoid particular common words and phrasings. Considering language and the potential of words as an abstract chaotic system with a high entropy, similarities can be drawn to the Maxwell's Demon thought experiment; authors subconsciously favour or filter certain words, modifying the probability profile in ways that could reflect their individuality and style. PMID:23826143
Tracer diffusion coefficients in a sheared inelastic Maxwell gas
NASA Astrophysics Data System (ADS)
Garzó, Vicente; Trizac, Emmanuel
2016-07-01
We study the transport properties of an impurity in a sheared granular gas, in the framework of the Boltzmann equation for inelastic Maxwell models. We investigate here the impact of a nonequilibrium phase transition found in such systems, where the tracer species carries a finite fraction of the total kinetic energy (ordered phase). To this end, the diffusion coefficients are first obtained for a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. In this situation, the set of coupled Boltzmann equations are solved by means of a Chapman–Enskog-like expansion around the (local) shear flow distributions for each species, thereby retaining all the hydrodynamic orders in the shear rate a. Due to the anisotropy induced by the shear flow, three tensorial quantities D ij , D p,ij , and D T,ij are required to describe the mass transport process instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled algebraic equations, which can be exactly solved as functions of the shear rate a, the coefficients of restitution {αsr} and the parameters of the mixture (masses and composition). Once the forms of D ij , D p,ij , and D T,ij are obtained for arbitrary mole fraction {{x}1}={{n}1}/≤ft({{n}1}+{{n}2}\\right) (where n r is the number density of species r), the tracer limit ({{x}1}\\to 0 ) is carefully considered for the above three diffusion tensors. Explicit forms for these coefficients are derived showing that their shear rate dependence is significantly affected by the order-disorder transition.
The James Clerk Maxwell Telescope Spectral Legacy Survey
NASA Astrophysics Data System (ADS)
Plume, R.; Fuller, G. A.; Helmich, F.; van der Tak, F. F. S.; Roberts, H.; Bowey, J.; Buckle, J.; Butner, H.; Caux, E.; Ceccarelli, C.; van Dishoeck, E. F.; Friberg, P.; Gibb, A. G.; Hatchell, J.; Hogerheijde, M. R.; Matthews, H.; Millar, T. J.; Mitchell, G.; Moore, T. J. T.; Ossenkopf, V.; Rawlings, J. M. C.; Richer, J.; Roellig, M.; Schilke, P.; Spaans, M.; Tielens, A. G. G. M.; Thompson, M. A.; Viti, S.; Weferling, B.; White, Glenn J.; Wouterloot, J.; Yates, J.; Zhu, M.
2007-01-01
Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes that can reveal the dynamics, physics, chemistry, and evolution of these regions, but our understanding of the molecular inventory of sources and how this is related to their physical state and evolution is rudimentary and incomplete. The Spectral Legacy Survey (SLS) is one of seven surveys recently approved by the James Clerk Maxwell Telescope (JCMT) Board of Directors. Beginning in 2007, the SLS will produce a spectral imaging survey of the content and distribution of all the molecules detected in the 345 GHz atmospheric window (between 332 and 373 GHz) toward a sample of five sources. Our intended targets are a low-mass core (NGC 1333 IRAS 4), three high-mass cores spanning a range of star-forming environments and evolutionary states (W49, AFGL 2591, and IRAS 20126), and a photodissociation region (the Orion Bar). The SLS will use the unique spectral imaging capabilities of HARP-B/ACSIS (Heterodyne Array Receiver Programme B/Auto-Correlation Spectrometer and Imaging System) to study the molecular inventory and the physical structure of these objects, which span different evolutionary stages and physical environments and to probe their evolution during the star formation process. As its name suggests, the SLS will provide a lasting data legacy from the JCMT that is intended to benefit the entire astronomical community. As such, the entire data set (including calibrated spectral data cubes, maps of molecular emission, line identifications, and calculations of the gas temperature and column density) will be publicly available.
Shi, Runhua; McLarty, Jerry W
2009-10-01
In this article, we introduced basic concepts of statistics, type of distributions, and descriptive statistics. A few examples were also provided. The basic concepts presented herein are only a fraction of the concepts related to descriptive statistics. Also, there are many commonly used distributions not presented herein, such as Poisson distributions for rare events and exponential distributions, F distributions, and logistic distributions. More information can be found in many statistics books and publications. PMID:19891281
ERIC Educational Resources Information Center
Petocz, Peter; Sowey, Eric
2008-01-01
As a branch of knowledge, Statistics is ubiquitous and its applications can be found in (almost) every field of human endeavour. In this article, the authors track down the possible source of the link between the "Siren song" and applications of Statistics. Answers to their previous five questions and five new questions on Statistics are presented.
ERIC Educational Resources Information Center
Callamaras, Peter
1983-01-01
This buyer's guide to seven major types of statistics software packages for microcomputers reviews Edu-Ware Statistics 3.0; Financial Planning; Speed Stat; Statistics with DAISY; Human Systems Dynamics package of Stats Plus, ANOVA II, and REGRESS II; Maxistat; and Moore-Barnes' MBC Test Construction and MBC Correlation. (MBR)
ERIC Educational Resources Information Center
Meyer, Donald L.
Bayesian statistical methodology and its possible uses in the behavioral sciences are discussed in relation to the solution of problems in both the use and teaching of fundamental statistical methods, including confidence intervals, significance tests, and sampling. The Bayesian model explains these statistical methods and offers a consistent…
Numerical Vlasov-Maxwell modelling of space plasma
NASA Astrophysics Data System (ADS)
Eliasson, Bengt Erik
The Vlasov equation describes the evolution of the distribution function of particles in phase space (x, v), where the particles interact with long-range forces, but where short-range “collisional” forces are neglected. A space plasma consists of low-mass electrically charged particles, and therefore the most important long-range forces acting in the plasma are the Lorentz forces created by electromagnetic fields. What makes the numerical solution of the Vlasov equation a challenging task is that the fully three-dimensional problem leads to a partial differential equation in the six-dimensional phase space, plus time, making it hard even to store a discretised solution in a computer's memory. Solutions to the Vlasov equation have also a tendency of becoming oscillatory in velocity space, due to free streaming terms (ballistic particles), in which steep gradients are created and problems of calculating the ν (velocity) derivative of the function accurately increase with time. In the present thesis, the numerical treatment is limited to one- and two-dimensional systems, leading to solutions in two- and four-dimensional phase space, respectively, plus time. The numerical method developed is based on the technique of Fourier transforming the Vlasov equation in velocity space and then solving the resulting equation, in which the small-scale information in velocity space is removed through outgoing wave boundary conditions in the Fourier transformed velocity space. The Maxwell equations are rewritten in a form which conserves the divergences of the electric and magnetic fields, by means of the Lorentz potentials. The resulting equations are solved numerically by high order methods, reducing the need for numerical over-sampling of the problem. The algorithm has been implemented in Fortran 90, and the code for solving the one-dimensional Vlasov equation has been parallelised by the method of domain decomposition, and has been implemented using the Message Passing
A class of staggered grid algorithms and analysis for time-domain Maxwell systems
NASA Astrophysics Data System (ADS)
Charlesworth, Alexander E.
We describe, implement, and analyze a class of staggered grid algorithms for efficient simulation and analysis of time-domain Maxwell systems in the case of heterogeneous, conductive, and nondispersive, isotropic, linear media. We provide the derivation of a continuous mathematical model from the Maxwell equations in vacuum; however, the complexity of this system necessitates the use of computational methods for approximately solving for the physical unknowns. The finite difference approximation has been used for partial differential equations and the Maxwell Equations in particular for many years. We develop staggered grid based finite difference discrete operators as a class of approximations to continuous operators based on second order in time and various order approximations to the electric and magnetic field at staggered grid locations. A generalized parameterized operator which can be specified to any of this class of discrete operators is then applied to the Maxwell system and hence we develop discrete approximations through various choices of parameters in the approximation. We describe analysis of the resulting discrete system as an approximation to the continuous system. Using the comparison of dispersion analysis for the discrete and continuous systems, we derive a third difference approximation, in addition to the known (2, 2) and (2, 4) schemes. We conclude by providing the comparison of these three methods by simulating the Maxwell system for several choices of parameters in the system.
Kogalovskii, M.R.
1995-03-01
This paper presents a review of problems related to statistical database systems, which are wide-spread in various fields of activity. Statistical databases (SDB) are referred to as databases that consist of data and are used for statistical analysis. Topics under consideration are: SDB peculiarities, properties of data models adequate for SDB requirements, metadata functions, null-value problems, SDB compromise protection problems, stored data compression techniques, and statistical data representation means. Also examined is whether the present Database Management Systems (DBMS) satisfy the SDB requirements. Some actual research directions in SDB systems are considered.
Smith, Alwyn
1969-01-01
This paper is based on an analysis of questionnaires sent to the health ministries of Member States of WHO asking for information about the extent, nature, and scope of morbidity statistical information. It is clear that most countries collect some statistics of morbidity and many countries collect extensive data. However, few countries relate their collection to the needs of health administrators for information, and many countries collect statistics principally for publication in annual volumes which may appear anything up to 3 years after the year to which they refer. The desiderata of morbidity statistics may be summarized as reliability, representativeness, and relevance to current health problems. PMID:5306722
Federal Register 2010, 2011, 2012, 2013, 2014
2012-04-02
... May 2, 2012. ADDRESSES: David Phillips, Curator of Archaeology, Maxwell Museum of Anthropology, MSC01... culturally affiliated with the sacred objects should contact David Phillips, Curator of Archaeology,...
ERIC Educational Resources Information Center
Petocz, Peter; Sowey, Eric
2008-01-01
In this article, the authors focus on hypothesis testing--that peculiarly statistical way of deciding things. Statistical methods for testing hypotheses were developed in the 1920s and 1930s by some of the most famous statisticians, in particular Ronald Fisher, Jerzy Neyman and Egon Pearson, who laid the foundations of almost all modern methods of…
Upscaling for the time-harmonic Maxwell equations with heterogeneous magnetic materials
NASA Astrophysics Data System (ADS)
Eberhard, Jens P.
2005-09-01
This paper presents a theoretical method for the upscaling of the time-harmonic Maxwell equations. We use the eddy current approximation of the Maxwell equations to describe the fields in heterogeneous materials. The magnetic permeability of the media is assumed to have random heterogeneities given by a Gaussian random field. The upscaling is based on the coarse graining method which applies projections and Green’s function formalism in Fourier space to scale the electric field. An upscaled Maxwell equation is derived which includes an effective magnetic permeability tensor. The effective permeability explicitly depends on the given scale for the upscaling. The scale-dependent permeability is calculated by a second-order perturbative expansion, and we discuss the future verification and the application of the results.
Ludwig Boltzmann als Experimentalphysiker: Frühe Bestätigung der Maxwell-Theorie
NASA Astrophysics Data System (ADS)
Rumpf, Klemens; Granitzer, Petra
2006-09-01
Am Beispiel von Boltzmanns Experimenten zur Bestätigung der Maxwell-Theorie wird dessen hervorragende Begabung auch als Experimentalphysiker deutlich. Die dargestellten Arbeiten fanden etwa 15 Jahre vor den Hertzschen Experimenten statt, zu einem Zeitpunkt also, als die noch junge Maxwell-Theorie dringend experimenteller Bestätigung bedurfte. Boltzmann konnte mit seinen experimentellen Untersuchungen eine direkte Konsequenz der Maxwellschen elektromagnetischen Theorie, die so genannte Maxwell-Relation, bestätigen. Seine Experimente stellten nicht nur lange Zeit den stärksten Beleg für die Richtigkeit der Maxwellschen Lichttheorie dar, sondern waren eine experimentelle Spitzenleistung an der Grenze des damals Möglichen. Besonders Boltzmanns Bestimmung der Dielektrizitätskonstanten von Gasen fand noch Jahrzehnte später Erwähnung in namhaften Lehrbüchern.
‘Square root’ of the Maxwell Lagrangian versus confinement in general relativity
NASA Astrophysics Data System (ADS)
Mazharimousavi, S. Habib; Halilsoy, M.
2012-04-01
We employ the 'square root' of the Maxwell Lagrangian (i.e. √{FμνFμν }), coupled with gravity to search for the possible linear potentials which are believed to play role in confinement. It is found that in the presence of magnetic charge no confining potential exists in such a model. Confining field solutions are found for radial geodesics in pure electrically charged Nariai-Bertotti-Robinson (NBR)-type spacetime with constant scalar curvature. Recently, Guendelman, Kaganovich, Nissimov and Pacheva (2011) [7] have shown that superposed square root with standard Maxwell Lagrangian yields confining potentials in spherically symmetric spacetimes with new generalized Reissner-Nordström-de Sitter/anti-de Sitter black hole solutions. In NBR spacetimes we show that confining potentials exist even when the standard Maxwell Lagrangian is relaxed.
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)
1995-01-01
This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that we currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Karr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)
1994-01-01
This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)
1994-01-01
This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.
Thermodynamics and efficiency of an autonomous on-chip Maxwell's demon.
Kutvonen, Aki; Koski, Jonne; Ala-Nissila, Tapio
2016-01-01
In his famous letter in 1870, Maxwell describes how Joule's law can be violated "only by the intelligent action of a mere guiding agent", later coined as Maxwell's demon by Lord Kelvin. In this letter we study thermodynamics of information using an experimentally feasible Maxwell's demon setup based a single electron transistor capacitively coupled to a single electron box, where both the system and the Demon can be clearly identified. Such an engineered on-chip Demon measures and performes feedback on the system, which can be observed as cooling whose efficiency can be adjusted. We present a detailed analysis of the system and the Demon, including the second law of thermodynamics for bare and coarse grained entropy production and the flow of information as well as efficiency of information production and utilization. Our results demonstrate how information thermodynamics can be used to improve functionality of modern nanoscale devices. PMID:26887504
Scaling theory for homogenization of the Maxwell equations
NASA Astrophysics Data System (ADS)
Vinogradov, Alexei P.
1997-11-01
The wide application of composite materials is a distinctive feature of modern technologies. This encourages scientists dealing with radio physics and optics, to search for new type of artificial materials. Recently such investigations have shifted in the field of materials with weak spatial dispersion: chiral, omega materials, artificial magnets, etc. By weak spatial dispersion we mean that the constitutive relations are still local but constitutive parameters depend upon a wavenumber k. It is the dependence that is responsible for non-encountered-in-nature properties of the materials such as chirality [a first order in (ka) effect] or artificial magnetism [a second order in (ka effect)]. Here a is a typical size of an inclusion. Certainly, all these effects are small enough unless there is a resonance interaction of electromagnetic wave with an inclusion. Near the resonance frequency the effects are significant and perturbation theory in (ka) fails. Nevertheless it is convenient to describe the effects in terms of orders in (ka), understanding this as a matter of classification. In spite of physical clarity of the classification the constitutive relations are treated in terms of multipole expansion. The multipoles naturally appear at field expansion in (d/R) where d is the source size and R is the distance between the source and recorder. Such an expansion is useful in 'molecular optics' approximation where d very much less than r, with r to be a mean distance between the 'molecules.' Though the 'molecular optics' ceases to be a good approximation if we deal with composites where d approximately equals r, the mean current in the right hand side of the Maxwell equations is still expressed through multipoles (see Fig. 1). Below we consider the reasons justifying this sight on things even if we are working beyond the 'molecular optics' approximation. To repel an accusation in abstract contemplation let us consider examples of the 'multipole' media. Permeable
NASA Astrophysics Data System (ADS)
Brenner, Howard
2009-05-01
According to the LeChatelier-Braun principle, when a closed quiescent system initially in an equilibrium or unstressed steady state is subjected to an externally imposed "stress" it responds in a manner tending to alleviate that stress. Use of this entropically based qualitative rule, in combination with the notion of Maxwell thermal stresses existing in nonisothermal gases and liquids, enables one to (i) derive Maxwell's thermal-creep boundary condition prevailing at the boundary between a solid and a fluid (either gas or liquid) and (ii) rationalize the phenomenon of thermophoresis in liquids, for which, in contrast with the case of gases, an elementary explanation is currently lacking. These two objectives are achieved by quantitatively interpreting the heretofore qualitative LeChatelier-Braun notion of stress in the present context as being the fluid's stress tensor, the latter including Maxwell's thermal stress. In effect, thermophoretic particle motion is interpreted as the manifestation of the fluid's attempt to expel the particle from its interior so as to alleviate the thermal stress that would otherwise ensue were the particle to remain at rest (thus obeying the traditional no slip rather than thermal-creep boundary condition) following its introduction into the previously stress-free quiescent fluid. With Kn the Knudsen number in the case of rarefied gases, Maxwell's thermal stress constitutes a noncontinuum phenomenon of O(Kn2), whereas his thermal-creep phenomenon constitutes a continuum phenomenon of O(Kn). That these two phenomena can, nevertheless, be proved to be synonymous (in the sense, so to speak, of being two sides of the same coin), as is done in the present paper, supports the "ghost effect" findings of Sone [Y. Sone, "Flows induced by temperature fields in a rarefied gas and their ghost effect on the behavior of a gas in the continuum limit," Annu. Rev. Fluid Mech 32, 779 (2000)], which, philosophically, imply the artificiality of the
NASA Astrophysics Data System (ADS)
Liang, Jun; Liu, Yan-Chun; Zhu, Qiao
2014-02-01
In order to further explore the effects of non-Gaussian smeared mass distribution on the thermodynamical properties of noncommutative black holes, we consider noncommutative black holes based on Maxwell-Boltzmann smeared mass distribution in (2+1)-dimensional spacetime. The thermodynamical properties of the black holes are investigated, including Hawking temperature, heat capacity, entropy and free energy. We find that multiple black holes with the same temperature do not exist, while there exists a possible decay of the noncommutative black hole based on Maxwell-Boltzmann smeared mass distribution into the rotating (commutative) BTZ black hole.
A stochastic multi-symplectic scheme for stochastic Maxwell equations with additive noise
Hong, Jialin; Zhang, Liying
2014-07-01
In this paper we investigate a stochastic multi-symplectic method for stochastic Maxwell equations with additive noise. Based on the stochastic version of variational principle, we find a way to obtain the stochastic multi-symplectic structure of three-dimensional (3-D) stochastic Maxwell equations with additive noise. We propose a stochastic multi-symplectic scheme and show that it preserves the stochastic multi-symplectic conservation law and the local and global stochastic energy dissipative properties, which the equations themselves possess. Numerical experiments are performed to verify the numerical behaviors of the stochastic multi-symplectic scheme.
The Maxwell Montes region, surveyed by the Venera 15, Venera 16 orbiters
NASA Astrophysics Data System (ADS)
Kotelnikov, V. A.; Akim, E. L.; Aleksandrov, Y. N.; Armand, N. A.; Bazilevskij, A. T.; Bogomolov, A. F.; Vyshlov, A. S.; Dubrovin, V. M.; Zherikhin, N. V.; Zakharov, A. I.; Zimov, V. E.; Kaevitser, V. I.; Kovtunenko, V. M.; Kremnev, R. S.; Krivtsov, A. P.; Krylov, G. A.; Krymov, A. A.; Kucheryavenkova, I. L.; Molotov, E. P.; Petrov, G. M.; Rzhiga, O. N.; Selivanov, A. S.; Sidorenko, A. I.; Sinilo, V. P.; Sknarya, A. V.; Sokolov, G. A.; Sorokin, V. P.; Sukhanov, K. G.; Tikhonov, V. F.; Tyuflin, Y. S.; Feldman, B. Y.; Shakhovskoj, A. M.; Shubin, V. A.
1984-12-01
Between November 1983 and July 1984 the radar systems on the Venera 15 and 16 orbiters mapped much of the Venus northern hemisphere at high resolution. In particular, Maxwell Montes (the highest range on Venus) and a large part of the surrounding terrain exhibit horizontal tectonic deformations of compressive origin resembling mountain folds on the earth. The plains contiguous to Maxwell Montes may comprise basaltic extrusions, like the maria found on other terrestrial planets and the moon. The 100-km depression called Patera Cleopatra actually has a structure analogous to double-ring impact craters rather than volcanic calderas.
Spectrum structure and behavior of the Vlasov-Maxwell-Boltzmann system without angular cutoff
NASA Astrophysics Data System (ADS)
Huang, Yongting
2016-02-01
The spectrum structure and behavior of the Vlasov-Maxwell-Boltzmann (VMB) system with physical angular non-cutoff intermolecular collisions are studied in this paper. The analysis shows the effect of the Lorentz force induced by the electro-magnetic field leads to some different spectrum structure from the non-cutoff Boltzmann equation. The spectrum structure in high frequency, quite different from the VMB system with angular cutoff assumption, also illustrates the hyperbolic structure of the Maxwell equation. Furthermore, the large time behavior and optimal convergence rates to the equilibrium of the non-cutoff VMB system are established on the spectrum analysis.
NASA Astrophysics Data System (ADS)
Friedberg, Richard; Manassah, Jamal T.
2008-07-01
The superradiance from a slab of inverted two-level atoms is theoretically analyzed in the linear regime from both the perspective of the expansion in eigenfunctions of the integral equation with the Lienard-Wiechert potential as kernel, and that of linearizing the Maxwell-Bloch equations. We show the equivalence of both approaches. We show that the so-called Reduced Maxwell-Bloch equations do not yield even approximately the correct solution when applied in the obvious way, but that they can be made to give the correct solution by adding a fictitious input field.
The Einstein-Maxwell Equations and Conformally Kähler Geometry
NASA Astrophysics Data System (ADS)
LeBrun, Claude
2016-06-01
Page's Einstein metric on {{{CP}}_2#overline{{CP}}_2} is conformally related to an extremal Kähler metric. Here we construct a family of conformally Kähler solutions of the Einstein-Maxwell equations that deforms the Page metric, while sweeping out the entire Kähler cone of {{{CP}}_2#overline{{CP}}_2}. The same method also yields analogous solutions on every Hirzebruch surface. This allows us to display infinitely many geometrically distinct families of solutions of the Einstein-Maxwell equations on the smooth 4-manifolds {S^2 × S^2} and {{{CP}}_2#overline{{CP}}_2}.
- criticality of AdS black hole in the Einstein-Maxwell-power-Yang-Mills gravity
NASA Astrophysics Data System (ADS)
Zhang, Ming; Yang, Zhan-Ying; Zou, De-Cheng; Xu, Wei; Yue, Rui-Hong
2015-02-01
We study the - critical behaivor of N-dimensional AdS black holes in Einstein-Maxwell-power-Yang-Mills gravity. Our results show the existence of the Van der Waals like small-large black hole phase transitions when taking some special values of charges of the Maxwell and Yang-Mills fields. Further to calculate the critical exponents of the black holes at the critical point, we find that they are the same as those in the Van der Waals liquid-gas system.
Cosmological solutions in five-dimensional Einstein-Maxwell-dilaton theory
NASA Astrophysics Data System (ADS)
Ghezelbash, A. M.
2015-04-01
We construct new classes of exact cosmological solutions to five-dimensional Einstein-Maxwell-dilaton theory with two coupling constants for the dilaton-Maxwell term and the dilaton-cosmological constant term. All the solutions are nonstationary, and the solutions where both coupling constants are nonzero are almost regular everywhere. The size of the spatial section of the asymptotic metric shrinks to zero at early times and increases to infinitely large at very late times. The cosmological constant depends on the dilaton coupling constant and can take positive, zero, or negative values.
NASA Technical Reports Server (NTRS)
Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James
2014-01-01
Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.
The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute works to provide information on cancer statistics in an effort to reduce the burden of cancer among the U.S. population.
... cancer statistics across the world. U.S. Cancer Mortality Trends The best indicator of progress against cancer is ... the number of cancer survivors has increased. These trends show that progress is being made against the ...
NASA Astrophysics Data System (ADS)
Hermann, Claudine
Statistical Physics bridges the properties of a macroscopic system and the microscopic behavior of its constituting particles, otherwise impossible due to the giant magnitude of Avogadro's number. Numerous systems of today's key technologies - such as semiconductors or lasers - are macroscopic quantum objects; only statistical physics allows for understanding their fundamentals. Therefore, this graduate text also focuses on particular applications such as the properties of electrons in solids with applications, and radiation thermodynamics and the greenhouse effect.
A 3+1 formalism for quantum electrodynamical corrections to Maxwell equations in general relativity
NASA Astrophysics Data System (ADS)
Pétri, J.
2015-08-01
Magnetized neutron stars constitute a special class of compact objects harbouring gravitational fields that deviate strongly from the Newtonian weak field limit. Moreover, strong electromagnetic fields anchored into the star give rise to non-linear corrections to Maxwell equations described by quantum electrodynamics (QED). Electromagnetic fields close to or above the critical value of BQ = 4.4 × 109 T are probably present in some pulsars and for most of the magnetars. To account properly for emission emanating from the neutron star surface like for instance thermal radiation and its polarization properties, it is important to include general relativistic (GR) effects simultaneously with non-linear electrodynamics. This can be achieved through a 3+1 formalism known in general relativity and that incorporates QED perturbations to Maxwell equations. Starting from the lowest order corrections to the Lagrangian for the electromagnetic field, as given for instance by Born-Infeld or Euler-Heisenberg theory, we derive the non-linear Maxwell equations in general relativity including quantum vacuum effects. We also derive a prescription for the force-free limit and show that these equations can be solved with classical finite volume methods for hyperbolic conservation laws. It is therefore straightforward to include general relativity and QED in the description of neutron star magnetospheres by using standard classical numerical techniques borrowed from Maxwell and Newton theory. As an application, we show that spin-down luminosity corrections associated with QED effects are negligible with respect to GR corrections.
Physical Variables of d=3 Maxwell-Chern-Simons Theory by Symplectic Projector Method
NASA Astrophysics Data System (ADS)
Helayel-Neto, J. A.; Santos, M. A.; Vancea, I. V.
2006-12-01
The Symplectic Projector Method is applied to derive the local physical degrees of freedom and the physical Hamiltonian of the Maxwell-Chern-Simons theory in $d=1+2$. The results agree with the ones obtained in the literature through different approaches.
A numerical Maxwell Schrödinger model for intense laser matter interaction and propagation
NASA Astrophysics Data System (ADS)
Lorin, E.; Chelkowski, S.; Bandrauk, A.
2007-12-01
We present in this paper an original ab initio Maxwell-Schrödinger model and a methodology to simulate intense ultrashort laser pulses interacting with a 3D H +2-gas in the nonlinear nonperturbative regime under and beyond Born-Oppenheimer approximation. The model we present is the first one to our knowledge (excepted in [E. Lorin, S. Chelkowski, A. Bandrauk, A Maxwell-Schrödinger model for non-perturbative laser-molecule interaction and some methods of numerical computation, Proceeding CRM, vol. 41, American Mathematics Society, 2007], where a one-dimensional version is presented) to be totally nonperturbative, vectorial and multidimensional, taking into account ionization, and high order nonlinearities going far beyond classical nonlinear Maxwell or Schrödinger models. After a presentation of the model and a short mathematical study, we examine some numerical approximations for its computation. In particular, we focus on the polarization computation allowing an efficient coupling between the Maxwell and time dependent Schrödinger equations (TDSE), and on an efficient parallelization. Examples of numerical computations of high order harmonic generation and of electric field propagation are presented for one molecule and up to 512, thus highlighting cooperative effects in harmonic generation at high order.
Canonical quantization of lattice Higgs-Maxwell-Chern-Simons fields: Krein Self-adjointness
Bowman, Daniel A.; Challifour, John L.
2006-10-15
It is shown how techniques from constructive quantum field theory may be applied to indefinite metric gauge theories in Hilbert space for the case of a Higgs-Maxwell-Chern-Simons theory on a lattice. The Hamiltonian operator is shown to be Krein essentially self-adjoint by means of unbounded but Krein unitary transformations relating the Hamiltonian to an essentially maximal accretive operator.
Canonical quantization of lattice Higgs-Maxwell-Chern-Simons fields: Osterwalder-Schrader positivity
Bowman, Daniel A.; Challifour, John L.
2011-03-15
A Euclidean representation is given for a canonically quantized relativistic Maxwell-Chern-Simons field on a lattice, which approximates a complex measure on a space of distributions. Using a path-space formula for the nonself-adjoint Hamiltonian, the relation between Euclidean Osterwalder-Schrader positivity, the Krein metric, and Gauss' law is examined.
An Exact Solution of Einstein-Maxwell Gravity Coupled to a Scalar Field
NASA Technical Reports Server (NTRS)
Turyshev, S. G.
1995-01-01
The general solution to low-energy string theory representing static spherically symmetric solution of the Einstein-Maxwell gravity with a massless scalar field has been found. Some of the partial cases appear to coincide with known solutions to black holes, naked singularities, and gravity and electromagnetic fields.
Analysis of a three phase induction motor directly from Maxwell's equations
NASA Astrophysics Data System (ADS)
Bhattacharjee, Shayak
2012-01-01
The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This formulation allows us to estimate the torque developed by a motor without knowing the details of its circuitry.
Quantum Gravity Effects on the Tunneling Radiation of the Einstein-Maxwell-Dilaton-Axion Black Hole
NASA Astrophysics Data System (ADS)
Cheng, Tianhu; Ren, Ruyi; Chen, Deyou; Liu, Zixiang; Li, Guopin
2016-07-01
Taking into account effects of quantum gravity, we investigate the evaporation of an Einstein-Maxwell-Dilaton-Axion black hole. The corrected Hawking temperature is gotten respectively by the scalar particle's and the fermion's tunneling across the horizon. This temperature is lower than the original one derived by Hawking, which means quantum gravity effects slow down the rise of the temperature.
NASA Astrophysics Data System (ADS)
Rogatko, Marek
2016-03-01
The uniqueness of a static asymptotically flat photon sphere for a static black hole solution in the Einstein-Maxwell-dilaton theory with an arbitrary coupling constant is proposed. Using the conformal positive energy theorem, we show that the dilaton photon sphere subject to the nonextremality condition constitutes a cylinder over a topological sphere.
NASA Astrophysics Data System (ADS)
Lin, Kai; Yang, Shu-Zheng
2009-10-01
Fermions tunneling of the non-stationary Dilaton-Maxwell black hole is investigated with general tortoise coordinate transformation. The Dirac equation is simplified by semiclassical approximation so that the Hamilton-Jacobi equation is generated. Finally the tunneling rate and the Hawking temperature is calculated.
Maxwell's Relations for a van der Waals Gas and a Nuclear Paramagnetic System.
ERIC Educational Resources Information Center
Herlihy, James; And Others
1981-01-01
Since Maxwell's relations are derived in general form from the first to second laws, and students often wonder what they mean and how they are used, appropriate partition functions for van der Waals gas and the nuclear paramagnetic system are used to obtain entropy expressions and equations of state. (Author/SK)
Colliding-wave generalizations of the Nutku-Halil metric in the Einstein-Maxwell theory
Garcia Diaz, A.
1988-08-01
A class of nondiagonal cylindrically symmetric algebraically general solutions of the Einstein-Maxwell equations is given. These solutions are interpretable as gravitational colliding waves supporting an electromagnetic field; they are generalizations of the Nutku-Halil solution. The new metric, derived by a Harrison transformation, is endowed with four free parameters.
An Infinite Number of Static Soliton Solutions to the 5D Einstein-Maxwell Equations
NASA Astrophysics Data System (ADS)
Azuma, T.; Koikawa, T.
2007-08-01
The soliton technique is applied to the 5D static Einstein-Maxwell equations, and an infinite number of solutions are explicitly obtained. We study the rod structure of 2-soliton solutions and show that the 5D Reissner-Nordström solution and the 5D Majumdar-Papapetrou-type solution are included among the 2-soliton solutions.
The Space-Time CE/SE Method for Solving Maxwell's Equations in Time-Domain
NASA Technical Reports Server (NTRS)
Wang, X. Y.; Chen, C. L.; Liu, Yen
2002-01-01
An innovative finite-volume-type numerical method named as the space-time conservation element and solution element (CE/SE) method is applied to solve time-dependent Maxwell's equations in this paper. Test problems of electromagnetics scattering and antenna radiation are solved for validations. Numerical results are presented and compared with the analytical solutions, showing very good agreements.
Simple Derivation of the Maxwell Stress Tensor and Electrostrictive Effects in Crystals
ERIC Educational Resources Information Center
Juretschke, H. J.
1977-01-01
Shows that local equilibrium and energy considerations in an elastic dielectric crystal lead to a simple derivation of the Maxwell stress tensor in anisotropic dielectric solids. The resulting equilibrium stress-strain relations are applied to determine the deformations of a charged parallel plate capacitor. (MLH)
A Problem and Its Solution Involving Maxwell's Equations and an Inhomogeneous Medium.
ERIC Educational Resources Information Center
Williamson, W., Jr.
1980-01-01
Maxwell's equation are solved for an inhomogeneous medium which has a coordinate-dependent dielectric function. The problem and its solutions are given in a format which should make it useful as an intermediate or advanced level problem in an electrodynamics course. (Author/SK)
The Vlasov-Maxwell-Boltzmann system with a uniform ionic background near Maxwellians
NASA Astrophysics Data System (ADS)
Lei, Yuanjie; Zhao, Huijiang
2016-02-01
The two-species Vlasov-Maxwell-Boltzmann system is an important model for plasma physics describing the time evolution of dilute charged particles consisting of electrons and ions under the influence of the self-consistent internally generated Lorentz forces. In physical situations the ion mass is usually much larger than the electron mass so that the electrons move much faster than the ions. Thus, the ions are often described by a fixed ion background and only the electrons move. For such a simple case, the two-species Vlasov-Maxwell-Boltzmann system is reduced to the one-species Vlasov-Maxwell-Boltzmann system. Although the one-species Vlasov-Maxwell-Boltzmann system is a simplified model of the two-species Vlasov-Maxwell-Boltzmann system, its global well-posedness theory near a given global Maxwellian in the perturbative framework is more difficult than the two-species case, which is partially due to the slow-decay of the electromagnetic field and up to now, the problem on the construction of global in time solutions near a given global Maxwellian in the perturbative framework for the Cauchy problem of the one-species Vlasov-Maxwell-Boltzmann system with cutoff non-hard sphere intermolecular collisions remains unsolved. It is shown in this paper that the Cauchy problem of the one-species Vlasov-Maxwell-Boltzmann system with cutoff non-hard sphere intermolecular collisions including the cutoff inverse power law potentials is globally well-posed provided that the perturbative initial data satisfies certain regularity, smallness, and integrability conditions. Our analysis is based on a new time-velocity weighted energy method with two key technical parts: one is to introduce the exponentially weighted estimates into the cutoff Boltzmann operator and the other is to design a delicate temporal energy X (t)-norm to obtain its uniform bound. As a by-product of our analysis, we can also deduce certain temporal decay estimates on the global solutions constructed above
NASA Astrophysics Data System (ADS)
Goodman, J. W.
This book is based on the thesis that some training in the area of statistical optics should be included as a standard part of any advanced optics curriculum. Random variables are discussed, taking into account definitions of probability and random variables, distribution functions and density functions, an extension to two or more random variables, statistical averages, transformations of random variables, sums of real random variables, Gaussian random variables, complex-valued random variables, and random phasor sums. Other subjects examined are related to random processes, some first-order properties of light waves, the coherence of optical waves, some problems involving high-order coherence, effects of partial coherence on imaging systems, imaging in the presence of randomly inhomogeneous media, and fundamental limits in photoelectric detection of light. Attention is given to deterministic versus statistical phenomena and models, the Fourier transform, and the fourth-order moment of the spectrum of a detected speckle image.
ERIC Educational Resources Information Center
Chicot, Katie; Holmes, Hilary
2012-01-01
The use, and misuse, of statistics is commonplace, yet in the printed format data representations can be either over simplified, supposedly for impact, or so complex as to lead to boredom, supposedly for completeness and accuracy. In this article the link to the video clip shows how dynamic visual representations can enliven and enhance the…
ERIC Educational Resources Information Center
Catley, Alan
2007-01-01
Following the announcement last year that there will be no more math coursework assessment at General Certificate of Secondary Education (GCSE), teachers will in the future be able to devote more time to preparing learners for formal examinations. One of the key things that the author has learned when teaching statistics is that it makes for far…
NASA Astrophysics Data System (ADS)
Goodman, Joseph W.
2000-07-01
The Wiley Classics Library consists of selected books that have become recognized classics in their respective fields. With these new unabridged and inexpensive editions, Wiley hopes to extend the life of these important works by making them available to future generations of mathematicians and scientists. Currently available in the Series: T. W. Anderson The Statistical Analysis of Time Series T. S. Arthanari & Yadolah Dodge Mathematical Programming in Statistics Emil Artin Geometric Algebra Norman T. J. Bailey The Elements of Stochastic Processes with Applications to the Natural Sciences Robert G. Bartle The Elements of Integration and Lebesgue Measure George E. P. Box & Norman R. Draper Evolutionary Operation: A Statistical Method for Process Improvement George E. P. Box & George C. Tiao Bayesian Inference in Statistical Analysis R. W. Carter Finite Groups of Lie Type: Conjugacy Classes and Complex Characters R. W. Carter Simple Groups of Lie Type William G. Cochran & Gertrude M. Cox Experimental Designs, Second Edition Richard Courant Differential and Integral Calculus, Volume I RIchard Courant Differential and Integral Calculus, Volume II Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume I Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume II D. R. Cox Planning of Experiments Harold S. M. Coxeter Introduction to Geometry, Second Edition Charles W. Curtis & Irving Reiner Representation Theory of Finite Groups and Associative Algebras Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume I Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume II Cuthbert Daniel Fitting Equations to Data: Computer Analysis of Multifactor Data, Second Edition Bruno de Finetti Theory of Probability, Volume I Bruno de Finetti Theory of Probability, Volume 2 W. Edwards Deming Sample Design in Business Research
Maxwell's fish-eye lens and the mirage of perfect imaging
NASA Astrophysics Data System (ADS)
Merlin, R.
2011-02-01
Recent claims that Maxwell's fish-eye is a perfect lens, capable of providing images with deep subwavelength resolution, are examined. We show that the imaging properties of a dispersionless fish-eye are very similar to those of an ideal spherical cavity. Using this correspondence, we prove that the correct solution to Maxwell equations in the fish-eye gives image sizes that are consistent with the standard diffraction limit. Perfect focusing is an optical illusion that results from placing a time-reversed source at the position of the geometrical image which, when combined with the field due to the primary (object) source, mimics the behavior of a perfect drain. Issues of causality are briefly discussed. We also demonstrate that passive outlets are not a good alternative to time-reversed sources for broadband drain-like behavior and that, even if they were, they could not do a better job than conventional optical systems at providing high resolution.
Hybrid resonance and long-time asymptotic of the solution to Maxwell's equations
NASA Astrophysics Data System (ADS)
Després, Bruno; Weder, Ricardo
2016-03-01
We study the long-time asymptotic of the solutions to Maxwell's equation in the case of an upper-hybrid resonance in the cold plasma model. We base our analysis in the transfer to the time domain of the recent results of B. Després, L.M. Imbert-Gérard and R. Weder (2014) [15], where the singular solutions to Maxwell's equations in the frequency domain were constructed by means of a limiting absorption principle and a formula for the heating of the plasma in the limit of vanishing collision frequency was obtained. Currently there is considerable interest in these problems, in particular, because upper-hybrid resonances are a possible scenario for the heating of plasmas, and since they can be a model for the diagnostics involving wave scattering in plasmas.
The Mean-Field Limit for a Regularized Vlasov-Maxwell Dynamics
NASA Astrophysics Data System (ADS)
Golse, François
2012-03-01
The present work establishes the mean-field limit of a N-particle system towards a regularized variant of the relativistic Vlasov-Maxwell system, following the work of Braun-Hepp [Commun Math Phys 56:101-113, 1977] and Dobrushin [Func Anal Appl 13:115-123, 1979] for the Vlasov-Poisson system. The main ingredients in the analysis of this system are (a) a kinetic formulation of the Maxwell equations in terms of a distribution of electromagnetic potential in the momentum variable, (b) a regularization procedure for which an analogue of the total energy—i.e. the kinetic energy of the particles plus the energy of the electromagnetic field—is conserved and (c) an analogue of Dobrushin's stability estimate for the Monge-Kantorovich-Rubinstein distance between two solutions of the regularized Vlasov-Poisson dynamics adapted to retarded potentials.
Maxwell's second- and third-order equations of transfer for non-Maxwellian gases
NASA Technical Reports Server (NTRS)
Baganoff, D.
1992-01-01
Condensed algebraic forms for Maxwell's second- and third-order equations of transfer are developed for the case of molecules described by either elastic hard spheres, inverse-power potentials, or by Bird's variable hard-sphere model. These hardly reduced, yet exact, equations provide a new point of origin, when using the moment method, in seeking approximate solutions in the kinetic theory of gases for molecular models that are physically more realistic than that provided by the Maxwell model. An important by-product of the analysis when using these second- and third-order relations is that a clear mathematical connection develops between Bird's variable hard-sphere model and that for the inverse-power potential.
Variational symmetries and conservation laws of the coupled Maxwell-Dirac equations
NASA Astrophysics Data System (ADS)
Fliss, Jackson; Menon, Balraj
2012-03-01
The role of symmetry groups has become increasing important in the study of modern physics. The theorems of Emmy Noether link conservation laws to symmetries of the action functional. Contact symmetries can be constructed from the invariance of the action under infinitesimal transformations that are dependent on the independent variables and the dependent variables. First-order generalized symmetries can be constructed by including the first derivatives of the dependent variables. In the case of the coupled Maxwell-Dirac equations, the independent variables and dependent variables are, respectively, the spacetime coordinates and the fields. In this talk I will review the familiar symmetries of field theory, as well as investigate the first-order generalized symmetries of the coupled Maxwell-Dirac equations. The local conservation laws associated with each of these, via the theorems of Noether, will be addressed as well.
Numerical solutions of Maxwell's equations for nonlinear-optical pulse propagation
NASA Astrophysics Data System (ADS)
Hile, Cheryl V.; Kath, William L.
1996-06-01
A model and numerical solutions of Maxwell's equations describing the propagation of short, solitonlike pulses in nonlinear dispersive optical media are presented. The model includes linear dispersion expressed in the time domain, a Kerr nonlinearity, and a coordinate system moving with the group velocity of the pulse. Numerical solutions of Maxwell's equations are presented for circularly polarized and linearly polarized electromagnetic fields. When the electromagnetic fields are assumed to be circularly polarized, numerical solutions are compared directly with solutions of the nonlinear Schrodinger (NLS) equation. These comparisons show good agreement and indicate that the NLS equation provides an excellent model for short-pulse propagation. When the electromagnetic fields are assumed to be linearly polarized, the propagation of daughter pulses, small-amplitude pulses at three times the frequency of the solitonlike pulse, are observed in the numerical solution. These daughter pulses are shown to be the direct result of third harmonics generated by the main, solitonlike, pulse.
Removal of self-interactions in the Dirac-Maxwell equations in one spatial dimension
NASA Astrophysics Data System (ADS)
Norris, S.; Unger, J.; Lv, Q. Z.; Su, Q.; Grobe, R.
2016-03-01
We propose a theoretical framework that permits us to eliminate the unphysical self-repulsion that occurs if a spatially localized charged particle interacts with its own electric field. As an example of this framework, we study the time-resolved interaction between an electronic and positronic wave packet by solving the coupled set of two-particle Dirac-Maxwell equations. The restriction of the dynamics to only one spatial dimension permits us to neglect the magnetic field and therefore any effects due to retardation are absent. Here the unwanted self-repulsion can be removed by separating the total electric field into two portions, each of which is generated by only one particle and is evolved independently of the other. For example, the Maxwell equation for the electronic field has only the electronic charge density as a source term and only this field is coupled to the positron in the two-particle Dirac equation.
1986-01-01
Official population data for the USSR are presented for 1985 and 1986. Part 1 (pp. 65-72) contains data on capitals of union republics and cities with over one million inhabitants, including population estimates for 1986 and vital statistics for 1985. Part 2 (p. 72) presents population estimates by sex and union republic, 1986. Part 3 (pp. 73-6) presents data on population growth, including birth, death, and natural increase rates, 1984-1985; seasonal distribution of births and deaths; birth order; age-specific birth rates in urban and rural areas and by union republic; marriages; age at marriage; and divorces. PMID:12178831
Shanker, B.; Lakhtakia, A. )
1993-01-01
Adhesives with dielectric loss are needed for microwave-assisted joining of polymeric substances. The dielectric loss in an otherwise suitable adhesive may be enhanced by doping it with fine metallic particles. Here we use a recently extended Maxwell Garnett formalism to estimate the complex dielectric constant of a metal-doped composite adhesive, with specific focus on the imaginary part of the dielectric constant of the composite adhesive. 14 refs.
Taub-NUT/bolt black holes in Gauss-Bonnet-Maxwell gravity
Dehghani, M.H.; Hendi, S. H.
2006-04-15
We present a class of higher-dimensional solutions to Gauss-Bonnet-Maxwell equations in 2k+2 dimensions with a U(1) fibration over a 2k-dimensional base space B. These solutions depend on two extra parameters, other than the mass and the Newman-Unti-Tamburino charge, which are the electric charge q and the electric potential at infinity V. We find that the form of metric is sensitive to geometry of the base space, while the form of electromagnetic field is independent of B. We investigate the existence of Taub-Newman-Unti-Tamburino/bolt solutions and find that in addition to the two conditions of uncharged Newman-Unti-Tamburino solutions, there exist two other conditions. These two extra conditions come from the regularity of vector potential at r=N and the fact that the horizon at r=N should be the outer horizon of the black hole. We find that for all nonextremal Newman-Unti-Tamburino solutions of Einstein gravity having no curvature singularity at r=N, there exist Newman-Unti-Tamburino solutions in Gauss-Bonnet-Maxwell gravity. Indeed, we have nonextreme Newman-Unti-Tamburino solutions in 2+2k dimensions only when the 2k-dimensional base space is chosen to be CP{sup 2k}. We also find that the Gauss-Bonnet-Maxwell gravity has extremal Newman-Unti-Tamburino solutions whenever the base space is a product of 2-torii with at most a 2-dimensional factor space of positive curvature, even though there a curvature singularity exists at r=N. We also find that one can have bolt solutions in Gauss-Bonnet-Maxwell gravity with any base space. The only case for which one does not have black hole solutions is in the absence of a cosmological term with zero curvature base space.
Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme
NASA Astrophysics Data System (ADS)
Squire, J.; Qin, H.; Tang, W. M.
2012-08-01
A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of discrete exterior calculus [Desbrun et al., e-print arXiv:math/0508341 (2005)], the field solver, interpolation scheme, and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law.
NASA Astrophysics Data System (ADS)
Hamelinck, Wouter
2008-09-01
Cavity resonators are modelled using a Maxwell eigenvalue problem. In order to obtain a reliable finite element approximation one has to carefully use an appropriate discrete finite element space. In the present paper we extend the known conditions to assure a correct approximation of the spectrum to the case where numerical integration occurs and where curvilinear boundaries are present. We present a set of sufficient conditions which are similar to the case where those so called variational crimes are absent.
Analytical and numerical study of Gauss-Bonnet holographic superconductors with Power-Maxwell field
NASA Astrophysics Data System (ADS)
Sheykhi, Ahmad; Salahi, Hamid Reza; Montakhab, Afshin
2016-04-01
We provide an analytical as well as a numerical study of the holographic s-wave superconductors in Gauss-Bonnet gravity with Power-Maxwell electrodynamics. We limit our study to the case where scalar and gauge fields do not have an effect on the background metric. We use a variational method, based on Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shooting method in order to compare with our analytical results. Interestingly enough, we observe that unlike Born-Infeld-like nonlinear electrodynamics which decrease the critical temperature compared to the linear Maxwell field, the Power-Maxwell electrodynamics is able to increase the critical temperature of the holographic superconductors in the sublinear regime. We find that requiring the finite value for the gauge field on the asymptotic boundary r → ∞, restricts the power parameter, q, of the Power-Maxwell field to be in the range 1 /2 < q < ( d - 1) /2. Our study indicates that it is quite possible to make condensation easier as q decreases in its allowed range. We also find that for all values of q, the condensation can be affected by the Gauss-Bonnet coefficient α. However, the presence of the Gauss-Bonnet term makes the transition slightly harder. Finally, we obtain an analytic expression for the order parameter and thus obtain the associated critical exponent near the phase transition. We find that the critical exponent has its universal value of β = 1 /2 regardless of the parameters q, α as well as dimension d, consistent with mean-field values obtained in previous studies.
NOTE: A note on the formulation of the Maxwell equations for a macroscopic medium
NASA Astrophysics Data System (ADS)
Leung, P. T.; Ni, G. J.
2008-07-01
In formulating the Maxwell equations for electrodynamics in the presence of a macroscopic continuous medium, it is common among standard textbooks to simply borrow expressions for the polarization charges and magnetization currents derived in electrostatics and magnetostatics, without much explicit justifications for using them in electrodynamics. Here we emphasize that these quantities must be introduced without resorting to results in statics, and must be derived directly from their definitions which remain valid in the general situation of electrodynamics.
Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme
Squire, J.; Tang, W. M.; Qin, H.
2012-08-15
A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of discrete exterior calculus [Desbrun et al., e-print arXiv:math/0508341 (2005)], the field solver, interpolation scheme, and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law.
Geometric Integration Of The Vlasov-Maxwell System With A Variational Particle-in-cell Scheme
J. Squire, H. Qin and W.M. Tang
2012-03-27
A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of Discrete Exterior Calculus [1], the field solver, interpolation scheme and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law.
Finite-surface method for the Maxwell equations with corner singularities
NASA Technical Reports Server (NTRS)
Vinokur, Marcel; Yarrow, Maurice
1994-01-01
The finite-surface method for the two-dimensional Maxwell equations in generalized coordinates is extended to treat perfect conductor boundaries with sharp corners. Known singular forms of the grid and the electromagnetic fields in the neighborhood of each corner are used to obtain accurate approximations to the surface and line integrals appearing in the method. Numerical results are presented for a harmonic plane wave incident on a finite flat plate. Comparisons with exact solutions show good agreement.
A sweeping preconditioner for time-harmonic Maxwell's equations with finite elements
NASA Astrophysics Data System (ADS)
Tsuji, Paul; Engquist, Bjorn; Ying, Lexing
2012-05-01
This paper is concerned with preconditioning the stiffness matrix resulting from finite element discretizations of Maxwell's equations in the high frequency regime. The moving PML sweeping preconditioner, first introduced for the Helmholtz equation on a Cartesian finite difference grid, is generalized to an unstructured mesh with finite elements. The method dramatically reduces the number of GMRES iterations necessary for convergence, resulting in an almost linear complexity solver. Numerical examples including electromagnetic cloaking simulations are presented to demonstrate the efficiency of the proposed method.
Large time behavior of the isentropic compressible Navier-Stokes-Maxwell system
NASA Astrophysics Data System (ADS)
Chen, Yan; Li, Fucai; Zhang, Zhipeng
2016-08-01
In this paper, we study the large time behavior of the isentropic compressible Navier-Stokes-Maxwell system introduced by Jiang and Li (Nonlinearity 25(6):1735-1752, 2012) in the whole space {{{R}}^3} when the initial data are a small perturbation of some given constant state. We obtain the desired result through taking the refined analysis on the time decay property and Green's function of the linearized system. Moreover, we also obtain the optimal time rate of the solution.
Spacetimes with Killing tensors. [for Einstein-Maxwell fields with certain spinor indices
NASA Technical Reports Server (NTRS)
Hughston, L. P.; Sommers, P.
1973-01-01
The characteristics of the Killing equation and the Killing tensor are discussed. A conformal Killing tensor is of interest inasmuch as it gives rise to a quadratic first integral for null geodesic orbits. The Einstein-Maxwell equations are considered together with the Bianchi identity and the conformal Killing tensor. Two examples for the application of the considered relations are presented, giving attention to the charged Kerr solution and the charged C-metric.
Analytic solutions of the geodesic equation for Einstein-Maxwell-dilaton-axion black holes
NASA Astrophysics Data System (ADS)
Flathmann, Kai; Grunau, Saskia
2015-11-01
In this article we study the geodesic motion of test particles and light in the Einstein-Maxwell-dilaton-axion black hole spacetime. We derive the equations of motion and present their solutions in terms of the Weierstraß ℘, σ and ζ functions. With the help of parametric diagrams and effective potentials we analyze the geodesic motion and give a list of all possible orbit types.
A comparison of Fick and Maxwell-Stefan diffusion formulations in PEMFC gas diffusion layers
NASA Astrophysics Data System (ADS)
Lindstrom, Michael; Wetton, Brian
2016-04-01
This paper explores the mathematical formulations of Fick and Maxwell-Stefan diffusion in the context of polymer electrolyte membrane fuel cell cathode gas diffusion layers. The simple Fick law with a diagonal diffusion matrix is an approximation of Maxwell-Stefan. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. For this application, the formulations can be compared computationally in a simple, one dimensional setting. Despite the models' seemingly different structure, it is observed that the predictions of the formulations are very similar on the cathode when air is used as oxidant. The two formulations give quite different results when the Nitrogen in the air oxidant is replaced by helium (this is often done as a diagnostic for fuel cells designs). The two formulations also give quite different results for the anode with a dilute Hydrogen stream. These results give direction to when Maxwell-Stefan diffusion, which is more complicated to implement computationally in many codes, should be used in fuel cell simulations.
Hidden in Plain View: The Material Invariance of Maxwell-Hertz-Lorentz Electrodynamics
NASA Astrophysics Data System (ADS)
Christov, C. I.
2006-04-01
Maxwell accounted for the apparent elastic behavior of the electromagnetic field through augmenting Ampere's law by the so-called displacement current much in the same way that he treated the viscoelasticity of gases. Original Maxwell constitutive relations for both electrodynamics and fluid dynamics were not material invariant, while combin- ing Faraday's law and the Lorentz force makes the first of Maxwell's equation material invariant. Later on, Oldroyd showed how to make a viscoelastic constitutive law mate- rial invariant. The main assumption was that the proper description of a constitutive law must be material invariant. Assuming that the electromagnetic field is a material field, we show here that if the upper convected Oldroyd derivative (related to Lie derivative) is used, the displacement current becomes material invariant. The new formulation ensures that the equation for conser- vation of charge is also material invariant which vindicates the choice of Oldroyd derivative over the standard convec- tive derivative. A material invariant field model is by ne- cessity Galilean invariant. We call the material field (the manifestation of which are the equations of electrodynam- ics the metacontinuum), in order to distinguish it form the standard material continua.
Thermodynamics of charged rotating dilaton black branes with power-law Maxwell field
NASA Astrophysics Data System (ADS)
Zangeneh, M. Kord; Sheykhi, A.; Dehghani, M. H.
2015-10-01
In this paper, we construct a new class of charged rotating dilaton black brane solutions, with a complete set of rotation parameters, which is coupled to a nonlinear Maxwell field. The Lagrangian of the matter field has the form of the power-law Maxwell field. We study the causal structure of the spacetime and its physical properties in ample details. We also compute thermodynamic and conserved quantities of the spacetime, such as the temperature, entropy, mass, charge, and angular momentum. We find a Smarr-formula for the mass and verify the validity of the first law of thermodynamics on the black brane horizon. Finally, we investigate the thermal stability of solutions in both the canonical and the grand-canonical ensembles and disclose the effects of dilaton field and nonlinearity of the Maxwell field on the thermal stability of the solutions. We find that, for α ≤ 1, charged rotating black brane solutions are thermally stable independent of the values of the other parameters. For α >1, the solutions can encounter an unstable phase depending on the metric parameters.
A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer
NASA Astrophysics Data System (ADS)
Kadry, Zakaria; Magdy, A. Sirwah; Sameh, A. Alkharashi
2011-06-01
Based on a modified-Darcy—Maxwell model, two-dimensional, incompressible and heat transfer flow of two bounded layers, through electrified Maxwell fluids in porous media is performed. The driving force for the instability under an electric field, is an electrostatic force exerted on the free charges accumulated at the dividing interface. Normal mode analysis is considered to study the linear stability of the disturbances layers. The solutions of the linearized equations of motion with the boundary conditions lead to an implicit dispersion relation between the growth rate and wave number. These equations are parameterized by Weber number, Reynolds number, Marangoni number, dimensionless conductivities, and dimensionless electric potentials. The case of long waves interfacial stability has been studied. The stability criteria are performed theoretically in which stability diagrams are obtained. In the limiting cases, some previously published results can be considered as particular cases of our results. It is found that the Reynolds number plays a destabilizing role in the stability criteria, while the damping influence is observed for the increasing of Marangoni number and Maxwell relaxation time.
Elastomeric composites with high dielectric constant for use in Maxwell stress actuators
NASA Astrophysics Data System (ADS)
Szabo, Jeffrey P.; Hiltz, Johnathan A.; Cameron, Colin G.; Underhill, Royale S.; Massey, Jason; White, Brian; Leidner, Jacob
2003-07-01
Electroactive polymer actuators that utilize the Maxwell stress effect have generated considerable interest in recent years for use in applications such as artificial muscles, sensors, and parasitic energy capture. In order to maximize performance, the dielectric layer in Maxwell stress actuators should ideally have a high dielectric constant and high dielectric breakdown strength. In this study, the effect of high dielectric constant fillers on the electrical and mechanical properties of thin elastomeric films was examined. The fillers studied included the inorganic compounds titanium dioxide (TiO2), barium titanate (BaTiO3), and lead magnesium niobate-lead titanate (Pb(Mg1/3Nb2/3)O3-PbTiO). A high dielectric constant filler based on a polymeric conjugated ligand-metal complex, poly(copper phthalocyanine), was also synthesized and studied. Maxwell stress actuators fabricated with BaTiO3 dispersed in a silicone elastomer matrix were evaluated and compared with unfilled systems. A model was presented which relates filler volume fraction to actuation stress, strain, and elastic energy density at fields below dielectric breakdown. The model and experimental results suggest that for the case of strong filler particle-elastomer matrix interaction, actuation strain decreases with increasing filler content.
Higher-derivative gravity with non-minimally coupled Maxwell field
NASA Astrophysics Data System (ADS)
Feng, Xing-Hui; Lü, H.
2016-04-01
We construct higher-derivative gravities with a non-minimally coupled Maxwell field. The Lagrangian consists of polynomial invariants built from the Riemann tensor and the Maxwell field strength in such a way that the equations of motion are second order for both the metric and the Maxwell potential. We also generalize the construction to involve a generic non-minimally coupled p-form field strength. We then focus on one low-lying example in four dimensions and construct the exact magnetically charged black holes. We also construct exact electrically charged z=2 Lifshitz black holes. We obtain approximate dyonic black holes for the small coupling constant or small charges. We find that the thermodynamics based on the Wald formalism disagrees with that derived from the Euclidean action procedure, suggesting this may be a general situation in higher-derivative gravities with non-minimally coupled form fields. As an application in the AdS/CFT correspondence, we study the entropy/viscosity ratio for the AdS or Lifshitz planar black holes, and find that the exact ratio can be obtained without having to know the details of the solutions, even for this higher-derivative theory.
Numerical Simulations of Self-Focused Pulses Using the Nonlinear Maxwell Equations
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)
1994-01-01
This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations. Abstract of a proposed paper for presentation at the meeting NONLINEAR OPTICS: Materials, Fundamentals, and Applications, Hyatt Regency Waikaloa, Waikaloa, Hawaii, July 24-29, 1994, Cosponsored by IEEE/Lasers and Electro-Optics Society and Optical Society of America
Analysis of a coupled spin drift-diffusion Maxwell-Landau-Lifshitz system
NASA Astrophysics Data System (ADS)
Zamponi, Nicola; Jüngel, Ansgar
2016-05-01
The existence of global weak solutions to a coupled spin drift-diffusion and Maxwell-Landau-Lifshitz system is proved. The equations are considered in a two-dimensional magnetic layer structure and are supplemented with Dirichlet-Neumann boundary conditions. The spin drift-diffusion model for the charge density and spin density vector is the diffusion limit of a spinorial Boltzmann equation for a vanishing spin polarization constant. The Maxwell-Landau-Lifshitz system consists of the time-dependent Maxwell equations for the electric and magnetic fields and of the Landau-Lifshitz-Gilbert equation for the local magnetization, involving the interaction between magnetization and spin density vector. The existence proof is based on a regularization procedure, L2-type estimates, and Moser-type iterations which yield the boundedness of the charge and spin densities. Furthermore, the free energy is shown to be nonincreasing in time if the magnetization-spin interaction constant in the Landau-Lifshitz equation is sufficiently small.
L2-stability of the Vlasov-Maxwell-Boltzmann system near global Maxwellians
NASA Astrophysics Data System (ADS)
Ha, Seung-Yeal; Xiao, Qinghua; Xiong, Linjie; Zhao, Huijiang
2013-12-01
We present a L2-stability theory of the Vlasov-Maxwell-Boltzmann system for the two-species collisional plasma. We show that in a perturbative regime of a global Maxwellian, the L2-distance between two strong solutions can be controlled by that between initial data in a Lipschitz manner. Our stability result extends earlier results [Ha, S.-Y. and Xiao, Q.-H., "A revisiting to the L2-stability theory of the Boltzmann equation near global Maxwellians," (submitted) and Ha, S.-Y., Yang, X.-F., and Yun, S.-B., "L2 stability theory of the Boltzmann equation near a global Maxwellian," Arch. Ration. Mech. Anal. 197, 657-688 (2010)] on the L2-stability of the Boltzmann equation to the Boltzmann equation coupled with self-consistent external forces. As a direct application of our stability result, we show that classical solutions in Duan et al. ["Optimal large-time behavior of the Vlasov-Maxwell-Boltzmann system in the whole space," Commun. Pure Appl. Math. 24, 1497-1546 (2011)] and Guo ["The Vlasov-Maxwell-Boltzmann system near Maxwellians," Invent. Math. 153(3), 593-630 (2003)] satisfy a uniform L2-stability estimate. This is the first result on the L2-stability of the Boltzmann equation coupled with self-consistent field equations in three dimensions.
NASA Astrophysics Data System (ADS)
Su, Hongling; Li, Shengtai
2016-04-01
In this paper, we propose two new energy/dissipation-preserving Birkhoffian multi-symplectic methods (Birkhoffian and Birkhoffian box) for Maxwell's equations with dissipation terms. After investigating the non-autonomous and autonomous Birkhoffian formalism for Maxwell's equations with dissipation terms, we first apply a novel generating functional theory to the non-autonomous Birkhoffian formalism to propose our Birkhoffian scheme, and then implement a central box method to the autonomous Birkhoffian formalism to derive the Birkhoffian box scheme. We have obtained four formal local conservation laws and three formal energy global conservation laws. We have also proved that both of our derived schemes preserve the discrete version of the global/local conservation laws. Furthermore, the stability, dissipation and dispersion relations are also investigated for the schemes. Theoretical analysis shows that the schemes are unconditionally stable, dissipation-preserving for Maxwell's equations in a perfectly matched layer (PML) medium and have second order accuracy in both time and space. Numerical experiments for problems with exact theoretical results are given to demonstrate that the Birkhoffian multi-symplectic schemes are much more accurate in preserving energy than both the exponential finite-difference time-domain (FDTD) method and traditional Hamiltonian scheme. We also solve the electromagnetic pulse (EMP) propagation problem and the numerical results show that the Birkhoffian scheme recovers the magnitude of the current source and reaction history very well even after long time propagation.
Non-Abelian Gauge Groups for Real and Complex Amended Maxwell's Equations
NASA Astrophysics Data System (ADS)
Rauscher, E. A.
2002-04-01
We have developed an eight dimensional complex Minkowski space M4, compiled of four real dimensions and four imaginary dimensions, which is constant with Lorentz invariance and analytic continuation in the complex plane(1). Complexification, of Maxwell's equations requires a non-Abelian gauge group, which amends the usual theory which utilizes the usual unimodular Weyl U1 group. We have examined the modification of gauge conditions using higher symmetry groups such as SU2, SUn and other groups such as the SL(2,c) double cover group of the rotational group SO(3,1). The mappability of the twistor algebra and the spinor calculus is analyzed in the context of the electromagnetic theory. Thus we are led to new and interesting physics involving extended metrical space constraints, the usual transverse and also longitudinal, non Hertzian electric and magnetic field solutions to Maxwell's equations, possibly leading to new communications systems and antennae theory, non-zero solutions to Ñ·B, and a possible finite but small rest mass of the photon. Comparison of our theoretical approach is made to the work of T.W. Barrett and H.F. Hermuth?s work on amended Maxwell's theories. (1) C. Ramon and E. A. Rauscher, Found. of Phys. 10, 661 (1980)
Reformulation of Maxwell's equations to incorporate near-solute solvent structure.
Yang, Pei-Kun; Lim, Carmay
2008-09-01
Maxwell's equations, which treat electromagnetic interactions between macroscopic charged objects in materials, have explained many phenomena and contributed to many applications in our lives. Derived in 1861 when no methods were available to determine the atomic structure of macromolecules, Maxwell's equations assume the solvent to be a structureless continuum. However, near-solute solvent molecules are highly structured, unlike far-solute bulk solvent molecules. Current methods cannot treat both the near-solute solvent structure and time-dependent electromagnetic interactions in a macroscopic system. Here, we derive "microscopic" electrodynamics equations that can treat macroscopic time-dependent electromagnetic field problems like Maxwell's equations and reproduce the solvent molecular and dipole density distributions observed in molecular dynamics simulations. These equations greatly reduce computational expense by not having to include explicit solvent molecules, yet they treat the solvent electrostatic and van der Waals effects more accurately than continuum models. They provide a foundation to study electromagnetic interactions between molecules in a macroscopic system that are ubiquitous in biology, bioelectromagnetism, and nanotechnology. The general strategy presented herein to incorporate the near-solute solvent structure would enable studies on how complex cellular protein-ligand interactions are affected by electromagnetic radiation, which could help to prevent harmful electromagnetic spectra or find potential therapeutic applications. PMID:18698705
Ronald C. Davidson; W. Wei-li Lee; Hong Qin; Edward Startsev
2001-11-08
This paper develops a clear procedure for solving the nonlinear Vlasov-Maxwell equations for a one-component intense charged particle beam or finite-length charge bunch propagating through a cylindrical conducting pipe (radius r = r(subscript)w = const.), and confined by an applied focusing force. In particular, the nonlinear Vlasov-Maxwell equations are Lorentz-transformed to the beam frame ('primed' variables) moving with axial velocity relative to the laboratory. In the beam frame, the particle motions are nonrelativistic for the applications of practical interest, already a major simplification. Then, in the beam frame, we make the electrostatic approximation which fully incorporates beam space-charge effects, but neglects any fast electromagnetic processes with transverse polarization (e.g., light waves). The resulting Vlasov-Maxwell equations are then Lorentz-transformed back to the laboratory frame, and properties of the self-generated fields and resulting nonlinear Vlasov-Maxwell equations in the laboratory frame are discussed.
NASA Astrophysics Data System (ADS)
Essén, Hanno; Nordmark, Arne B.
2016-09-01
The canonical Poisson bracket algebra of four-dimensional relativistic mechanics is used to derive the equation of motion for a charged particle, with the Lorentz force, and the homogeneous Maxwell equations.
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Taflove, Allen
1992-01-01
The initial results for femtosecond electromagnetic soliton propagation and collision obtained from first principles, i.e., by a direct time integration of Maxwell's equations are reported. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit the modeling of 2D and 3D optical soliton propagation, scattering, and switching from the full-vector Maxwell's equations.
A Probabilistic Foundation of Elementary Particle Statistics. Part II.
NASA Astrophysics Data System (ADS)
Costantini, Domenico; Garibaldi, Ubaldo
The long history of ergodic and quasi-ergodic hypotheses provides the best example of the attempt to supply non-probabilistic justifications for the use of statistical mechanics in describing mechanical systems. In this paper we reverse the terms of the problem. We aim to show that accepting a probabilistic foundation of elementary particle statistics dispenses with the need to resort to ambiguous non-probabilistic notions like that of (in)distinguishability. In the quantum case, starting from suitable probability conditions, it is possible to deduce elementary particle statistics in a unified way. Following our approach Maxwell-Boltzmann statistics can also be deduced, and this deduction clarifies its status. Thus our primary aim in this paper is to give a mathematically rigorous deduction of the probability of a state with given energy for a perfect gas in statistical equilibrium; that is, a deduction of the equilibrium distributions for a perfect gas. A crucial step in this deduction is the statement of a unified statistical theory based on clearly formulated probability conditions from which the particle statistics follows. We believe that such a deduction represents an important improvement in elementary particle statistics, and a step towards a probabilistic foundation of statistical mechanics. The present Part II is devoted to this deduction. Part I presented the necessary tools. After the deduction of the probability of a state with given energy for a system in statistical equilibrium, we will propose in the last section a simple model giving an ergodic interpretation of the equilibrium distributions.
Self-consistent Maxwell-Bloch theory of quantum-dot-population switching in photonic crystals
Takeda, Hiroyuki; John, Sajeev
2011-05-15
We theoretically demonstrate the population switching of quantum dots (QD's), modeled as two-level atoms in idealized one-dimensional (1D) and two-dimensional (2D) photonic crystals (PC's) by self-consistent solution of the Maxwell-Bloch equations. In our semiclassical theory, energy states of the electron are quantized, and electron dynamics is described by the atomic Bloch equation, while electromagnetic waves satisfy the classical Maxwell equations. Near a waveguide cutoff in a photonic band gap, the local electromagnetic density of states (LDOS) and spontaneous emission rates exhibit abrupt changes with frequency, enabling large QD population inversion driven by both continuous and pulsed optical fields. We recapture and generalize this ultrafast population switching using the Maxwell-Bloch equations. Radiative emission from the QD is obtained directly from the surrounding PC geometry using finite-difference time-domain simulation of the electromagnetic field. The atomic Bloch equations provide a source term for the electromagnetic field. The total electromagnetic field, consisting of the external input and radiated field, drives the polarization components of the atomic Bloch vector. We also include a microscopic model for phonon dephasing of the atomic polarization and nonradiative decay caused by damped phonons. Our self-consistent theory captures stimulated emission and coherent feedback effects of the atomic Mollow sidebands, neglected in earlier treatments. This leads to remarkable high-contrast QD-population switching with relatively modest (factor of 10) jump discontinuities in the electromagnetic LDOS. Switching is demonstrated in three separate models of QD's placed (i) in the vicinity of a band edge of a 1D PC, (ii) near a cutoff frequency in a bimodal waveguide channel of a 2D PC, and (iii) in the vicinity of a localized defect mode side coupled to a single-mode waveguide channel in a 2D PC.
NASA Astrophysics Data System (ADS)
Munro, Peter R. T.; Curatolo, Andrea; Sampson, David D.
2016-03-01
Existing models of image formation in optical coherence tomography are based upon the extended Huygens-Fresnel formalism. These models all, to varying degrees, rely on scatterer ensemble averages, rather than deterministic scattering distributions. Whilst the former is sometimes preferable, there are a growing number of applications where the ability to predict image formation based upon deterministic refractive index distributions is of great interest, including, for example, image formation in turbid tissue. A rigorous model based upon three-dimensional solutions of Maxwell's equations offers a number of tantalising opportunities. For example, shedding light on features near or below the resolution of an OCT system and on the impact of phenomena usually described as diffraction, interference and scattering, but which more generally result from light scattering satisfying Maxwell's equations. A rigorous model allows inverse scattering methods to be developed not requiring the first-order Born approximation. Finally, a rigorous model can provide gold standard verification of myriad quantitative techniques currently being developed throughout the field. We have developed the first such model of image formation based upon three-dimensional solutions of Maxwell's equations, which has vastly different properties to models based on two-dimensional solutions. Although we present simulated B-scans, this model is equally applicable to C-scans. This has been made possible by advances in computational techniques and in computational resources routinely available. We will present the main features of our model, comparisons of measured and simulated image formation for phantoms and discuss the future of rigorous modelling in optical coherence tomography research and application.
L{sup 2}-stability of the Vlasov-Maxwell-Boltzmann system near global Maxwellians
Ha, Seung-Yeal Xiao, Qinghua; Xiong, Linjie Zhao, Huijiang
2013-12-15
We present a L{sup 2}-stability theory of the Vlasov-Maxwell-Boltzmann system for the two-species collisional plasma. We show that in a perturbative regime of a global Maxwellian, the L{sup 2}-distance between two strong solutions can be controlled by that between initial data in a Lipschitz manner. Our stability result extends earlier results [Ha, S.-Y. and Xiao, Q.-H., “A revisiting to the L{sup 2}-stability theory of the Boltzmann equation near global Maxwellians,” (submitted) and Ha, S.-Y., Yang, X.-F., and Yun, S.-B., “L{sup 2} stability theory of the Boltzmann equation near a global Maxwellian,” Arch. Ration. Mech. Anal. 197, 657–688 (2010)] on the L{sup 2}-stability of the Boltzmann equation to the Boltzmann equation coupled with self-consistent external forces. As a direct application of our stability result, we show that classical solutions in Duan et al. [“Optimal large-time behavior of the Vlasov-Maxwell-Boltzmann system in the whole space,” Commun. Pure Appl. Math. 24, 1497–1546 (2011)] and Guo [“The Vlasov-Maxwell-Boltzmann system near Maxwellians,” Invent. Math. 153(3), 593–630 (2003)] satisfy a uniform L{sup 2}-stability estimate. This is the first result on the L{sup 2}-stability of the Boltzmann equation coupled with self-consistent field equations in three dimensions.
Using quantum erasure to exorcize Maxwell's demon: I. Concepts and context
NASA Astrophysics Data System (ADS)
Scully, Marlan O.; Rostovtsev, Yuri; Sariyanni, Zoe-Elizabeth; Suhail Zubairy, M.
2005-10-01
Szilard [L. Szilard, Zeitschrift für Physik, 53 (1929) 840] made a decisive step toward solving the Maxwell demon problem by introducing and analyzing the single atom heat engine. Bennett [Sci. Am. 255 (1987) 107] completed the solution by pointing out that there must be an entropy, ΔS=kln2, generated as the result of information erased on each cycle. Nevertheless, others have disagreed. For example, philosophers such as Popper “have found the literature surrounding Maxwell's demon deeply problematic.” We propose and analyze a new kind of single atom quantum heat engine which allows us to resolve the Maxwell demon paradox simply, and without invoking the notions of information or entropy. The energy source of the present quantum engine [Scully, Phys. Rev. Lett. 87 (2001) 22601] is a Stern-Gerlach apparatus acting as a demonesque heat sorter. An isothermal compressor acts as the entropy sink. In order to complete a thermodynamic cycle, an energy of ΔW=kTln2 must be expended. This energy is essentially a “reset” or “eraser” energy. Thus Bennett's entropy ΔS=ΔW/T emerges as a simple consequence of the quantum thermodynamics of our heat engine. It would seem that quantum mechanics contains the kernel of information entropy at its very core. That is the concept of information erasure as it appears in quantum mechanics [Scully and Drühl, Phys. Rev. A 25 (1982) 2208] and the present quantum heat engine have a deep common origin.
Thermal equilibrium and statistical thermometers in special relativity.
Cubero, David; Casado-Pascual, Jesús; Dunkel, Jörn; Talkner, Peter; Hänggi, Peter
2007-10-26
There is an intense debate in the recent literature about the correct generalization of Maxwell's velocity distribution in special relativity. The most frequently discussed candidate distributions include the Jüttner function as well as modifications thereof. Here we report results from fully relativistic one-dimensional molecular dynamics simulations that resolve the ambiguity. The numerical evidence unequivocally favors the Jüttner distribution. Moreover, our simulations illustrate that the concept of "thermal equilibrium" extends naturally to special relativity only if a many-particle system is spatially confined. They make evident that "temperature" can be statistically defined and measured in an observer frame independent way. PMID:17995314
Quantization of the Maxwell fish-eye problem and the quantum-classical correspondence
Makowski, A. J.; Gorska, K. J.
2009-05-15
The so-called fish-eye model, originally investigated by Maxwell in geometrical optics, is studied both in the classical as well as in the quantum formulations. The best agreement between the two approaches is achieved by using a suitably constructed coherent state, which is of the SU(2) type. The perfect quantum-classical correspondence is obtained in the sense that classical rays go exactly over maxima of the corresponding quantum probability distributions. The distributions are made of linear combinations of the E=0 bound states of the considered model.
First Order Solutions for Klein-Gordon-Maxwell Equations in a Specific Curved Manifold Case
Murariu, Gabriel
2009-05-22
The aim of this paper is to study the SO(3,1)xU(1) gauge minimally coupled charged spinless field to a spherically symmetric curved space-time. It is derived the first order analytically approximation solution for the system of Klein-Gordon-Maxwell equations. Using these solutions, it evaluated the system electric charge density. The considered space -time manifold generalize an anterior studied one. The chosen space time configuration is of S diagonal type from the MAPLE GRTensor II metrics package.
Exact Solutions to the Einstein-Maxwell Equations Describing Wormholes and Handles
NASA Astrophysics Data System (ADS)
Khlestkov, Yu. A.; Sukhanova, L. A.
2016-06-01
On the basis of the exact solutions to the non-stationary spherically symmetric Einstein and Maxwell equations for dust matter and radial electromagnetic field, a model of a wormhole with the pulsating in time inner world and two static throats has been developed. It has been shown that such a wormhole with an arbitrary radius of the Gaussian curvature can connect both two different asymptotically flat space-times and two regions of the selfsame space-time (handles of the Wheeler type). The problem of the fulfilment of the energy conditions in this wormhole has been investigated, as well as the problem of its traversability investigation has been set.
Markel, Vadim A; Schotland, John C
2012-06-01
We consider the problem of homogenizing the Maxwell equations for periodic composites. The analysis is based on Bloch-Floquet theory. We calculate explicitly the reflection coefficient for a half space and derive and implement a computationally efficient continued-fraction expansion for the effective permittivity. Our results are illustrated by numerical computations for the case of two-dimensional systems. The homogenization theory of this paper is designed to predict various physically measurable quantities rather than to simply approximate certain coefficients in a partial differential equation. PMID:23005233
Submillimeter observations of the sun from the James Clerk Maxwell Telescope
NASA Technical Reports Server (NTRS)
Lindsey, Charles A.; Yee, Selwyn; Roellig, Thomas L.; Hills, Richard; Brock, David
1990-01-01
The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun.
On the problem of a thin rigid inclusion embedded in a Maxwell material
NASA Astrophysics Data System (ADS)
Popova, T.; Rogerson, G. A.
2016-08-01
We consider a plane viscoelastic body, composed of Maxwell material, with a crack and a thin rigid inclusion. The statement of the problem includes boundary conditions in the form of inequalities, together with an integral condition describing the equilibrium conditions of the inclusion. An equivalent variational statement is provided and used to prove the uniqueness of the problem's solution. The analysis is carried out in respect of perfect and non-perfect bonding of the rigid inclusion. Additional smoothness properties of the solutions, namely the existence of the time derivative, are also established.
NASA Astrophysics Data System (ADS)
Jana, Pradip Kumar; Sarkar, Sudipta; Chaudhuri, B. K.
2007-01-01
KxTiyNi1-x-yO(x = 0.05 0.3, y = 0.02 0.25) ceramics (abbreviated as KTNO) have been synthesized showing high permittivity. All the KTNO samples of varying compositions exhibit high dielectric permittivity (~104) near room temperature, which is comparable to that of the recently discovered CaCu3Ti4O12 (CCTO) ceramic. The high dielectric constant of KTNO depends on both the K and Ti content and can be attributed to the Maxwell Wagner polarization mechanism and to a thermally activated mechanism.
On-Chip Maxwell's Demon as an Information-Powered Refrigerator.
Koski, J V; Kutvonen, A; Khaymovich, I M; Ala-Nissila, T; Pekola, J P
2015-12-31
We present an experimental realization of an autonomous Maxwell's demon, which extracts microscopic information from a system and reduces its entropy by applying feedback. It is based on two capacitively coupled single-electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the demon and the system as well as their mutual information exchange. The operation of the demon is directly observed as a temperature drop in the system. We also observe a simultaneous temperature rise in the demon arising from the thermodynamic cost of generating the mutual information. PMID:26764980
J. Squire, H. Qin and W.M. Tang
2012-09-25
We present a new variational principle for the gyrokinetic system, similar to the Maxwell-Vlasov action presented in Ref. 1. The variational principle is in the Eulerian frame and based on constrained variations of the phase space fluid velocity and particle distribution function. Using a Legendre transform, we explicitly derive the field theoretic Hamiltonian structure of the system. This is carried out with the Dirac theory of constraints, which is used to construct meaningful brackets from those obtained directly from Euler-Poincare theory. Possible applications of these formulations include continuum geometric integration techniques, large-eddy simulation models and Casimir type stability methods. __________________________________________________
What Maxwell theory in d≠4 teaches us about scale and conformal invariance
NASA Astrophysics Data System (ADS)
El-Showk, Sheer; Nakayama, Yu; Rychkov, Slava
2011-07-01
The free Maxwell theory in d≠4 dimensions provides a physical example of a unitary, scale invariant theory which is NOT conformally invariant. The easiest way to see this is that the field strength operator F is neither a primary nor a descendant. We show how conformal multiplets can be completed, and conformality restored, by adding new local operators to the theory. In d≥5, this can only be done by sacrificing unitarity of the extended Hilbert space. We analyze the full symmetry structure of the extended theory, which turns out to be related to the OSp(d,2|2) superalgebra.
Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme
NASA Astrophysics Data System (ADS)
Squire, Jonathan; Qin, Hong; Tang, William
2012-10-01
A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of Discrete Exterior Calculus [1], the field solver, interpolation scheme and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law. This work was supported by USDOE Contract DE-AC02-09CH11466.[4pt] [1] M. Desbrun, A. N. Hirani, M. Leok, and J. E. Marsden, (2005), arXiv:math/0508341
Finite-Difference Time-Domain solution of Maxwell's equations for the dispersive ionosphere
NASA Astrophysics Data System (ADS)
Nickisch, L. J.; Franke, P. M.
1992-10-01
The Finite-Difference Time-Domain (FDTD) technique is a conceptually simple, yet powerful, method for obtaining numerical solutions to electromagnetic propagation problems. However, the application of FDTD methods to problems in ionospheric radiowave propagation is complicated by the dispersive nature of the ionospheric plasma. In the time domain, the electric displacement is the convolution of the dielectric tensor with the electric field, and thus requires information from the entire signal history. This difficulty can be avoided by returning to the dynamical equations from which the dielectric tensor is derived. By integrating these differential equations simultaneously with the Maxwell equations, temporal dispersion is fully incorporated.
Submillimeter observations of the sun from the James Clerk Maxwell Telescope
Lindsey, C.A.; Yee, S.; Roellig, T.L.; Hills, R.; Brock, D. NASA, Ames Research Center, Moffett Field, CA Mullard Radio Astronomy Observatory, Cambridge Joint Astronomy Centre, Hilo, HI )
1990-04-01
The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun. 7 refs.
A Fourier collocation time domain method for numerically solving Maxwell's equations
NASA Technical Reports Server (NTRS)
Shebalin, John V.
1991-01-01
A new method for solving Maxwell's equations in the time domain for arbitrary values of permittivity, conductivity, and permeability is presented. Spatial derivatives are found by a Fourier transform method and time integration is performed using a second order, semi-implicit procedure. Electric and magnetic fields are collocated on the same grid points, rather than on interleaved points, as in the Finite Difference Time Domain (FDTD) method. Numerical results are presented for the propagation of a 2-D Transverse Electromagnetic (TEM) mode out of a parallel plate waveguide and into a dielectric and conducting medium.
Approximate local magnetic-to-electric surface operators for time-harmonic Maxwell's equations
El Bouajaji, M.
2014-12-15
The aim of this paper is to propose new local and accurate approximate magnetic-to-electric surface boundary operators for the three-dimensional time-harmonic Maxwell's equations. After their construction where their accuracy is improved through a regularization process, a localization of these operators and a full finite element approximation is introduced. Next, their numerical efficiency and accuracy is investigated in detail for different scatterers when these operators are used in the extreme situation of On-Surface Radiation Conditions methods.
Breakdown of hydrodynamics in the inelastic Maxwell model of granular gases.
Brey, J Javier; García de Soria, M I; Maynar, P
2010-08-01
Both the right and left eigenfunctions and eigenvalues of the linearized homogeneous Boltzmann equation for inelastic Maxwell molecules corresponding to the hydrodynamic modes are calculated. Also, some nonhydrodynamic modes are identified. It is shown that below a critical value of the parameter characterizing the inelasticity, one of the kinetic modes decays slower than one of the hydrodynamic ones. As a consequence, a closed hydrodynamic description does not exist in that regime. Some implications of this behavior on the formally computed Navier-Stokes transport coefficients are discussed. PMID:20866802
Efficient solution on solving 3D Maxwell equations using stable semi-implicit splitting method
NASA Astrophysics Data System (ADS)
Cen, Wei; Gu, Ning
2016-05-01
In this paper, we propose an efficient solution on solving 3-dimensional (3D) time-domain Maxwell equations using the semi-implicit Crank-Nicholson (CN) method for time domain discretization with advantage of unconditional time stability. By applying the idea of fractional steps method (FSM) to the CN scheme, the proposed method provides a much simpler and efficient implementation than a direct implementation of the CN scheme. Compared with the alternating-direction implicit (ADI) method and explicit finite-difference time-domain approach (FDTD), it significantly saves the computational resource like memory and CPU time while remains similar numerical accuracy.
Through-the-wall radar detection analysis via numerical modeling of Maxwell's equations
NASA Astrophysics Data System (ADS)
Charnley, Matthew; Wood, Aihua
2016-05-01
The problem of through-the-wall imaging is considered. A numerical method for Maxwell's Equations is developed and implemented with the goal of generating an approximate solution to this problem. The forward problem is solved using the Yee Scheme, and this solver is used in the inverse problem of detecting and analyzing objects inside a room, with no direct vision of the inside. It is shown how different sizes and shapes of objects have different responses to source waves, and these differences can be used to approximate the object. Numerical results show that this reconstruction procedure gives an accurate approximation to the boundary of the object.
NASA Technical Reports Server (NTRS)
Madsen, Niel K.
1992-01-01
Several new discrete surface integral (DSI) methods for solving Maxwell's equations in the time-domain are presented. These methods, which allow the use of general nonorthogonal mixed-polyhedral unstructured grids, are direct generalizations of the canonical staggered-grid finite difference method. These methods are conservative in that they locally preserve divergence or charge. Employing mixed polyhedral cells, (hexahedral, tetrahedral, etc.) these methods allow more accurate modeling of non-rectangular structures and objects because the traditional stair-stepped boundary approximations associated with the orthogonal grid based finite difference methods can be avoided. Numerical results demonstrating the accuracy of these new methods are presented.
A Spectral Algorithm for Solving the Relativistic Vlasov-Maxwell Equations
NASA Technical Reports Server (NTRS)
Shebalin, John V.
2001-01-01
A spectral method algorithm is developed for the numerical solution of the full six-dimensional Vlasov-Maxwell system of equations. Here, the focus is on the electron distribution function, with positive ions providing a constant background. The algorithm consists of a Jacobi polynomial-spherical harmonic formulation in velocity space and a trigonometric formulation in position space. A transform procedure is used to evaluate nonlinear terms. The algorithm is suitable for performing moderate resolution simulations on currently available supercomputers for both scientific and engineering applications.
The Singularity Mystery Associated with a Radially Continuous Maxwell Viscoelastic Structure
NASA Technical Reports Server (NTRS)
Fang, Ming; Hager, Bradford H.
1995-01-01
The singularity problem associated with a radially continuous Maxwell viscoclastic structure is investigated. A special tool called the isolation function is developed. Results calculated using the isolation function show that the discrete model assumption is no longer valid when the viscoelastic parameter becomes a continuous function of radius. Continuous variations in the upper mantle viscoelastic parameter are especially powerful in destroying the mode-like structures. The contribution to the load Love numbers of the singularities is sensitive to the convexity of the viscoelastic parameter models. The difference between the vertical response and the horizontal response found in layered viscoelastic parameter models remains with continuous models.
Conformally covariant quantization of the Maxwell field in de Sitter space
NASA Astrophysics Data System (ADS)
Faci, S.; Huguet, E.; Queva, J.; Renaud, J.
2009-12-01
In this article, we quantize the Maxwell (“massless spin one”) de Sitter field in a conformally invariant gauge. This quantization is invariant under the SO0(2,4) group and consequently under the de Sitter group. We obtain a new de Sitter-invariant two-point function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in R6 and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.
Information Loss and Tunneling Radiation of the Non-Stationary Dilaton-Maxwell Black Hole
NASA Astrophysics Data System (ADS)
Chen, Deyou; Yang, Shuzheng
Taking the self-gravitational interaction and unfixed background space-time into account, we discuss the tunneling radiation of the Dilaton-Maxwell black hole by the Hamilton-Jacobi method. The result shows that the tunneling rate is related not only to the change of Bekenstein-Hawking entropy, but also to a subtle integral about the black hole mass, which does not satisfy the unitary theory and is different from Parikh and Wilczek's result. This implies that information loss in black hole evaporation is possible.
Exact Solutions to the Einstein-Maxwell Equations Describing Wormholes and Handles
NASA Astrophysics Data System (ADS)
Khlestkov, Yu. A.; Sukhanova, L. A.
2016-03-01
On the basis of the exact solutions to the non-stationary spherically symmetric Einstein and Maxwell equations for dust matter and radial electromagnetic field, a model of a wormhole with the pulsating in time inner world and two static throats has been developed. It has been shown that such a wormhole with an arbitrary radius of the Gaussian curvature can connect both two different asymptotically flat space-times and two regions of the selfsame space-time (handles of the Wheeler type). The problem of the fulfilment of the energy conditions in this wormhole has been investigated, as well as the problem of its traversability investigation has been set.
Noncommutative Maxwell-Chern-Simons theory: One-loop dispersion relation analysis
NASA Astrophysics Data System (ADS)
Ghasemkhani, M.; Bufalo, R.
2016-04-01
In this paper, we study the three-dimensional noncommutative Maxwell-Chern-Simons theory. In the present analysis, a complete account for the gauge field two-point function renormalizability is presented and physical significant quantities are carefully established. The respective form factor expressions from the gauge field self-energy are computed at one-loop order. More importantly, an analysis of the gauge field dispersion relation, in search of possible noncommutative anomalies and infrared finiteness, is performed for three special cases, with particular interest in the highly noncommutative limit.
Visinescu, M.
2012-10-15
Hidden symmetries in a covariant Hamiltonian framework are investigated. The special role of the Stackel-Killing and Killing-Yano tensors is pointed out. The covariant phase-space is extended to include external gauge fields and scalar potentials. We investigate the possibility for a higher-order symmetry to survive when the electromagnetic interactions are taken into account. Aconcrete realization of this possibility is given by the Killing-Maxwell system. The classical conserved quantities do not generally transfer to the quantized systems producing quantum gravitational anomalies. As a rule the conformal extension of the Killing vectors and tensors does not produce symmetry operators for the Klein-Gordon operator.
Development of a Godunov method for Maxwell's equations with Adaptive Mesh Refinement
NASA Astrophysics Data System (ADS)
Barbas, Alfonso; Velarde, Pedro
2015-11-01
In this paper we present a second order 3D method for Maxwell's equations based on a Godunov scheme with Adaptive Mesh Refinement (AMR). In order to achieve it, we apply a limiter which better preserves extrema and boundary conditions based on a characteristic fields decomposition. Despite being more complex, simplifications in the boundary conditions make the resulting method competitive in computer time consumption and accuracy compared to FDTD. AMR allows us to simulate systems with a sharp step in material properties with negligible rebounds and also large domains with accuracy in small wavelengths.
On-Chip Maxwell's Demon as an Information-Powered Refrigerator
NASA Astrophysics Data System (ADS)
Koski, J. V.; Kutvonen, A.; Khaymovich, I. M.; Ala-Nissila, T.; Pekola, J. P.
2015-12-01
We present an experimental realization of an autonomous Maxwell's demon, which extracts microscopic information from a system and reduces its entropy by applying feedback. It is based on two capacitively coupled single-electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the demon and the system as well as their mutual information exchange. The operation of the demon is directly observed as a temperature drop in the system. We also observe a simultaneous temperature rise in the demon arising from the thermodynamic cost of generating the mutual information.
The free-electron laser - Maxwell's equations driven by single-particle currents
NASA Technical Reports Server (NTRS)
Colson, W. B.; Ride, S. K.
1980-01-01
It is shown that if single particle currents are coupled to Maxwell's equations, the resulting set of self-consistent nonlinear equations describes the evolution of the electron beam and the amplitude and phase of the free-electron-laser field. The formulation is based on the slowly varying amplitude and phase approximation, and the distinction between microscopic and macroscopic scales, which distinguishes the microscopic bunching from the macroscopic pulse propagation. The capabilities of this new theoretical approach become apparent when its predictions for the ultrashort pulse free-electron laser are compared to experimental data; the optical pulse evolution, determined simply and accurately, agrees well with observations.
Maxwell Wagner Relaxation in Common Minerals and a Desert Soil at Low Water Contents
NASA Astrophysics Data System (ADS)
Arcone, S. A.
2010-12-01
Maxwell-Wagner type dielectric permittivity relaxation in soils is caused by macro-dipolar inclusions, usually of grain size dimensions, and generally within a more dielectric matrix. We discuss laboratory measurements of the complex permittivity of quartz, feldspars, calcite, two forms of gypsum and a simple desert soil at 4-7 percent volumetric water content, and in which we interpret Maxwell-Wagner processes to have dominated. We used Fourier Transform time domain reflectometry, measured from 1 MHz to 6 GHz, and used small samples with grain sizes less than 53 microns. Using XRD and SEM, we found the soil contained quartz, gypsum and feldspars at 80, 10 and 10 percent by weight, respectively, with the gypsum appearing as crystallites and crustations on the quartz particles. All samples show low conductivity, and low-frequency dispersion. The montmorillonite, gypsum crystallites, and desert soil exhibit unusually strong and broad low-frequency dispersion, and strong attenuation rates above 100 MHz. The one-way attenuation rates of the soil exceed those of its constituents, are similar to that of montmorillonite, and exceed 100 dB/m by 1 GHz. Through modeling using the CRIM approach, we attribute all permittivity behavior to a combination of Maxwell-Wagner and free water relaxations, with the former dominant and able to contribute significantly to attenuation rates into the GHz range because of Cole-Cole broadened relaxation frequencies centered from 1-20 MHz, while the latter is centered at 20 GHz. The lack of sufficient surface area to support adsorbed water relaxation, the lack of salts, clay and magnetic minerals, and the inadequacy of measured conductivity values to explain the high loss further justify our Maxwell-Wagner interpretation. The polarized inclusions within the soil are likely to have been conductive wet gypsum particles, whereby films of water that coated the particles polarized. The source of the charge was likely to have been ions dissolved
Development and analysis of computational algorithm of the Maxwell's equations in flat domains
NASA Astrophysics Data System (ADS)
Boronina, M. A.; Vshivkov, V. A.
2016-06-01
We present a new scheme for the Maxwell's equations computations in threedimensional domains, where size in one direction is much smaller than the other sizes. The scheme is based on the Langdon-Lasinski scheme, which is standard for numerical experiments in plasma physics. Our study is devoted to analysis of correct wave propagation due to the effects of using a finite-difference approximation. To show the main dependencies we present numerical results in one-dimensional case. The results demonstrate, that the new scheme maintains the wave amplitude, the propagation speed and allows using of bigger time step in comparison with the Langdon-Lasinski scheme.
Sakiadis flow of Maxwell fluid considering magnetic field and convective boundary conditions
Mustafa, M.; Khan, Junaid Ahmad; Hayat, T.; Alsaedi, A.
2015-02-15
In this paper we address the flow of Maxwell fluid due to constantly moving flat radiative surface with convective condition. The flow is under the influence of non-uniform transverse magnetic field. The velocity and temperature distributions have been evaluated numerically by shooting approach. The solution depends on various interesting parameters including local Deborah number De, magnetic field parameter M, Prandtl number Pr and Biot number Bi. We found that variation in velocity with an increase in local Deborah number De is non-monotonic. However temperature is a decreasing function of local Deborah number De.
A Derivation of the Magnetohydrodynamic System from Navier-Stokes-Maxwell Systems
NASA Astrophysics Data System (ADS)
Arsénio, Diogo; Ibrahim, Slim; Masmoudi, Nader
2015-06-01
We provide a full and rigorous derivation of the standard viscous magnetohydrodynamic system (MHD) as the asymptotic limit of Navier-Stokes-Maxwell systems when the speed of light is infinitely large. We work in the physical setting provided by the natural energy bounds and therefore mainly consider Leray solutions of fluid dynamical systems. Our methods are based on a direct analysis of frequencies and we are able to establish the weak stability of a crucial nonlinear term (the Lorentz force), neither assuming any strong compactness of the components nor applying standard compensated compactness methods (which actually fail in this case).
NASA Astrophysics Data System (ADS)
Lu, Qiang; Wang, Zhan-jiang
2016-06-01
The governing equations for viscoelastic spherical divergent stress waves are formulated, and the solutions for spherical stress waves are analytically given in the Laplace domain. Based on the generalized Maxwell model, the propagation coefficient for viscoelastic spherical stress waves is obtained analytically and the characteristics of the attenuation coefficient and the phase velocity are discussed. Meanwhile, the solutions for viscoelastic spherical stress waves are calculated by using the numerical method of the inverse Laplace transform in the case of cavity explosion. The propagating characteristics for strong discontinuous visco-elastic spherical waves and steady-state values caused by the cavity pressure are discussed using theoretical and numerical methods.
Ismagilov, Timur Z.
2015-02-01
This paper presents a second order finite volume scheme for numerical solution of Maxwell's equations with discontinuous dielectric permittivity and magnetic permeability on unstructured meshes. The scheme is based on Godunov scheme and employs approaches of Van Leer and Lax–Wendroff to increase the order of approximation. To keep the second order of approximation near dielectric permittivity and magnetic permeability discontinuities a novel technique for gradient calculation and limitation is applied near discontinuities. Results of test computations for problems with linear and curvilinear discontinuities confirm second order of approximation. The scheme was applied to modelling propagation of electromagnetic waves inside photonic crystal waveguides with a bend.
Theory of Maxwell's fish eye with mutually interacting sources and drains
NASA Astrophysics Data System (ADS)
Leonhardt, Ulf; Sahebdivan, Sahar
2015-11-01
Maxwell's fish eye is predicted to image with a resolution not limited by the wavelength of light. However, interactions between sources and drains may ruin the subwavelength imaging capabilities of this and similar absolute optical instruments. Nevertheless, as we show in this paper, at resonance frequencies of the device, an array of drains may resolve a single source, or alternatively, a single drain may scan an array of sources, no matter how narrowly spaced they are. It seems that near-field information can be obtained from far-field distances.
NASA Astrophysics Data System (ADS)
Wang, Mengjie; Herdeiro, Carlos
2016-03-01
Scalar and gravitational perturbations on Kerr-anti-de Sitter (Kerr-AdS) black holes have been addressed in the literature and have been shown to exhibit a rich phenomenology. In this paper, we complete the analysis of bosonic fields on this background by studying Maxwell perturbations, focusing on superradiant instabilities and vector clouds. For this purpose, we solve the Teukolsky equations numerically, imposing the boundary conditions we have proposed in [1] for the radial Teukolsky equation. As found therein, two Robin boundary conditions can be imposed for Maxwell fields on Kerr-AdS black holes, one of which produces a new set of quasinormal modes even for Schwarzschild-AdS black holes. Here, we show these different boundary conditions produce two different sets of superradiant modes. Interestingly, the "new modes" may be unstable in a larger parameter space. We then study stationary Maxwell clouds that exist at the threshold of the superradiant instability, with the two Robin boundary conditions. These clouds, obtained at the linear level, indicate the existence of a new family of black hole solutions at the nonlinear level, within the Einstein-Maxwell-AdS system, branching off from the Kerr-Newman-AdS family. As a comparison with the Maxwell clouds, scalar clouds on Kerr-AdS black holes are also studied, and it is shown there are Kerr-AdS black holes that are stable against scalar, but not vector, modes with the same "quantum numbers".
Cosmetic Plastic Surgery Statistics
2014 Cosmetic Plastic Surgery Statistics Cosmetic Procedure Trends 2014 Plastic Surgery Statistics Report Please credit the AMERICAN SOCIETY OF PLASTIC SURGEONS when citing statistical data or using ...
Raikher, Yu L; Rusakov, V V
2005-12-01
We study magnetic response of an assembly of ferroparticles suspended in a viscoelastic matrix which is modeled by a Maxwell fluid with a unique stress relaxation time. The problem refers to the magnetic microrheology approach where deformational properties of a complex fluid are tested with the aid of embedded nanoparticle probes set to motion by an external ac magnetic field. A possibility is considered to simplify the description of the orientational kinetics of the system at the expense of neglecting inertia effects in particle rotary motion. It is shown that in this aspect a Maxwell matrix differs essentially from the Newtonian one. In the latter the inertialess approximation for the particles of the approximately 10nm size is valid practically unboundedly. For a viscoelastic matrix the inertialess approximation means an important restriction on the value of the stress relaxation time. Assuming weak nonequilibrium, the magneto-orientational relaxation times are found and low-frequency magnetic spectra of a viscoelastic suspension are determined in the presence of a constant (magnetizing) field. PMID:16485946
New two-sided bound on the isotropic Lorentz-violating parameter of modified Maxwell theory
Klinkhamer, F. R.; Schreck, M.
2008-10-15
There is a unique Lorentz-violating modification of the Maxwell theory of photons, which maintains gauge invariance, CPT, and renormalizability. Restricting the modified-Maxwell theory to the isotropic sector and adding a standard spin-(1/2) Dirac particle p{sup {+-}} with minimal coupling to the nonstandard photon {gamma}-tilde, the resulting modified-quantum-electrodynamics model involves a single dimensionless 'deformation parameter', {kappa}-tilde{sub tr}. The exact tree-level decay rates for two processes have been calculated: vacuum Cherenkov radiation p{sup {+-}}{yields}p{sup {+-}}{gamma}-tilde for the case of positive {kappa}-tilde{sub tr} and photon decay {gamma}-tilde{yields}p{sup +}p{sup -} for the case of negative {kappa}-tilde{sub tr}. From the inferred absence of these decays for a particular high-quality ultrahigh-energy-cosmic-ray event detected at the Pierre Auger Observatory and a well-established excess of TeV gamma-ray events observed by the High Energy Stereoscopic System telescopes, a two-sided bound on {kappa}-tilde{sub tr} is obtained, which improves by 8 orders of magnitude upon the best direct laboratory bound. The implications of this result are briefly discussed.
A High-Order Accurate Parallel Solver for Maxwell's Equations on Overlapping Grids
Henshaw, W D
2005-09-23
A scheme for the solution of the time dependent Maxwell's equations on composite overlapping grids is described. The method uses high-order accurate approximations in space and time for Maxwell's equations written as a second-order vector wave equation. High-order accurate symmetric difference approximations to the generalized Laplace operator are constructed for curvilinear component grids. The modified equation approach is used to develop high-order accurate approximations that only use three time levels and have the same time-stepping restriction as the second-order scheme. Discrete boundary conditions for perfect electrical conductors and for material interfaces are developed and analyzed. The implementation is optimized for component grids that are Cartesian, resulting in a fast and efficient method. The solver runs on parallel machines with each component grid distributed across one or more processors. Numerical results in two- and three-dimensions are presented for the fourth-order accurate version of the method. These results demonstrate the accuracy and efficiency of the approach.
NASA Astrophysics Data System (ADS)
Macke, Andreas; Mishchenko, Michael I.
2016-07-01
The 15th Electromagnetic and Light Scattering Conference (ELS-XV) was held in Leipzig, Germany from 21 to 26 of June 2015 (Fig. 1). This conference built on the great success of the previous meetings held in Amsterdam (1995) [1], Helsinki (1997) [2], New York City (1998) [3], Vigo (1999), Halifax (2000) [4], Gainesville (2002) [5], Bremen (2003) [6], Salobreña (2005) [7], St. Petersburg (2006) [8], Bodrum (2007) [9], Hatfield (2008) [10], Helsinki (2010) [11], Taormina (2011) [12], and Lille [13] as well as the workshops held in Bremen (1996, 1998) and Moscow (1997). As usual, the main objective of this conference was to bring together scientists, engineers, and PhD students studying various aspects of electromagnetic scattering and to provide a relaxed atmosphere for in-depth discussion of theory, measurements, and applications. Furthermore, ELS-XV supported the United Nations "Year of Light" and celebrated the 150th anniversary of Maxwell's electromagnetics. Maxwell's paper on "A Dynamical Theory of the Electromagnetic Field" [14] was published in 1865 and has widely been acknowledged as one of the supreme achievements in the history of science.
Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization
Jóźwiak, Bertrand; Orczykowska, Magdalena; Dziubiński, Marek
2015-01-01
The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G’ and G” and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process. PMID:26599756
NASA Astrophysics Data System (ADS)
Khanal, U.
2006-07-01
Maxwell and Dirac fields in Friedmann Robertson Walker (FRW) spacetime are investigated using the Newman Penrose method. The variables are all separable, with the angular dependence given by spin-weighted spherical harmonics. All the radial parts reduce to the barrier penetration problem, with mostly repulsive potentials representing the centrifugal energies. Both the helicity states of the photon field see the same potential, but that of the Dirac field see different ones; one component even sees attractive potential in the open universe. The massless fields have the usual exponential time dependences; that of the massive Dirac field is coupled to the evolution of the cosmic scale factor a. The case of the radiation-filled flat universe is solved in terms of the Whittaker function. A formal series solution, valid in any FRW universe, is also presented. The energy density of the Maxwell field is explicitly shown to scale as a-4. The co-moving particle number density of the massless Dirac field is found to be conserved, but that of the massive one is not. Particles flow out of certain regions, and into others, creating regions that are depleted of certain linear and angular momenta states, and others with excess. Such a current of charged particles would constitute an electric current that could generate a cosmic magnetic field. In contrast, the energy density of these massive particles still scales as a-4.
Comparisons of the Maxwell and CLL gas/surface interaction models using DSMC
NASA Technical Reports Server (NTRS)
Hedahl, Marc O.; Wilmoth, Richard G.
1995-01-01
The behavior of two different models of gas-surface interactions is studied using the Direct Simulation Monte Carlo (DSMC) method. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between the Maxwell and the Cercignani-Lampis-Lord (CLL) models for flat plate configurations at freestream conditions corresponding to a 140 km orbit around Venus. The size of the flat plate represents one of the solar panels on the Magellan spacecraft, and the freestream conditions correspond to those experienced during aerobraking maneuvers. Results are presented for both a single flat plate and a two-plate configuration as a function of angle of attack and gas-surface accommodation coefficients. The two-plate system is not representative of the Magellan geometry but is studied to explore possible experiments that might be used to differentiate between the two gas-surface interaction models. The Maxwell and CLL models produce qualitatively similar results for the aerodynamic forces and heat transfer on a single flat plate. However, the flow fields produced with the two models are qualitatively different for both the single-plate and two-plate calculations. These differences in the flowfield lead to predictions of the angle of attack for maximum heat transfer in a two plate configuration that are distinctly different for the two gas-surface interactions models.
NASA Astrophysics Data System (ADS)
Lim, Eunju; Manaka, Takaaki; Tamura, Ryosuke; Iwamoto, Mitsumasa
2006-04-01
The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of pentacene field effect transistors (FETs) were examined to clarify channel formation in conjunction with the UV/ozone treatment of the source and drain metal (Au) electrodes. Analyzing the I-V and C-V characteristics of FETs using the Maxwell-Wagner model showed that the main charge carriers in the FET channel are holes injected from the source, and that a pentacene FET with a UV/ozone-treated substrate shows a high effective mobility owing to holes smoothly injected into the FET channel. Furthermore, the pentacene film thickness dependence on FET characteristics showed that a channel sheet with a thickness less than 20 nm is formed at the pentacene/SiO2 interface. Finally, the employment of the Maxwell-Wagner model for the analysis of the C-V characteristics was shown to give a good approximation even when taking into account the presence of a charge sheet at the interface.
Radiating black holes in Einstein-Maxwell-dilaton theory and cosmic censorship violation
NASA Astrophysics Data System (ADS)
Aniceto, Pedro; Pani, Paolo; Rocha, Jorge V.
2016-05-01
We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a = 1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null fluids and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a = 1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, when a = 1 we show that an electrically charged black hole in this theory can be overcharged by bombarding it with a stream of electrically charged null fluid, resulting in the formation of a naked singularity. This provides an example of cosmic censorship violation in an exact dynamical solution to low-energy effective string theory and in a case in which the total stress-energy tensor satisfies all energy conditions. When a ≠ 1, our solutions necessarily have a time-independent scalar field and consequently cannot be overcharged.
Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization.
Jóźwiak, Bertrand; Orczykowska, Magdalena; Dziubiński, Marek
2015-01-01
The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G' and G" and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process. PMID:26599756
NASA Astrophysics Data System (ADS)
Konkowski, Deborah A.; Arndt, Valerie; Helliwell, Thomas M.
2002-04-01
Klein-Gordon, Maxwell and Dirac fields are studied in quasiregular spacetimes, spacetimes with a classical quasiregular singularity, the mildest true classical singularity [G.F.R. Ellis and B.G. Schmidt, Gen. Rel. Grav.8, 915 (1977)]. A class of static quasiregular spacetimes possessing disclinations and dislocations [R.A. Puntigam and H.H. Soleng, Class. Quantum Grav. 14, 1129 (1997)] is shown to have field operators which are not essentially self-adjoint. This class of spacetimes includes an idealized cosmic string, i.e., a four-dimensional spacetime with a conical singularity [L.H. Ford and A. Vilenkin, J. Phys. A: Math. Gen. 14, 2353 (1981)], and a Galtsov/Letelier/Tod spacetime featuring a screw dislocation [K.P. Tod, Class. Quantum Grav. 11, 1331 (1994); D.V. Galtsov and P.S. Letelier, Phys. Rev. D47, 4273 (1993)]. The definition of G. T. Horowitz and D. Marolf [Phys. Rev. D52, 5670 (1995)] for a quantum-mechanically singular spacetime as one in which the spatial-derivative operator in the Klein-Gordon equation for a massive scalar field is not essentially self-adjoint is extended in the case of quasiregular spacetimes to include Maxwell and Dirac fields. Therefore, the class of static quasiregular spacetimes under consideration is quantum-mechanically singular independent of the type of test field.
NASA Astrophysics Data System (ADS)
Andrade, Tomás; Kelly, William R.; Marolf, Donald
2015-10-01
The gravitational Dirichlet problem—in which the induced metric is fixed on boundaries at finite distance from the bulk—is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise asymptotically flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image source against electrostatic attraction to an oppositely signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. One may also surround the black hole with an additional (roughly spherical) Dirichlet wall to impose a regulator whose physics is more clear. Negative kinetic energies remain, though new terms do appear in the moduli space metric. The regulator dependence indicates that the adiabatic approximation may be ill-defined for classical extreme black holes with Dirichlet walls.
NASA Astrophysics Data System (ADS)
Chen, Chuchu; Hong, Jialin; Zhang, Liying
2016-02-01
Stochastic Maxwell equations with additive noise are a system of stochastic Hamiltonian partial differential equations intrinsically, possessing the stochastic multi-symplectic conservation law. It is shown that the averaged energy increases linearly with respect to the evolution of time and the flow of stochastic Maxwell equations with additive noise preserves the divergence in the sense of expectation. Moreover, we propose three novel stochastic multi-symplectic methods to discretize stochastic Maxwell equations in order to investigate the preservation of these properties numerically. We make theoretical discussions and comparisons on all of the three methods to observe that all of them preserve the corresponding discrete version of the averaged divergence. Meanwhile, we obtain the corresponding dissipative property of the discrete averaged energy satisfied by each method. Especially, the evolution rates of the averaged energies for all of the three methods are derived which are in accordance with the continuous case. Numerical experiments are performed to verify our theoretical results.
Uniqueness theorem for black holes with Kaluza-Klein asymptotic in 5D Einstein-Maxwell gravity
Yazadjiev, Stoytcho
2010-07-15
In the present paper, we prove a uniqueness theorem for stationary multi-black hole configurations with Kaluza-Klein asymptotic in a certain sector of 5D Einstein-Maxwell gravity. As a part of the technical assumptions in the theorem, we assume that the Killing vector associated with the compact dimension is orthogonal to the other Killing vectors and that it is also hypersurface orthogonal. About the Maxwell field, we assume that it is invariant under the Killing symmetries and has a nonzero component only along the Killing vector associated with the compact dimension. We show that such multi-black hole configurations are uniquely specified by the interval structure, angular momenta of the horizons, magnetic charges, and the magnetic flux. A straightforward generalization of the uniqueness theorem for 5D Einstein-Maxwell-dilaton gravity is also given.
Gaussian statistics for palaeomagnetic vectors
Love, J.J.; Constable, C.G.
2003-01-01
With the aim of treating the statistics of palaeomagnetic directions and intensities jointly and consistently, we represent the mean and the variance of palaeomagnetic vectors, at a particular site and of a particular polarity, by a probability density function in a Cartesian three-space of orthogonal magnetic-field components consisting of a single (unimoda) non-zero mean, spherically-symmetrical (isotropic) Gaussian function. For palaeomagnetic data of mixed polarities, we consider a bimodal distribution consisting of a pair of such symmetrical Gaussian functions, with equal, but opposite, means and equal variances. For both the Gaussian and bi-Gaussian distributions, and in the spherical three-space of intensity, inclination, and declination, we obtain analytical expressions for the marginal density functions, the cumulative distributions, and the expected values and variances for each spherical coordinate (including the angle with respect to the axis of symmetry of the distributions). The mathematical expressions for the intensity and off-axis angle are closed-form and especially manageable, with the intensity distribution being Rayleigh-Rician. In the limit of small relative vectorial dispersion, the Gaussian (bi-Gaussian) directional distribution approaches a Fisher (Bingham) distribution and the intensity distribution approaches a normal distribution. In the opposite limit of large relative vectorial dispersion, the directional distributions approach a spherically-uniform distribution and the intensity distribution approaches a Maxwell distribution. We quantify biases in estimating the properties of the vector field resulting from the use of simple arithmetic averages, such as estimates of the intensity or the inclination of the mean vector, or the variances of these quantities. With the statistical framework developed here and using the maximum-likelihood method, which gives unbiased estimates in the limit of large data numbers, we demonstrate how to
NASA Astrophysics Data System (ADS)
Vincenti, H.; Vay, J.-L.
2016-03-01
Very high order or pseudo-spectral Maxwell solvers are the method of choice to reduce discretization effects (e.g. numerical dispersion) that are inherent to low order Finite-Difference Time-Domain (FDTD) schemes. However, due to their large stencils, these solvers are often subject to truncation errors in many electromagnetic simulations. These truncation errors come from non-physical modifications of Maxwell's equations in space that may generate spurious signals affecting the overall accuracy of the simulation results. Such modifications for instance occur when Perfectly Matched Layers (PMLs) are used at simulation domain boundaries to simulate open media. Another example is the use of arbitrary order Maxwell solver with domain decomposition technique that may under some condition involve stencil truncations at subdomain boundaries, resulting in small spurious errors that do eventually build up. In each case, a careful evaluation of the characteristics and magnitude of the errors resulting from these approximations, and their impact at any frequency and angle, requires detailed analytical and numerical studies. To this end, we present a general analytical approach that enables the evaluation of numerical errors of fully three-dimensional arbitrary order finite-difference Maxwell solver, with arbitrary modification of the local stencil in the simulation domain. The analytical model is validated against simulations of domain decomposition technique and PMLs, when these are used with very high-order Maxwell solver, as well as in the infinite order limit of pseudo-spectral solvers. Results confirm that the new analytical approach enables exact predictions in each case. It also confirms that the domain decomposition technique can be used with very high-order Maxwell solvers and a reasonably low number of guard cells with negligible effects on the whole accuracy of the simulation.
Ripoll, Jorge
2011-08-01
In this paper the expression for the radiative transfer equation (RTE) commonly used when describing light propagation in biological tissues is derived directly from the equation of energy conservation of Maxwell's equations (Poynting's theorem) by making use of a volume-averaged expression for the time-averaged flow of energy. The derivation is presented step by step with Maxwell's equations as the starting point, analyzing all approximations taken in order to arrive at the expression of the scalar RTE employed in biomedical applications, which neglects particle nonsphericity and orientation, depolarization, and coherence effects. PMID:21811340
The combined non-relativistic and quasi-neutral limit of two-fluid Euler-Maxwell equations
NASA Astrophysics Data System (ADS)
Li, Yachun; Peng, Yue-Jun; Xi, Shuai
2015-12-01
We consider two-fluid Euler-Maxwell equations for magnetized plasmas composed of electrons and ions. By using the method of asymptotic expansions, we analyze the combined non-relativistic and quasi-neutral limit for periodic problems with well-prepared initial data. It is shown that the small parameter problems have a unique solution existing in a finite time interval where the corresponding limit problems (compressible Euler equations) have smooth solutions. The proof is based on energy estimates for symmetrizable hyperbolic equations and on the exploration of the coupling between the Euler equations and the Maxwell equations.
NASA Astrophysics Data System (ADS)
Lan, Xiao-Gang
2013-05-01
By introducing a new tortoise coordinate transformation, we apply Damour-Ruffini-Sannan method to study the Hawking radiation of massive scalar particles in a dynamic Dilaton-Maxwell black hole. We find that Hawking radiation spectrum shows still the blackbody one, while the Hawking temperature is significantly changed. Additionally, by adopting the thin film method, we calculate the entropy of a dynamic Dilaton-Maxwell black hole. The result indicates that the entropy for such a black hole is still in proportional to the area of its event horizon.
NASA Technical Reports Server (NTRS)
Joseph, Rose M.; Hagness, Susan C.; Taflove, Allen
1991-01-01
The initial results for femtosecond pulse propagation and scattering interactions for a Lorentz medium obtained by a direct time integration of Maxwell's equations are reported. The computational approach provides reflection coefficients accurate to better than 6 parts in 10,000 over the frequency range of dc to 3 x 10 to the 16th Hz for a single 0.2-fs Gaussian pulse incident upon a Lorentz-medium half-space. New results for Sommerfeld and Brillouin precursors are shown and compared with previous analyses. The present approach is robust and permits 2D and 3D electromagnetic pulse propagation directly from the full-vector Maxwell's equations.
Einstein-Maxwell system in 3+1 form and initial data for multiple charged black holes
Alcubierre, Miguel; Degollado, Juan Carlos; Salgado, Marcelo
2009-11-15
We consider the Einstein-Maxwell system as a Cauchy initial value problem taking the electric and magnetic fields as independent variables. Maxwell's equations in curved spacetimes are derived in detail using a 3+1 formalism and their hyperbolic properties are analyzed, showing that the resulting system is symmetric hyperbolic. We also focus on the problem of finding initial data for multiple charged black holes assuming time-symmetric initial data and using a puncturelike method to solve the Hamiltonian and the Gauss constraints. We study the behavior of the resulting initial data families, and show that previous results in this direction can be obtained as particular cases of our approach.
If Maxwell had worked between Ampère and Faraday: An historical fable with a pedagogical moral
NASA Astrophysics Data System (ADS)
Jammer, Max; Stachel, John
1980-01-01
If one drops the Faraday induction term from Maxwell's equations, they become exactly Galilei invariant. This suggests that if Maxwell had worked between Ampère and Faraday, he could have developed this Galilei-invariant electromagnetic theory so that Faraday's discovery would have confronted physicists with the dilemma: give up the Galileian relativity principle for electromagnetism (ether hypothesis), or modify it (special relativity). This suggests a new pedagogical approach to electromagnetic theory, in which the displacement current and the Galileian relativity principle are introduced before the induction term is discussed.
NASA Astrophysics Data System (ADS)
Slavchov, Radomir I.; Dimitrova, Iglika M.; Ivanov, Tzanko
2015-10-01
The quadrupolar Maxwell electrostatic equations predict several qualitatively different results compared to Poisson's classical equation in their description of the properties of a dielectric interface. All interfaces between dielectrics possess surface dipole moment which results in a measurable surface potential jump. The surface dipole moment is conjugated to the bulk quadrupole moment density (the quadrupolarization) similarly to Gauss's relation between surface charge and bulk polarization. However, the classical macroscopic Maxwell equations completely neglect the quadrupolarization of the medium. Therefore, the electrostatic potential distribution near an interface of intrinsic dipole moment can be correctly described only within the quadrupolar macroscopic equations of electrostatics. They predict that near the polarized interface a diffuse dipole layer exists, which bears many similarities to the diffuse charge layer near a charged surface, in agreement with existing molecular dynamics simulation data. It turns out that when the quadrupole terms are kept in the multipole expansion of the laws of electrostatics, the solutions for the potential and the electric field are continuous functions at the surface. A well-defined surface electric field exists, interacting with the adsorbed dipoles. This allows for a macroscopic description of the surface dipole-surface dipole and the surface dipole-bulk quadrupole interactions. They are shown to have considerable contribution to the interfacial tension—of the order of tens of mN/m! To evaluate it, the Maxwell stress tensor in quadrupolar medium is deduced, including the electric field gradient action on the quadrupoles, as well as quadrupolar image force and quadrupolar electrostriction. The dependence of the interfacial tension on the external normal electric field (the dielectrocapillary curve) is predicted and the dielectric susceptibility of the dipolar double layer is related to the quadrupolarizabilities of
NASA Astrophysics Data System (ADS)
Caudillo Mata, L.; Haber, E.
2013-12-01
Luz Angelica Caudillo-Mata, Eldad Haber Geophysics Department, The University of British Columbia. 4013-2207 Main Mall, Vancouver, B.C., Canada. Z. C. V6R 1Z4 Key words: Finite Volume, Quasi-static Maxwell's Equations, Optimization, Upscaling, Homogenization, Exploration Geophysics. Abstract: Mineral exploration has exploited the application of mathematical modelling and inversion methods to electromagnetic data by creating a thoughtful workflow that assists in the identification of potential geological targets, the understanding of the larger scale stratigraphy and structure in which a deposit might be located, or delineating finer scale detail in an existing deposit. [1] In recent years, electromagnetic modelling and inversion techniques based on finite volume and finite elements have been studied extensively due to their usefulness in theory as well as in practice [2]. Although the theoretical foundation for these methods is straight-forward, it can face major difficulties when used to simulate realistic situations. One of the fundamental issues is modelling the vast heterogeneity of geological targets in terms of scale, magnitude and anisotropy. Robust and accurate simulations require very fine meshes, especially when the earth is highly heterogeneous. Such meshes are difficult-to-work-with and may lead to very expensive-to-compute simulations when considering large earth-multiscale scenarios. For instance, geological characterizations typically contain on the order of 1e7 to 1e8 cells. These models, which are referred as fine models, represent geological variations on very fine scales vertically, though their areal resolution is still relatively coarse [3]. Numerical upscaling is a mathematical procedure that strive to develop coarse scale models to accurately approximate fine scale ones. Therefore, it is a useful resource to alleviate the computational cost. Upscaling of Maxwell's equations presents big challenges such as choosing the appropriate upscaling
Predict! Teaching Statistics Using Informational Statistical Inference
ERIC Educational Resources Information Center
Makar, Katie
2013-01-01
Statistics is one of the most widely used topics for everyday life in the school mathematics curriculum. Unfortunately, the statistics taught in schools focuses on calculations and procedures before students have a chance to see it as a useful and powerful tool. Researchers have found that a dominant view of statistics is as an assortment of tools…
Statistics Poker: Reinforcing Basic Statistical Concepts
ERIC Educational Resources Information Center
Leech, Nancy L.
2008-01-01
Learning basic statistical concepts does not need to be tedious or dry; it can be fun and interesting through cooperative learning in the small-group activity of Statistics Poker. This article describes a teaching approach for reinforcing basic statistical concepts that can help students who have high anxiety and makes learning and reinforcing…
New infinite-dimensional hidden symmetries for the Einstein Maxwell dilaton axion theory
NASA Astrophysics Data System (ADS)
Gao, Ya-Jun
2003-11-01
An Ernst-like 4 × 4 matrix complex potential is introduced and the motion equations of the stationary axisymmetric Einstein Maxwell dilaton axion (EMDA) theory are written as a so-called Hauser Ernst (HE)-like self-dual relation for the matrix potential. Two HE-type linear systems are established and based on which some explicit formulations of new parametrized symmetry transformations for the EMDA theory are constructed. These hidden symmetries are proved to constitute an infinite-dimensional Lie algebra, which is a semidirect product of the Kac Moody algebra sp(4, R) otimes R(t, t-1) and Virasoro algebra (without centre charges). As a part of that, the positive-half sub-Kac Moody algebra sp(4, R) otimes R(t) corresponds to the Geroch-like symmetries for the EMDA theory.
NASA Technical Reports Server (NTRS)
Yarrow, Maurice; Vastano, John A.; Lomax, Harvard
1992-01-01
Generic shapes are subjected to pulsed plane waves of arbitrary shape. The resulting scattered electromagnetic fields are determined analytically. These fields are then computed efficiently at field locations for which numerically determined EM fields are required. Of particular interest are the pulsed waveform shapes typically utilized by radar systems. The results can be used to validate the accuracy of finite difference time domain Maxwell's equations solvers. A two-dimensional solver which is second- and fourth-order accurate in space and fourth-order accurate in time is examined. Dielectric media properties are modeled by a ramping technique which simplifies the associated gridding of body shapes. The attributes of the ramping technique are evaluated by comparison with the analytic solutions.
Casimir Force for a Maxwell-Chern-Simons System via Model Transformation
NASA Astrophysics Data System (ADS)
de Medeiros Neto, J. F.; Ozela, Rodrigo F.; Correa, R. O.; Ramos, Rudnei O.
2014-12-01
We show that the Hamiltonian for a Maxwell-Chern-Simons (MCS) model can be expressed in a diagonalized equivalent form involving only a massive scalar field variable in a three-dimensional space-time. We use this mapping between the two models, the MCS and a single massive scalar field, to understand the agreement of the Casimir force between parallel lines derived in both models. Since the Casimir force is heavily dependent on the boundary conditions (BC), we show that only certain types of BC can be considered for the two models, within the method of calculation outlined here. We also discuss the behavior of the BC with respect to the gauge symmetry present in the initial model.
A New Continuation Criterion for the Relativistic Vlasov-Maxwell System
NASA Astrophysics Data System (ADS)
Luk, Jonathan; Strain, Robert M.
2014-11-01
The global existence of solutions to the relativistic Vlasov-Maxwell system given sufficiently regular finite energy initial data is a longstanding open problem. The main result of Glassey and Strauss (Arch Ration Mech Anal 92:59-90, 1986) shows that a solution ( f, E, B) remains C 1 as long as the momentum support of f remains bounded. Alternate proofs were later given by Bouchut et al. (Arch Ration Mech Anal 170:1-15, 2003) and Klainerman and Staffilani (Commun Pure Appl Anal 1:103-125, 2002). We show that only the boundedness of the momentum support of f after projecting to any two dimensional plane is needed for ( f, E, B) to remain C 1.
Causal-Path Local Time-Stepping in the discontinuous Galerkin method for Maxwell's equations
NASA Astrophysics Data System (ADS)
Angulo, L. D.; Alvarez, J.; Teixeira, F. L.; Pantoja, M. F.; Garcia, S. G.
2014-01-01
We introduce a novel local time-stepping technique for marching-in-time algorithms. The technique is denoted as Causal-Path Local Time-Stepping (CPLTS) and it is applied for two time integration techniques: fourth-order low-storage explicit Runge-Kutta (LSERK4) and second-order Leap-Frog (LF2). The CPLTS method is applied to evolve Maxwell's curl equations using a Discontinuous Galerkin (DG) scheme for the spatial discretization. Numerical results for LF2 and LSERK4 are compared with analytical solutions and the Montseny's LF2 technique. The results show that the CPLTS technique improves the dispersive and dissipative properties of LF2-LTS scheme.
Light-opals interaction modeling by direct numerical solution of Maxwell's equations.
Vaccari, Alessandro; Lesina, Antonino Calà; Cristoforetti, Luca; Chiappini, Andrea; Crema, Luigi; Calliari, Lucia; Ramunno, Lora; Berini, Pierre; Ferrari, Maurizio
2014-11-01
This work describes a 3-D Finite-Difference Time-Domain (FDTD) computational approach for the optical characterization of an opal photonic crystal. To fully validate the approach we compare the computed transmittance of a crystal model with the transmittance of an actual crystal sample, as measured over the 400 ÷ 750 nm wavelength range. The opal photonic crystal considered has a face-centered cubic (FCC) lattice structure of spherical particles made of polystyrene (a non-absorptive material with constant relative dielectric permittivity). Light-matter interaction is described by numerically solving Maxwell's equations via a parallelized FDTD code. Periodic boundary conditions (PBCs) at the outer edges of the crystal are used to effectively enforce an infinite lateral extension of the sample. A method to study the propagating Bloch modes inside the crystal bulk is also proposed, which allows the reconstruction of the ω-k dispersion curve for k sweeping discretely the Brillouin zone of the crystal. PMID:25401918
Motion-induced radiation from electrons moving in Maxwell's fish-eye.
Liu, Yangjie; Ang, L K
2013-01-01
In Čerenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang et al., we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of Čerenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation. PMID:24166002
Squire, J.; Tang, W. M.; Qin, H.; Chandre, C.
2013-02-15
We present a new variational principle for the gyrokinetic system, similar to the Maxwell-Vlasov action presented in H. Cendra et al., [J. Math. Phys. 39, 3138 (1998)]. The variational principle is in the Eulerian frame and based on constrained variations of the phase space fluid velocity and particle distribution function. Using a Legendre transform, we explicitly derive the field theoretic Hamiltonian structure of the system. This is carried out with a modified Dirac theory of constraints, which is used to construct meaningful brackets from those obtained directly from Euler-Poincare theory. Possible applications of these formulations include continuum geometric integration techniques, large-eddy simulation models, and Casimir type stability methods.
Implicit scheme for Maxwell equations solution in case of flat 3D domains
NASA Astrophysics Data System (ADS)
Boronina, Marina; Vshivkov, Vitaly
2016-02-01
We present a new finite-difference scheme for Maxwell's equations solution for three-dimensional domains with different scales in different directions. The stability condition of the standard leap-frog scheme requires decreasing of the time-step with decreasing of the minimal spatial step, which depends on the minimal domain size. We overcome the conditional stability by modifying the standard scheme adding implicitness in the direction of the smallest size. The new scheme satisfies the Gauss law for the electric and magnetic fields in the final- differences. The approximation order, the maintenance of the wave amplitude and propagation speed, the invariance of the wave propagation on angle with the coordinate axes are analyzed.
E. M. SYMBALISTY
2001-07-01
The recent interest in high altitude discharges known as red sprites, blue jets, and elves has stimulated the modeling of transient atmospheric electricity. The modeling of these high altitude discharges require an initiating cloud-to-ground or intracloud lightning event in order to pre-condition the electric field between the cloud tops and the ionosphere. In this short paper we describe a finite difference time domain (FDTD) numerical solution of Maxwell's equations based on the Yee (Yee 1966) algorithm coupled with a uniaxial perfectly matched layer (PML, Berenger 1994) boundary treatment. The PML theory has advanced considerably since its original formulation in cartesian coordinates for lossless media, and is computationally efficient to implement. Another boundary treatment possibility for our sources that produce radiative and electrostatic fields, which we do not consider here, is a multipole expansion in the time domain for the electromagnetic fields.
A New Comment on Dyson's Exposition of Feynman's Proof of Maxwell Equations
Pombo, Claudia
2009-03-10
A paper by Dyson, published nearly two decades ago, describing Feynman's proof of Maxwell equations, has generated many comments, analysis, discussions and generalizations of the proof. Feynman's derivation is assumed to be based on two main sets of equations. One is supposed to be the second law of Newton and the other a set of basic commutation relations from quantum physics.Here we present a new comment on this paper, focusing mainly on the initial arguments and applying a new method of analysis and interpretation of physics, named observational realism. The present discussion does not alter the technical steps of Feynman, but do clarify their basis. We show that Newton's physics is not a starting point in Feynman's derivation, neither is quantum physics involved in it, but the foundations of relativity only.
Comparisons of the Maxwell and CLL Gas/Surface Interaction Models Using DSMC
NASA Technical Reports Server (NTRS)
Hedahl, Marc O.
1995-01-01
Two contrasting models of gas-surface interactions are studied using the Direct Simulation Monte Carlo (DSMC) method. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between the Maxwell and Cercignani-Lampis-Lord (CLL) models for flat plate configurations at freestream conditions corresponding to a 140 km orbit around Venus. The size of the flat plate is that of one of the solar panels on the Magellan spacecraft, and the freestream conditions are one of those experienced during aerobraking maneuvers. Results are presented for both a single flat plate and a two-plate configuration as a function of angle of attack and gas-surface accommodation coefficients. The two plate system is not representative of the Magellan geometry, but is studied to explore possible experiments that might be used to differentiate between the two gas surface interaction models.
Motion-induced radiation from electrons moving in Maxwell's fish-eye
Liu, Yangjie; Ang, L. K.
2013-01-01
In Čerenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang et al., we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of Čerenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation. PMID:24166002
High order resolution of the Maxwell-Fokker-Planck-Landau model intended for ICF applications
Duclous, Roland Dubroca, Bruno Filbet, Francis Tikhonchuk, Vladimir
2009-08-01
A high order, deterministic direct numerical method is proposed for the non-relativistic 2D{sub x}x3D{sub v} Vlasov-Maxwell system, coupled with Fokker-Planck-Landau collision operators. The magnetic field is perpendicular to the 2D{sub x} plane surface of computation, whereas the electric fields occur in this plane. Such a system is devoted to modelling of electron transport and energy deposition in the general frame of Inertial Confinement Fusion applications. It is able to describe the kinetics of the plasma electrons in the nonlocal equilibrium regime, and permits to consider a large anisotropy degree of the distribution function. We develop specific methods and approaches for validation, that might be used in other fields where couplings between equations, multiscale physics, and high dimensionality are involved. Fast algorithms are employed, which makes this direct approach computationally affordable for simulations of hundreds of collisional times.
Kurz, S; Becker, U; Maisch, H
2001-05-01
This paper describes the state-of-the-art of dynamic simulation of electromechanical systems. Electromechanical systems can be split into electromagnetic and mechanical subsystems, which are described by Maxwell's equations and by Newton's law, respectively. Since such systems contain moving parts, the concepts of Lorentz and Galilean relativity are briefly addressed. The laws of physics are formulated in terms of (partial) differential equations. Numerical methods ultimately aim at linear systems of equations, which can be solved efficiently on digital computers. The various discretization methods for performing this task are discussed. Special emphasis is placed on domain decomposition as a framework for the coupling of different numerical methods such as the finite element method and the boundary element method. The paper concludes with descriptions of some applications of industrial relevance: a high performance injection valve and an electromechanical relay. PMID:11482431
NASA Astrophysics Data System (ADS)
Vidal-Sallé, Emmanuelle; Chassagne, Pierre
2007-06-01
This paper presents a nonlinear viscoelastic orthotropic constitutive equation applied to wood material. The proposed model takes into account mechanical and mechanosorptive creep via a 3D stress ratio and moisture change rate for a cylindrical orthotropic material. Orthotropic frame is based on the grain direction (L), radial (R) and hoop (T) directions, which are natural wood directions. Particular attention is taken to ensure the model to fulfill the necessary dissipation conditions. It is based on a rheological generalized Maxwell model with two elements in parallel in addition with a single linear spring taking into account the long term response. The proposed model is implemented in the finite element code ABAQUS/Standard® via a user subroutine UMAT and simple example is shown to demonstrate the capability of the proposed model. Future works would deal with damage and fracture prediction for wooden structures submitted to climate variations and mechanical loading.
On solutions of Maxwell's equations with dipole sources over a thin conducting film
NASA Astrophysics Data System (ADS)
Margetis, Dionisios; Luskin, Mitchell
2016-04-01
We derive and interpret solutions of time-harmonic Maxwell's equations with a vertical and a horizontal electric dipole near a planar, thin conducting film, e.g., graphene sheet, lying between two unbounded isotropic and non-magnetic media. Exact expressions for all field components are extracted in terms of rapidly convergent series of known transcendental functions when the ambient media have equal permittivities and both the dipole and observation point lie on the plane of the film. These solutions are simplified for all distances from the source when the film surface resistivity is large in magnitude compared to the intrinsic impedance of the ambient space. The formulas reveal the analytical structure of two types of waves that can possibly be excited by the dipoles and propagate on the film. One of these waves is intimately related to the surface plasmon-polariton of transverse-magnetic polarization of plane waves.
Image denoising via Bayesian estimation of local variance with Maxwell density prior
NASA Astrophysics Data System (ADS)
Kittisuwan, Pichid
2015-10-01
The need for efficient image denoising methods has grown with the massive production of digital images and movies of all kinds. The distortion of images by additive white Gaussian noise (AWGN) is common during its processing and transmission. This paper is concerned with dual-tree complex wavelet-based image denoising using Bayesian techniques. Indeed, one of the cruxes of the Bayesian image denoising algorithms is to estimate the local variance of the image. Here, we employ maximum a posteriori (MAP) estimation to calculate local observed variance with Maxwell density prior for local observed variance and Gaussian distribution for noisy wavelet coefficients. Evidently, our selection of prior distribution is motivated by analytical and computational tractability. The experimental results show that the proposed method yields good denoising results.
NASA Astrophysics Data System (ADS)
Knoblauch, Kenneth; McMahon, Matthew J.
1995-10-01
We tested the Maxwell-Cornsweet conjecture that differential spectral filtering of the two eyes can increase the dimensionality of a dichromat's color vision. Sex-linked dichromats wore filters that differentially passed long- and middle-wavelength regions of the spectrum to each eye. Monocularly, temporal modulation thresholds (1.5 Hz) for color mixtures from the Rayleigh region of the spectrum were accounted for by a single, univariant mechanism. Binocularly, univariance was rejected because, as in monocular viewing by trichromats, in no color direction could silent substitution of the color mixtures be obtained. Despite the filter-aided increase in dimension, estimated wavelength discrimination was quite poor in this spectral region, suggesting a limit to the effectiveness of this technique. binocular summation.
NASA Technical Reports Server (NTRS)
Collier, Richard S.; Mckenna, Paul M.; Perala, Rodney A.
1991-01-01
The objective here is to describe the lightning hazards to buildings and their internal environments using advanced formulations of Maxwell's Equations. The method described is the Three Dimensional Finite Difference Time Domain Solution. It can be used to solve for the lightning interaction with such structures in three dimensions with the inclusion of a considerable amount of detail. Special techniques were developed for including wire, plumbing, and rebar into the model. Some buildings have provisions for lightning protection in the form of air terminals connected to a ground counterpoise system. It is shown that fields and currents within these structures can be significantly high during a lightning strike. Time lapse video presentations were made showing the electric and magnetic field distributions on selected cross sections of the buildings during a simulated lightning strike.
Outflow boundary conditions for the Fourier transformed three-dimensional Vlasov Maxwell system
NASA Astrophysics Data System (ADS)
Eliasson, B.
2007-08-01
A problem with the solution of the Vlasov equation is its tendency to become filamented/oscillatory in velocity space, which in numerical simulations can give rise to unphysical oscillations and recurrence effects. We present a three-dimensional Vlasov-Maxwell solver (three spatial and velocity dimensions, plus time), in which the Vlasov equation is Fourier transformed in velocity space and the resulting equations solved numerically. By designing absorbing outflow boundary conditions in the Fourier transformed velocity space, the highest Fourier modes in velocity space are removed from the numerical solution. This introduces a dissipative effect in velocity space and the numerical recurrence effect is strongly reduced. The well-posedness of the boundary conditions is proved analytically, while the stability of the numerical implementation is assessed by long-time numerical simulations. Well-known wave-modes in magnetized plasmas are shown to be reproduced by the numerical scheme.
Newton’s second law, radiation reaction and type II Einstein-Maxwell fields
NASA Astrophysics Data System (ADS)
Newman, Ezra T.
2011-12-01
Considering perturbations of the Reissner-Nordström metric while keeping the perturbations in the class of type II Einstein-Maxwell metrics, we perform a spherical harmonic expansion of all the variables up to the quadrupole term. This leads to rather surprising results. Referring to the source of the metric as a type II particle (analogous to referring to a Schwarzschild-Reissner-Nordström or Kerr-Newman particle), we see immediately that the Bondi momentum of the particle takes the classical form of mass times velocity plus an electromagnetic radiation reaction term, while the Bondi mass loss equation becomes the classical gravitational and electromagnetic (electric and magnetic) dipole and quadrupole radiation. The Bondi momentum loss equation turns into Newton’s second law of motion containing the Abraham-Lorentz-Dirac radiation reaction force plus a momentum recoil (rocket) force, while the reality condition on the Bondi mass aspect yields the conservation of angular momentum. Two things must be pointed out: (1) these results, (equations of motion, etc) take place, not in the spacetime of the type II metric but in an auxiliary space referred to as {H}-space, whose physical meaning is rather obscure and (2) this analysis of the type II field equations is a very special case of a similar analysis of the general asymptotically flat Einstein-Maxwell equations. Although the final results are similar (though not the same), the analysis uses different equations (specifically, the type II field equations) and is vastly simpler than the general case. Without a great deal of the technical structures needed in the general case, one can see rather easily where the basic results reside in the type II field equations.
NASA Astrophysics Data System (ADS)
Gauthier, Robert C.; Alzahrani, Mohammed A.; Jafari, Seyed Hamed
2015-02-01
The plane wave expansion (PWM) technique applied to Maxwell's wave equations provides researchers with a supply of information regarding the optical properties of dielectric structures. The technique is well suited for structures that display a linear periodicity. When the focus is directed towards optical resonators and structures that lack linear periodicity the eigen-process can easily exceed computational resources and time constraints. In the case of dielectric structures which display cylindrical or spherical symmetry, a coordinate system specific set of basis functions have been employed to cast Maxwell's wave equations into an eigen-matrix formulation from which the resonator states associated with the dielectric profile can be obtained. As for PWM, the inverse of the dielectric and field components are expanded in the basis functions (Fourier-Fourier-Bessel, FFB, in cylindrical and Fourier- Bessel-Legendre, BLF, in spherical) and orthogonality is employed to form the matrix expressions. The theoretical development details will be presented indicating how certain mathematical complications in the process have been overcome and how the eigen-matrix can be tuned to a specific mode type. The similarities and differences in PWM, FFB and BLF are presented. In the case of structures possessing axial cylindrical symmetry, the inclusion of the z axis component of propagation constant makes the technique applicable to photonic crystal fibers and other waveguide structures. Computational results will be presented for a number of different dielectric geometries including Bragg ring resonators, cylindrical space slot channel waveguides and bottle resonators. Steps to further enhance the computation process will be reported.
Maxwell's macroscopic equations, the energy-momentum postulates, and the Lorentz law of force.
Mansuripur, Masud; Zakharian, Armis R
2009-02-01
We argue that the classical theory of electromagnetism is based on Maxwell's macroscopic equations, an energy postulate, a momentum postulate, and a generalized form of the Lorentz law of force. These seven postulates constitute the foundation of a complete and consistent theory, thus eliminating the need for actual (i.e., physical) models of polarization P and magnetization M , these being the distinguishing features of Maxwell's macroscopic equations. In the proposed formulation, P(r,t) and M(r,t) are arbitrary functions of space and time, their physical properties being embedded in the seven postulates of the theory. The postulates are self-consistent, comply with the requirements of the special theory of relativity, and satisfy the laws of conservation of energy, linear momentum, and angular momentum. One advantage of the proposed formulation is that it sidesteps the long-standing Abraham-Minkowski controversy surrounding the electromagnetic momentum inside a material medium by simply "assigning" the Abraham momentum density E(r,t)xH(r,t)/c2 to the electromagnetic field. This well-defined momentum is thus taken to be universal as it does not depend on whether the field is propagating or evanescent, and whether or not the host medium is homogeneous, transparent, isotropic, dispersive, magnetic, linear, etc. In other words, the local and instantaneous momentum density is uniquely and unambiguously specified at each and every point of the material system in terms of the E and H fields residing at that point. Any variation with time of the total electromagnetic momentum of a closed system results in a force exerted on the material media within the system in accordance with the generalized Lorentz law. PMID:19391864
NASA Technical Reports Server (NTRS)
Joseph, Rose M.; Goorijan, Peter M.; Taflove, Allen
1993-01-01
Solution of 2D vector nonlinear Maxwell's equations is described for material media with linear and nonlinear instantaneous and Lorentz dispersion effects in the electric polarization. Finite difference time domain method is used in the analysis. The method discussed here achieves robustness by enforcing vector-field boundary conditions at all interfaces of dissimilar media.
Hydrodynamics with conserved current via AdS/CFT correspondence in the Maxwell-Gauss-Bonnet gravity
Hu Yapeng; Sun Peng; Zhang Jianhui
2011-06-15
Using the AdS/CFT correspondence, we study the hydrodynamics with conserved current from the dual Maxwell-Gauss-Bonnet gravity. After constructing the perturbative solution to the first order based on the boosted black brane solution in the bulk Maxwell-Gauss-Bonnet gravity, we extract the stress tensor and conserved current of the dual conformal fluid on its boundary, and also find the effect of the Gauss-Bonnet term on the dual conformal fluid. Our results show that the Gauss-Bonnet term can affect the parameters such as the shear viscosity {eta}, entropy density s, thermal conductivity {kappa} and electrical conductivity {sigma}. However, it does not affect the so-called Wiedemann-Franz law which relates {kappa} to {sigma}, while it affects the ratio {eta}/s. In addition, another interesting result is that {eta}/s can also be affected by the bulk Maxwell field in our case, which is consistent with some previous results predicted through the Kubo formula. Moreover, the anomalous magnetic and vortical effects by adding the Chern-Simons term are also considered in our case in the Maxwell-Gauss-Bonnet gravity.
NASA Astrophysics Data System (ADS)
Yazadjiev, Stoytcho
2013-06-01
In this paper, we consider 5D spacetimes satisfying the Einstein-Maxwell-dilaton gravity equations which are U(1)2 axisymmetric but otherwise highly dynamical. We derive inequalities between the area, the angular momenta, the electric charge and the magnetic fluxes for any smooth stably outer marginally trapped surface.
The development of ensemble theory. A new glimpse at the history of statistical mechanics
NASA Astrophysics Data System (ADS)
Inaba, Hajime
2015-12-01
This paper investigates the history of statistical mechanics from the viewpoint of the development of the ensemble theory from 1871 to 1902. In 1871, Ludwig Boltzmann introduced a prototype model of an ensemble that represents a polyatomic gas. In 1879, James Clerk Maxwell defined an ensemble as copies of systems of the same energy. Inspired by H.W. Watson, he called his approach "statistical". Boltzmann and Maxwell regarded the ensemble theory as a much more general approach than the kinetic theory. In the 1880s, influenced by Hermann von Helmholtz, Boltzmann made use of ensembles to establish thermodynamic relations. In Elementary Principles in Statistical Mechanics of 1902, Josiah Willard Gibbs tried to get his ensemble theory to mirror thermodynamics, including thermodynamic operations in its scope. Thermodynamics played the role of a "blind guide". His theory of ensembles can be characterized as more mathematically oriented than Einstein's theory proposed in the same year. Mechanical, empirical, and statistical approaches to foundations of statistical mechanics are presented. Although it was formulated in classical terms, the ensemble theory provided an infrastructure still valuable in quantum statistics because of its generality.
Thermodynamics and statistical mechanics. [thermodynamic properties of gases
NASA Technical Reports Server (NTRS)
1976-01-01
The basic thermodynamic properties of gases are reviewed and the relations between them are derived from the first and second laws. The elements of statistical mechanics are then formulated and the partition function is derived. The classical form of the partition function is used to obtain the Maxwell-Boltzmann distribution of kinetic energies in the gas phase and the equipartition of energy theorem is given in its most general form. The thermodynamic properties are all derived as functions of the partition function. Quantum statistics are reviewed briefly and the differences between the Boltzmann distribution function for classical particles and the Fermi-Dirac and Bose-Einstein distributions for quantum particles are discussed.
Neuroendocrine Tumor: Statistics
... Tumor > Neuroendocrine Tumor - Statistics Request Permissions Neuroendocrine Tumor - Statistics Approved by the Cancer.Net Editorial Board , 04/ ... the body. It is important to remember that statistics on how many people survive this type of ...
NASA Technical Reports Server (NTRS)
Liu, Yen; Vinokur, Marcel; Wang, Z. J.
2004-01-01
A three-dimensional, high-order, conservative, and efficient discontinuous spectral volume (SV) method for the solutions of Maxwell's equations on unstructured grids is presented. The concept of discontinuous 2nd high-order loca1 representations to achieve conservation and high accuracy is utilized in a manner similar to the Discontinuous Galerkin (DG) method, but instead of using a Galerkin finite-element formulation, the SV method is based on a finite-volume approach to attain a simpler formulation. Conventional unstructured finite-volume methods require data reconstruction based on the least-squares formulation using neighboring cell data. Since each unknown employs a different stencil, one must repeat the least-squares inversion for every cell at each time step, or to store the inversion coefficients. In a high-order, three-dimensional computation, the former would involve impractically large CPU time, while for the latter the memory requirement becomes prohibitive. In the SV method, one starts with a relatively coarse grid of triangles or tetrahedra, called spectral volumes (SVs), and partition each SV into a number of structured subcells, called control volumes (CVs), that support a polynomial expansion of a desired degree of precision. The unknowns are cell averages over CVs. If all the SVs are partitioned in a geometrically similar manner, the reconstruction becomes universal as a weighted sum of unknowns, and only a few universal coefficients need to be stored for the surface integrals over CV faces. Since the solution is discontinuous across the SV boundaries, a Riemann solver is thus necessary to maintain conservation. In the paper, multi-parameter and symmetric SV partitions, up to quartic for triangle and cubic for tetrahedron, are first presented. The corresponding weight coefficients for CV face integrals in terms of CV cell averages for each partition are analytically determined. These discretization formulas are then applied to the integral form of
Statistical Reference Datasets
National Institute of Standards and Technology Data Gateway
Statistical Reference Datasets (Web, free access) The Statistical Reference Datasets is also supported by the Standard Reference Data Program. The purpose of this project is to improve the accuracy of statistical software by providing reference datasets with certified computational results that enable the objective evaluation of statistical software.
A Fourth Order Difference Scheme for the Maxwell Equations on Yee Grid
Fathy, Aly E; Wilson, Joshua L
2008-09-01
The Maxwell equations are solved by a long-stencil fourth order finite difference method over a Yee grid, in which different physical variables are located at staggered mesh points. A careful treatment of the numerical values near the boundary is introduced, which in turn leads to a 'symmetric image' formula at the 'ghost' grid points. Such a symmetric formula assures the stability of the boundary extrapolation. In turn, the fourth order discrete curl operator for the electric and magnetic vectors gives a complete set of eigenvalues in the purely imaginary axis. To advance the dynamic equations, the four-stage Runge-Kutta method is utilized, which results in a full fourth order accuracy in both time and space. A stability constraint for the time step is formulated at both the theoretical and numerical levels, using an argument of stability domain. An accuracy check is presented to verify the fourth order precision, using a comparison between exact solution and numerical solutions at a fixed final time. In addition, some numerical simulations of a loss-less rectangular cavity are also carried out and the frequency is measured precisely.
NASA Astrophysics Data System (ADS)
Chakraborty, Brahmananda; Wang, Jin; Eapen, Jacob
2013-05-01
Multicomponent diffusional mechanisms in the ternary LiCl-KCl system are elucidated using the Green-Kubo formalism and equilibrium molecular dynamics simulations. The Maxwell-Stefan (MS) diffusion matrix is evaluated from the Onsager dynamical matrix that contains the diffusion flux correlation functions. From the temporal behavior of the correlation functions, we observe that the Li-Li and Li-Cl ion pairs have a pronounced cage dynamics that remains noticeably strong even at high temperatures. Even though the Onsager coefficients, which are the time integrals of the diffusion flux correlation functions, portray a relatively smooth variation across various compositions and temperatures, we observe a sign change and a divergent-like behavior for the MS diffusivity of the K-Li ion pair at a temperature of ˜1100 K for the eutectic composition, and at a KCl mole fraction of ˜0.49 at 1043 K. Negative MS diffusivities, while unusual, are however shown to satisfy the nonnegative entropic constraints.
An optimally blended finite-spectral element scheme with minimal dispersion for Maxwell equations
NASA Astrophysics Data System (ADS)
Wajid, Hafiz Abdul; Ayub, Sobia
2012-10-01
We study the dispersive properties of the time harmonic Maxwell equations for optimally blended finite-spectral element scheme using tensor product elements defined on rectangular grid in d-dimensions. We prove and give analytical expressions for the discrete dispersion relations for this scheme. We find that for a rectangular grid (a) the analytical expressions for the discrete dispersion error in higher dimensions can be obtained using one dimensional discrete dispersion error expressions; (b) the optimum value of the blending parameter is p/(p+1) for all p∈N and for any number of spatial dimensions; (c) analytical expressions for the discrete dispersion relations for finite element and spectral element schemes can be obtained when the value of blending parameter is chosen to be 0 and 1 respectively; (d) the optimally blended scheme guarantees two additional orders of accuracy compared with standard finite element and spectral element schemes; and (e) the absolute accuracy of the optimally blended scheme is O(p-2) and O(p-1) times better than that of the pure finite element and spectral element schemes respectively.
Core-envelope and regular models in Einstein-Maxwell fields
NASA Astrophysics Data System (ADS)
Hansraj, Sudan; Maharaj, Sunil Dutt; Mlaba, Sphakamiso
2016-01-01
New classes of exact solutions which could serve as sources for the Reissner-Nordstrom metric representing the exterior gravitational field of an isolated charged sphere are derived. Firstly, we sacrifice the requirement that the stellar centre is free of a singularity and then obtain a core-envelope model. The charged fluid envelope is matched suitably to the neutral core and the vacuum exterior solution. Next we investigate models of charged stars that are regular at the stellar centre. The Einstein-Maxwell system of partial differential equations is reduced to the study of a single first-order differential equation in which two of the matter or geometrical variables must be specified at the outset. In each case mentioned above, new exact models are found by choosing functional forms for the electric field intensity and one of the gravitational potentials. A Riccati equation is then solved to obtain the remaining potential. The charged spherical shell model as well as the non-singular models are shown to display necessary qualitative features that are demanded for physical acceptability. It is shown that the regular model has a vanishing pressure-free hypersurface. The density and pressure profiles are positive and monotonically decreasing outwards from the centre of the sphere for a chosen set of parameters. The weak strong and dominant energy conditions are also satisfied. A drawback of the model is that the causality criterion is not satisfied within the fluid boundary.
Thermodynamics of rotating solutions in (n+1)-dimensional Einstein-Maxwell-dilaton gravity
Sheykhi, A.; Riazi, N.; Pakravan, J.; Dehghani, M. H.
2006-10-15
We construct a class of charged, rotating solutions of (n+1)-dimensional Einstein-Maxwell-dilaton gravity with cylindrical or toroidal horizons in the presence of Liouville-type potentials and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black brane, with inner and outer event horizons, an extreme black brane or a naked singularity provided the parameters of the solutions are chosen suitably. We also compute temperature, entropy, charge, electric potential, mass and angular momentum of the black brane solutions, and find that these quantities satisfy the first law of thermodynamics. We find a Smarr-type formula and perform a stability analysis by computing the heat capacity in the canonical ensemble. We find that the system is thermally stable when the coupling constant between the dilaton and matter field {alpha}{<=}1, while for {alpha}>1 the system has an unstable phase. This shows that the dilaton field makes the solution unstable, while it is stable even in Lovelock gravity.
Magnetic branes in (n+1)-dimensional Einstein-Maxwell-dilaton gravity
Sheykhi, A.; Riazi, N.; Dehghani, M. H.
2007-02-15
We construct two new classes of spacetimes generated by spinning and traveling magnetic sources in (n+1)-dimensional Einstein-Maxwell-dilaton gravity with Liouville-type potential. These solutions are neither asymptotically flat nor (A)dS. The first class of solutions which yields a (n+1)-dimensional spacetime with a longitudinal magnetic field and k rotation parameters have no curvature singularity and no horizons, but have a conic geometry. We show that when one or more of the rotation parameters are nonzero, the spinning branes have a net electric charge that is proportional to the magnitude of the rotation parameters. The second class of solutions yields a static spacetime with an angular magnetic field and has no curvature singularity, no horizons, and no conical singularity. Although one may add linear momentum to the second class of solutions by a boost transformation, one does not obtain a new solution. We find that the net electric charge of these traveling branes with one or more nonzero boost parameters is proportional to the magnitude of the velocity of the branes. We also use the counterterm method and calculate the conserved quantities of the solutions.
Electrical Maxwell demon and Szilard engine utilizing Johnson noise, measurement, logic and control.
Kish, Laszlo Bela; Granqvist, Claes-Göran
2012-01-01
We introduce a purely electrical version of Maxwell's demon which does not involve mechanically moving parts such as trapdoors, etc. It consists of a capacitor, resistors, amplifiers, logic circuitry and electronically controlled switches and uses thermal noise in resistors (Johnson noise) to pump heat. The only types of energy of importance in this demon are electrical energy and heat. We also demonstrate an entirely electrical version of Szilard's engine, i.e., an information-controlled device that can produce work by employing thermal fluctuations. The only moving part is a piston that executes work, and the engine has purely electronic controls and it is free of the major weakness of the original Szilard engine in not requiring removal and repositioning the piston at the end of the cycle. For both devices, the energy dissipation in the memory and other binary informatics components are insignificant compared to the exponentially large energy dissipation in the analog part responsible for creating new information by measurement and decision. This result contradicts the view that the energy dissipation in the memory during erasure is the most essential dissipation process in a demon. Nevertheless the dissipation in the memory and information processing parts is sufficient to secure the Second Law of Thermodynamics. PMID:23077525
Hybrid Vlasov-Maxwell simulations of two-dimensional turbulence in plasmas
Valentini, F.; Servidio, S.; Veltri, P.; Perrone, D.; Califano, F.; Matthaeus, W. H.
2014-08-15
Turbulence in plasmas is a very challenging problem since it involves wave-particle interactions, which are responsible for phenomena such as plasma dissipation, acceleration mechanisms, heating, temperature anisotropy, and so on. In this work, a hybrid Vlasov-Maxwell numerical code is employed to study local kinetic processes in a two-dimensional turbulent regime. In the present model, ions are treated as a kinetic species, while electrons are considered as a fluid. As recently reported in [S. Servidio, Phys. Rev. Lett. 108, 045001 (2012)], nearby regions of strong magnetic activity, kinetic effects manifest through a deformation of the ion velocity distribution function that consequently departs from the equilibrium Maxwellian configuration. Here, the structure of turbulence is investigated in detail in phase space, by evaluating the high-order moments of the particle velocity distribution, i.e., temperature, skewness, and kurtosis. This analysis provides quantitative information about the non-Maxwellian character of the system dynamics. This departure from local thermodynamic equilibrium triggers several processes commonly observed in many astrophysical and laboratory plasmas.
Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole
Wei, Shao-Wen; Liu, Yu-Xiao E-mail: liuyx@lzu.edu.cn
2013-11-01
In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.
Nanoscale roughness effect on Maxwell-like boundary conditions for the Boltzmann equation
NASA Astrophysics Data System (ADS)
Brull, S.; Charrier, P.; Mieussens, L.
2016-08-01
It is well known that the roughness of the wall has an effect on microscale gas flows. This effect can be shown for large Knudsen numbers by using a numerical solution of the Boltzmann equation. However, when the wall is rough at a nanometric scale, it is necessary to use a very small mesh size which is much too expansive. An alternative approach is to incorporate the roughness effect in the scattering kernel of the boundary condition, such as the Maxwell-like kernel introduced by the authors in a previous paper. Here, we explain how this boundary condition can be implemented in a discrete velocity approximation of the Boltzmann equation. Moreover, the influence of the roughness is shown by computing the structure scattering pattern of mono-energetic beams of the incident gas molecules. The effect of the angle of incidence of these molecules, of their mass, and of the morphology of the wall is investigated and discussed in a simplified two-dimensional configuration. The effect of the azimuthal angle of the incident beams is shown for a three-dimensional configuration. Finally, the case of non-elastic scattering is considered. All these results suggest that our approach is a promising way to incorporate enough physics of gas-surface interaction, at a reasonable computing cost, to improve kinetic simulations of micro- and nano-flows.
NASA Astrophysics Data System (ADS)
Brenner, Thomas; Reitzle, Dominik; Kienle, Alwin
2016-04-01
An algorithm for the simulation of image formation in Fourier domain optical coherence tomography (OCT) for an infinitely long cylinder is presented. The analytical solution of Maxwell's equations for light scattering by a single cylinder is employed for the case of perpendicular incidence to calculate OCT images. The A-scans and the time-resolved scattered intensities are compared to geometrical optics results calculated with a ray tracing approach. The reflection peaks, including the whispering gallery modes, are identified. Additionally, the Debye series expansion is employed to identify single peaks in the OCT A-scans. Furthermore, a Gaussian beam is implemented in order to simulate lateral scanning over the cylinder for two-dimensional B-scans. The fields are integrated over a certain angular range to simulate a detection aperture. In addition, the solution for light scattering by layered cylinders is employed and the various layers are identified in the resulting OCT image. Overall, the simulations in this work show that OCT images do not always display the real surface of investigated samples.
Parallel numerical integration of Maxwell's full-vector equations in nonlinear focusing media
NASA Astrophysics Data System (ADS)
Bennett, Paul Murray
Maxwell's equations governing the evolution of ultrashort intense coherent pulses of light in a nonlinear focusing dielectric are presented. A discretization of this model using Kane Yee's grid is presented. Initial and boundary conditions are derived, and a serial finite difference algorithm using Yee's grid with the initial and boundary conditions is given. A parallelization of the serial algorithm to more aptly handle the large computational size is performed, and speedup and efficiency results of the parallel program are presented. The parallel code is first used to study the effect of the focusing nonlinearity upon dispersionless pulse propagation. Indications are given of the development of shocks on the optical carrier wave and upon the pulse envelope. The parallel code is then used to study the effect of varying the focusing of the light by varying the intensity as a way to compensate linear dispersion. Blow-up of the pulse in finite propagation distance is demonstrated, and the dependence of the blow-up position upon the intensity of the light is presented. Optical saturation is considered to counter blow-up of intense pulses. Finally, the parallel code is used to study the evolution of intense ultrashort optical pulses in a model featuring nonlinear dispersion, focusing, and optical saturation.
Centrifugal instability of pulsed Taylor-Couette flow in a Maxwell fluid.
Riahi, Mehdi; Aniss, Saïd; Ouazzani Touhami, Mohamed; Skali Lami, Salah
2016-08-01
Centrifugal instability of a pulsed flow in a viscoelastic fluid confined in a Taylor-Couette system is investigated. Both cylinders are subject to an out-of-phase modulation of rotation with equal modulation amplitude and modulation frequency. The fluid is assumed to obey a linear Maxwell fluid with a relaxation time and a constant viscosity. Attention is focused on the linear stability analysis and on the effect of Deborah and frequency numbers on the critical values of the Taylor and wave numbers. Using Floquet theory, we show that in the limit of low frequency, the Deborah number has no effect on the stability of the basic state which tends to the classical configuration of steady circular Couette flow. When the frequency number increases, the stability of the basic flow is enhanced and the Deborah number has a destabilizing effect which is strongly pronounced in the high-frequency limit. In this frequency limit, the critical parameters tend to constant values independently of the frequency number. These numerical results are in good agreement with the asymptotic solutions obtained in the limit of low and high frequencies. Moreover, a correlation between the rheological proprieties of the fluid in a rheometric experience, especially the loss and storage modulus, and this hydrodynamical instability behavior is presented. PMID:27589859
The spatial fourth-order energy-conserved S-FDTD scheme for Maxwell's equations
NASA Astrophysics Data System (ADS)
Liang, Dong; Yuan, Qiang
2013-06-01
In this paper we develop a new spatial fourth-order energy-conserved splitting finite-difference time-domain method for Maxwell's equations. Based on the staggered grids, the splitting technique is applied to lead to a three-stage energy-conserved splitting scheme. At each stage, using the spatial fourth-order difference operators on the strict interior nodes by a linear combination of two central differences, one with a spatial step and the other with three spatial steps, we first propose the spatial high-order near boundary differences on the near boundary nodes which ensure the scheme to preserve energy conservations and to have fourth-order accuracy in space step. The proposed scheme has the important properties: energy-conserved, unconditionally stable, non-dissipative, high-order accurate, and computationally efficient. We first prove that the scheme satisfies energy conversations and is in unconditional stability. We then prove the optimal error estimates of fourth-order in spatial step and second-order in time step for the electric and magnetic fields and obtain the convergence and error estimate of divergence-free as well. Numerical dispersion analysis and numerical experiments are presented to confirm our theoretical results.
Spatial contraction of the Poincare group and Maxwell's equations in the electric limit
Reich, H.T. Wickramasekara, S.
2010-05-15
The contraction of the Poincare group with respect to the space translations subgroup gives rise to a group that bears a certain duality relation to the Galilei group, that is, the contraction limit of the Poincare group with respect to the time translations subgroup. In view of this duality, we call the former the dual Galilei group. A rather remarkable feature of the dual Galilei group is that the time translations constitute a central subgroup. Therewith, in unitary irreducible representations (UIRs) of the group, the Hamiltonian appears as a Casimir operator proportional to the identity H = EI, with E (and a spin value s) uniquely characterizing the representation. Hence, a physical system characterized by a UIR of the dual Galilei group displays no non-trivial time evolution. Moreover, the combined U(1) gauge group and the dual Galilei group underlie a non-relativistic limit of Maxwell's equations known as the electric limit. The analysis presented here shows that only electrostatics is possible for the electric limit, wholly in harmony with the trivial nature of time evolution governed by the dual Galilei group.
Higher-order brick-tetrahedron hybrid method for Maxwell's equations in time domain
NASA Astrophysics Data System (ADS)
Winges, Johan; Rylander, Thomas
2016-09-01
We present a higher-order brick-tetrahedron hybrid method for Maxwell's equations in time domain. Brick-shaped elements are used for large homogeneous parts of the computational domain, where we exploit mass-lumping and explicit time-stepping. In regions with complex geometry, we use an unstructured mesh of tetrahedrons that share an interface with the brick-shaped elements and, at the interface, tangential continuity of the electric field is imposed in the weak sense by means of Nitsche's method. Implicit time-stepping is used for the tetrahedrons together with the interface. For cavity resonators, the hybrid method reproduces the lowest non-zero eigenvalues with correct multiplicity and, for geometries without field singularities from sharp corners or edges, the numerical eigenvalues converge towards the analytical result with an error that is approximately proportional to h2p, where h is the cell size and p is the polynomial order of the elements. For a rectangular waveguide, a layer of tetrahedrons embedded in a grid of brick-shaped elements yields a low reflection coefficient that scales approximately as h2p. Finally, we demonstrate hybrid time-stepping for a lossless closed cavity resonator, where the time-domain response is computed for 300,000 time steps without any signs of instabilities.
Maxwell-Dirac stress-energy tensor in terms of Fierz bilinear currents
NASA Astrophysics Data System (ADS)
Inglis, Shaun; Jarvis, Peter
2016-03-01
We analyse the stress-energy tensor for the self-coupled Maxwell-Dirac system in the bilinear current formalism, using two independent approaches. The first method used is that attributed to Belinfante: starting from the spinor form of the action, the well-known canonical stress-energy tensor is augmented, by extending the Noether symmetry current to include contributions from the Lorentz group, to a manifestly symmetric form. This form admits a transcription to bilinear current form. The second method used is the variational derivation based on the covariant coupling to general relativity. The starting point here at the outset is the transcription of the action using, as independent field variables, both the bilinear currents, together with a gauge invariant vector field (a proxy for the electromagnetic vector potential). A central feature of the two constructions is that they both involve the mapping of the Dirac contribution to the stress-energy from the spinor fields to the equivalent set of bilinear tensor currents, through the use of appropriate Fierz identities. Although this mapping is done at quite different stages, nonetheless we find that the two forms of the bilinear stress-energy tensor agree. Finally, as an application, we consider the reduction of the obtained stress-energy tensor in bilinear form, under the assumption of spherical symmetry.
Einstein-Cartan Theory of Gravitation: Kinematical Parameters and Maxwell Equations
NASA Astrophysics Data System (ADS)
Katkar, L. N.
2015-03-01
In the space-time manifold of Einstein-Cartan Theory (ECT) of gravitation, the expressions for the time-like kinematical parameters are derived and the propagation equation for expansion is obtained.It has been observed that when the spin tensor is u-orthogonal the spin of the gravitating matter has no influence on the propagation equation of expansion while it has influence when it is not u-orthogonal. The usual formula for the curl of gradient of a scalar function is not zero in ECT. So is the case with the divergence of the curl of a vector.Their expressions on the space-time manifold of ECT are derived. A new derivative operator d ∗ is introduced to develop the calculus on space-time manifold of ECT. It is obtained by taking the covariant derivative of an associated tensor of a form with respect to an asymmetric connections. We have used this differential operator to obtain the form of the Maxwell's equations in the ECT of gravitation. Cartan's equations of structure are also derived through the new derivative operator. It has been shown that unlike the consequences of exterior derivative in Einstein space-time, the repetition of d ∗ on a form of any degree is not zero.
Asymptotic structure of the Einstein-Maxwell theory on AdS3
NASA Astrophysics Data System (ADS)
Pérez, Alfredo; Riquelme, Miguel; Tempo, David; Troncoso, Ricardo
2016-02-01
The asymptotic structure of AdS spacetimes in the context of General Relativity coupled to the Maxwell field in three spacetime dimensions is analyzed. Although the fall-off of the fields is relaxed with respect to that of Brown and Henneaux, the variation of the canonical generators associated to the asymptotic Killing vectors can be shown to be finite once required to span the Lie derivative of the fields. The corresponding surface integrals then acquire explicit contributions from the electromagnetic field, and become well-defined provided they fulfill suitable integrability conditions, implying that the leading terms of the asymptotic form of the electromagnetic field are functionally related. Consequently, for a generic choice of boundary conditions, the asymptotic symmetries are broken down to {R}⊗ U(1)⊗ U(1) . Nonetheless, requiring compatibility of the boundary conditions with one of the asymptotic Virasoro symmetries, singles out the set to be characterized by an arbitrary function of a single variable, whose precise form depends on the choice of the chiral copy. Remarkably, requiring the asymptotic symmetries to contain the full conformal group selects a very special set of boundary conditions that is labeled by a unique constant parameter, so that the algebra of the canonical generators is given by the direct sum of two copies of the Virasoro algebra with the standard central extension and U (1). This special set of boundary conditions makes the energy spectrum of electrically charged rotating black holes to be well-behaved.
Yong, Wen-An; Zhao, Weifeng; Luo, Li-Shi
2016-03-01
We propose using the Maxwell iteration to derive the hydrodynamic equations from the lattice Boltzmann equation (LBE) with an external forcing term. The proposed methodology differs from existing approaches in several aspects. First, it need not explicitly introduce multiple-timescales or the Knudsen number, both of which are required in the Chapman-Enskog analysis. Second, it need not use the Hilbert expansion of the hydrodynamic variables, which is necessary in the asymptotic analysis of the LBE. The proposed methodology assumes the acoustic scaling (or the convective scaling) δ_{t}∼δ_{x}, thus δ_{t} is the only expansion parameter in the analysis of the LBE system, and it leads to the Navier-Stokes equations in compressible form. The forcing density derived in this work can reproduce existing forcing schemes by adjusting appropriate parameters. The proposed methodology also analyzes the numerical accuracy of the LBE. In particular, it shows the Mach number Ma should scale as O(δ_{t}^{1/3}) to maintain the truncation errors due to Ma and δ_{t} in balance when δ_{t}→0, so that the LBE can converge to the expected hydrodynamic equations effectively and efficiently. PMID:27078487
NASA Astrophysics Data System (ADS)
Yong, Wen-An; Zhao, Weifeng; Luo, Li-Shi
2016-03-01
We propose using the Maxwell iteration to derive the hydrodynamic equations from the lattice Boltzmann equation (LBE) with an external forcing term. The proposed methodology differs from existing approaches in several aspects. First, it need not explicitly introduce multiple-timescales or the Knudsen number, both of which are required in the Chapman-Enskog analysis. Second, it need not use the Hilbert expansion of the hydrodynamic variables, which is necessary in the asymptotic analysis of the LBE. The proposed methodology assumes the acoustic scaling (or the convective scaling) δt˜δx , thus δt is the only expansion parameter in the analysis of the LBE system, and it leads to the Navier-Stokes equations in compressible form. The forcing density derived in this work can reproduce existing forcing schemes by adjusting appropriate parameters. The proposed methodology also analyzes the numerical accuracy of the LBE. In particular, it shows the Mach number Ma should scale as O (δt1 /3) to maintain the truncation errors due to Ma and δt in balance when δt→0 , so that the LBE can converge to the expected hydrodynamic equations effectively and efficiently.
Geometric properties of static Einstein-Maxwell dilaton horizons with a Liouville potential
Abdolrahimi, Shohreh; Shoom, Andrey A.
2011-05-15
We study nondegenerate and degenerate (extremal) Killing horizons of arbitrary geometry and topology within the Einstein-Maxwell-dilaton model with a Liouville potential (the EMdL model) in d-dimensional (d{>=}4) static space-times. Using Israel's description of a static space-time, we construct the EMdL equations and the space-time curvature invariants: the Ricci scalar, the square of the Ricci tensor, and the Kretschmann scalar. Assuming that space-time metric functions and the model fields are real analytic functions in the vicinity of a space-time horizon, we study the behavior of the space-time metric and the fields near the horizon and derive relations between the space-time curvature invariants calculated on the horizon and geometric invariants of the horizon surface. The derived relations generalize similar relations known for horizons of static four- and five-dimensional vacuum and four-dimensional electrovacuum space-times. Our analysis shows that all the extremal horizon surfaces are Einstein spaces. We present the necessary conditions for the existence of static extremal horizons within the EMdL model.
Complete spin and orbital evolution of close-in bodies using a Maxwell viscoelastic rheology
NASA Astrophysics Data System (ADS)
Boué, Gwenaël; Correia, Alexandre C. M.; Laskar, Jacques
2016-07-01
In this paper, we present a formalism designed to model tidal interaction with a viscoelastic body made of Maxwell material. Our approach remains regular for any spin rate and orientation, and for any orbital configuration including high eccentricities and close encounters. The method is to integrate simultaneously the rotation and the position of the planet as well as its deformation. We provide the equations of motion both in the body frame and in the inertial frame. With this study, we generalize preexisting models to the spatial case and to arbitrary multipole orders using a formalism taken from quantum theory. We also provide the vectorial expression of the secular tidal torque expanded in Fourier series. Applying this model to close-in exoplanets, we observe that if the relaxation time is longer than the revolution period, the phase space of the system is characterized by the presence of several spin-orbit resonances, even in the circular case. As the system evolves, the planet spin can visit different spin-orbit configurations. The obliquity is decreasing along most of these resonances, but we observe a case where the planet tilt is instead growing. These conclusions derived from the secular torque are successfully tested with numerical integrations of the instantaneous equations of motion on HD 80606 b. Our formalism is also well adapted to close-in super-Earths in multiplanet systems which are known to have non-zero mutual inclinations.
High-order continuum Vlasov-Maxwell simulations of collisionless plasmas
NASA Astrophysics Data System (ADS)
Vogman, G. V.; Colella, P.; Shumlak, U.
2015-11-01
Plasma kinetic theory treats each constituent species as a probability distribution function in phase space. Numerically, the velocity dependence of the distribution function can be sampled discretely as in particle-in-cell methods, or represented smoothly as in continuum methods. Continuum methods for solving kinetic theory governing equations are advantageous in that they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods, which provide enhanced solution accuracy. A fourth-order accurate finite volume method has been developed to solve the continuum kinetic Vlasov-Maxwell equation system in 2D2V phase space using the Chombo library. The evolving species are collisionless, and are coupled through electromagnetic fields. The algorithm is validated against theoretical predictions using benchmarks based on the Dory-Guest-Harris instability and the Harris current sheet. Extension of the algorithm to cylindrical coordinates and its application to axisymmetric plasma configurations like the Z-pinch are also presented.
Rogue waves of the Hirota and the Maxwell-Bloch equations
NASA Astrophysics Data System (ADS)
Li, Chuanzhong; He, Jingsong; Porseizan, K.
2013-01-01
In this paper, we derive a Darboux transformation of the Hirota and the Maxwell-Bloch (H-MB) system which is governed by femtosecond pulse propagation through an erbium doped fiber and further generalize it to the matrix form of the n-fold Darboux transformation of this system. This n-fold Darboux transformation implies the determinant representation of nth solutions of (E[n],p[n],η[n]) generated from the known solution of (E,p,η). The determinant representation of (E[n],p[n],η[n]) provides soliton solutions, positon solutions, and breather solutions (both bright and dark breathers) of the H-MB system. From the breather solutions, we also construct a bright and dark rogue wave solution for the H-MB system, which is currently one of the hottest topics in mathematics and physics. Surprisingly, the rogue wave solution for p and η has two peaks because of the order of the numerator and denominator of them. Meanwhile, after fixing the time and spatial parameters and changing two other unknown parameters α and β, we generate a rogue wave shape.
Application of a GPU-Assisted Maxwell Code to Electromagnetic Wave Propagation in ITER
NASA Astrophysics Data System (ADS)
Kubota, S.; Peebles, W. A.; Woodbury, D.; Johnson, I.; Zolfaghari, A.
2014-10-01
The Low Field Side Reflectometer (LSFR) on ITER is envisioned to provide capabilities for electron density profile and fluctuations measurements in both the plasma core and edge. The current design for the Equatorial Port Plug 11 (EPP11) employs seven monostatic antennas for use with both fixed-frequency and swept-frequency systems. The present work examines the characteristics of this layout using the 3-D version of the GPU-Assisted Maxwell Code (GAMC-3D). Previous studies in this area were performed with either 2-D full wave codes or 3-D ray- and beam-tracing. GAMC-3D is based on the FDTD method and can be run with either a fixed-frequency or modulated (e.g. FMCW) source, and with either a stationary or moving target (e.g. Doppler backscattering). The code is designed to run on a single NVIDIA Tesla GPU accelerator, and utilizes a technique based on the moving window method to overcome the size limitation of the onboard memory. Effects such as beam drift, linear mode conversion, and diffraction/scattering will be examined. Comparisons will be made with beam-tracing calculations using the complex eikonal method. Supported by U.S. DoE Grants DE-FG02-99ER54527 and DE-AC02-09CH11466, and the DoE SULI Program at PPPL.
DAY,DAVID M.; NEWMAN,GREGORY A.
1999-10-01
A fast precondition technique has been developed which accelerates the finite difference solutions of the 3D Maxwell's equations for geophysical modeling. The technique splits the electric field into its curl free and divergence free projections, and allows for the construction of an inverse operator. Test examples show an order of magnitude speed up compared with a simple Jacobi preconditioner. Using this preconditioner a low frequency Neumann series expansion is developed and used to compute responses at multiple frequencies very efficiently. Simulations requiring responses at multiple frequencies, show that the Neumann series is faster than the preconditioned solution, which must compute solutions at each discrete frequency. A Neumann series expansion has also been developed in the high frequency limit along with spectral Lanczos methods in both the high and low frequency cases for simulating multiple frequency responses with maximum efficiency. The research described in this report was to have been carried out over a two-year period. Because of communication difficulties, the project was funded for first year only. Thus the contents of this report are incomplete with respect to the original project objectives.
NASA Technical Reports Server (NTRS)
Vinh, Hoang; Dwyer, Harry A.; Van Dam, C. P.
1992-01-01
The applications of two CFD-based finite-difference methods to computational electromagnetics are investigated. In the first method, the time-domain Maxwell's equations are solved using the explicit Lax-Wendroff scheme and in the second method, the second-order wave equations satisfying the Maxwell's equations are solved using the implicit Crank-Nicolson scheme. The governing equations are transformed to a generalized curvilinear coordinate system and solved on a body-conforming mesh using the scattered-field formulation. The induced surface current and the bistatic radar cross section are computed and the results are validated for several two-dimensional test cases involving perfectly-conducting scatterers submerged in transverse-magnetic plane waves.
NASA Astrophysics Data System (ADS)
Hinschberger, Y.; Manfredi, G.; Hervieux, P.-A.
2016-04-01
We present a self-consistent mean-field model based on a two-component Pauli-like equation that incorporates quantum and relativistic effects (up to second order in 1 /c ) for both external and internal electromagnetic fields. By taking the semirelativistic limit of the Dirac-Maxwell equations in the presence of an external electromagnetic field we obtain an analytical expression of a coherent light-induced mean-field Hamiltonian. The latter exhibits several mechanisms that involve the internal mean fields created by all the electrons and the external electromagnetic field (laser). The role played by the light-induced current density and the light-induced second-order charge density acting as sources in Maxwell's equations are clarified. In particular, we identify clearly four different mechanisms involving the spins that may play an important role in coherent ultrafast spin dynamics.
NASA Astrophysics Data System (ADS)
Mo, Jie-Xiong; Li, Gu-Qiang; Xu, Xiao-Bao
2016-04-01
The effects of a power-law Maxwell field on the critical phenomena of higher dimensional dilaton black holes are probed in detail. We successfully derive the analytic solutions of the critical point and carry out some checks to ensure that these critical quantities are positive. It is shown that the constraint on the parameter α describing the strength of the coupling of the electromagnetic field and the scalar field turns out to be 0 <α2<1 , which is tighter than that in the nonextended phase space. It is also shown that these critical quantities and the ratio Pcvc/Tc are affected by the power-law Maxwell field. Moreover, critical exponents are found to coincide with those of other anti-de Sitter black holes, showing the powerful influence of mean field theory.
Ha, Yong H; Han, Byung H; Lee, Soo Y
2010-02-01
We introduce a square coil system for remote magnetic navigation of a magnetic device without any physical movements of the coils. We used three square-Helmholtz coils and a square-Maxwell coil for magnetic propulsion of a small magnet along the desired path. All the square coils are mountable on a cubic frame that has an opening to accommodate a living subject. The square-Helmholtz coils control the magnetic propulsion direction by generating uniform magnetic field along the desired direction while the square-Maxwell coil controls the propulsion force by generating magnetic gradient field. We performed magnetic propulsion experiments with a down-scaled coil set and a three-channel coil driver. Experimental results demonstrate that we can use the square coil set for magnetic navigation of a magnetic device without any physical movements of the coils. PMID:20054666
Exact, zero-energy, square-integrable solutions of a model related to the Maxwell's fish-eye problem
Makowski, Adam J.
2009-12-15
A model, which admits normalizable wave functions of the Schroedinger equation at the energy of E = 0, is exactly solved and the solutions are compared to the corresponding classical trajectories. The wave functions are proved to be square-integrable for discrete (quantized) values of the coupling constant of the used potential. We also show that our model is a specific version of the well-known Maxwell's fish-eye. This is performed with the help of a suitably chosen conformal mapping.
NASA Astrophysics Data System (ADS)
Wang, Weike; Xu, Xin
2016-06-01
In this paper, the Cauchy problem for the nonisentropic Euler-Maxwell system with a nonconstant background density is studied. The global existence of classical solution is constructed in three space dimensions provided the initial perturbation is sufficiently small. The proof is mainly based on classical energy estimate and the techniques of symmetrizer. And the time decay of the solution is also established by combining the decay estimate of the Green's function with some time-weighted estimate.
Shehzad, Sabir Ali; Alsaedi, Ahmad; Hayat, Tasawar
2013-01-01
This paper investigates the steady hydromagnetic three-dimensional boundary layer flow of Maxwell fluid over a bidirectional stretching surface. Both cases of prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations are made for the velocities and temperatures. Results are plotted and analyzed for PST and PHF cases. Convergence analysis is presented for the velocities and temperatures. Comparison of PST and PHF cases is given and examined. PMID:23874523
Tsallis non-extensive statistics and solar wind plasma complexity
NASA Astrophysics Data System (ADS)
Pavlos, G. P.; Iliopoulos, A. C.; Zastenker, G. N.; Zelenyi, L. M.; Karakatsanis, L. P.; Riazantseva, M. O.; Xenakis, M. N.; Pavlos, E. G.
2015-03-01
This article presents novel results revealing non-equilibrium phase transition processes in the solar wind plasma during a strong shock event, which took place on 26th September 2011. Solar wind plasma is a typical case of stochastic spatiotemporal distribution of physical state variables such as force fields (B → , E →) and matter fields (particle and current densities or bulk plasma distributions). This study shows clearly the non-extensive and non-Gaussian character of the solar wind plasma and the existence of multi-scale strong correlations from the microscopic to the macroscopic level. It also underlines the inefficiency of classical magneto-hydro-dynamic (MHD) or plasma statistical theories, based on the classical central limit theorem (CLT), to explain the complexity of the solar wind dynamics, since these theories include smooth and differentiable spatial-temporal functions (MHD theory) or Gaussian statistics (Boltzmann-Maxwell statistical mechanics). On the contrary, the results of this study indicate the presence of non-Gaussian non-extensive statistics with heavy tails probability distribution functions, which are related to the q-extension of CLT. Finally, the results of this study can be understood in the framework of modern theoretical concepts such as non-extensive statistical mechanics (Tsallis, 2009), fractal topology (Zelenyi and Milovanov, 2004), turbulence theory (Frisch, 1996), strange dynamics (Zaslavsky, 2002), percolation theory (Milovanov, 1997), anomalous diffusion theory and anomalous transport theory (Milovanov, 2001), fractional dynamics (Tarasov, 2013) and non-equilibrium phase transition theory (Chang, 1992).
A probabilistic foundation of elementary particle statistics. Part I
NASA Astrophysics Data System (ADS)
Costantini, Domenico; Garibaldi, Ubaldo
The long history of ergodic and quasi-ergodic hypotheses provides the best example of the attempt to supply non-probabilistic justifications for the use of statistical mechanics in describing mechanical systems. In this paper we reverse the terms of the problem. We aim to show that accepting a probabilistic foundation of elementary particle statistics dispenses with the need to resort to ambiguous non-probabilistic notions like that of (in)distinguishability. In the quantum case, starting from suitable probability conditions, it is possible to deduce elementary particle statistics in a unified way. Following our approach Maxwell-Boltzmann statistics can also be deduced, and this deduction clarifies its status. Thus our primary aim in this paper is to give a mathematically rigorous deduction of the probability of a state with given energy for a perfect gas in statistical equilibrium; that is, a deduction of the equilibrium distribution for a perfect gas. A crucial step in this deduction is the statement of a unified statistical theory based on clearly formulated probability conditions from which the particle statistics follows. We believe that such a deduction represents an important improvement in elementary particle statistics, and a step towards a probabilistic foundation of statistical mechanics. In this Part I we first present some history: we recall some results of Boltzmann and Brillouin that go in the direction we will follow. Then we present a number of probability results we shall use in Part II. Finally, we state a notion of entropy referring to probability distributions, and give a natural solution to Gibbs' paradox.
Thermodynamics of topological black holes in Brans-Dicke gravity with a power-law Maxwell field
NASA Astrophysics Data System (ADS)
Zangeneh, M. Kord; Dehghani, M. H.; Sheykhi, A.
2015-11-01
In this paper, we present a new class of higher-dimensional exact topological black hole solutions of the Brans-Dicke theory in the presence of a power-law Maxwell field as the matter source. For this aim, we introduce a conformal transformation which transforms the Einstein-dilaton-power-law Maxwell gravity Lagrangian to the Brans-Dicke-power-law Maxwell theory one. Then, by using this conformal transformation, we obtain the desired solutions. Next, we study the properties of the solutions and conditions under which we have black holes. Interestingly enough, we show that there is a cosmological horizon in the presence of a negative cosmological constant. Finally, we calculate the temperature and charge and then by calculating the Euclidean action, we obtain the mass, the entropy and the electromagnetic potential energy. We find that the entropy does not respect the area law, and also the conserved and thermodynamic quantities are invariant under conformal transformation. Using these thermodynamic and conserved quantities, we show that the first law of black hole thermodynamics is satisfied on the horizon.
NASA Astrophysics Data System (ADS)
Dubina, Sean Hyun; Wedgewood, Lewis Edward
2016-07-01
Ferrofluids are often favored for their ability to be remotely positioned via external magnetic fields. The behavior of particles in ferromagnetic clusters under uniformly applied magnetic fields has been computationally simulated using the Brownian dynamics, Stokesian dynamics, and Monte Carlo methods. However, few methods have been established that effectively handle the basic principles of magnetic materials, namely, Maxwell's equations. An iterative constraint method was developed to satisfy Maxwell's equations when a uniform magnetic field is imposed on ferrofluids in a heterogeneous Brownian dynamics simulation that examines the impact of ferromagnetic clusters in a mesoscale particle collection. This was accomplished by allowing a particulate system in a simple shear flow to advance by a time step under a uniformly applied magnetic field, then adjusting the ferroparticles via an iterative constraint method applied over sub-volume length scales until Maxwell's equations were satisfied. The resultant ferrofluid model with constraints demonstrates that the magnetoviscosity contribution is not as substantial when compared to homogeneous simulations that assume the material's magnetism is a direct response to the external magnetic field. This was detected across varying intensities of particle-particle interaction, Brownian motion, and shear flow. Ferroparticle aggregation was still extensively present but less so than typically observed.
NASA Astrophysics Data System (ADS)
Dolean, Victorita; Gander, Martin J.; Lanteri, Stephane; Lee, Jin-Fa; Peng, Zhen
2015-01-01
The time-harmonic Maxwell equations describe the propagation of electromagnetic waves and are therefore fundamental for the simulation of many modern devices we have become used to in everyday life. The numerical solution of these equations is hampered by two fundamental problems: first, in the high frequency regime, very fine meshes need to be used in order to avoid the pollution effect well known for the Helmholtz equation, and second the large scale systems obtained from the vector valued equations in three spatial dimensions need to be solved by iterative methods, since direct factorizations are not feasible any more at that scale. As for the Helmholtz equation, classical iterative methods applied to discretized Maxwell equations have severe convergence problems. We explain in this paper a family of domain decomposition methods based on well chosen transmission conditions. We show that all transmission conditions proposed so far in the literature, both for the first and second order formulation of Maxwell's equations, can be written and optimized in the common framework of optimized Schwarz methods, independently of the first or second order formulation one uses, and the performance of the corresponding algorithms is identical. We use a decomposition into transverse electric and transverse magnetic fields to describe these algorithms, which greatly simplifies the convergence analysis of the methods. We illustrate the performance of our algorithms with large scale numerical simulations.
... Research AMIGAS Fighting Cervical Cancer Worldwide Stay Informed Statistics for Other Kinds of Cancer Breast Cervical Colorectal ( ... Skin Vaginal and Vulvar Cancer Home Uterine Cancer Statistics Language: English Español (Spanish) Recommend on Facebook Tweet ...
Mathematical and statistical analysis
NASA Technical Reports Server (NTRS)
Houston, A. Glen
1988-01-01
The goal of the mathematical and statistical analysis component of RICIS is to research, develop, and evaluate mathematical and statistical techniques for aerospace technology applications. Specific research areas of interest include modeling, simulation, experiment design, reliability assessment, and numerical analysis.
NASA Astrophysics Data System (ADS)
Wittenberg, Nina; Hass, Christian; Kuhn, Gerhard
2013-04-01
The Western Antarctic Peninsula experiences a temperature increase that is higher than in other parts of Antarctica. Within the last 50 years the tidewater glaciers in the tributary fjords of Maxwell Bay (King George Island) have retreated landwards with increasing speed. Meltwaters mobilize fine-grained sediments and transport those in plumes out of the coves into Maxwell Bay. Our hypothesis is that meltwater sediments characterize warmer climate periods of the Holocene. Marine sediment cores recovered along a profile of the eastern slope of Maxwell Bay were studied. The cores were taken in high-accumulation areas at the entrances of Collins Harbor, Marian and Potter coves. We measured the grain-size distribution in 1-cm steps in each core with a Laser diffraction particle analyzer (range 0.04-2500 µm) in order to resolve shifts in grain size compositions in very high resolution. We undertook different approaches for reliable age determination of the sediments. Since marine biogenic carbonate suitable for radiocarbon age determination is sparse, radiocarbon dating of the extracted humic acid fraction of the bulk sediment was included. Unfortunately, these age determinations turned out to be not reliable, likely because they are overprinted by an unknown older radiocarbon source. Preliminary results suggest that the cores cover approximately the last 2000 years. The magnetic susceptibility (MS) parameter fluctuates throughout the cores. It is negatively correlated to the amount of total organic carbon (TOC) and biogenic opal, suggesting dilution of the MS signal through higher input of organic material. Together with the bathymetry data, sub-bottom profiles reveal information on the interior of the topography and the geometry of the deposited sediments. The profiles obtained in Potter Cove show almost no sediment penetration suggesting either a very thin sediment cover and/or highly reworked unsorted sediments. The sub-bottom profiles from Maxwell Bay penetrate
Minnesota Health Statistics 1988.
ERIC Educational Resources Information Center
Minnesota State Dept. of Health, St. Paul.
This document comprises the 1988 annual statistical report of the Minnesota Center for Health Statistics. After introductory technical notes on changes in format, sources of data, and geographic allocation of vital events, an overview is provided of vital health statistics in all areas. Thereafter, separate sections of the report provide tables…
ERIC Educational Resources Information Center
Lenard, Christopher; McCarthy, Sally; Mills, Terence
2014-01-01
There are many different aspects of statistics. Statistics involves mathematics, computing, and applications to almost every field of endeavour. Each aspect provides an opportunity to spark someone's interest in the subject. In this paper we discuss some ethical aspects of statistics, and describe how an introduction to ethics has been…
ERIC Educational Resources Information Center
Strasser, Nora
2007-01-01
Avoiding statistical mistakes is important for educators at all levels. Basic concepts will help you to avoid making mistakes using statistics and to look at data with a critical eye. Statistical data is used at educational institutions for many purposes. It can be used to support budget requests, changes in educational philosophy, changes to…
Statistical quality management
NASA Astrophysics Data System (ADS)
Vanderlaan, Paul
1992-10-01
Some aspects of statistical quality management are discussed. Quality has to be defined as a concrete, measurable quantity. The concepts of Total Quality Management (TQM), Statistical Process Control (SPC), and inspection are explained. In most cases SPC is better than inspection. It can be concluded that statistics has great possibilities in the field of TQM.
Maxwell, Hertz and Marconi, using the history of science and technology in science education
NASA Astrophysics Data System (ADS)
Zito, Fredrick Anthony
This dissertation examines the possibility of using a Kuhnian framework to enhance the use of history in the teaching of science. The Kuhnian framework of "revolutionary" and "normal" science, it is noted, provides a simplifying yet explanatory framework for students of science, at the same time making it possible to show the daily life of scientists. Rather than focus only on heroes of science, the work examines the important work of the "normal" scientist and their interplay with "revolutionary" scientists. It is argued that seeing the daily life of the scientist within this framework can show students of science the profound impact of the seemingly simple contributions of the work of scientists. In addition, it is noted that viewing the history of science as shifting paradigms and scientific revolutions will not only enhance students' scientific literacy, but possibly enhance their willingness to pursue science education. A review of the theoretical literature surrounding Kuhn, his followers and his critics, suggest the framework is still salient among educators. A review of the empirical literature and some educational practices suggests that educators see this approach to be effective, especially when the framework and case materials are carefully crafted. The empirical literature also suggests that there is a gap between the prescribed standards (national and state) for teaching the history of science, and actual classroom practice. The Kuhnian framework shows promise for bridging this gap. The dissertation then uses a case history of the discovery of electromagnetic radiation by Faraday, Maxwell, and Hertz et al., culminating in the development wireless telegraphy by Marconi, making possible radio, television, radar, and other contemporary technologies. The dissertation concludes by noting that the use of history as an arena for understanding science, in some way resembles the concept of "reflective thinking", which is often utilized as a framework for
Thermodynamics of Taub-NUT/bolt black holes in Einstein-Maxwell gravity
Dehghani, M.H.; Khodam-Mohammadi, A.
2006-06-15
First, we construct the Taub-NUT/bolt solutions of (2k+2)-dimensional Einstein-Maxwell gravity, when all the factor spaces of 2k-dimensional base space B have positive curvature. These solutions depend on two extra parameters, other than the mass and the NUT charge. These are electric charge q and electric potential at infinity V. We investigate the existence of Taub-NUT solutions and find that in addition to the two conditions of uncharged NUT solutions, there exist two extra conditions. These two extra conditions come from the regularity of vector potential at r=N and the fact that the horizon at r=N should be the outer horizon of the NUT charged black hole. We find that the NUT solutions in 2k+2 dimensions have no curvature singularity at r=N, when the 2k-dimensional base space is chosen to be CP{sup 2k}. For bolt solutions, there exists an upper limit for the NUT parameter which decreases as the potential parameter increases. Second, we study the thermodynamics of these spacetimes. We compute temperature, entropy, charge, electric potential, action and mass of the black hole solutions, and find that these quantities satisfy the first law of thermodynamics. We perform a stability analysis by computing the heat capacity, and show that the NUT solutions are not thermally stable for even k's, while there exists a stable phase for odd k's, which becomes increasingly narrow with increasing dimensionality and wide with increasing V. We also study the phase behavior of the 4 and 6 dimensional bolt solutions in canonical ensemble and find that these solutions have a stable phase, which becomes smaller as V increases.
NASA Astrophysics Data System (ADS)
Menon, Govind K.
The Reissner-Nordstrom solution possesses a naked singularity when e2 > m2, where m is the mass and e is the net charge of the system. Also, the singularity at r = 0 is repulsive (i.e., no timelike geodesics (neutral particles) can reach the singularity). These unusual properties of the Reissner-Nordstrom geometry are considered as an accident resulting from the highly symmetric nature of the space-time. Here we wish to generalize the condition of spherical symmetry to axial symmetry and to probe into the issues of naked singularity and gravitational repulsion. To do this, we must construct a nonspherical solution to the Einstein-Maxwell set of equations in the event that e2 > m2. The Erez-Rosen extension of the vacuum Schwarzschild solution to the non-spherical case gave one of the first physically significant solutions of the Einstein field equations. Nonvacuum extensions of the Erez-Rosen solution representing a non-spherical mass containing a very high net charge (i.e., when e2 > m2) will be discussed. The special case of spherical symmetry, as would be expected, results in the Reissner-Nordstrom solution. The search for the physical singularities involves the calculation of a nontrivial scalar constructed from the Riemann curvature tensor. As it turns out, the resulting geometry does indeed possess a naked singularity. In addition, the space-time also entertains gravitational repulsion. However, unlike the Reissner-Nordstrom solution, it has been found that all timelike geodesics are not necessarily repelled from the origin.
Strichartz Estimates and Moment Bounds for the Relativistic Vlasov-Maxwell System
NASA Astrophysics Data System (ADS)
Luk, Jonathan; Strain, Robert M.
2016-01-01
We consider the relativistic Vlasov-Maxwell system with data of unrestricted size and without compact support in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, Glassey-Schaeffer proved (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:331-354, 1998; Arch Ration Mech Anal. 141:355-374, 1998) that for regular initial data with compact momentum support this system has unique global in time classical solutions. In this work we do not assume compact momentum support for the initial data and instead require only that the data have polynomial decay in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, we prove the global existence, uniqueness and regularity for solutions arising from this class of initial data. To this end we use Strichartz estimates and prove that suitable moments of the solution remain bounded. Moreover, we obtain a slight improvement of the temporal growth of the {L^∞_x} norms of the electromagnetic fields compared to Glassey and Schaeffer (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:355-374, 1998). In the three-dimensional case, we apply Strichartz estimates and moment bounds to show that a regular solution can be extended as long as {{|p_0^{θ} f |_{LqxL^1p}}} remains bounded for {θ > 2/q}, {2 < q ≤q ∞}. This improves previous results of Pallard (Indiana Univ Math J 54(5):1395-1409, 2005; Commun Math Sci 13(2):347-354, 2015).
Explorations in statistics: statistical facets of reproducibility.
Curran-Everett, Douglas
2016-06-01
Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This eleventh installment of Explorations in Statistics explores statistical facets of reproducibility. If we obtain an experimental result that is scientifically meaningful and statistically unusual, we would like to know that our result reflects a general biological phenomenon that another researcher could reproduce if (s)he repeated our experiment. But more often than not, we may learn this researcher cannot replicate our result. The National Institutes of Health and the Federation of American Societies for Experimental Biology have created training modules and outlined strategies to help improve the reproducibility of research. These particular approaches are necessary, but they are not sufficient. The principles of hypothesis testing and estimation are inherent to the notion of reproducibility in science. If we want to improve the reproducibility of our research, then we need to rethink how we apply fundamental concepts of statistics to our science. PMID:27231259
Maxwell-Wagner relaxation in common minerals and a desert soil at low water contents
NASA Astrophysics Data System (ADS)
Arcone, Steven A.; Boitnott, Ginger E.
2012-06-01
Penetration of 100- to 1000-MHz ground-penetrating radar (GPR) signals is virtually non-existent in arid and desert soils despite their low water content and moderate conductivity, the latter of which cannot explain the loss. Under the hypothesis that strong dielectric relaxation supplements DC conductivity to cause high intrinsic attenuation rates, we compared the complex permittivity of a desert soil sample with that of controlled samples of quartz, feldspars, calcite, coarse and crystallite gypsum, kaolinite and montmorillonite. The soil had 80% quartz, 10% feldspars and 10% gypsum by weight, with the latter composed of crystallites and crustations. All samples had 4-7% volumetric water content. We measured permittivity most accurately from 1.6 MHz to 4 GHz with Fourier Transform time domain reflectometry, and used grain sizes less than 53 μm. All samples show low-frequency dispersion with the soil, gypsum crystallites and montmorillonite having the strongest below 100 MHz, the highest attenuation rates, and conductivity values unable to account for these rates. The soil rate exceeded 100 dB m- 1 by 1 GHz. Through modeling we find that a broadened relaxation centered from 2 to 16 MHz sufficiently supplements losses caused by conductivity and free water relaxation to account for loss rates in all our samples, and accounts for low-frequency dispersion below 1 GHz. We interpret the relaxation to be of the Maxwell-Wagner (MW) type because of the 2- to 16-MHz values, relaxation broadening, the lack of salt, clay and magnetic minerals, and insufficient surface area to support adsorbed water. The likely MW dipolar soil inclusions within the predominantly quartz matrix were gypsum particles coated with water containing ions dissolved from the gypsum, and the conducting water layers themselves. The inclusions for the monomineralic soils were likely ionized partially or completely water-filled interstices, and partially filled galleries for the montmorillonite. The low
NASA Astrophysics Data System (ADS)
Schieve, William C.; Horwitz, Lawrence P.
2009-04-01
1. Foundations of quantum statistical mechanics; 2. Elementary examples; 3. Quantum statistical master equation; 4. Quantum kinetic equations; 5. Quantum irreversibility; 6. Entropy and dissipation: the microscopic theory; 7. Global equilibrium: thermostatics and the microcanonical ensemble; 8. Bose-Einstein ideal gas condensation; 9. Scaling, renormalization and the Ising model; 10. Relativistic covariant statistical mechanics of many particles; 11. Quantum optics and damping; 12. Entanglements; 13. Quantum measurement and irreversibility; 14. Quantum Langevin equation: quantum Brownian motion; 15. Linear response: fluctuation and dissipation theorems; 16. Time dependent quantum Green's functions; 17. Decay scattering; 18. Quantum statistical mechanics, extended; 19. Quantum transport with tunneling and reservoir ballistic transport; 20. Black hole thermodynamics; Appendix; Index.
Statistical distribution sampling
NASA Technical Reports Server (NTRS)
Johnson, E. S.
1975-01-01
Determining the distribution of statistics by sampling was investigated. Characteristic functions, the quadratic regression problem, and the differential equations for the characteristic functions are analyzed.
Albrecht-Marc, M.; Ghizzo, A.; Johnston, T. W.; Reveille, T.; Del Sarto, D.; Bertrand, P.
2007-07-15
The influence of low-frequency nonlinear Bernstein-Greene-Kruskal (BGK)-type waves induced by trapped electrons in backward stimulated Raman scattering is investigated in optical mixing. Semi-Lagrangian Vlasov-Maxwell simulations show two nonlinear behaviors. First, there is a Morales-O'Neil plasma wave frequency downshift retuned by a small wavenumber shift which maintains the Stimulated Raman Scattering (SRS) resonance. The saturation of Raman backscattering begins with phase space vortex merging followed by a transition to lower wavenumbers following the (nonlinear) dispersion relation, resembling weak turbulence.
Mazharimousavi, S. Habib; Halilsoy, M.; Amirabi, Z.
2010-05-15
Recently in [Phys. Rev. D 76, 087502 (2007) and Phys. Rev. D 77, 089903 (2008)] a thin-shell wormhole has been introduced in five-dimensional Einstein-Maxwell-Gauss-Bonnet gravity which was supported by normal matter. We wish to consider this solution and investigate its stability. Our analysis shows that for the Gauss-Bonnet parameter {alpha}<0, stability regions form for a narrow band of finely tuned mass and charge. For the case {alpha}>0, we iterate once more that no stable, normal matter thin-shell wormhole exists.
NASA Technical Reports Server (NTRS)
Roberts, Dana Aaron; Abraham-Shrauner, Barbara
1987-01-01
The phase trajectories of particles in a plasma described by the one-dimensional Vlasov-Maxwell equations are determined qualitatively, analyzing exact general similarity solutions for the cases of temporally damped and growing (sinusoidal or localized) electric fields. The results of numerical integration in both untransformed and Lie-group point-transformed coordinates are presented in extensive graphs and characterized in detail. The implications of the present analysis for the stability of BGK equilibria are explored, and the existence of nonlinear solutions arbitrarily close to and significantly different from the BGK solutions is demonstrated.
Koning, J; Rieben, R; Rodrigue, G
2004-12-09
We measure the loss of power incurred by the bending of a single mode step-indexed optical fiber using vector finite element modeling of the full-wave Maxwell equations in the optical regime. We demonstrate fewer grid elements can be used to model light transmission in longer fiber lengths by using high-order basis functions in conjunction with a high order energy conserving time integration method. The power in the core is measured at several points to determine the percentage loss. We also demonstrate the effect of bending on the light polarization.
Covariant quantization of the Maxwell field in de Sitter space from SO0(2,4)-invariance
NASA Astrophysics Data System (ADS)
Huguet, E.; Faci, S.; Queva, J.; Renaud, J.
2011-03-01
We present a SO0(2,4)-invariant quantization of the free electromagnetic field in de Sitter space. Precisely, we quantize the Maxwell ("massless spin one") de Sitter field in a conformally invariant gauge. This result is obtained thanks to a canonical quantization scheme of the Gupta-Bleuler type and to a geometrical formalism in which the Minkowski, de Sitter and anti-de Sitter spaces are realized as intersections of the five dimensional null cone of ℝ6 and a moving hyperplane. We obtain a new and simple de Sitter invariant two-point function.
NASA Astrophysics Data System (ADS)
Blanco, R.; Pesquera, L.
1986-01-01
We analyze in detail the validity of the compatibility between the Maxwell-Boltzmann (MB) distribution and the Rayleigh-Jeans (RJ) spectrum obtained in recent works by the authors for classical relativistic systems. We show that the MB distribution and the RJ spectrum are not compatible if we do not remove high enough frequencies. By analyzing the applicability of the approximation methods used in previous works to obtain the MB distribution from the RJ spectrum, we conclude that these methods are valid only if we introduce a high-frequency cutoff in the RJ spectrum. A short discussion is made on the meaning of this cutoff.
NASA Technical Reports Server (NTRS)
Joseph, Rose M.; Goorjian, Peter M.; Taflove, Allen
1993-01-01
We present what are to our knowledge first-time calculations from vector nonlinear Maxwell's equations of femtosecond soliton propagation and scattering, including carrier waves, in two-dimensional dielectric waveguides. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and the nonlinear convolution accounts for two quantum effects, the Kerr and Raman interactions. By retaining the optical carrier, the new method solves for fundamental quantities - optical electric and magnetic fields in space and time - rather than a nonphysical envelope function. It has the potential to provide an unprecedented two- and three-dimensional modeling capability for millimeter-scale integrated-optical circuits with submicrometer engineered inhomogeneities.
NASA Technical Reports Server (NTRS)
Yefet, Amir; Petropoulos, Peter G.
1999-01-01
We consider a divergence-free non-dissipative fourth-order explicit staggered finite difference scheme for the hyperbolic Maxwell's equations. Special one-sided difference operators are derived in order to implement the scheme near metal boundaries and dielectric interfaces. Numerical results show the scheme is long-time stable, and is fourth-order convergent over complex domains that include dielectric interfaces and perfectly conducting surfaces. We also examine the scheme's behavior near metal surfaces that are not aligned with the grid axes, and compare its accuracy to that obtained by the Yee scheme.
NASA Astrophysics Data System (ADS)
Zeng, Xiao-Xiong; Liu, Xiong-Wei; Yang, Shu-Zheng
2008-12-01
Hawking radiation of particles with electric and magnetic charges from the Einstein Maxwell-Dilaton Axion black hole is derived via the anomaly cancellation method, initiated by Robinson and Wilczek and elaborated by Banerjee and Kulkarni recently. We reconstruct the electromagnetic field tensor to redefine the gauge potential and equivalent charge corresponding to the source with electric and magnetic charges. We only adopt the covariant gauge and gravitational anomalies to discuss the near-horizon quantum anomaly in the dragging coordinate frame. Our result shows that Hawking radiation in this case also can be reproduced from the viewpoint of anomaly.
NASA Astrophysics Data System (ADS)
Wang, Lei; Zhu, Yu-Jie; Wang, Zi-Qi; Xu, Tao; Qi, Feng-Hua; Xue, Yu-Shan
2016-02-01
We study the nonlinear localized waves on constant backgrounds of the Hirota-Maxwell-Bloch (HMB) system arising from the erbium doped fibers. We derive the asymmetric breather, rogue wave (RW) and semirational solutions of the HMB system. We show that the breather and RW solutions can be converted into various soliton solutions. Under different conditions of parameters, we calculate the locus of the eigenvalues on the complex plane which converts the breathers or RWs into solitons. Based on the second-order solutions, we investigate the interactions among different types of nonlinear waves including the breathers, RWs and solitons.
Ghezelbash, A. M.
2010-02-15
We construct nonstationary exact solutions to five-dimensional Einstein-Maxwell-Chern-Simons theory with positive cosmological constant. The solutions are based on four-dimensional Atiyah-Hitchin space. In asymptotic regions, the solutions approach Gibbons-Perry-Sorkin monopole solutions. On the other hand, near the four-dimensional bolt of Atiyah-Hitchin space, our solutions show a bolt structure in five dimensions. The c function for the solutions shows monotonic increase in time, in agreement with the general expected behavior of the c function in asymptotically de Sitter spacetimes.
Explorations in Statistics: Regression
ERIC Educational Resources Information Center
Curran-Everett, Douglas
2011-01-01
Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This seventh installment of "Explorations in Statistics" explores regression, a technique that estimates the nature of the relationship between two things for which we may only surmise a mechanistic or predictive connection.…
Multidimensional Visual Statistical Learning
ERIC Educational Resources Information Center
Turk-Browne, Nicholas B.; Isola, Phillip J.; Scholl, Brian J.; Treat, Teresa A.
2008-01-01
Recent studies of visual statistical learning (VSL) have demonstrated that statistical regularities in sequences of visual stimuli can be automatically extracted, even without intent or awareness. Despite much work on this topic, however, several fundamental questions remain about the nature of VSL. In particular, previous experiments have not…
ERIC Educational Resources Information Center
Huberty, Carl J.
An approach to statistical testing, which combines Neyman-Pearson hypothesis testing and Fisher significance testing, is recommended. The use of P-values in this approach is discussed in some detail. The author also discusses some problems which are often found in introductory statistics textbooks. The problems involve the definitions of…
Deconstructing Statistical Analysis
ERIC Educational Resources Information Center
Snell, Joel
2014-01-01
Using a very complex statistical analysis and research method for the sake of enhancing the prestige of an article or making a new product or service legitimate needs to be monitored and questioned for accuracy. 1) The more complicated the statistical analysis, and research the fewer the number of learned readers can understand it. This adds a…
Explorations in Statistics: Power
ERIC Educational Resources Information Center
Curran-Everett, Douglas
2010-01-01
Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fifth installment of "Explorations in Statistics" revisits power, a concept fundamental to the test of a null hypothesis. Power is the probability that we reject the null hypothesis when it is false. Four things affect…
ERIC Educational Resources Information Center
Huizingh, Eelko K. R. E.
2007-01-01
Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…
Vijayaraj, Veeraraghavan; Cheriyadat, Anil M; Bhaduri, Budhendra L; Vatsavai, Raju; Bright, Eddie A
2008-01-01
Statistical properties of high-resolution overhead images representing different land use categories are analyzed using various local and global statistical image properties based on the shape of the power spectrum, image gradient distributions, edge co-occurrence, and inter-scale wavelet coefficient distributions. The analysis was performed on a database of high-resolution (1 meter) overhead images representing a multitude of different downtown, suburban, commercial, agricultural and wooded exemplars. Various statistical properties relating to these image categories and their relationship are discussed. The categorical variations in power spectrum contour shapes, the unique gradient distribution characteristics of wooded categories, the similarity in edge co-occurrence statistics for overhead and natural images, and the unique edge co-occurrence statistics of downtown categories are presented in this work. Though previous work on natural image statistics has showed some of the unique characteristics for different categories, the relationships for overhead images are not well understood. The statistical properties of natural images were used in previous studies to develop prior image models, to predict and index objects in a scene and to improve computer vision models. The results from our research findings can be used to augment and adapt computer vision algorithms that rely on prior image statistics to process overhead images, calibrate the performance of overhead image analysis algorithms, and derive features for better discrimination of overhead image categories.
Understanding Undergraduate Statistical Anxiety
ERIC Educational Resources Information Center
McKim, Courtney
2014-01-01
The purpose of this study was to understand undergraduate students' views of statistics. Results reveal that students with less anxiety have a higher interest in statistics and also believe in their ability to perform well in the course. Also students who have a more positive attitude about the class tend to have a higher belief in their…
Croarkin, M. Carroll
2001-01-01
For more than 50 years, the Statistical Engineering Division (SED) has been instrumental in the success of a broad spectrum of metrology projects at NBS/NIST. This paper highlights fundamental contributions of NBS/NIST statisticians to statistics and to measurement science and technology. Published methods developed by SED staff, especially during the early years, endure as cornerstones of statistics not only in metrology and standards applications, but as data-analytic resources used across all disciplines. The history of statistics at NBS/NIST began with the formation of what is now the SED. Examples from the first five decades of the SED illustrate the critical role of the division in the successful resolution of a few of the highly visible, and sometimes controversial, statistical studies of national importance. A review of the history of major early publications of the division on statistical methods, design of experiments, and error analysis and uncertainty is followed by a survey of several thematic areas. The accompanying examples illustrate the importance of SED in the history of statistics, measurements and standards: calibration and measurement assurance, interlaboratory tests, development of measurement methods, Standard Reference Materials, statistical computing, and dissemination of measurement technology. A brief look forward sketches the expanding opportunity and demand for SED statisticians created by current trends in research and development at NIST.
ERIC Educational Resources Information Center
Hodgson, Ted; Andersen, Lyle; Robison-Cox, Jim; Jones, Clain
2004-01-01
Water quality experiments, especially the use of macroinvertebrates as indicators of water quality, offer an ideal context for connecting statistics and science. In the STAR program for secondary students and teachers, water quality experiments were also used as a context for teaching statistics. In this article, we trace one activity that uses…
ERIC Educational Resources Information Center
Council of Ontario Universities, Toronto.
Summary statistics on application and registration patterns of applicants wishing to pursue full-time study in first-year places in Ontario universities (for the fall of 1987) are given. Data on registrations were received indirectly from the universities as part of their annual submission of USIS/UAR enrollment data to Statistics Canada and MCU.…
Introduction to Statistical Physics
NASA Astrophysics Data System (ADS)
Casquilho, João Paulo; Ivo Cortez Teixeira, Paulo
2014-12-01
Preface; 1. Random walks; 2. Review of thermodynamics; 3. The postulates of statistical physics. Thermodynamic equilibrium; 4. Statistical thermodynamics – developments and applications; 5. The classical ideal gas; 6. The quantum ideal gas; 7. Magnetism; 8. The Ising model; 9. Liquid crystals; 10. Phase transitions and critical phenomena; 11. Irreversible processes; Appendixes; Index.
Reform in Statistical Education
ERIC Educational Resources Information Center
Huck, Schuyler W.
2007-01-01
Two questions are considered in this article: (a) What should professionals in school psychology do in an effort to stay current with developments in applied statistics? (b) What should they do with their existing knowledge to move from surface understanding of statistics to deep understanding? Written for school psychologists who have completed…
Statistical Mapping by Computer.
ERIC Educational Resources Information Center
Utano, Jack J.
The function of a statistical map is to provide readers with a visual impression of the data so that they may be able to identify any geographic characteristics of the displayed phenomena. The increasingly important role played by the computer in the production of statistical maps is manifested by the varied examples of computer maps in recent…
The purpose of the Disability Statistics Center is to produce and disseminate statistical information on disability and the status of people with disabilities in American society and to establish and monitor indicators of how conditions are changing over time to meet their health...
Statistics 101 for Radiologists.
Anvari, Arash; Halpern, Elkan F; Samir, Anthony E
2015-10-01
Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. PMID:26466186
Januszyk, Michael; Gurtner, Geoffrey C
2011-01-01
The scope of biomedical research has expanded rapidly during the past several decades, and statistical analysis has become increasingly necessary to understand the meaning of large and diverse quantities of raw data. As such, a familiarity with this lexicon is essential for critical appraisal of medical literature. This article attempts to provide a practical overview of medical statistics, with an emphasis on the selection, application, and interpretation of specific tests. This includes a brief review of statistical theory and its nomenclature, particularly with regard to the classification of variables. A discussion of descriptive methods for data presentation is then provided, followed by an overview of statistical inference and significance analysis, and detailed treatment of specific statistical tests and guidelines for their interpretation. PMID:21200241
Statistical mechanics in the context of special relativity. II.
Kaniadakis, G
2005-09-01
The special relativity laws emerge as one-parameter (light speed) generalizations of the corresponding laws of classical physics. These generalizations, imposed by the Lorentz transformations, affect both the definition of the various physical observables (e.g., momentum, energy, etc.), as well as the mathematical apparatus of the theory. Here, following the general lines of [Phys. Rev. E 66, 056125 (2002)], we show that the Lorentz transformations impose also a proper one-parameter generalization of the classical Boltzmann-Gibbs-Shannon entropy. The obtained relativistic entropy permits us to construct a coherent and self-consistent relativistic statistical theory, preserving the main features of the ordinary statistical theory, which is recovered in the classical limit. The predicted distribution function is a one-parameter continuous deformation of the classical Maxwell-Boltzmann distribution and has a simple analytic form, showing power law tails in accordance with the experimental evidence. Furthermore, this statistical mechanics can be obtained as the stationary case of a generalized kinetic theory governed by an evolution equation obeying the H theorem and reproducing the Boltzmann equation of the ordinary kinetics in the classical limit. PMID:16241516
Noise and fluctuation statistics in mesoscopic heat transport
NASA Astrophysics Data System (ADS)
Averin, Dmitri
2012-02-01
Fluctuations play important role in thermodynamics of small systems. In the talk, I will discuss two recent results on fluctuations in mesosopic heat transport. One is the demonstration [1] that the fluctuation-dissipation theorem for thermal conductance of a mesocopic junction is not valid at non-zero frequencies φ. Finite relaxation energy creates fluctuations of the energy flux in the junction even at vanishing temperature, T=0, when the conductance vanishes. This suggest that in contract to electrical conductance, there is no ``Kubo-Green formula'' for equilibrium thermal conductance at φ 0. Non-equilibrium heat transfer satisfies general ``fluctuation relations'' of non-equilibrium thermodynamics. Recently, we have established the conditions of applicability of these relations to single-electron tunneling (SET), and calculated explicitly the statistics of dissipated energy in driven SET transitions [2], which gives an example of general statistics of energy dissipation in reversible information processing. An interesting consequence of this statistics is the possibility of implementing the electronic version of Maxwell's demon in the SET structures [3]. [4pt] [1] D.V. Averin and J.P. Pekola, Phys. Rev. Lett. 104, 220601 (2010). [0pt] [2] D.V. Averin and J.P. Pekola, arXiv:1105.041. [0pt] [3] D.V. Averin, M. Mottonen, and J.P. Pekola, arXiv:1108.5435.
Comparison of a 3-D GPU-Assisted Maxwell Code and Ray Tracing for Reflectometry on ITER
NASA Astrophysics Data System (ADS)
Gady, Sarah; Kubota, Shigeyuki; Johnson, Irena
2015-11-01
Electromagnetic wave propagation and scattering in magnetized plasmas are important diagnostics for high temperature plasmas. 1-D and 2-D full-wave codes are standard tools for measurements of the electron density profile and fluctuations; however, ray tracing results have shown that beam propagation in tokamak plasmas is inherently a 3-D problem. The GPU-Assisted Maxwell Code utilizes the FDTD (Finite-Difference Time-Domain) method for solving the Maxwell equations with the cold plasma approximation in a 3-D geometry. Parallel processing with GPGPU (General-Purpose computing on Graphics Processing Units) is used to accelerate the computation. Previously, we reported on initial comparisons of the code results to 1-D numerical and analytical solutions, where the size of the computational grid was limited by the on-board memory of the GPU. In the current study, this limitation is overcome by using domain decomposition and an additional GPU. As a practical application, this code is used to study the current design of the ITER Low Field Side Reflectometer (LSFR) for the Equatorial Port Plug 11 (EPP11). A detailed examination of Gaussian beam propagation in the ITER edge plasma will be presented, as well as comparisons with ray tracing. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No.DE-AC02-09CH11466 and DE-FG02-99-ER54527.
NASA Astrophysics Data System (ADS)
Bradford, R. A. W.
2015-10-01
Stationary, static, spherically symmetric solutions of the Maxwell-Dirac system, treated as classical fields, have been found which are localised and normalisable. The solutions apply to any bound energy eigenvalue in the range 0 < E < m, where m is the bare mass in the Dirac equation. A point charge of any magnitude and either sign may be placed at the origin and the solutions remain well behaved and bound. However, no such central charge is necessary to result in a bound solution. As found previously by Radford, the magnetic flux density is equal to that of a monopole at the origin. However, no monopole is present, the magnetic flux being a result of the dipole moment distribution of the Dirac field. The Dirac field magnetic dipole moment is aligned with the magnetic flux density and so the resulting magnetic self-energy is negative. It is this which results in the states being bound (E < m). The case which omits any central point charge is therefore a self-sustaining bound state solution of the Maxwell-Dirac system which is localised, normalisable, and requires no arbitrarily added "external" features (i.e., it is a soliton). As far as the author is aware, this is the first time that such an exact solution with a positive energy eigenvalue has been reported. However, the solution is not unique since the energy eigenvalue is arbitrary within the range 0 < E < m. The stability of the solution has not been addressed.
NASA Astrophysics Data System (ADS)
Kahnert, Michael
2016-07-01
Numerical solution methods for electromagnetic scattering by non-spherical particles comprise a variety of different techniques, which can be traced back to different assumptions and solution strategies applied to the macroscopic Maxwell equations. One can distinguish between time- and frequency-domain methods; further, one can divide numerical techniques into finite-difference methods (which are based on approximating the differential operators), separation-of-variables methods (which are based on expanding the solution in a complete set of functions, thus approximating the fields), and volume integral-equation methods (which are usually solved by discretisation of the target volume and invoking the long-wave approximation in each volume cell). While existing reviews of the topic often tend to have a target audience of program developers and expert users, this tutorial review is intended to accommodate the needs of practitioners as well as novices to the field. The required conciseness is achieved by limiting the presentation to a selection of illustrative methods, and by omitting many technical details that are not essential at a first exposure to the subject. On the other hand, the theoretical basis of numerical methods is explained with little compromises in mathematical rigour; the rationale is that a good grasp of numerical light scattering methods is best achieved by understanding their foundation in Maxwell's theory.
Awais, Muhammad; Hayat, Tasawar; Irum, Sania; Alsaedi, Ahmed
2015-01-01
Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM) has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion “Db” and thermophoresis effects “Dt” occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis. PMID:26115101
NASA Astrophysics Data System (ADS)
Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich; Qi, Naiming
2013-11-01
A physics-based fractional-order Maxwell resistive capacitor (FOMRC) model is proposed to characterize nonlinear hysteresis and creep behaviors of a piezoelectric actuator (PEA). The Maxwell resistive capacitor (MRC) model is interpreted physically in the electric domain for PEAs. Based on this interpretation, the MRC model is modified to directly describe the relationship between the input voltage and the output displacement of a PEA. Then a procedure is developed to identify the parameters of the MRC model. This procedure is capable of being carried out using the measured input and output of a PEA only. A fractional-order dynamics is integrated into the MRC model to describe the effect of creep, as well as the detachment of hysteresis loops caused by creep. Moreover, the inverse FOMRC model is constructed to compensate for hysteresis and creep in an open-loop positioning application of PEAs. Simulation and experiments are carried out to validate the proposed model. The PEA compensated by the inverse FOMRC model shows an excellent linear behavior.
Awais, Muhammad; Hayat, Tasawar; Irum, Sania; Alsaedi, Ahmed
2015-01-01
Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM) has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion "Db" and thermophoresis effects "Dt" occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis. PMID:26115101
Ector, Hugo
2010-12-01
I still remember my first book on statistics: "Elementary statistics with applications in medicine and the biological sciences" by Frederick E. Croxton. For me, it has been the start of pursuing understanding statistics in daily life and in medical practice. It was the first volume in a long row of books. In his introduction, Croxton pretends that"nearly everyone involved in any aspect of medicine needs to have some knowledge of statistics". The reality is that for many clinicians, statistics are limited to a "P < 0.05 = ok". I do not blame my colleagues who omit the paragraph on statistical methods. They have never had the opportunity to learn concise and clear descriptions of the key features. I have experienced how some authors can describe difficult methods in a well understandable language. Others fail completely. As a teacher, I tell my students that life is impossible without a basic knowledge of statistics. This feeling has resulted in an annual seminar of 90 minutes. This tutorial is the summary of this seminar. It is a summary and a transcription of the best pages I have detected. PMID:21302664
Winters, Ryan; Winters, Andrew; Amedee, Ronald G.
2010-01-01
The Accreditation Council for Graduate Medical Education sets forth a number of required educational topics that must be addressed in residency and fellowship programs. We sought to provide a primer on some of the important basic statistical concepts to consider when examining the medical literature. It is not essential to understand the exact workings and methodology of every statistical test encountered, but it is necessary to understand selected concepts such as parametric and nonparametric tests, correlation, and numerical versus categorical data. This working knowledge will allow you to spot obvious irregularities in statistical analyses that you encounter. PMID:21603381
Statistics of football dynamics
NASA Astrophysics Data System (ADS)
Mendes, R. S.; Malacarne, L. C.; Anteneodo, C.
2007-06-01
We investigate the dynamics of football matches. Our goal is to characterize statistically the temporal sequence of ball movements in this collective sport game, searching for traits of complex behavior. Data were collected over a variety of matches in South American, European and World championships throughout 2005 and 2006. We show that the statistics of ball touches presents power-law tails and can be described by q-gamma distributions. To explain such behavior we propose a model that provides information on the characteristics of football dynamics. Furthermore, we discuss the statistics of duration of out-of-play intervals, not directly related to the previous scenario.
Playing at Statistical Mechanics
ERIC Educational Resources Information Center
Clark, Paul M.; And Others
1974-01-01
Discussed are the applications of counting techniques of a sorting game to distributions and concepts in statistical mechanics. Included are the following distributions: Fermi-Dirac, Bose-Einstein, and most probable. (RH)
Cooperative Learning in Statistics.
ERIC Educational Resources Information Center
Keeler, Carolyn M.; And Others
1994-01-01
Formal use of cooperative learning techniques proved effective in improving student performance and retention in a freshman level statistics course. Lectures interspersed with group activities proved effective in increasing conceptual understanding and overall class performance. (11 references) (Author)
Understanding Solar Flare Statistics
NASA Astrophysics Data System (ADS)
Wheatland, M. S.
2005-12-01
A review is presented of work aimed at understanding solar flare statistics, with emphasis on the well known flare power-law size distribution. Although avalanche models are perhaps the favoured model to describe flare statistics, their physical basis is unclear, and they are divorced from developing ideas in large-scale reconnection theory. An alternative model, aimed at reconciling large-scale reconnection models with solar flare statistics, is revisited. The solar flare waiting-time distribution has also attracted recent attention. Observed waiting-time distributions are described, together with what they might tell us about the flare phenomenon. Finally, a practical application of flare statistics to flare prediction is described in detail, including the results of a year of automated (web-based) predictions from the method.
Titanic: A Statistical Exploration.
ERIC Educational Resources Information Center
Takis, Sandra L.
1999-01-01
Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)
... and Statistics Recommend on Facebook Tweet Share Compartir Plague in the United States Plague was first introduced ... per year in the United States: 1900-2012. Plague Worldwide Plague epidemics have occurred in Africa, Asia, ...
NASA Astrophysics Data System (ADS)
Grégoire, G.
2016-05-01
This chapter is devoted to two objectives. The first one is to answer the request expressed by attendees of the first Astrostatistics School (Annecy, October 2013) to be provided with an elementary vademecum of statistics that would facilitate understanding of the given courses. In this spirit we recall very basic notions, that is definitions and properties that we think sufficient to benefit from courses given in the Astrostatistical School. Thus we give briefly definitions and elementary properties on random variables and vectors, distributions, estimation and tests, maximum likelihood methodology. We intend to present basic ideas in a hopefully comprehensible way. We do not try to give a rigorous presentation, and due to the place devoted to this chapter, can cover only a rather limited field of statistics. The second aim is to focus on some statistical tools that are useful in classification: basic introduction to Bayesian statistics, maximum likelihood methodology, Gaussian vectors and Gaussian mixture models.
Tuberculosis Data and Statistics
... Organization Chart Advisory Groups Federal TB Task Force Data and Statistics Language: English Español (Spanish) Recommend on ... United States publication. PDF [6 MB] Interactive TB Data Tool Online Tuberculosis Information System (OTIS) OTIS is ...
NASA Astrophysics Data System (ADS)
Richfield, Jon; bookfeller
2016-07-01
In reply to Ralph Kenna and Pádraig Mac Carron's feature article “Maths meets myths” in which they describe how they are using techniques from statistical physics to characterize the societies depicted in ancient Icelandic sagas.
... facts and statistics here include brain and central nervous system tumors (including spinal cord, pituitary and pineal gland ... U.S. living with a primary brain and central nervous system tumor. This year, nearly 17,000 people will ...