Chandrasekhar limit: an elementary approach based on classical physics and quantum theory
Pinochet, Jorge; Van Sint Jan, Michael
2016-05-01
In a brief article published in 1931, Subrahmanyan Chandrasekhar made public an important astronomical discovery. In his article, the then young Indian astrophysicist introduced what is now known as the Chandrasekhar limit. This limit establishes the maximum mass of a stellar remnant beyond which the repulsion force between electrons due to the exclusion principle can no longer stop the gravitational collapse. In the present article, we create an elemental approximation to the Chandrasekhar limit, accessible to non-graduate science and engineering students. The article focuses especially on clarifying the origins of Chandrasekhar’s discovery and the underlying physical concepts. Throughout the article, only basic algebra is used as well as some general notions of classical physics and quantum theory.
Chandrasekhar Limit: An Elementary Approach Based on Classical Physics and Quantum Theory
Pinochet, Jorge; Van Sint Jan, Michael
2016-01-01
In a brief article published in 1931, Subrahmanyan Chandrasekhar made public an important astronomical discovery. In his article, the then young Indian astrophysicist introduced what is now known as the "Chandrasekhar limit." This limit establishes the maximum mass of a stellar remnant beyond which the repulsion force between electrons…
Periodic Chandrasekhar recursions
Aknouche, Abdelhakim; Hamdi, Fayçal
2007-01-01
This paper extends the Chandrasekhar-type recursions due to Morf, Sidhu, and Kailath "Some new algorithms for recursive estimation in constant, linear, discrete-time systems, IEEE Trans. Autom. Control 19 (1974) 315-323" to the case of periodic time-varying state-space models. We show that the S-lagged increments of the one-step prediction error covariance satisfy certain recursions from which we derive some algorithms for linear least squares estimation for periodic state-space models. The p...
Chandrasekhar and Modern Stellar Dynamics
Evans, N W
2011-01-01
Stellar dynamics occupied Chandrasekhar's interest for a brief interlude between his more prolonged studies of stellar structure and radiative transfer. This paper traces the history of one of his ideas -- namely, that the shape of the galactic potential controls the orientation of the stellar velocity dispersion tensor. It has its roots in papers by Eddington (1915) and Chandrasekhar (1939), and provoked a fascinating dispute between these two great scientists -- less well-known than their famous controversy over the white dwarf stars. In modern language, Eddington claimed that the integral curves of the eigenvectors of the velocity dispersion tensor provide a one-dimensional foliation into mutually orthogonal surfaces. Chandrasekhar challenged this, and explicitly constructed a counter-example. In fact, the work of neither of these great scientists was without flaws, though further developments in stellar dynamics were to ultimately draw more on Eddington's insight than Chandrasekhar's. We conclude with a d...
Scalo, J M
1999-01-01
The series of papers by Chandrasekhar and Munch in the 1950s were concerned with the use of statistical models to infer the properties of interstellar clouds based on the observed spatial brightness fluctuations of the Milky Way. The present paper summarizes the subsequent influence of this work, concentrating on the departure from their earlier discrete cloud model to a continuous stochastic model in Paper V of the series. The contrast between the two models anticipated and parallels current tensions in the interpretation of interstellar structure, as well as intergalactic Lyman alpha clouds. The case of interstellar structure is discussed in some detail. Implications concerning the reification of models and the ability of scientific abstraction to model complex phenomena are also briefly discussed.
Improved algorithm for calculating the Chandrasekhar function
Jablonski, A.
2013-02-01
Theoretical models of electron transport in condensed matter require an effective source of the Chandrasekhar H(x,omega) function. A code providing the H(x,omega) function has to be both accurate and very fast. The current revision of the code published earlier [A. Jablonski, Comput. Phys. Commun. 183 (2012) 1773] decreased the running time, averaged over different pairs of arguments x and omega, by a factor of more than 20. The decrease of the running time in the range of small values of the argument x, less than 0.05, is even more pronounced, reaching a factor of 30. The accuracy of the current code is not affected, and is typically better than 12 decimal places. New version program summaryProgram title: CHANDRAS_v2 Catalogue identifier: AEMC_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEMC_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 976 No. of bytes in distributed program, including test data, etc.: 11416 Distribution format: tar.gz Programming language: Fortran 90 Computer: Any computer with a Fortran 90 compiler Operating system: Windows 7, Windows XP, Unix/Linux RAM: 0.7 MB Classification: 2.4, 7.2 Catalogue identifier of previous version: AEMC_v1_0 Journal reference of previous version: Comput. Phys. Commun. 183 (2012) 1773 Does the new version supersede the old program: Yes Nature of problem: An attempt has been made to develop a subroutine that calculates the Chandrasekhar function with high accuracy, of at least 10 decimal places. Simultaneously, this subroutine should be very fast. Both requirements stem from the theory of electron transport in condensed matter. Solution method: Two algorithms were developed, each based on a different integral representation of the Chandrasekhar function. The final algorithm is edited by mixing these two
Chandrasekhar's Dynamical Friction and non-extensive statistics
Silva, J M; de Souza, R E; Del Popolo, A; Delliou, Morgan Le; Lee, Xi-Guo
2016-01-01
The motion of a point like object of mass $M$ passing through the background potential of massive collisionless particles ($m << M$) suffers a steady deceleration named dynamical friction. In his classical work, Chandrasekhar assumed a Maxwellian velocity distribution in the halo and neglected the self gravity of the wake induced by the gravitational focusing of the mass $M$. In this paper, by relaxing the validity of the Maxwellian distribution due to the presence of long range forces, we derive an analytical formula for the dynamical friction in the context of the $q$-nonextensive kinetic theory. In the extensive limiting case ($q = 1$), the classical Gaussian Chandrasekhar result is recovered. As an application, the dynamical friction timescale for Globular Clusters spiraling to the galactic center is explicitly obtained. Our results suggest that the problem concerning the large timescale as derived by numerical $N$-body simulations or semi-analytical models can be understood as a departure from the ...
Chandrasekhar's dynamical friction and non-extensive statistics
Silva, J. M.; Lima, J. A. S.; de Souza, R. E.; Del Popolo, A.; Le Delliou, Morgan; Lee, Xi-Guo
2016-05-01
The motion of a point like object of mass M passing through the background potential of massive collisionless particles (m ll M) suffers a steady deceleration named dynamical friction. In his classical work, Chandrasekhar assumed a Maxwellian velocity distribution in the halo and neglected the self gravity of the wake induced by the gravitational focusing of the mass M. In this paper, by relaxing the validity of the Maxwellian distribution due to the presence of long range forces, we derive an analytical formula for the dynamical friction in the context of the q-nonextensive kinetic theory. In the extensive limiting case (q = 1), the classical Gaussian Chandrasekhar result is recovered. As an application, the dynamical friction timescale for Globular Clusters spiraling to the galactic center is explicitly obtained. Our results suggest that the problem concerning the large timescale as derived by numerical N-body simulations or semi-analytical models can be understood as a departure from the standard extensive Maxwellian regime as measured by the Tsallis nonextensive q-parameter.
S Chandrasekhar the man behind the legend
1997-01-01
Subrahmanyan Chandrasekhar - known simply as Chandra throughout the scientific world - has become a legendary figure for his prolific contributions to physics, astrophysics, and applied mathematics. Before his death in 1995, Chandra had forbidden a memorial of the conventional sort, celebrating his life. This book, which contains some thirty articles by his former students, his associates, and his colleagues, is in a sense a memorial volume. It says little about Chandra's great scientific achievements, but shows his human side and the various facets of his brilliant personality, his incredible
Mrs. Chandrasekhar addresses the media in TRW Media Hospitality Tent
1999-01-01
Mrs. Lalitha Chandrasekhar (at podium), wife of the late Indian- American Nobel Laureate Subrahmanyan Chandrasekhar, addresses the media and other invited guests in the TRW Media Hospitality Tent at the NASA Press Site at KSC. Other participants in the program (seated facing the audience, left to right) are the winners of the contest to rename the telescope, Jatila van der Veen, academic coordinator and lecturer, Physics Dept., University of Santa Barbara, Calif., and Tyrel Johnson, high school student, Laclede, Idaho; Joanne Maguire, vice-president and general manager, TRW Space & Laser Programs Division; and Dr. Alan Bunner, Science Program Director, Structure and Evolution of the Universe, Office of Space Science, NASA Headquarters, Washington, D.C. The name 'Chandra,' a shortened version of Chandrasekhar, was the name the Nobel Laureate preferred among friends and colleagues. 'Chandra' also means 'Moon' or 'luminous' in Sanskrit. The observatory is scheduled to be launched aboard Columbia on Space Shuttle mission STS-93.
Mrs. Chandrasekhar addresses the media in TRW Media Hospitality Tent
1999-01-01
Mrs. Lalitha Chandrasekhar (right), wife of the late Indian- American Nobel Laureate Subrahmanyan Chandrasekhar, addresses the media and other invited guests in the TRW Media Hospitality Tent at the NASA Press Site at KSC as Dr. Alan Bunner, Science Program Director, Structure and Evolution of the Universe, Office of Space Science, NASA Headquarters, Washington, D.C., looks on. The name 'Chandra,' a shortened version of her husband's name which he preferred among friends and colleagues, was chosen in a contest to rename the Advanced X-ray Astrophysics Facility. 'Chandra' also means 'Moon' or 'luminous' in Sanskrit. The observatory is scheduled to be launched aboard Columbia on Space Shuttle mission STS-93.
The legacy of S Chandrasekhar (1910–1995)
Kameshwar C Wali
2011-07-01
Subrahmanyan Chandrasekhar, known simply as Chandra in the scientiﬁc world, is one of the foremost scientists of the 20th century. In celebrating his birth centenary, I present a biographical portrait of an extraordinary, but a highly private individual unknown to the world at large. Drawing upon his own ``A Scientiﬁc Autobiography,” I reﬂect upon his legacy as a scientist and a great human being.
S. Chandrasekhar: White Dwarfs, $H^-$ ion,.., Black holes, Gravitational waves
Gupta, Patrick Das
2011-01-01
This is a concise review, addressed to undergraduate students, of S. Chandrasekhar's oeuvre in astrophysics, ranging from his early studies on white dwarfs using relativistic quantum statistics to topics as diverse as dynamical friction, negative hydrogen ion, fluid dynamical instabilities, black holes and gravitational waves. The exposition is based on simple physical explanations in the context of observational astronomy. Black holes and their role as central engines of active, compact, hig...
Sub-Chandrasekhar Mass Models For Type Ia Supernovae
Woosley, S.E.; Kasen, Daniel
2010-01-01
For carbon-oxygen white dwarfs accreting hydrogen or helium at rates in the range ~1-10 x 10^(-8) Msun/y, a variety of explosive outcomes is possible well before the star reaches the Chandrasekhar mass. These outcomes are surveyed for a range of white dwarf masses (0.7 - 1.1 Msun), accretion rates (1 - 7 x 10^(-8) Msun/y), and initial white dwarf temperatures (0.01 and 1 Lsun). The results are particularly sensitive to the convection that goes on during the last few minutes before the explosi...
SNe Ia: Can Chandrasekhar Mass Explosions Reproduce the Observed Zoo?
Baron, E
2014-01-01
The question of the nature of the progenitor of Type Ia supernovae (SNe Ia) is important both for our detailed understanding of stellar evolution and for their use as cosmological probes of the dark energy. Much of the basic features of SNe Ia can be understood directly from the nuclear physics, a fact which Gerry would have appreciated. We present an overview of the current observational and theoretical situation and show that it not incompatible with most SNe Ia being the results of thermonuclear explosions near the Chandrasekhar mass.
SNe Ia: Can Chandrasekhar mass explosions reproduce the observed zoo?
The question of the nature of the progenitor of Type Ia supernovae (SNe Ia) is important both for our detailed understanding of stellar evolution and for their use as cosmological probes of the dark energy. Much of the basic features of SNe Ia can be understood directly from the nuclear physics, a fact which Gerry would have appreciated. We present an overview of the current observational and theoretical situation and show that it not incompatible with most SNe Ia being the results of thermonuclear explosions near the Chandrasekhar mass
Beyond the Chandrasekhar limit: Structure and formation of compact stars
Dipankar Bhattacharya
2011-07-01
The concept of limiting mass, introduced by Chandrasekhar in case of white dwarfs, plays an important role in the formation and stability of compact objects such as neutron stars and black holes. Like white dwarfs, neutron stars have their own mass limit, and a compact conﬁguration would progress from one family to the next, more dense one once a mass limit is crossed. The mass limit of neutron stars depends on the nature of nuclear forces at very high density, which has so far not been determined conclusively. This article reviews how observational determinations of the properties of neutron stars are starting to impose signiﬁcant constraints on the state of matter at high density
Chandrasekhar's Relation and Stellar Rotation in the Kepler Field
Silva, J. R. P.; Soares, B. B.; de Freitas, D. B.
2014-11-01
According to the statistical law of large numbers, the expected mean of identically distributed random variables of a sample tends toward the actual mean as the sample increases. Under this law, it is possible to test the Chandrasekhar's relation (CR), langVrang = (π/4)-1langVsin irang, using a large amount of Vsin i and V data from different samples of similar stars. In this context, we conducted a statistical test to check the consistency of the CR in the Kepler field. In order to achieve this, we use three large samples of V obtained from Kepler rotation periods and a homogeneous control sample of Vsin i to overcome the scarcity of Vsin i data for stars in the Kepler field. We used the bootstrap-resampling method to estimate the mean rotations (langVrang and langVsin irang) and their corresponding confidence intervals for the stars segregated by effective temperature. Then, we compared the estimated means to check the consistency of CR, and analyzed the influence of the uncertainties in radii measurements, and possible selection effects. We found that the CR with langsin irang = π/4 is consistent with the behavior of the langVrang as a function of langVsin irang for stars from the Kepler field as there is a very good agreement between such a relation and the data.
Highly super-Chandrasekhar white dwarfs in an extensive GRMHD framework
Das, Upasana
2016-01-01
Our consistent effort to unravel the mystery of super-Chandrasekhar white dwarfs (WDs), by exploiting the potential of magnetic fields, has brought this topic considerable attention. This is also evident from the recent surge in the corresponding literature. In the present work, by means of full-scale general relativistic magnetohydrodynamic (GRMHD) numerical analysis, we confirm the existence of stable, highly magnetized, significantly super-Chandrasekhar WDs having mass exceeding 3 solar mass. We have explored various possible field configurations, namely, poloidal, toroidal and mixed, by self-consistently incorporating the departure from spherical symmetry induced by a strong magnetic field. Such super-Chandrasekhar WDs can be ideal progenitors of peculiar, over-luminous type Ia supernovae.
Ultraviolet Observations of Super-Chandrasekhar Mass Type Ia Supernova Candidates with Swift UVOT
Brown, P. J.; Smitka, M. T.; Krisciunas, K; Wang, L.; Kuin, P.; De Pasquale, M.; Scalzo, R.; Holland, S.; Milne, P.
2014-01-01
Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe - 2009dc, 2011aa, and 2012dn - observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the br...
Seitenzahl, Ivo R; Roepke, Friedrich K; Ruiter, Ashley J
2013-01-01
Context: Manganese is predominantly synthesised in Type Ia supernova (SN Ia) explosions. Owing to the entropy dependence of the Mn yield in explosive thermonuclear burning, SNe Ia involving near Chandrasekhar-mass white dwarfs (WDs) are predicted to produce Mn to Fe ratios significantly exceeding those of SN Ia explosions involving sub-Chandrasekhar mass primary WDs. Of all current supernova explosion models, only SN Ia models involving near-Chandrasekhar mass WDs produce [Mn/Fe] > 0.0. Aims: Using the specific yields for competing SN Ia scenarios, we aim to constrain the relative fractions of exploding near-Chandrasekhar mass to sub-Chandrasekhar mass primary WDs in the Galaxy. Methods: We extract the Mn yields from three-dimensional thermonuclear supernova simulations referring to different initial setups and progenitor channels. We then compute the chemical evolution of Mn in the Solar neighborhood, assuming SNe Ia are made up of different relative fractions of the considered explosion models. Results: We ...
Cho, Jungyeon
2016-01-01
The Chandrasekhar-Fermi method is a powerful technique for estimating the strength of the mean magnetic field projected on the plane of the sky. In this paper, we present a technique for improving the Chandrasekhar-Fermi method, in which we take into account the averaging effect arising from independent eddies along the line of sight . In the conventional Chandrasekhar-Fermi method, the strength of fluctuating magnetic field divided by $\\sqrt{4 \\pi \\bar{\\rho}}$, where $\\bar{\\rho}$ is average density, is assumed to be comparable to the line-of-sight velocity dispersion. This however is not true when the driving scale of turbulence $L_f$, i.e. the outer scale of turbulence, is smaller than the size of the system along the line of sight $L_{los}$. In fact, the conventional Chandrasekhar-Fermi method over-estimates the strength of the mean plane-of-the-sky magnetic field by a factor of $\\sim \\sqrt{ L_{los}/L_f}$. We show that the standard deviation of centroid velocities divided by the average line-of-sight veloc...
The Role of Electron Captures in Chandrasekhar Mass Models for Type Ia Supernovae
Brachwitz, F; Hix, W R; Iwamoto, K; Langanke, K; Martínez-Pinedo, G; Nomoto, K; Strayer, M R; Thielemann, F K; Umeda, H; Brachwitz, Franziska; Dean, David J.; Iwamoto, Koichi; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Nomoto, Ken'ichi; Strayer, Michael R.; Thielemann, Friedrich-K.; Umeda, Hideyuki
2000-01-01
The Chandrasekhar mass model for Type Ia Supernovae (SNe Ia) has received increasing support from recent comparisons of observations with light curve predictions and modeling of synthetic spectra. It explains SN Ia events via thermonuclear explosions of accreting white dwarfs in binary stellar systems, being caused by central carbon ignition when the white dwarf approaches the Chandrasekhar mass. As the electron gas in white dwarfs is degenerate, characterized by high Fermi energies for the high density regions in the center, electron capture on intermediate mass and Fe-group nuclei plays an important role in explosive burning. Electron capture affects the central electron fraction Y_e, which determines the composition of the ejecta from such explosions. Up to the present, astrophysical tabulations based on shell model matrix elements were only available for light nuclei in the sd-shell. Recently new Shell Model Monte Carlo (SMMC) and large-scale shell model diagonalization calculations have also been perform...
Strong constraints on magnetized white dwarfs surpassing the Chandrasekhar mass limit
Nityananda, Rajaram
2013-01-01
We show that recently proposed white dwarf models with masses well in excess of the Chandrasekhar limit, based on modifying the equation of state by a super-strong magnetic field in the centre, are very far from equilibrium because of the neglect of Lorentz forces. An upper bound on the central magnetic fields, from a spherically averaged hydrostatic equation, appears to be much smaller than the values assumed. Robust estimates of the Lorentz forces are also made without assuming spherical averaging. These again bear out the results obtained from a spherically averaged model. In our assessment, these rule out the possibility that magnetic tension could change the situation in favour of larger magnetic fields. We conclude that such super-Chandrasekhar models are unphysical and exploration of their astrophysical consequences is premature.
On properties of Velikhov-Chandrasekhar MRI in ideal and non-ideal plasma
Shakura, N I
2014-01-01
Conditions of Velikhov-Chandrasekhar magneto-rotational instability in ideal and non-ideal plasmas are examined. Linear WKB analysis of hydromagnetic axially symmetric flows shows that in the Rayleigh-unstable hydrodynamic case where the angular momentum decreases with radius, the MRI branch becomes stable, and the magnetic field suppresses the Rayleigh instability at small wavelengths. We investigate the limiting transition from hydromagnetic flows to hydrodynamic flows. The Rayleigh mode smoothly transits to the hydrodynamic case, while the Velikhov-Chandrasekhar MRI mode completely disappears without the magnetic field. The effects of viscosity and magnetic diffusivity in plasma on the MRI conditions in thin accretion discs are studied. We find the limits on the mean free-path of ions allowing MRI to operate in such discs.
Super-Chandrasekhar dynamical friction in a constant-density spherical star system
Zelnikov, M. I.; Kuskov, D. S.
2016-02-01
N-body modelling of massive body motion in constant density-cores shows deviations in the dynamical friction force from Chandrasekhar's formula. When the body orbit falls within the core, the body experiences a stage of enhanced friction after which the friction force becomes very low or zero. This effect takes place for circular as well as radial and elliptic orbits of the massive perturber. Previously developed perturbative treatment of dynamical friction in spherical systems cannot be directly applied to constant density cores because of the importance of non-linear resonant effects in this case. This feature is caused by the full resonance of the moving body with all the stars in the harmonic potential. There has been a successful attempt at semi-analytical treatment of the problem, but there remains a lack of any analytical description of this phenomenon. We study the motion of a massive point-like object in a strictly constant density sphere analytically and obtain a formula for the energy decay rate of the object at the stage of super-Chandrasekhar friction. We show that the dynamical friction force at this stage is half an order in Mobject/Mcore stronger than in Chandrasekhar's case. Our numerical simulations for both circular and radial orbits of the perturber reveal the stage of enhanced friction and the stalling stage afterwards. Dependence of the decay time at the super-Chandrasekhar stage on the perturber mass confirms our analytical relationship. We compare our analytical formula with N-body results of other authors for the enhanced friction stage and find good agreement.
Some criteria of decay process of Chandrasekhar's equation of decay for hydromagnetic turbulence
Heisenburg's (1948) equation for the decay of eddy turbulence possesses a more general type of self-preserving solution as given by Sen (1951). In the present work, it is found that such types of self-preserving solutions also satisfy Chandrasekhar's equation for the decay of hydromagnetic turbulence in the limiting situations of zero viscosity and infinite electrical conductivity. The asymptotic solutions for these cases have been obtained. (author)
Mukhopadhyay, Banibrata
2015-01-01
Since 2012, we have initiated developing systematically the simplistic to rigorous models to prove that highly super-Chandrasekhar, as well as highly sub-Chandrasekhar, limiting mass white dwarfs are possible to exist. We show that the mass of highly magnetized or modified Einstein's gravity induced white dwarfs could be significantly super-Chandrasekhar and such white dwarfs could altogether have a different mass-limit. On the other hand, type Ia supernovae (SNeIa), a key to unravel the evolutionary history of the universe, are believed to be triggered in white dwarfs having mass close to the Chandrasekhar-limit. However, observations of several peculiar, over- and under-luminous SNeIa argue for exploding masses widely different from this limit. We argue that explosions of super-Chandrasekhar limiting mass white dwarfs result in over-luminous SNeIa. We arrive at this revelation, first by considering simplistic, spherical, Newtonian white dwarfs with constant magnetic fields. Then we relax the Newtonian assum...
Double-detonation sub-Chandrasekhar supernovae: can minimum helium shell masses detonate the core?
Fink, M.; Roepke, F. K.; Hillebrandt, W.; Seitenzahl, I. R.; Sim, S. A.; Kromer, M.
2010-01-01
The explosion of sub-Chandrasekhar mass white dwarfs via the double detonation scenario is a potential explanation for type Ia supernovae. In this scenario, a surface detonation in a helium layer initiates a detonation in the underlying carbon/oxygen core leading to an explosion. For a given core mass, a lower bound has been determined on the mass of the helium shell required for dynamical burning during a helium flash, which is a necessary prerequisite for detonation. For a range of core and...
Double Detonation of Sub-Chandrasekhar White Dwarfs and Subluminous Type Ia Supernovae
Sivaram, C; Arun, Kenath
2010-01-01
Type Ia supernovae are thought to result from thermonuclear explosions of carbon-oxygen white dwarf stars. This model generally explains the observed properties with certain exceptions, like sub-luminous supernovae. Here we discuss the possibility of sub-Chandrasekhar WDs detonating due to the build up of a layer of helium on the C-O WD by accreting from a helium rich companion star to explain observed deviations such as subluminous type Ia. We also detail some of the energetics involved that...
Bera, Prasanta
2016-01-01
In the presence of a strong magnetic field a stellar equilibrium configuration, aided by the Lorentz force, can support a larger mass than a non-magnetic one. This has been considered a possible explanation of the super-Chandrasekhar mass white dwarfs giving rise to over-luminous Type-Ia supernovae. We present here linear and non-linear perturbation studies of such strongly magetised configurations and show that axisymmetric configurations with poloidal or toroidal fields are unstable. The numerical evolution of the perturbations shows instability after about an Alfv\\'en crossing time. This time scale is very short for the magnetically supported super-Chandrasekhar mass white dwarfs. Uniform rotation about the symmetry axis can reduce the growth rate but can not stabilize the super-massive configurations. It is concluded that long-lived super-Chandrasekhar mass white dwarfs supported by magnetic field are unlikely to occur in Nature.
Mukhopadhyay, Banibrata
2016-01-01
Observations of several peculiar, under- and over-luminous type Ia supernovae (SNeIa) argue for exploding masses widely different from the Chandrasekhar-limit. We explore the modification to Einstein's gravity in white dwarfs for the first time in the literature, which shows that depending on the (density dependent) modified gravity parameter $\\alpha$, chosen for the present purpose of representation, limiting mass of white dwarfs could be significantly sub- as well as super-Chandrasekhar. Hence, this unifies the apparently disjoint classes of SNeIa, establishing the importance of modified Einstein's gravity in white dwarfs. Our discovery questions both the global validity of Einstein's gravity and the uniqueness of Chandrasekhar's limit.
An Intermediate Type Ia Supernova Between Normal And Super-Chandrasekhar
Cao, Yi; Nugent, Peter E; Goobar, A; Nordin, Jakob; Kulkarni, S R; Cenko, S Bradley; Fox, Ori; Kasliwal, Mansi M; Fremling, C; Amanullah, R; Hsiao, E Y; Perley, D A; Bue, Brian D; Masci, Frank J; Lee, William H; Chotard, Nicolas
2016-01-01
While recent observations provide evidence that super-Chandrasekhar Type Ia supernovae and at least a fraction of normal Type Ia supernovae probably originate from double-degenerate systems, these two subclasses show distinct characteristics observationally. Here we report an intermediate supernova iPTF13asv that may bridge this gap. On the one hand, similar to normal Type Ia supernovae, the over-luminous iPTF13asv follows the empirical relation between the peak magnitude, the lightcurve shape and its intrinsic color, and shows a near-IR secondary maximum like normal supernovae. On the other hand, similar to super-Chandrasekhar events, it has strong UV emission around maximum, low expansion velocities and persistent carbon absorption. We estimate a $^{56}$Ni mass of $0.81^{+0.10}_{-0.18}M_\\odot$ and a total ejecta mass of $1.44^{+0.44}_{-0.12}M_\\odot$. Despite these similarities, iPTF13asv lacks iron absorption in its early-phase spectra, indicating a stratified ejecta structure with weak mixing. Based on the...
The Role of Electron Captures in Chandrasekhar-Mass Models for Type Ia Supernovae
The Chandrasekhar-mass model for Type Ia supernovae (SNe Ia) has received increasing support from recent comparisons of observations with light-curve predictions and modeling of synthetic spectra. It explains SN Ia events via thermonuclear explosions of accreting white dwarfs in binary stellar systems, being caused by central carbon ignition when the white dwarf approaches the Chandrasekhar mass. As the electron gas in white dwarfs is degenerate, characterized by high Fermi energies for the high-density regions in the center, electron capture on intermediate-mass and Fe group nuclei plays an important role in explosive burning. Electron capture affects the central electron fraction Ye, which determines the composition of the ejecta from such explosions. Up to the present, astrophysical tabulations based on shell model matrix elements were available only for light nuclei in the sd-shell. Recently, new shell model Monte Carlo and large-scale shell model diagonalization calculations have also been performed for pf-shell nuclei. These lead in general to a reduction of electron capture rates in comparison with previous, more phenomenological, approaches. Making use of these new shell model-based rates, we present the first results for the composition of Fe group nuclei produced in the central regions of SNe Ia and possible changes in the constraints on model parameters like ignition densities ρign and burning front speeds vdef. (c) 2000 The American Astronomical Society
The Evolution and Fate of Super-Chandrasekhar Mass White Dwarf Merger Remnants
Schwab, Josiah; Kasen, Daniel
2016-01-01
We present stellar evolution calculations of the remnant of the merger of two carbon-oxygen white dwarfs (CO WDs). We focus on cases that have a total mass in excess of the Chandrasekhar mass. After the merger, the remnant manifests as an $L \\sim 3 \\times 10^4 L_\\odot$ source for $\\sim 10^4$ yr. A dusty wind may develop, leading these sources to be self-obscured and to appear similar to extreme AGB stars. Roughly $\\sim 10$ such objects should exist in the Milky Way and M31 at any time. As found in previous work, off-center carbon fusion is ignited within the merger remnant and propagates inward via a carbon flame, converting the WD to an oxygen-neon (ONe) composition. By following the evolution for longer than previous calculations, we demonstrate that after carbon-burning reaches the center, neutrino-cooled Kelvin-Helmholtz contraction leads to off-center neon ignition in remnants with masses $\\ge 1.35 M_\\odot$. The resulting neon flame converts the core to a silicon WD. Thus, super-Chandrasekhar WD merger r...
Approach to Chandrasekhar-Kendall-Woltjer State in a Chiral Plasma
Xia, Xiao-liang; Wang, Qun
2016-01-01
We study the time evolution of the magnetic field in a plasma with a chiral magnetic current. The Vector Spherical Harmonic functions (VSH) are used to expand all fields. We define a measure for the Chandrasekhar-Kendall-Woltjer (CKW) state, which has a simple form in VSH expansion. We propose the conditions for a general class of initial momentum spectra that will evolve into the CKW state. For this class of initial conditions, to approach the CKW state, (i) a non-vanishing chiral magnetic conductivity is necessary, and (ii) the time integration of the product of the electric resistivity and chiral magnetic conductivity must grow faster than the time integration of the resistivity. We give a few examples to test these conditions numerically which work very well.
Frequency band of the f-mode Chandrasekhar-Friedman-Schutz instability
Rapidly rotating neutron stars can be unstable to the gravitational-wave-driven Chandrasekhar-Friedman-Schutz (CFS) mechanism if they have a neutral point in the spectrum of nonaxisymmetric f-modes. We investigate the frequencies of these modes in two sequences of uniformly rotating polytropes using nonlinear simulations in full general relativity, determine the approximate locations of the neutral points, and derive limits on the observable frequency band available to the instability in these sequences. We find that general relativity enhances the detectability of a CFS-unstable neutron star substantially, both by widening the instability window and enlarging the band into the optimal range for interferometric detectors like LIGO, VIRGO, and GEO-600.
Solar abundance of manganese: a case for near Chandrasekhar-mass Type Ia supernova progenitors
Seitenzahl, Ivo R.; Cescutti, Gabriele; Röpke, Friedrich K.; Ruiter, Ashley J.; Pakmor, Rüdiger
2013-11-01
Context. Manganese is predominantly synthesised in Type Ia supernova (SN Ia) explosions. Owing to the entropy dependence of the Mn yield in explosive thermonuclear burning, SNe Ia involving near Chandrasekhar-mass (MCh) white dwarfs (WDs) are predicted to produce Mn-to-Fe ratios that significantly exceed those of SN Ia explosions involving sub-Chandrasekhar mass primary WDs. Of all current supernova explosion models, only SN Ia models involving near-MCh WDs produce [Mn/Fe] ≳ 0.0. Aims: Using the specific yields for competing SN Ia scenarios, we aim to constrain the relative fractions of exploding near-MCh to sub-MCh primary WDs in the Galaxy. Methods: We extract the Mn yields from three-dimensional thermonuclear supernova simulations that refer to different initial setups and progenitor channels. We then compute the chemical evolution of Mn in the solar neighborhood, assuming SNe Ia are made up of different relative fractions of the considered explosion models. Results: We find that due to the entropy dependence of freeze-out yields from nuclear statistical equilibrium, [Mn/Fe] depends strongly on the mass of the exploding WD, with near-MCh WDs producing substantially higher [Mn/Fe] than sub-MCh WDs. Of all nucleosynthetic sources potentially influencing the chemical evolution of Mn, only explosion models involving the thermonuclear incineration of near-MCh WDs predict solar or super-solar [Mn/Fe]. Consequently, we find in our chemical evolution calculations that the observed [Mn/Fe] in the solar neighborhood at [Fe/H] ≳ 0.0 cannot be reproduced without near-MCh SN Ia primaries. Assuming that 50% of all SNe Ia stem from explosive thermonuclear burning in near-MCh WDs results in a good match to data.
Subramanian, Sathyawageeswar
2015-01-01
Here we extend the exploration of significantly super-Chandrasekhar magnetised white dwarfs by numerically computing axisymmetric stationary equilibria of differentially rotating magnetised polytropic compact stars in general relativity (GR), within the ideal magnetohydrodynamic regime. We use a general relativistic magnetohydrodynamic (GRMHD) framework that describes rotating and magnetised axisymmetric white dwarfs, choosing appropriate rotation laws and magnetic field profiles (toroidal and poloidal). The numerical procedure for finding solutions in this framework uses the 3+1 formalism of numerical relativity, implemented in the open source XNS code. We construct equilibrium sequences by varying different physical quantities in turn, and highlight the plausible existence of super-Chandrasekhar white dwarfs, with masses in the range of 2-3 solar mass, with central (deep interior) magnetic fields of the order of $10^{14}$ Gauss and differential rotation with surface time periods of about 1-10 seconds. We no...
We present optical photometry and spectroscopy of five Type Ia supernovae discovered by the Nearby Supernova Factory selected to be spectroscopic analogs of the candidate super-Chandrasekhar-mass events SN 2003fg and SN 2007if. Their spectra are characterized by hot, highly ionized photospheres near maximum light, for which SN 1991T supplies the best phase coverage among available close spectral templates. Like SN 2007if, these supernovae are overluminous (–19.5 V 56Ni mass, total progenitor mass, and masses of shells and surrounding carbon/oxygen envelopes. We find that the reconstructed total progenitor mass distribution of the events (including SN 2007if) is bounded from below by the Chandrasekhar mass, with SN 2007if being the most massive. We discuss the relationship of these events to the emerging class of super-Chandrasekhar-mass SNe Ia, estimate the relative rates, compare the mass distribution to that expected for double-degenerate SN Ia progenitors from population synthesis, and consider implications for future cosmological Hubble diagrams.
Chandrasekhar's relation and stellar rotation in the Kepler field
Silva, J. R. P.; Soares, B. B. [Grupo de Astroestatística, Departamento de Física, Universidade do Estado do Rio Grande do Norte, Mossoró-RN (Brazil); De Freitas, D. B., E-mail: joseronaldo@uern.br, E-mail: brauliosoares@uern.br, E-mail: danielbrito@dfte.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal-RN (Brazil)
2014-11-20
According to the statistical law of large numbers, the expected mean of identically distributed random variables of a sample tends toward the actual mean as the sample increases. Under this law, it is possible to test the Chandrasekhar's relation (CR), (V) = (π/4){sup –1}(Vsin i), using a large amount of Vsin i and V data from different samples of similar stars. In this context, we conducted a statistical test to check the consistency of the CR in the Kepler field. In order to achieve this, we use three large samples of V obtained from Kepler rotation periods and a homogeneous control sample of Vsin i to overcome the scarcity of Vsin i data for stars in the Kepler field. We used the bootstrap-resampling method to estimate the mean rotations ((V) and (Vsin i)) and their corresponding confidence intervals for the stars segregated by effective temperature. Then, we compared the estimated means to check the consistency of CR, and analyzed the influence of the uncertainties in radii measurements, and possible selection effects. We found that the CR with (sin i) = π/4 is consistent with the behavior of the (V) as a function of (Vsin i) for stars from the Kepler field as there is a very good agreement between such a relation and the data.
The double-degenerate, super-Chandrasekhar nucleus of the planetary nebula Henize 2-428
Santander-García, M; Corradi, R L M; Jones, D; Miszalski, B; Boffin, H M J; Rubio-Díez, M M; Kotze, M M
2016-01-01
The planetary nebula (PN) stage is the ultimate fate of stars with mass 1 to 8 solar masses (M$_\\odot$). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as it expands during the Asymptotic Giant Branch (AGB) phase. The excess material ends up forming a common-envelope (CE) surrounding both stars. Drag forces would then result in the envelope being ejected into a bipolar PN whose equator is coincident with the orbital plane of the system. Systems in which both stars have ejected their envelopes and evolve towards the white dwarf (WD) stage are called double-degenerates. Here we report that Henize 2-428 has a double-degenerate core with a combined mass unambiguously above the Chandrasekhar limit of 1.4 M$_\\odot$. According to its short orbital period (4.2 hours) and total mass (1.76 M$_\\odot$), the system shoul...
Scalzo, R A; Sim, S A
2014-01-01
The ejected mass distribution of type Ia supernovae directly probes progenitor evolutionary history and explosion mechanisms, with implications for their use as cosmological probes. Although the Chandrasekhar mass is a natural mass scale for the explosion of white dwarfs as type Ia supernovae, models allowing type Ia supernovae to explode at other masses have attracted much recent attention. Using an empirical relation between the ejected mass and the light curve width, we derive ejected masses $M_\\mathrm{ej}$ and $^{56}$Ni masses $M_\\mathrm{Ni}$ for a sample of 337 type Ia supernovae with redshifts $z < 0.7$ used in recent cosmological analyses. We use hierarchical Bayesian inference to reconstruct the joint $M_\\mathrm{ej}$-$M_\\mathrm{Ni}$ distribution, accounting for measurement errors. The inferred marginal distribution of $M_\\mathrm{ej}$ has a long tail towards sub-Chandrasekhar masses, but cuts off sharply above 1.4 $M_\\odot$. Our results imply that 25\\%-50\\% of normal type Ia supernovae are inconsist...
We present photometric and spectroscopic observations of SN 2007if, an overluminous (MV = -20.4), red (B - V = 0.16 at B-band maximum), slow-rising (trise = 24 days) type Ia supernova (SN Ia) in a very faint (Mg = -14.10) host galaxy. A spectrum at 5 days past B-band maximum light is a direct match to the super-Chandrasekhar-mass candidate SN Ia 2003fg, showing Si II and C II at ∼9000 km s-1. A high signal-to-noise co-addition of the SN spectral time series reveals no Na I D absorption, suggesting negligible reddening in the host galaxy, and the late-time color evolution has the same slope as the Lira relation for normal SNe Ia. The ejecta appear to be well mixed, with no strong maximum in I band and a diversity of iron-peak lines appearing in near-maximum-light spectra. SN 2007if also displays a plateau in the Si II velocity extending as late as +10 days, which we interpret as evidence for an overdense shell in the SN ejecta. We calculate the bolometric light curve of the SN and use it and the Si II velocity evolution to constrain the mass of the shell and the underlying SN ejecta, and demonstrate that SN 2007if is strongly inconsistent with a Chandrasekhar-mass scenario. Within the context of a 'tamped detonation' model appropriate for double-degenerate mergers, and assuming no host extinction, we estimate the total mass of the system to be 2.4 ± 0.2 Msun, with 1.6 ± 0.1 Msun of 56Ni and with 0.3-0.5 Msun in the form of an envelope of unburned carbon/oxygen. Our modeling demonstrates that the kinematics of shell entrainment provide a more efficient mechanism than incomplete nuclear burning for producing the low velocities typical of super-Chandrasekhar-mass SNe Ia.
Gleiser, Marcelo
2013-01-01
Spatially-bound objects across diverse length and energy scales are characterized by a binding energy. We propose that their spatial structure is mathematically encoded as information in their momentum modes and described by a measure known as configurational entropy (CE). Investigating solitonic Q-balls and stars with a polytropic equation of state $P = K{\\rho}^{\\gamma}$, we show that objects with large binding energy have low CE, whereas those at the brink of instability (zero binding energy) have near maximal CE. In particular, we use the CE to find the critical charge allowing for classically stable Q-balls and the Chandrasekhar limit for white dwarfs $({\\gamma} = 4/3)$ with an accuracy of a few percent.
Gleiser, Marcelo, E-mail: mgleiser@dartmouth.edu; Sowinski, Damian, E-mail: Damian.Sowinski.GR@dartmouth.edu
2013-11-25
Spatially-bound objects across diverse length and energy scales are characterized by a binding energy. We propose that their spatial structure is mathematically encoded as information in their momentum modes and described by a measure known as configurational entropy (CE) [1]. Investigating solitonic Q-balls and stars with a polytropic equation of state P=Kρ{sup γ}, we show that objects with large binding energy have low CE, whereas those at the brink of instability (zero binding energy) have near maximal CE. In particular, we use the CE to find the critical charge allowing for classically stable Q-balls and the Chandrasekhar limit for white dwarfs (γ=4/3) with an accuracy of a few percent.
Yamaguchi, Hiroya; Foster, Adam R; Bravo, Eduardo; Williams, Brian J; Maeda, Keiichi; Nobukawa, Masayoshi; Eriksen, Kristoffer A; Brickhouse, Nancy S; Petre, Robert; Koyama, Katsuji
2015-01-01
Despite decades of intense efforts, many fundamental aspects of Type Ia supernova (SNe Ia) remain elusive. One of the major open questions is whether the mass of the exploding white dwarf (WD) is close to the Chandrasekhar limit. Here we report the detection of strong K-shell emission from stable Fe-peak elements in the Suzaku X-ray spectrum of the Type Ia supernova remnant (SNR) 3C 397. The high Ni/Fe and Mn/Fe mass ratios (0.11-0.24 and 0.018-0.033, respectively) in the hot plasma component that dominates the K-shell emission lines indicate a degree of neutronization in the SN ejecta which can only be achieved by electron captures in the dense cores of exploding WDs with a near-Chandrasekhar mass. This suggests a single-degenerate origin for 3C 397, since Chandrasekhar mass progenitors are expected naturally if the WD accretes mass slowly from a companion. Together with other results supporting the double-degenerate scenario, our work adds to the mounting evidence that both progenitor channels make a signif...
In the version of the single-degenerate scenario of Type Ia supernovae (SNe Ia) studied here, a carbon-oxygen white dwarf explodes close to the Chandrasekhar limit after accreting material from a non-degenerate helium (He) companion star. In the present study, we employ the STELLAR GADGET code to perform three-dimensional hydrodynamical simulations of the interaction of the SN Ia ejecta with the He companion star taking into account its orbital motion and spin. It is found that only 2%-5% of the initial companion mass is stripped off from the outer layers of He companion stars due to the supernova (SN) impact. The dependence of the unbound mass (or the kick velocity) on the orbital separation can be fitted to a good approximation by a power law for a given companion model. After the SN impact, the outer layers of a He donor star are significantly enriched with heavy elements from the low-expansion-velocity tail of SN Ia ejecta. The total mass of accumulated SN-ejecta material on the companion surface reaches about ∼> 10–3 M☉ for different companion models. This enrichment with heavy elements provides a potential way to observationally identify the surviving companion star in SN remnants. Finally, by artificially adjusting the explosion energy of the W7 explosion model, we find that the total accumulation of SN ejecta on the companion surface is also dependent on the explosion energy with a power-law relation to a good approximation
Stritzinger, M D; Hoeflich, P; Baron, E; Phillips, M M; Taddia, F; Foley, R J; Hsiao, E Y; Jha, S W; McCully, C; Pandya, V; Simon, J D; Benetti, S; Brown, P J; Burns, C R; Campillay, A; Contreras, C; Forster, F; Holmbo, S; Marion, G H; Morrell, N; Pignata, G
2014-01-01
We present UV through NIR broad-band photometry, and optical and NIR spectroscopy of Type Iax supernova 2012Z. The data set consists of both early and late-time observations, including the first late phase NIR spectrum obtained for a spectroscopically classified SN Iax. Simple model calculations of its bolometric light curve suggest SN 2012Z produced ~0.3 M_sun of (56)Ni, ejected about a Chandrasekhar mass of material, and had an explosion energy of ~10^51 erg, making it one of the brightest and most energetic SN Iax yet observed. The late phase NIR spectrum of SN 2012Z is found to broadly resemble similar epoch spectra of normal SNe Ia; however, like other SNe Iax, corresponding visual-wavelength spectra differ substantially compared to all supernova types. Constraints from the distribution of IMEs, e.g. silicon and magnesium, indicate that the outer ejecta did not experience significant mixing during or after burning, and the late phase NIR line profiles suggests most of the (56)Ni is produced during high d...
Second post-Newtonian approximation of Einstein-aether theory
Xie, Yi; Huang, Tian-yi
2008-01-01
In this paper, second post-Newtonian approximation of Einstein-aether theory is obtained by Chandrasekhar's approach. Five parameterized post-Newtonian parameters in first post-Newtonian approximation are presented after a time transformation and they are identical with previous works, in which $\\gamma=1$, $\\beta=1$ and two preferred-frame parameters remain. Meanwhile, in second post-Newtonian approximation, a parameter, which represents third order nonlinearity for gravity, is zero the same ...
Stritzinger, M. D.; Valenti, S.; Hoeflich, P.; Baron, E.; Phillips, M. M.; Taddia, F.; Foley, R. J.; Hsiao, E. Y.; Jha, S. W.; McCully, C.; Pandya, V.; Simon, J. D.; Benetti, S.; Brown, P. J.; Burns, C. R.; Campillay, A.; Contreras, C.; Förster, F.; Holmbo, S.; Marion, G. H.; Morrell, N.; Pignata, G.
2015-01-01
We present ultraviolet through near-infrared (NIR) broadband photometry, and visual-wavelength and NIR spectroscopy of the Type Iax supernova (SN) 2012Z. The data set consists of both early- and late-time observations, including the first late phase NIR spectrum obtained for a spectroscopically classified SN Iax. Simple model calculations of its bolometric light curve suggest SN 2012Z produced ~0.3 M⊙ of 56Ni, ejected about a Chandrasekhar mass of material, and had an explosion energy of ~1051 erg, making it one of the brightest (MB = -18.3 mag) and most energetic SN Iax yet observed. The late phase (+269d) NIRspectrum of SN 2012Z is found to broadly resemble similar epoch spectra of normal SNe Ia; however, like other SNe Iax, corresponding visual-wavelength spectra differ substantially from all supernova types. Constraints from the distribution of intermediate mass elements, e.g., silicon and magnesium, indicate that the outer ejecta did not experience significant mixing during or after burning, and the late phase NIR line profiles suggests most of the 56Ni is produced during high density burning. The various observational properties of SN 2012Z are found to be consistent with the theoretical expectations of a Chandrasekhar mass white dwarf progenitor that experiences a pulsational delayed detonation, which produced several tenths of a solar mass of 56Ni during the deflagration burning phase and little (or no) 56Ni during the detonation phase. Within this scenario only a moderate amount of Rayleigh-Taylor mixing occurs both during the deflagration and fallback phase of the pulsation, and the layered structure of the intermediate mass elements is a product of the subsequent denotation phase. The fact that the SNe Iax population does not follow a tight brightness-decline relation similar to SNe Ia can then be understood in the framework of variable amounts of mixing during pulsational rebound and variable amounts of 56Ni production during the early subsonic phase
Chandrasekhar: The all rounder
J F Mckenzie
2011-09-01
This paper provides a very brief introduction to three of Chandrasekhar’s famous books on Stellar Structure, Hydrodynamics and Black Holes. In particular we summarize Chandra’s treatment of the “Thermal Instability” which plays such a crucial role in the understanding of convection zones in stellar atmospheres. We also outline three important ideas in ﬂuid dynamics which are inexplicably omitted from Chandrasekhar’s Hydrodynamic and Hydromagnetic Stability; the ﬁrst is the Brunt–Väisȧlä frequency which appears in internal gravity waves and is closely related to Schwarzschild’s stability criterion; the second is the baroclinic instability which is important in atmospheric dynamics and meteorology, and the third is the conservation of potential vorticity which is central to the understanding of the planetary scale – Rossby waves.
Jacobs, Adam M; Nonaka, Andy; Almgren, Ann S; Bell, John B
2015-01-01
The dynamics of helium shell convection driven by nuclear burning establish the conditions for runaway in the sub-Chandrasekhar mass, double detonation model for Type Ia supernovae, as well as for a variety of other explosive phenomena. We explore these convection dynamics for a range of white dwarf core and helium shell masses in three dimensions using the low Mach number hydrodynamics code Maestro. We present calculations of the bulk properties of this evolution, including time-series evolution of global diagnostics, lateral averages of the 3D state, and the global 3D state. We find a variety of outcomes including quasi-equilibrium, localized runaway, and nova-like runaway. Our results suggest the double detonation progenitor model is promising, that 3D, dynamic convection plays a key role, and that these systems warrant further study.
Blondin, Stéphane; Hillier, D John
2015-01-01
We present 1D non-local thermodynamic equilibrium (non-LTE) time-dependent radiative-transfer simulations of a Chandrasekhar-mass delayed-detonation model which synthesizes 0.51 Msun of 56Ni, and confront our results to the Type Ia supernova (SN Ia) 2002bo over the first 100 days of its evolution. Assuming only homologous expansion, this same model reproduces the bolometric and multi-band light curves, the secondary near-infrared (NIR) maxima, and the optical and NIR spectra. The chemical stratification of our model qualitatively agrees with previous inferences by Stehle et al., but reveals significant quantitative differences for both iron-group and intermediate-mass elements. We show that +/-0.1 Msun (i.e., +/-20 per cent) variations in 56Ni mass have a modest impact on the bolometric and colour evolution of our model. One notable exception is the U-band, where a larger abundance of iron-group elements results in less opaque ejecta through ionization effects, our model with more 56Ni displaying a higher nea...
Yamanaka, Masayuki; Tanaka, Masaomi; Tominaga, Nozomu; Kawabata, Koji S; Takaki, Katsutoshi; Kawabata, Miho; Nakaoka, Tatsuya; Ueno, Issei; Akitaya, Hiroshi; Nagayama, Takahiro; Takahashi, Jun; Honda, Satoshi; Omodaka, Toshihiro; Miyanoshita, Ryo; Nagao, Takashi; Watanabe, Makoto; Isogai, Mizuki; Arai, Akira; Itoh, Ryosuke; Ui, Takahiro; Uemura, Makoto; Yoshida, Michitoshi; Hanayama, Hidekazu; Kuroda, Daisuke; Ukita, Nobuharu; Yanagisawa, Kenshi; Izumiura, Hideyuki; Saito, Yoshihiko; Masumoto, Kazunari; Ono, Rikako; Noguchi, Ryo; Matsumoto, Katsura; Nogami, Daisaku; Morokuma, Tomoki; Oasa, Yumiko; Sekiguchi, Kazuhiro
2016-01-01
We present extensively dense observations of the super-Chandrasekhar supernova (SC SN) candidate SN 2012dn from $-11$ to $+140$ days after the date of its $B$-band maximum in the optical and near-infrared (NIR) wavelengths conducted through the OISTER ToO program. The NIR light curves and color evolutions up to 35 days after the $B$-band maximum provided an excellent match with those of another SC SN 2009dc, providing a further support to the nature of SN 2012dn as a SC SN. We found that SN 2012dn exhibited strong excesses in the NIR wavelengths from $30$ days after the $B$-band maximum. The $H$ and $K_{s}$-band light curves exhibited much later maximum dates at $40$ and $70$ days after the $B$-band maximum, respectively, compared with those of normal SNe Ia. The $H$ and $K_{s}$-band light curves subtracted by those of SN 2009dc displayed plateaued evolutions, indicating a NIR echo from the surrounding dust. The distance to the inner boundary of the dust shell is limited to be $4.8 - 6.4\\times10^{-2}$ pc. No ...
We present Keck LRIS spectroscopy and g-band photometry of the metal-poor, low-luminosity host galaxy of the super-Chandrasekhar-mass Type Ia supernova SN 2007if. Deep imaging of the host reveals its apparent magnitude to be mg = 23.15 ± 0.06, which at the spectroscopically measured redshift of zhelio = 0.07450 ± 0.00015 corresponds to an absolute magnitude of Mg = -14.45 ± 0.06. Galaxy g - r color constrains the mass-to-light ratio, giving a host stellar mass estimate of log(M*/Msun) = 7.32 ± 0.17. Balmer absorption in the stellar continuum, along with the strength of the 4000 A break, constrains the age of the dominant starburst in the galaxy to be tburst = 123+165-77 Myr, corresponding to a main-sequence turnoff mass of M/Msun = 4.6+2.6-1.4. Using the R23 method of calculating metallicity from the fluxes of strong emission lines, we determine the host oxygen abundance to be 12 + log(O/H)KK04 = 8.01 ± 0.09, significantly lower than any previously reported spectroscopically measured Type Ia supernova host galaxy metallicity. Our data show that SN 2007if is very likely to have originated from a young, metal-poor progenitor.
Yamanaka, Masayuki; Maeda, Keiichi; Tanaka, Masaomi; Tominaga, Nozomu; Kawabata, Koji S.; Takaki, Katsutoshi; Kawabata, Miho; Nakaoka, Tatsuya; Ueno, Issei; Akitaya, Hiroshi; Nagayama, Takahiro; Takahashi, Jun; Honda, Satoshi; Omodaka, Toshihiro; Miyanoshita, Ryo; Nagao, Takashi; Watanabe, Makoto; Isogai, Mizuki; Arai, Akira; Itoh, Ryosuke; Ui, Takahiro; Uemura, Makoto; Yoshida, Michitoshi; Hanayama, Hidekazu; Kuroda, Daisuke; Ukita, Nobuharu; Yanagisawa, Kenshi; Izumiura, Hideyuki; Saito, Yoshihiko; Masumoto, Kazunari; Ono, Rikako; Noguchi, Ryo; Matsumoto, Katsura; Nogami, Daisaku; Morokuma, Tomoki; Oasa, Yumiko; Sekiguchi, Kazuhiro
2016-05-01
We present extensively dense observations of the super-Chandrasekhar supernova (SC SN) candidate SN 2012dn from -11 to +140 d after the date of its B-band maximum in the optical and near-infrared (NIR) wavelengths conducted through the OISTER ToO (Optical and Infrared Synergetic Telescopes for Education and Research Target of Opportunity) program. The NIR light curves and color evolutions up to 35 days after the B-band maximum provided an excellent match with those of another SC SN 2009dc, providing further support to the nature of SN 2012dn as an SC SN. We found that SN 2012dn exhibited strong excesses in the NIR wavelengths from 30 d after the B-band maximum. The H- and Ks-band light curves exhibited much later maximum dates at 40 and 70 d after the B-band maximum, respectively, compared with those of normal SNe Ia. The H- and Ks-band light curves subtracted by those of SN 2009dc displayed plateaued evolutions, indicating an NIR echo from the surrounding dust. The distance to the inner boundary of the dust shell is limited to 4.8-6.4 × 10-2 pc. No emission lines were found in its early phase spectra, suggesting that the ejecta-circumstellar material interaction could not occur. On the other hand, we found no signature that strongly supports the scenario of dust formation. The mass-loss rate of the pre-explosion system is estimated to be 10-6-10-5 M⊙ yr-1, assuming that the wind velocity of the system is 10-100 km s-1, which suggests that the progenitor of SN 2012dn could be a recurrent nova system. We conclude that the progenitor of this SC SN could be explained by the single-degenerate scenario.
Rachid Ouyed; Jan Staff
2013-01-01
We show that,by appealing to a Quark-Nova (QN) in a tight binary system containing a massive neutron star and a CO white dwarf (WD),a Type Ia explosion could occur.The QN ejecta collides with the WD,driving a shock that triggers carbon burning under degenerate conditions (the QN-Ia).The conditions in the compressed low-mass WD (MWD ＜ 0.9 M☉) in our model mimic those of a Chandrasekhar mass WD.The spin-down luminosity from the QN compact remnant (the quark star) provides additional power that makes the QN-Ia light-curve brighter and broader than a standard SN-Ia with similar 56Ni yield.In QNe-Ia,photometry and spectroscopy are not necessarily linked since the kinetic energy of the ejecta has a contribution from spin-down power and nuclear decay.Although QNe-Ia may not obey the Phillips relationship,their brightness and their relatively "normal looking" light-curves mean they could be included in the cosmological sample.Light-curve fitters would be confused by the discrepancy between spectroscopy at peak and photometry and would correct for it by effectively brightening or dimming the QNe-Ia apparent magnitudes,thus over-or under-estimating the true magnitude of these spin-down powered SNe-Ia.Contamination of QNe-Ia in samples of SNe-Ia used for cosmological analyses could systematically bias measurements of cosmological parameters if QNe-Ia are numerous enough at high-redshift.The strong mixing induced by spin-down wind combined with the low 56Ni yields in QNe-Ia means that these would lack a secondary maximum in the i-band despite their luminous nature.We discuss possible QNe-Ia progenitors.
Das, Rabindra Nath
2007-01-01
In this paper, the new forms obtained for Chandrasekhar's H- function in Radiative Transfer by one of the authors both for non-conservative and conservative cases for isotropic scattering in a semi-infinite plane parallel atmosphere are used to obtain exclusively new forms for the first and second derivatives of H-function . The numerics for evaluation of zero of dispersion function, for evaluation of H-function and its derivatives and its zeroth, the first and second moments are outlined. Those are used to get ready and accurate extensive tables of H-function and its derivatives, pole and moments for different albedo for scattering by iteration and Simpson's one third rule . The schemes for interpolation of H-function for any arbitrary value of the direction parameter for a given albedo are also outlined. Good agreement has been observed in checks with the available results within one unit of ninth decimal
Chavanis, Pierre-Henri; Sire, Clément
2008-03-01
We point out a remarkable analogy between the limiting mass of relativistic white dwarf stars (Chandrasekhar’s limit) and the critical mass of bacterial populations in a generalized Keller Segel model of chemotaxis [P.H. Chavanis, C. Sire, Phys. Rev. E 69 (2004) 016116]. This model is based on generalized stochastic processes leading to the Tsallis statistics. The equilibrium states correspond to polytropic configurations similar to gaseous polytropes in astrophysics. For the critical index n3=d/(d-2) (where d≥2 is the dimension of space), the theory of polytropes leads to a unique value of the mass M that we interpret as a limiting mass. In d=3, we find M=202.8956… and in d=2, we recover the well-known result M=8π (in suitable units). For MM, the system collapses and forms a Dirac peak containing a mass M surrounded by a halo. This paper exposes the model and shows, by simple considerations, the origin of the critical mass. A detailed description of the critical dynamics of the generalized Keller Segel model will be given in a forthcoming paper.
Relativistic Feynman-Metropolis-Teller theory for white dwarfs in general relativity
The recent formulation of the relativistic Thomas-Fermi model within the Feynman-Metropolis-Teller theory for compressed atoms is applied to the study of general relativistic white dwarf equilibrium configurations. The equation of state, which takes into account the β-equilibrium, the nuclear and the Coulomb interactions between the nuclei and the surrounding electrons, is obtained as a function of the compression by considering each atom constrained in a Wigner-Seitz cell. The contribution of quantum statistics, weak, nuclear, and electromagnetic interactions is obtained by the determination of the chemical potential of the Wigner-Seitz cell. The further contribution of the general relativistic equilibrium of white dwarf matter is expressed by the simple formula √(g00)μws=constant, which links the chemical potential of the Wigner-Seitz cell μws with the general relativistic gravitational potential g00 at each point of the configuration. The configuration outside each Wigner-Seitz cell is strictly neutral and therefore no global electric field is necessary to warranty the equilibrium of the white dwarf. These equations modify the ones used by Chandrasekhar by taking into due account the Coulomb interaction between the nuclei and the electrons as well as inverse β decay. They also generalize the work of Salpeter by considering a unified self-consistent approach to the Coulomb interaction in each Wigner-Seitz cell. The consequences on the numerical value of the Chandrasekhar-Landau mass limit as well as on the mass-radius relation of 4He, 12C, 16O and 56Fe white dwarfs are presented. All these effects should be taken into account in processes requiring a precision knowledge of the white dwarf parameters.
Wæver, Ole
2009-01-01
Kenneth N. Waltz's 1979 book, Theory of International Politics, is the most influential in the history of the discipline. It worked its effects to a large extent through raising the bar for what counted as theoretical work, in effect reshaping not only realism but rivals like liberalism and......-empiricism and anti-positivism of his position. Followers and critics alike have treated Waltzian neorealism as if it was at bottom a formal proposition about cause-effect relations. The extreme case of Waltz being so victorious in the discipline, and yet being consistently mis-interpreted on the question of...
Jara, Pascual; Torrecillas, Blas
1988-01-01
The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.
Marino Beiras, Marcos
2001-01-01
We give an overview of the relations between matrix models and string theory, focusing on topological string theory and the Dijkgraaf--Vafa correspondence. We discuss applications of this correspondence and its generalizations to supersymmetric gauge theory, enumerative geometry and mirror symmetry. We also present a brief overview of matrix quantum mechanical models in superstring theory.
Golledge, Reginald G.
2001-01-01
The emergence of geographical theory was an inevitable product of the desire to systematize existing geographic knowledge and to use that systematized base to explore new areas of knowledge. Although the usefulness of theory and predictive models in geography is by now a matter of record, it was not always the case. The usefulness and need for theories was often disputed, despite the oft-repeated argument that theories of location explained the laws of spatial distributions, theories of inter...
The paper traces the development of the String Theory, and was presented at Professor Sir Rudolf Peierls' 80sup(th) Birthday Symposium. The String theory is discussed with respect to the interaction of strings, the inclusion of both gauge theory and gravitation, inconsistencies in the theory, and the role of space-time. The physical principles underlying string theory are also outlined. (U.K.)
Of all supergravity theories, the maximal, i.e., N = 8 in 4-dimension or N = 1 in 11-dimension, theory should perform the unification since it owns the highest degree of symmetry. As to the N = 1 in d = 11 theory, it has been investigated how to compactify to the d = 4 theories. From the phenomenological point of view, local SUSY GUTs, i.e., N = 1 SUSY GUTs with soft breaking terms, have been studied from various angles. The structures of extended supergravity theories are less understood than those of N = 1 supergravity theories, and matter couplings in N = 2 extended supergravity theories are under investigation. The harmonic superspace was recently proposed which may be useful to investigate the quantum effects of extended supersymmetry and supergravity theories. As to the so-called Kaluza-Klein supergravity, there is another possibility. (Mori, K.)
Linder, Stefan; Foss, Nicolai Juul
2015-01-01
Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting, and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....
Linder, Stefan; Foss, Nicolai Juul
Agency theory studies the problems and solutions linked to delegation of tasks from principals to agents in the context of conflicting interests between the parties. Beginning from clear assumptions about rationality, contracting and informational conditions, the theory addresses problems of ex...... agency theory to enjoy considerable scientific impact on social science; however, it has also attracted considerable criticism....
This article is devoted to a nontechnical review on the present status of string theory towards an ultimate unification of all fundamental interactions including gravity. In particular, we emphasize the importance of string theory as a new theoretical framework in which the long-standing conflict between quantum theory and general relativity is resolved. (author)
Williams, Jeffrey
1994-01-01
Considers the recent flood of anthologies of literary criticism and theory as exemplifications of the confluence of pedagogical concerns, economics of publishing, and other historical factors. Looks specifically at how these anthologies present theory. Cites problems with their formatting theory and proposes alternative ways of organizing theory…
Rowen, Louis H
1991-01-01
This is an abridged edition of the author's previous two-volume work, Ring Theory, which concentrates on essential material for a general ring theory course while ommitting much of the material intended for ring theory specialists. It has been praised by reviewers:**""As a textbook for graduate students, Ring Theory joins the best....The experts will find several attractive and pleasant features in Ring Theory. The most noteworthy is the inclusion, usually in supplements and appendices, of many useful constructions which are hard to locate outside of the original sources....The audience of non
Loring, FH
2014-01-01
Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec
Jaques, Thomas
2010-01-01
Generative Linguistics can and should be engaged by those with an interest in Translation Studies while developing their own positions on literary theory in general, but translation theory in particular. Generative theory provides empirical evidence for a free, creative mind that can comprehend, read, speak and translate a language. What is being proposed here contrasts radically with the dominant position of this generation's Translation Studies specialists, who freely incorporate Post-struc...
Aubin, Jean-Pierre; Saint-Pierre, Patrick
2011-01-01
Viability theory designs and develops mathematical and algorithmic methods for investigating the adaptation to viability constraints of evolutions governed by complex systems under uncertainty that are found in many domains involving living beings, from biological evolution to economics, from environmental sciences to financial markets, from control theory and robotics to cognitive sciences. It involves interdisciplinary investigations spanning fields that have traditionally developed in isolation. The purpose of this book is to present an initiation to applications of viability theory, explai
Sanfilippo, Antonio P.
2005-12-27
Graph theory is a branch of discrete combinatorial mathematics that studies the properties of graphs. The theory was pioneered by the Swiss mathematician Leonhard Euler in the 18th century, commenced its formal development during the second half of the 19th century, and has witnessed substantial growth during the last seventy years, with applications in areas as diverse as engineering, computer science, physics, sociology, chemistry and biology. Graph theory has also had a strong impact in computational linguistics by providing the foundations for the theory of features structures that has emerged as one of the most widely used frameworks for the representation of grammar formalisms.
Hashiguchi, Koichi
2009-01-01
This book details the mathematics and continuum mechanics necessary as a foundation of elastoplasticity theory. It explains physical backgrounds with illustrations and provides descriptions of detailed derivation processes..
Cox, David A
2012-01-01
Praise for the First Edition ". . .will certainly fascinate anyone interested in abstract algebra: a remarkable book!"—Monatshefte fur Mathematik Galois theory is one of the most established topics in mathematics, with historical roots that led to the development of many central concepts in modern algebra, including groups and fields. Covering classic applications of the theory, such as solvability by radicals, geometric constructions, and finite fields, Galois Theory, Second Edition delves into novel topics like Abel’s theory of Abelian equations, casus irreducibili, and the Galo
Manning, Phillip
2011-01-01
The study of quantum theory allowed twentieth-century scientists to examine the world in a new way, one that was filled with uncertainties and probabilities. Further study also led to the development of lasers, the atomic bomb, and the computer. This exciting new book clearly explains quantum theory and its everyday uses in our world.
Hjørland, Birger
2009-01-01
, evaluate and use such systems. Based on "a post-Kuhnian view" of paradigms this paper put forward arguments that the best understanding and classification of theories of concepts is to view and classify them in accordance with epistemological theories (empiricism, rationalism, historicism and pragmatism...
After noting some advantages of using perturbation theory some of the various types are related on a chart and described, including many-body nonlinear summations, quartic force-field fit for geometry, fourth-order correlation approximations, and a survey of some recent work. Alternative initial approximations in perturbation theory are also discussed. 25 references
Liu, Baoding
2015-01-01
When no samples are available to estimate a probability distribution, we have to invite some domain experts to evaluate the belief degree that each event will happen. Perhaps some people think that the belief degree should be modeled by subjective probability or fuzzy set theory. However, it is usually inappropriate because both of them may lead to counterintuitive results in this case. In order to rationally deal with belief degrees, uncertainty theory was founded in 2007 and subsequently studied by many researchers. Nowadays, uncertainty theory has become a branch of axiomatic mathematics for modeling belief degrees. This is an introductory textbook on uncertainty theory, uncertain programming, uncertain statistics, uncertain risk analysis, uncertain reliability analysis, uncertain set, uncertain logic, uncertain inference, uncertain process, uncertain calculus, and uncertain differential equation. This textbook also shows applications of uncertainty theory to scheduling, logistics, networks, data mining, c...
Lukeš, Jaroslav; Netuka, Ivan; Veselý, Jiří
1988-01-01
Within the tradition of meetings devoted to potential theory, a conference on potential theory took place in Prague on 19-24, July 1987. The Conference was organized by the Faculty of Mathematics and Physics, Charles University, with the collaboration of the Institute of Mathematics, Czechoslovak Academy of Sciences, the Department of Mathematics, Czech University of Technology, the Union of Czechoslovak Mathematicians and Physicists, the Czechoslovak Scientific and Technical Society, and supported by IMU. During the Conference, 69 scientific communications from different branches of potential theory were presented; the majority of them are in cluded in the present volume. (Papers based on survey lectures delivered at the Conference, its program as well as a collection of problems from potential theory will appear in a special volume of the Lecture Notes Series published by Springer-Verlag). Topics of these communications truly reflect the vast scope of contemporary potential theory. Some contributions deal...
Kleiss, Ronald H P
1999-01-01
In these lectures I will build up the concept of field theory using the language of Feynman diagrams. As a starting point, field theory in zero spacetime dimensions is used as a vehicle to develop all the necessary techniques: path integral, Feynman diagrams, Schwinger-Dyson equations, asymptotic series, effective action, renormalization etc. The theory is then extended to more dimensions, with emphasis on the combinatorial aspects of the diagrams rather than their particular mathematical structure. The concept of unitarity is used to, finally, arrive at the various Feynman rules in an actual, four-dimensional theory. The concept of gauge-invariance is developed, and the structure of a non-abelian gauge theory is discussed, again on the level of Feynman diagrams and Feynman rules.
Bohm, David
1951-01-01
This superb text by David Bohm, formerly Princeton University and Emeritus Professor of Theoretical Physics at Birkbeck College, University of London, provides a formulation of the quantum theory in terms of qualitative and imaginative concepts that have evolved outside and beyond classical theory. Although it presents the main ideas of quantum theory essentially in nonmathematical terms, it follows these with a broad range of specific applications that are worked out in considerable mathematical detail. Addressed primarily to advanced undergraduate students, the text begins with a study of t
Lubliner, Jacob
2008-01-01
The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and
Hočevar, Mitja
2015-01-01
This BCs thesis deals with topics from graph theory. Ramsey theory in its most basic form deals with the problem of determining the minimal positive integer, such that for any edge-coloring of the complete graph of this size with a prescribed number of colors one can find a subgraph of predefined size all of whose edges are of the same colour. These minimal sizes are called Ramsey numbers. In this BCs thesis we present basic notions of graph theory needed to understand the basic theorem of...
Andrews, George E
1994-01-01
Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl
Victor, Oluwafemi Oludu
2015-01-01
From ages to ages there had been expectation of individuals on a specific predictions and future occurrences. So also in a game, different participant that involves in those specified game have their various expectations of the results or the output of the game they are involved in. That is why we need a mathematical theory that helps in prediction of the future expectations in our day to day activities. Therefore the Martingale Theory is a very good theory that explains and dissects the expe...
This report discusses concepts in nuclear theory such as: neutrino nucleosynthesis; double beta decay; neutrino oscillations; chiral symmetry breaking; T invariance; quark propagator; cold fusion; and other related topics
Hodges, Wilfrid
1993-01-01
An up-to-date and integrated introduction to model theory, designed to be used for graduate courses (for students who are familiar with first-order logic), and as a reference for more experienced logicians and mathematicians.
Nel, Louis
2016-01-01
This book presents a detailed, self-contained theory of continuous mappings. It is mainly addressed to students who have already studied these mappings in the setting of metric spaces, as well as multidimensional differential calculus. The needed background facts about sets, metric spaces and linear algebra are developed in detail, so as to provide a seamless transition between students' previous studies and new material. In view of its many novel features, this book will be of interest also to mature readers who have studied continuous mappings from the subject's classical texts and wish to become acquainted with a new approach. The theory of continuous mappings serves as infrastructure for more specialized mathematical theories like differential equations, integral equations, operator theory, dynamical systems, global analysis, topological groups, topological rings and many more. In light of the centrality of the topic, a book of this kind fits a variety of applications, especially those that contribute to ...
A series of lectures on plasma theory with the main headings: introduction; charged particles moving in em fields; the liquid model; transport phenomena in the plasma; wave propagation in plasmas; plasma instabilities. 57 figs. (qui)
Gould, Ronald
2012-01-01
This introduction to graph theory focuses on well-established topics, covering primary techniques and including both algorithmic and theoretical problems. The algorithms are presented with a minimum of advanced data structures and programming details. This thoroughly corrected 1988 edition provides insights to computer scientists as well as advanced undergraduates and graduate students of topology, algebra, and matrix theory. Fundamental concepts and notation and elementary properties and operations are the first subjects, followed by examinations of paths and searching, trees, and networks. S
Murdin, P.
2000-11-01
A theory based on the premise that, on the microscopic scale, physical quantities have discrete, rather than a continuous range of, values. The theory was devised in the early part of the twentieth century to account for certain phenomena that could not be explained by classical physics. In 1900, the German physicist, Max Planck (1858-1947), was able precisely to describe the previously unexplaine...
Adaptive integral equation methods in transport theory
In this paper, an adaptive multilevel algorithm for integral equations is described that has been developed with the Chandrasekhar H equation and its generalizations in mind. The algorithm maintains good performance when the Frechet derivative of the nonlinear map is singular at the solution, as happens in radiative transfer with conservative scattering and in critical neutron transport. Numerical examples that demonstrate the algorithm's effectiveness are presented
Effective theories of universal theories
Wells, James D.; Zhang, Zhengkang
2016-01-01
It is well-known but sometimes overlooked that constraints on the oblique parameters (most notably S and T parameters) are generally speaking only applicable to a special class of new physics scenarios known as universal theories. In the effective field theory (EFT) framework, the oblique parameters should not be associated with Wilson coefficients in a particular operator basis, unless restrictions have been imposed on the EFT so that it describes universal theories. We work out these restrictions, and present a detailed EFT analysis of universal theories. We find that at the dimension-6 level, universal theories are completely characterized by 16 parameters. They are conveniently chosen to be: 5 oblique parameters that agree with the commonly-adopted ones, 4 anomalous triple-gauge couplings, 3 rescaling factors for the h 3, hf f , hV V vertices, 3 parameters for hV V vertices absent in the Standard Model, and 1 four-fermion coupling of order y f 2 . All these parameters are defined in an unambiguous and basis-independent way, allowing for consistent constraints on the universal theories parameter space from precision electroweak and Higgs data.
Possibility Theory versus Probability Theory in Fuzzy Measure Theory
Parul Agarwal
2015-05-01
Full Text Available The purpose of this paper is to compare probability theory with possibility theory, and to use this comparison in comparing probability theory with fuzzy set theory. The best way of comparing probabilistic and possibilistic conceptualizations of uncertainty is to examine the two theories from a broader perspective. Such a perspective is offered by evidence theory, within which probability theory and possibility theory are recognized as special branches. While the various characteristic of possibility theory within the broader framework of evidence theory are expounded in this paper, we need to introduce their probabilistic counterparts to facilitate our discussion.
Carroll, Joseph; Clasen, Mathias; Jonsson, Emelie;
2015-01-01
Biocultural theory is an integrative research program designed to investigate the causal interactions between biological adaptations and cultural constructions. From the biocultural perspective, cultural processes are rooted in the biological necessities of the human life cycle: specifically human...... ideological beliefs, and artistic practices such as music, dance, painting, and storytelling. Establishing biocultural theory as a program that self-consciously encompasses the different particular forms of human evolutionary research could help scholars and scientists envision their own specialized areas of...... research as contributions to a coherent, collective research program. This article argues that a mature biocultural paradigm needs to be informed by at least 7 major research clusters: (a) gene-culture coevolution; (b) human life history theory; (c) evolutionary social psychology; (d) anthropological...
Stewart, Ian
2003-01-01
Ian Stewart's Galois Theory has been in print for 30 years. Resoundingly popular, it still serves its purpose exceedingly well. Yet mathematics education has changed considerably since 1973, when theory took precedence over examples, and the time has come to bring this presentation in line with more modern approaches.To this end, the story now begins with polynomials over the complex numbers, and the central quest is to understand when such polynomials have solutions that can be expressed by radicals. Reorganization of the material places the concrete before the abstract, thus motivating the g
This textbook for students of physics is oriented in the selection of matter by the contents of a two-semester course about quantum theory. Thereby the foundations of quantum theory, among them the quantum-mechanical measurement process, the mathematical formalism, and Bell's inequalities, are extensively treated. Also modern concepts like feynman's path integral are regarded. This work is equally suited for a self-study, as course-accompanying lecture, and for preparations of examina. Application examples, supplementary explanations, and numerous illustration take car for a good understanding of the theoretical contents
Effective theories of universal theories
Wells, James D
2015-01-01
It is well-known but sometimes overlooked that constraints on the oblique parameters (most notably $S$ and $T$ parameters) are only applicable to a special class of new physics scenarios known as universal theories. In the effective field theory (EFT) framework, the oblique parameters should not be associated with Wilson coefficients in a particular operator basis, unless restrictions have been imposed on the EFT so that it describes universal theories. We work out these restrictions, and present a detailed EFT analysis of universal theories. We find that at the dimension-6 level, universal theories are completely characterized by 16 parameters. They are conveniently chosen to be: 5 oblique parameters that agree with the commonly-adopted ones, 4 anomalous triple-gauge couplings, 3 rescaling factors for the $h^3$, $hff$, $hVV$ vertices, 3 parameters for $hVV$ vertices absent in the Standard Model, and 1 four-fermion coupling of order $y_f^2$. All these parameters are defined in an unambiguous and basis-indepen...
The explosion mechanism of core-collapse supernovae: progress in supernova theory and experiments
Foglizzo, Thierry; Guilet, Jérôme; Masset, Frédéric; González, Matthias; Krueger, Brendan K; Novak, Jérôme; Oertel, Micaela; Margueron, Jérôme; Faure, Julien; Martin, Noël; Blottiau, Patrick; Peres, Bruno; Durand, Gilles
2015-01-01
The explosion of core-collapse supernova depends on a sequence of events taking place in less than a second in a region of a few hundred kilometers at the center of a supergiant star, after the stellar core approaches the Chandrasekhar mass and collapses into a proto-neutron star, and before a shock wave is launched across the stellar envelope. Theoretical efforts to understand stellar death focus on the mechanism which transforms the collapse into an explosion. Progress in understanding this mechanism is reviewed with particular attention to its asymmetric character. We highlight a series of successful studies connecting observations of supernova remnants and pulsars properties to the theory of core-collapse using numerical simulations. The encouraging results from first principles models in axisymmetric simulations is tempered by new puzzles in 3D. The diversity of explosion paths and the dependence on the pre-collapse stellar structure is stressed, as well as the need to gain a better understanding of hydr...
2PN Light Propagation in the Scalar-Tensor Theory: an $N$-Point-Masses Case
Deng, Xue-Mei
2012-01-01
Within the framework of the scalar-tensor theory (STT), its second post-Newtonian (2PN) approximation is obtained with Chandrasekhar's approach. By focusing on an $N$-point-masses system as the first step, we reduce the metric to its 2PN form for light propagation. Unlike previous works, at 2PN order, we abandon the hierarchized hypothesis and do not assume two parametrized post-Newtonian (PPN) parameters $\\gamma$ and $\\beta$ to be unity. We find that although there exist $\\gamma$ and $\\beta$ in the 2PN metric, only $\\gamma$ appears in the 2PN equations of light. As a simple example for applications, a gauge-invariant angle between the directions of two incoming photons for a differential measurement is investigated after the light trajectory is solved in a static and spherically symmetric spacetime. It shows the deviation from the general relativity (GR) $\\delta\\theta_{\\mathrm{STT}}$ does \\emph{not} depend on $\\beta$ even at 2PN level in this circumstance, which is consistent with previous results. A more co...
This is a summary of the advances in magnetic fusion energy theory research presented at the 17th International Atomic Energy Agency Fusion Energy Conference from 19 24 October, 1998 in Yokohama, Japan. Theory and simulation results from this conference provided encouraging evidence of significant progress in understanding the physics of thermonuclear plasmas. Indeed, the grand challenge for this field is to acquire the basic understanding that can readily enable the innovations which would make fusion energy practical. In this sense, research in fusion energy is increasingly able to be categorized as fitting well the 'Pasteur's Quadrant' paradigm, where the research strongly couples basic science ('Bohr's Quadrant') to technological impact ('Edison's Quadrant'). As supported by some of the work presented at this conference, this trend will be further enhanced by advanced simulations. Eventually, realistic three-dimensional modeling capabilities, when properly combined with rapid and complete data interpretation of results from both experiments and simulations, can contribute to a greatly enhanced cycle of understanding and innovation. Plasma science theory and simulation have provided reliable foundations for this improved modeling capability, and the exciting advances in high-performance computational resources have further accelerated progress. There were 68 papers presented at this conference in the area of magnetic fusion energy theory
Monthoux, Pierre Guillet de; Statler, Matt
2014-01-01
The recent Carnegie report (Colby, et al., 2011) characterizes the goal of business education as the development of practical wisdom. In this chapter, the authors reframe Scharmer’s Theory U as an attempt to develop practical wisdom by applying certain European philosophical concepts. Specifically...
Written by the author of the widely acclaimed textbook. Theoretical Atomic Physics Includes sections on quantum reflection, tunable Feshbach resonances and Efimov states. Useful for advanced students and researchers. This book presents a concise and modern coverage of scattering theory. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. The level of abstraction is kept as low as at all possible, and deeper questions related to mathematical foundations of scattering theory are passed by. The book should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. It is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Hall, Marshall
2011-01-01
Includes proof of van der Waerden's 1926 conjecture on permanents, Wilson's theorem on asymptotic existence, and other developments in combinatorics since 1967. Also covers coding theory and its important connection with designs, problems of enumeration, and partition. Presents fundamentals in addition to latest advances, with illustrative problems at the end of each chapter. Enlarged appendixes include a longer list of block designs.
Smith, Shelley
This paper came about within the context of a 13-month research project, Focus Area 1 - Method and Theory, at the Center for Public Space Research at the Royal Academy of the Arts School of Architecture in Copenhagen, Denmark. This project has been funded by RealDania. The goals of the research p...
Plummer, MD
1986-01-01
This study of matching theory deals with bipartite matching, network flows, and presents fundamental results for the non-bipartite case. It goes on to study elementary bipartite graphs and elementary graphs in general. Further discussed are 2-matchings, general matching problems as linear programs, the Edmonds Matching Algorithm (and other algorithmic approaches), f-factors and vertex packing.
The text book composed of five parts, which are summary of this book, arrangement of electricity theory including electricity nad magnetism, a direct current, and alternating current. It has two dictionary electricity terms for a synonym. The last is an appendix. It is for preparing for test of officer, electricity engineer and fire fighting engineer.
An introduction to the unified gauge theories of weak and electromagnetic interactions is given. The ingredients of gauge theories and symmetries and conservation laws lead to discussion of local gauge invariance and QED, followed by weak interactions and quantum flavor dynamics. The construction of the standard SU(2)xU(1) model precedes discussion of the unification of weak and electromagnetic interactions and weak neutral current couplings in this model. Presentation of spontaneous symmetry breaking and spontaneous breaking of a local symmetry leads to a spontaneous breaking scheme for the standard SU(2)xU(1) model. Consideration of quarks, leptons, masses and the Cabibbo angles, of the four quark and six quark models and CP violation lead finally to grand unification, followed by discussion of mixing angles in the Georgi-Glashow model, the Higgses of the SU(5) model and proton/ neutron decay in SU(5). (JIW)
Hashiguchi, Koichi
2014-01-01
This book was written to serve as the standard textbook of elastoplasticity for students, engineers and researchers in the field of applied mechanics. The present second edition is improved thoroughly from the first edition by selecting the standard theories from various formulations and models, which are required to study the essentials of elastoplasticity steadily and effectively and will remain universally in the history of elastoplasticity. It opens with an explanation of vector-tensor analysis and continuum mechanics as a foundation to study elastoplasticity theory, extending over various strain and stress tensors and their rates. Subsequently, constitutive equations of elastoplastic and viscoplastic deformations for monotonic, cyclic and non-proportional loading behavior in a general rate and their applications to metals and soils are described in detail, and constitutive equations of friction behavior between solids and its application to the prediction of stick-slip phenomena are delineated. In additi...
Helms, Lester L
2014-01-01
Potential Theory presents a clear path from calculus to classical potential theory and beyond, with the aim of moving the reader into the area of mathematical research as quickly as possible. The subject matter is developed from first principles using only calculus. Commencing with the inverse square law for gravitational and electromagnetic forces and the divergence theorem, the author develops methods for constructing solutions of Laplace's equation on a region with prescribed values on the boundary of the region. The latter half of the book addresses more advanced material aimed at those with the background of a senior undergraduate or beginning graduate course in real analysis. Starting with solutions of the Dirichlet problem subject to mixed boundary conditions on the simplest of regions, methods of morphing such solutions onto solutions of Poisson's equation on more general regions are developed using diffeomorphisms and the Perron-Wiener-Brelot method, culminating in application to Brownian motion. In ...
2015-01-01
A one-sentence definition of operator theory could be: The study of (linear) continuous operations between topological vector spaces, these being in general (but not exclusively) Fréchet, Banach, or Hilbert spaces (or their duals). Operator theory is thus a very wide field, with numerous facets, both applied and theoretical. There are deep connections with complex analysis, functional analysis, mathematical physics, and electrical engineering, to name a few. Fascinating new applications and directions regularly appear, such as operator spaces, free probability, and applications to Clifford analysis. In our choice of the sections, we tried to reflect this diversity. This is a dynamic ongoing project, and more sections are planned, to complete the picture. We hope you enjoy the reading, and profit from this endeavor.
Stein, Irene F.; Stelter, Reinhard
2011-01-01
ascribe specific meanings to their experiences, their actions in life or work, and their interactions. Meaning is reshaped, adapted, and transformed in every communication encounter. Furthermore, meaning is cocreated in dialogues or in communities of practice, such as in teams at a workplace or in school......Communication theory covers a wide variety of theories related to the communication process (Littlejohn, 1999). Communication is not simply an exchange of information, in which we have a sender and a receiver. This very technical concept of communication is clearly outdated; a human being...... is not a data processing device. In this chapter, communication is understood as a process of shared meaning-making (Bruner, 1990). Human beings interpret their environment, other people, and themselves on the basis of their dynamic interaction with the surrounding world. Meaning is essential because people...
Milgrom, Mordehai
2014-01-01
A general account of MOND theory is given. I start with the basic tenets of MOND, which posit departure from standard dynamics in the limit of low acceleration -- below an acceleration constant a0 -- where dynamics become scale invariant. I list some of the salient predictions of these tenets. The special role of a0 and its significance are then discussed. In particular, I stress its coincidence with cosmologically relevant accelerations. The deep-MOND limit and the consequences of its scale ...
Petrosjan, L A
1996-01-01
Game theory is a branch of modern applied mathematics that aims to analyze various problems of conflict between parties that have opposed, similar or simply different interests.Games are grouped into several classes according to some important features. In this volume zero-sum two-person games, strategic n-person games in normal form, cooperative games, games in extensive form with complete and incomplete information, differential pursuit games and differential cooperative n-person games are considered.
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
Blyth, T S; Sneddon, I N; Stark, M
1972-01-01
Residuation Theory aims to contribute to literature in the field of ordered algebraic structures, especially on the subject of residual mappings. The book is divided into three chapters. Chapter 1 focuses on ordered sets; directed sets; semilattices; lattices; and complete lattices. Chapter 2 tackles Baer rings; Baer semigroups; Foulis semigroups; residual mappings; the notion of involution; and Boolean algebras. Chapter 3 covers residuated groupoids and semigroups; group homomorphic and isotone homomorphic Boolean images of ordered semigroups; Dubreil-Jacotin and Brouwer semigroups; and loli
Diestel, Reinhard
2012-01-01
HauptbeschreibungThis standard textbook of modern graph theory, now in its fourth edition, combinesthe authority of a classic with the engaging freshness of style that is the hallmarkof active mathematics. It covers the core material of the subject with concise yetreliably complete proofs, while offering glimpses of more advanced methodsin each field by one or two deeper results, again with proofs given in full detail.The book can be used as a reliable text for an introductory course, as a graduatetext, and for self-study. Rezension"Deep, clear, wonderful. This is a serious book about the
This book is divided into fourteen chapters, which deals with circuit theory of basis, sinusoidal alternating current on cycle and frequency, basics current circuit about R.L, C circuit and resonant circuit, current power, general linear circuit, inductive coupling circuit and vector locus on an alternating current bridge and mutual inductance and coupling coefficient, multiphase alternating current and method of symmetrical coordinates, non-sinusoidal alternating current, two terminal network, four terminal network, transient of circuits, distributed line circuit constant, frequency characteristic and a filter and Laplace transformation.
Techniques used in conventional project appraisal are mathematically very simple in comparison to those used in reservoir modelling, and in the geosciences. Clearly it would be possible to value assets in mathematically more sophisticated ways if it were meaningful and worthwhile so to do. The DCf approach in common use has recognized limitations; the inability to select a meaningful discount rate being particularly significant. Financial Theory has advanced enormously over the last few years, along with computational techniques, and methods are beginning to appear which may change the way we do project evaluations in practice. The starting point for all of this was a paper by Black and Scholes, which asserts that almost all corporate liabilities can be viewed as options of varying degrees of complexity. Although the financial presentation may be unfamiliar to engineers and geoscientists, some of the concepts used will not be. This paper outlines, in plain English, the basis of option pricing theory for assessing the market value of a project. it also attempts to assess the future role of this type of approach in practical Petroleum Exploration and Engineering economics. Reference is made to relevant published Natural Resource literature
With reference to highly debated sustainable growth strategies to counter pressing interrelated global environmental and socio-economic problems, this paper reviews economic and resource development theories proposed by classical and neoclassical economists. The review evidences the growing debate among public administration decision makers regarding appropriate methods to assess the worth of natural resources and ecosystems. Proposed methods tend to be biased either towards environmental protection or economic development. Two major difficulties in the effective implementation of sustainable growth strategies are also evidenced - the management of such strategies would require appropriate revisions to national accounting systems, and the dynamic flow of energy and materials between an economic system and the environment would generate a sequence of unstable structures evolving in a chaotic and unpredictable way
St-Amant, Patrick
2010-01-01
We will see that key concepts of number theory can be defined for arbitrary operations. We give a generalized distributivity for hyperoperations (usual arithmetic operations and operations going beyond exponentiation) and a generalization of the fundamental theorem of arithmetic for hyperoperations. We also give a generalized definition of the prime numbers that are associated to an arbitrary n-ary operation and take a few steps toward the development of its modulo arithmetic by investigating a generalized form of Fermat's little theorem. Those constructions give an interesting way to interpret diophantine equations and we will see that the uniqueness of factorization under an arbitrary operation can be linked with the Riemann zeta function. This language of generalized primes and composites can be used to restate and extend certain problems such as the Goldbach conjecture.
Diestel, Reinhard
2000-01-01
This book is a concise, yet carefully written, introduction to modern graph theory, covering all its major recent developments. It can be used both as a reliable textbook for an introductory course and as a graduate text: on each topic it covers all the basic material in full detail, and adds one or two deeper results (again with detailed proofs) to illustrate the more advanced methods of that field. This second edition extends the first in two ways. It offers a thoroughly revised and updated chapter on graph minors, which now includes full new proofs of two of the central Robertson-Seymour theorems (as well as a detailed sketch of the entire proof of their celebrated Graph Minor Theorem). Second, there is now a section of hints for all the exercises, to enhance their value for both individual study and classroom use.
Chong, Chi Tat; Friedman, Sy D.
1996-01-01
In this article, intended for the Handbook of Recursion Theory, we survey recursion theory on the ordinal numbers, with sections devoted to $\\alpha$-recursion theory, $\\beta$-recursion theory and the study of the admissibility spectrum.
Polchinski, Joseph
1994-01-01
The first part is an introduction to conformal field theory and string perturbation theory. The second part deals with the search for a deeper answer to the question posed in the title. Contents: 1. Conformal Field Theory 2. String Theory 3. Vacua and Dualities 4. String Field Theory or Not String Field Theory 5. Matrix Models
This chapter presents the basic principles of cluster dynamics as a particular case of mesoscopic rate theory models developed to investigate fuel behaviour under irradiation such as in UO2. It is shown that as this method simulates the evolution of the concentration of every type of point or aggregated defect in a grain of material. It produces rich information that sheds light on the mechanisms involved in microstructure evolution and gas behaviour that are not accessible through conventional models but yet can provide for improvements in those models. Cluster dynamics parameters are mainly the energetic values governing the basic evolution mechanisms of the material (diffusion, trapping and thermal resolution). In this sense, the model has a general applicability to very different operational situations (irradiation, ion-beam implantation, annealing) provided that they rely on the same basic mechanisms, without requiring additional data fitting, as is required for more empirical conventional models. This technique, when applied to krypton implanted and annealed samples, yields a precise interpretation of the release curves and helps assess migration mechanisms and the krypton diffusion coefficient, for which data is very difficult to obtain due to the low solubility of the gas. (authors)
THEORIES OF CORPORATE GOVERNANCE
Sorin Nicolae BORLEA
2013-03-01
Full Text Available This study attempts to provide a theoretical framework for the corporate governance debate. The review of various corporate governance theories enhances the major objective of corporate governance which is maximizing the value for shareholders by ensuring good social and environment performances. The theories of corporate governance are rooted in agency theory with the theory of moral hazard’s implications, further developing within stewardship theory and stakeholder theory and evolving at resource dependence theory, transaction cost theory and political theory. Later, to these theories was added ethics theory, information asymmetry theory or the theory of efficient markets. These theories are defined based on the causes and effects of variables such as: the configuration of the board of directors, audit committee, independence of managers, the role of top management and their social relations beyond the legal regulatory framework. Effective corporate governance requires applying a combination
Theory and Vocational Education.
Swanson, Gordon I.
1988-01-01
The search for an explanation of day-to-day problems is the appropriate framework for describing theory. Theory and research have reciprocal relationships: Theory gives direction to research and research refines theory. Vocational education occurs in the context of many theoretical frames. Understanding this theory relatedness is important to…
Copter: Cosmological perturbation theory
Carlson, Jordan
2013-04-01
Copter is a software package for doing calculations in cosmological perturbation theory. Specifically, Copter includes code for computing statistical observables in the large-scale structure of matter using various forms of perturbation theory, including linear theory, standard perturbation theory, renormalized perturbation theory, and many others. Copter is written in C++ and makes use of the Boost C++ library headers.
de Boer, Jan
2002-01-01
An overview of some of the developments in string theory over the past two years is given, focusing on four topics: realistic (standard model like) models from string theory, geometric engineering and theories with fluxes, the gauge theory-gravity correspondence, and time dependent backgrounds and string theory. Plenary talk at ICHEP'02, Amsterdam, July 24-31, 2002.
K-theory and representation theory
This contribution includes K-theory of orders, group-rings and modules over EI categories, equivariant higher algebraic K-theory for finite, profinite and compact Lie group actions together with their relative generalisations and applications
Intuitionistic fixed point theories over set theories
Arai, Toshiyau
2013-01-01
In this paper we show that the intuitionistic fixed point theory FiX^{i}(X) over set theories T is a conservative extension of T if T can manipulate finite sequences and has the full foundation schema.
Quasi-stars and the Sch\\"onberg-Chandrasekhar limit
Ball, Warrick H
2012-01-01
The mechanism by which the supermassive black holes that power bright quasars at high redshift form remains unknown. One possibility is that ... the monolithic collapse of a massive protogalactic disc ... leads to the formation of a quasi-star: a growing black hole, initially of typical stellar-mass, embedded in a hydrostatic giant-like envelope. Quasi-stars are the main object of study in this dissertation. ... In Chapter 1, I introduce the problem posed by the supermassive black holes that power high-redshift quasars. ... In Chapter 2, I outline the Cambridge STARS code and the modifications that are made to model quasi-star envelopes. In Chapter 3, I present models of quasi-stars where the base of the envelope is located at the Bondi radius of the black hole. The black holes in these models are subject to a robust upper fractional mass limit of about one tenth. In addition, the final black hole mass is sensitive to the choice of the inner boundary radius of the envelope. In Chapter 4, I construct alternati...
'Super-Chandrasekhar' Type Ia Supernovae at nebular epochs
Taubenberger, Stefan; Hachinger, Stephan; Mazzali, Paolo A; Benetti, Stefano; Nugent, Peter E; Scalzo, Richard A; Pakmor, Rüdiger; Stanishev, Vallery; Spyromilio, Jason; Bufano, Filomena; Sim, Stuart A; Leibundgut, Bruno; Hillebrandt, Wolfgang
2013-01-01
We present a first systematic comparison of superluminous Type Ia supernovae (SNe Ia) at late epochs, including previously unpublished photometric and spectroscopic observations of SN 2007if, SN 2009dc and SNF20080723-012. Photometrically, the objects of our sample show a diverse late-time behaviour, some of them fading quite rapidly after a light-curve break at ~150-200d. The latter is likely the result of flux redistribution into the infrared, possibly caused by dust formation, rather than a true bolometric effect. Nebular spectra of superluminous SNe Ia are characterised by weak or absent [Fe III] emission, pointing at a low ejecta ionisation state as a result of high densities. To constrain the ejecta and 56Ni masses of superluminous SNe Ia, we compare the observed bolometric light curve of SN 2009dc with synthetic model light curves, focusing on the radioactive tail after ~60d. Models with enough 56Ni to explain the light-curve peak by radioactive decay, and at the same time sufficient mass to keep the e...
Decidability of formal theories and hyperincursivity theory
Grappone, Arturo G.
2000-05-01
This paper shows the limits of the Proof Standard Theory (briefly, PST) and gives some ideas of how to build a proof anticipatory theory (briefly, PAT) that has no such limits. Also, this paper considers that Gödel's proof of the undecidability of Principia Mathematica formal theory is not valid for axiomatic theories that use a PAT to build their proofs because the (hyper)incursive functions are self-representable.
Guerra, Francesco
2005-01-01
A coincise review about Euclidean (Quantum) Field Theory is presented. It deals with the general structural properties, the connections with Quantum Field Theory, the exploitation in Constructive Quantum Field Theory, and the physical interpretation.
Decoding the architectural theory
Gu Mengchao
2008-01-01
Starting from the illustration of the definition and concept of the architectural theory, the author established his unique understanding about the framework of the architectural theory and the innovation of the architectural theory underlined by Chinese characteristics.
Review of Hydroelasticity Theories
Chen, Xu-jun; Wu, You-sheng; Cui, Wei-cheng;
2006-01-01
Existing hydroelastic theories are reviewed. The theories are classified into different types: two-dimensional linear theory, two-dimensional nonlinear theory, three-dimensional linear theory and three-dimensional nonlinear theory. Applications to analysis of very large floating structures (VLFS)......) are reviewed and discussed in details. Special emphasis is placed on papers from China and Japan (in native languages) as these papers are not generally publicly known in the rest of the world....
THEORIES OF CORPORATE GOVERNANCE
Sorin Nicolae BORLEA; Monica-Violeta ACHIM
2013-01-01
This study attempts to provide a theoretical framework for the corporate governance debate. The review of various corporate governance theories enhances the major objective of corporate governance which is maximizing the value for shareholders by ensuring good social and environment performances. The theories of corporate governance are rooted in agency theory with the theory of moral hazard’s implications, further developing within stewardship theory and stakeholder theory and evolving at re...
Foundations for a theory of gravitation theories
Thorne, K. S.; Lee, D. L.; Lightman, A. P.
1972-01-01
A foundation is laid for future analyses of gravitation theories. This foundation is applicable to any theory formulated in terms of geometric objects defined on a 4-dimensional spacetime manifold. The foundation consists of (1) a glossary of fundamental concepts; (2) a theorem that delineates the overlap between Lagrangian-based theories and metric theories; (3) a conjecture (due to Schiff) that the Weak Equivalence Principle implies the Einstein Equivalence Principle; and (4) a plausibility argument supporting this conjecture for the special case of relativistic, Lagrangian-based theories.
Supersymmetric Gauge Theories from String Theory
Metzger, Steffen
2005-01-01
The subject of this thesis are various ways to construct four-dimensional quantum field theories from string theory. In a first part we study the generation of a supersymmetric Yang-Mills theory, coupled to an adjoint chiral superfield, from type IIB string theory on non-compact Calabi-Yau manifolds, with D-branes wrapping certain subcycles. Properties of the gauge theory are then mapped to the geometric structure of the Calabi-Yau space. In particular, the low energy effective superpotential...
New Trade Theory Takes Over Monetary Theory
Gani, M.
2004-01-01
Prevailing trade theory is a neglected stepchild of economics. Micro rejects the sole reason for trade’s occurrence. It declares zero profit in equilibrium. Monetary theory and macroeconomics dismiss concerns of trade financing. They assert that money has nothing to do with traded output, but everything to do with storing value. But now a new trade theory takes over monetary theory, by reducing money into a mere tool of trade, as just a means of payment. It takes over theory of exchange, abol...
The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references
Jardine, John F
2015-01-01
This monograph on the homotopy theory of topologized diagrams of spaces and spectra gives an expert account of a subject at the foundation of motivic homotopy theory and the theory of topological modular forms in stable homotopy theory. Beginning with an introduction to the homotopy theory of simplicial sets and topos theory, the book covers core topics such as the unstable homotopy theory of simplicial presheaves and sheaves, localized theories, cocycles, descent theory, non-abelian cohomology, stacks, and local stable homotopy theory. A detailed treatment of the formalism of the subject is interwoven with explanations of the motivation, development, and nuances of ideas and results. The coherence of the abstract theory is elucidated through the use of widely applicable tools, such as Barr's theorem on Boolean localization, model structures on the category of simplicial presheaves on a site, and cocycle categories. A wealth of concrete examples convey the vitality and importance of the subject in topology, n...
Rationality, Theory Acceptance and Decision Theory
J. Nicolas Kaufmann
1998-06-01
Full Text Available Following Kuhn's main thesis according to which theory revision and acceptance is always paradigm relative, I propose to outline some possible consequences of such a view. First, asking the question in what sense Bayesian decision theory could serve as the appropriate (normative theory of rationality examined from the point of view of the epistemology of theory acceptance, I argue that Bayesianism leads to a narrow conception of theory acceptance. Second, regarding the different types of theory revision, i.e. expansion, contraction, replacement and residuals shifts, I extract from Kuhn's view a series of indications showing that theory replacement cannot be rationalized within the framework of Bayesian decision theory, not even within a more sophisticated version of that model. Third, and finally, I will point to the need for a more comprehensive model of rationality than the Bayesian expected utility maximization model, the need for a model which could better deal with the different aspects of theory replacement. I will show that Kuhn's distinction between normal and revolutionary science gives us several hints for a more adequate theory of rationality in science. I will also show that Kuhn is not in a position to fully articulate his main ideas and that he well be confronted with a serious problem concerning collective choice of a paradigm.
de Bruin, B.P.
2005-01-01
Game theory is the mathematical study of strategy and conflict. It has wide applications in economics, political science, sociology, and, to some extent, in philosophy. Where rational choice theory or decision theory is concerned with individual agents facing games against nature, game theory deals
Moschovakis, YN
1987-01-01
Now available in paperback, this monograph is a self-contained exposition of the main results and methods of descriptive set theory. It develops all the necessary background material from logic and recursion theory, and treats both classical descriptive set theory and the effective theory developed by logicians.
Hendricks, Vincent F.
Game Theory is a collection of short interviews based on 5 questions presented to some of the most influential and prominent scholars in game theory. We hear their views on game theory, its aim, scope, use, the future direction of game theory and how their work fits in these respects....
Lassig, Michael
2011-01-01
A systematic theory is introduced that describes stochastic effects in game theory. In a biological context, such effects are relevant for the evolution of finite populations with frequency-dependent selection. They are characterized by quantum Nash equilibria, a generalization of the well-known Nash equilibrium points in classical game theory. The implications of this theory for biological systems are discussed in detail.
't Hooft, Gerardus; Witten, Edward
2005-01-01
In his later years, Einstein sought a unified theory that would extend general relativity and provide an alternative to quantum theory. There is now talk of a "theory of everything"; fifty years after his death, how close are we to such a theory? (3 pages)
Bursa, Francis; Kroyter, Michael
2010-01-01
String field theory is a candidate for a full non-perturbative definition of string theory. We aim to define string field theory on a space-time lattice to investigate its behaviour at the quantum level. Specifically, we look at string field theory in a one dimensional linear dilaton background. We report the first results of our simulations.
梁景宏
2010-01-01
In this essay, I wish to invite young scholars to learn, use, and contribute to accounting theory. In this invitation, I argue theory has lineage, is important and can be fun. Its lineage comes from the post-WWII scientific revolution in management education and research. Theory is important because it is the successful interaction between theory and empirical work that ultimately advances an academic discipline. Theory can be fun because when done well, learning, using and contributing to theory can be an enjoyable activity for all scholars, either as consumers or as producers of theory.
Zimmerman Jones, Andrew
2010-01-01
Making Everything Easier!. String Theory for Dummies. Learn:. The basic concepts of this controversial theory;. How string theory builds on physics concepts;. The different viewpoints in the field;. String theory's physical implications. Andrew Zimmerman Jones. Physics Guide, About.com. with Daniel Robbins, PhD in Physics. Your plain-English guide to this complex scientific theory. String theory is one of the most complicated sciences being explored today. Not to worry though! This informative guide clearly explains the basics of this hot topic, discusses the theory's hypotheses and prediction
Quantum Theory is an Information Theory
D'Ariano, Giacomo M.; Perinotti, Paolo
2016-03-01
In this paper we review the general framework of operational probabilistic theories (OPT), along with the six axioms from which quantum theory can be derived. We argue that the OPT framework along with a relaxed version of five of the axioms, define a general information theory. We close the paper with considerations about the role of the observer in an OPT, and the interpretation of the von Neumann postulate and the Schrödinger-cat paradox.
无
2003-01-01
The basic ideas of game theory were originated from the problems of maximum and minimum given by J.Yon Neumann in 1928. Later, wars accelerated the study of game theory, there are many developments that contributed to the advancement of game theory, many problems of optimum appeared in economic development process. Scientists applied mathematic methods to studying game theory to make the theory more profound and perfect. The axiomatic structure of game theory was nearly complete in 1944. The path of the development of game theory started from finite to infinite, from two players to many players, from expressing gains with quantity to showing the ending of game theory with abstract result, and from certainty problems to random problems. Thus development of game theory is closely related to the economic development. In recent years, the research on the non-differentiability of Shapley value posed by Belgian Mertens is one of the advanced studies in game theory.
Gauge theory loop operators and Liouville theory
We propose a correspondence between loop operators in a family of four dimensional N=2 gauge theories on S4 - including Wilson, 't Hooft and dyonic operators - and Liouville theory loop operators on a Riemann surface. This extends the beautiful relation between the partition function of these N=2 gauge theories and Liouville correlators found by Alday, Gaiotto and Tachikawa. We show that the computation of these Liouville correlators with the insertion of a Liouville loop operator reproduces Pestun's formula capturing the expectation value of a Wilson loop operator in the corresponding gauge theory. We prove that our definition of Liouville loop operators is invariant under modular transformations, which given our correspondence, implies the conjectured action of S-duality on the gauge theory loop operators. Our computations in Liouville theory make an explicit prediction for the exact expectation value of 't Hooft and dyonic loop operators in these N=2 gauge theories. The Liouville loop operators are also found to admit a simple geometric interpretation within quantum Teichmueller theory as the quantum operators representing the length of geodesics. We study the algebra of Liouville loop operators and show that it gives evidence for our proposal as well as providing definite predictions for the operator product expansion of loop operators in gauge theory. (orig.)
Nonrelativistic closed string theory
Gomis, Jaume; Ooguri, Hirosi
2001-01-01
We construct a Galilean invariant nongravitational closed string theory whose excitations satisfy a nonrelativistic dispersion relation. This theory can be obtained by taking a consistent low energy limit of any of the conventional string theories, including the heterotic string. We give a finite first order worldsheet Hamiltonian for this theory and show that this string theory has a sensible perturbative expansion, interesting high energy behavior of scattering amplitudes and a Hagedorn tra...
Conlon, Joseph
2016-01-01
Is string theory a fraud or one of the great scientific advances? Why do so many physicists work on string theory if it cannot be tested? This book provides insight into why such a theory, with little direct experimental support, plays such a prominent role in theoretical physics. The book gives a modern and accurate account of string theory and science, explaining what string theory is, why it is regarded as so promising, and why it is hard to test.
Ali Rabbani Khorasghani; Mohammad Abbaszadeh
2010-01-01
AbstractAccording to social changes in global level, social scientist introduced new theories to explanation of socialphenomena. According to appearance new theories, research methods have changed. The Idea is that,Simultaneity with Appearance post positivist theories, research approaches such a grounded theory hasestablished. This method, acts in the base of qualitative methods and use systematic complex of multipleProcedures to gathering data for theory development upon induction. This meth...
Uniformly hyperbolic control theory
Kawan, Christoph
2015-01-01
This paper gives a summary of a body of work at the intersection of control theory and smooth nonlinear dynamics. The main idea is to transfer the concept of uniform hyperbolicity, central to the theory of smooth dynamical systems, to control-affine systems. Combining the strength of geometric control theory and the hyperbolic theory of dynamical systems, it is possible to deduce control-theoretic results of non-local nature that reveal remarkable analogies to the classical hyperbolic theory ...
Teaching Theory X and Theory Y in Organizational Communication
Noland, Carey
2014-01-01
The purpose of the activity described here is to integrate McGregor's Theory X and Theory Y into a group application: design a syllabus that embodies either Theory X or Theory Y tenets. Students should be able to differentiate between Theory X and Theory Y, create a syllabus based on Theory X or Theory Y tenets, evaluate the different syllabi…
Elements of a theory of algebraic theories
Hyland, Martin
2013-01-01
Kleisli bicategories are a natural environment in which the combinatorics involved in various notions of algebraic theory can be handled in a uniform way. The setting allows a clear account of comparisons between such notions. Algebraic theories, symmetric operads and nonsymmetric operads are treated as examples.
[Topics in field theory and string theory
In the past year, I have continued to investigate the relations between conformal field theories and lattice statistical mechanical models. I have also tried to extend some of these results to higher dimensions and to find applications in string theories and other contexts
Generalizability theory and item response theory
Glas, C.A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.
2012-01-01
Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a s
Fabris, J C
2015-01-01
General Relativity is the modern theory of gravitation. It has replaced the newtonian theory in the description of the gravitational phenomena. In spite of the remarkable success of the General Relativity Theory, the newtonian gravitational theory is still largely employed, since General Relativity, in most of the cases, just makes very small corrections to the newtonian predictions. Moreover, the newtonian theory is much simpler, technically and conceptually, when compared to the relativistic theory. In this text, we discuss the possibility of extending the traditional newtonian theory in order to incorporate typical relativistic effects, but keeping the simplicity of the newtonian framework. We denominate these extensions neo-newtonian theories. These theories are discussed mainly in the contexts of cosmology and compact astrophysical objects.
Ali Rabbani Khorasghani
2010-01-01
Full Text Available AbstractAccording to social changes in global level, social scientist introduced new theories to explanation of socialphenomena. According to appearance new theories, research methods have changed. The Idea is that,Simultaneity with Appearance post positivist theories, research approaches such a grounded theory hasestablished. This method, acts in the base of qualitative methods and use systematic complex of multipleProcedures to gathering data for theory development upon induction. This method with characteristics as ifflexibility, reflexivity, has caused many of researchers used it. In the present article, we paid to introductionof grounded theory and its critics.
Regina Szylit Bousso
2014-02-01
Full Text Available The theory framework of nursing science is built in a dynamic process that arises from practice and is reproduced through research, mainly by analysis and development of concepts and theories. This study presents a theory reflection on nursing knowledge construction and points out subsidies for future studies in the area. The interrelation among theory, research, and clinical practice is required for continuous development of nursing as a profession and science. Ideally, the practice must be based on theory that is validated by research. Therefore, theory, research, and practice affect each other reciprocally and continuously.
Supersymmetric gauge theories from string theory
This thesis presents various ways to construct four-dimensional quantum field theories from string theory. In a first part we study the generation of a supersymmetric Yang-Mills theory, coupled to an adjoint chiral superfield, from type IIB string theory on non-compact Calabi-Yau manifolds, with D-branes wrapping certain sub-cycles. Properties of the gauge theory are then mapped to the geometric structure of the Calabi-Yau space. Even if the Calabi-Yau geometry is too complicated to evaluate the geometric integrals explicitly, one can then always use matrix model perturbation theory to calculate the effective superpotential. The second part of this work covers the generation of four-dimensional super-symmetric gauge theories, carrying several important characteristic features of the standard model, from compactifications of eleven-dimensional supergravity on G2-manifolds. If the latter contain conical singularities, chiral fermions are present in the four-dimensional gauge theory, which potentially lead to anomalies. We show that, locally at each singularity, these anomalies are cancelled by the non-invariance of the classical action through a mechanism called 'anomaly inflow'. Unfortunately, no explicit metric of a compact G2-manifold is known. Here we construct families of metrics on compact weak G2-manifolds, which contain two conical singularities. Weak G2-manifolds have properties that are similar to the ones of proper G2-manifolds, and hence the explicit examples might be useful to better understand the generic situation. Finally, we reconsider the relation between eleven-dimensional supergravity and the E8 x E8-heterotic string. This is done by carefully studying the anomalies that appear if the supergravity theory is formulated on a ten-manifold times the interval. Again we find that the anomalies cancel locally at the boundaries of the interval through anomaly inflow, provided one suitably modifies the classical action. (author)
Introduction to percolation theory
Stauffer, Dietrich
1991-01-01
Percolation theory deals with clustering, criticallity, diffusion, fractals, phase transitions and disordered systems. This book covers the basic theory for the graduate, and also professionals dealing with it for the first time
Covariant Noncommutative Field Theory
The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced
Clemmensen, Torkil; Kaptelinin, Victor; Nardi, Bonnie
2016-01-01
This paper reports a study of the use of activity theory in human–computer interaction (HCI) research. We analyse activity theory in HCI since its first appearance about 25 years ago. Through an analysis and meta-synthesis of 109 selected HCI activity theory papers, we created a taxonomy of 5...... different ways of using activity theory: (1) analysing unique features, principles, and problematic aspects of the theory; (2) identifying domain-specific requirements for new theoretical tools; (3) developing new conceptual accounts of issues in the field of HCI; (4) guiding and supporting empirical...... analyses of HCI phenomena; and (5) providing new design illustrations, claims, and guidelines. We conclude that HCI researchers are not only users of imported theory, but also theory-makers who adapt and develop theory for different purposes....
Combinatorics and field theory
Bender, Carl M.; Brody, Dorje C.; Meister, Bernhard K.
2006-01-01
For any given sequence of integers there exists a quantum field theory whose Feynman rules produce that sequence. An example is illustrated for the Stirling numbers. The method employed here offers a new direction in combinatorics and graph theory.
Farmer, David W.
2004-01-01
Comment: 11 pages, to appear in the proceedings of the school ``Recent Perspectives in Random Matrix Theory and Number Theory'' held at the Isaac Newton Institute, April 2004. Added appendix on big-O and
Zielenkiewicz, Wojciech
2004-01-01
The purpose of this book is to give a comprehensive description of the theoretical fundamentals of calorimetry. The considerations are based on the relations deduced from the laws and general equations of heat exchange theory and steering theory.
Theories of Career Development. A Comparison of the Theories.
Osipow, Samuel H.
These seven theories of career development are examined in previous chapters: (1) Roe's personality theory, (2) Holland's career typology theory, (3) the Ginzberg, Ginsburg, Axelrod, and Herma Theory, (4) psychoanalytic conceptions, (5) Super's developmental self-concept theory, (6) other personality theories, and (7) social systems theories.…
Quantum algorithmic information theory
Svozil, Karl
1995-01-01
The agenda of quantum algorithmic information theory, ordered `top-down,' is the quantum halting amplitude, followed by the quantum algorithmic information content, which in turn requires the theory of quantum computation. The fundamental atoms processed by quantum computation are the quantum bits which are dealt with in quantum information theory. The theory of quantum computation will be based upon a model of universal quantum computer whose elementary unit is a two-port interferometer capa...
We begin with a general discussion of topological field theories, their defining properties, and classification. The first model we consider in detail (section 3) is supersymmetric quantum mechanics. Topological sigma models, their observables, and the associated mathematics of complex geometry and intersection theory are presented in section 4. Following this, topological gauge theories are discussed in section 5, with particular emphasis on Donaldson theory. The matematics here is necessarily much more sophisticated than at any other point in this report, and to bridge this gap, a mathematical review of gauge theory and moduli spaces has been included. An analysis of the geometry underlying Donaldson theory gives a general recipe for constructing field theories associated to moduli spaces in arbitrary dimensions, and as an example, we analyze in detail the super BF theories associated with flat connections. Chern-Simons theory and related BF models are the subject of section 6. The connections with knot theory are briefly reviewed and the link with 2D conformal field theory is sketched. We also consider 3D gravity from the Chern-Simons point of view. A presentation of the metric and gauge theory approaches to topological gravity in two dimensions is given. As in all quantum field theories, the issues of renormalization needs to be addressed, and one is obliged to show that the formal topological properties of these theories survive quantization. This point is considered in section 8. We present a detailed analysis of the beta function in certain Witten type theories, and compute one-loop effects in Chern-Simons theory. (orig./HSI)
Birmingham, D. (CERN, Geneva (Switzerland). Theory Div.); Blau, M. (CNRS, 13 - Marseille (France). Centre de Physique Theorique NIKHEF-H, Amsterdam (Netherlands)); Rakowski, M.; Thompson, G. (Mainz Univ. (Germany). Inst. fuer Physik)
1991-12-01
We begin with a general discussion of topological field theories, their defining properties, and classification. The first model we consider in detail (section 3) is supersymmetric quantum mechanics. Topological sigma models, their observables, and the associated mathematics of complex geometry and intersection theory are presented in section 4. Following this, topological gauge theories are discussed in section 5, with particular emphasis on Donaldson theory. The matematics here is necessarily much more sophisticated than at any other point in this report, and to bridge this gap, a mathematical review of gauge theory and moduli spaces has been included. An analysis of the geometry underlying Donaldson theory gives a general recipe for constructing field theories associated to moduli spaces in arbitrary dimensions, and as an example, we analyze in detail the super BF theories associated with flat connections. Chern-Simons theory and related BF models are the subject of section 6. The connections with knot theory are briefly reviewed and the link with 2D conformal field theory is sketched. We also consider 3D gravity from the Chern-Simons point of view. A presentation of the metric and gauge theory approaches to topological gravity in two dimensions is given. As in all quantum field theories, the issues of renormalization needs to be addressed, and one is obliged to show that the formal topological properties of these theories survive quantization. This point is considered in section 8. We present a detailed analysis of the beta function in certain Witten type theories, and compute one-loop effects in Chern-Simons theory. (orig./HSI).
A survey of the present state of fission theory is attempted. The basic requirements of a theory of a physical process are outlined and against this background the state of fission theory is summarized, with special emphasis on developments in the past few years. An attempt is made to bring out the most important outstanding problems to be settled by future experiments and theory. (author)
Güth, Werner
2000-01-01
Whereas orthodox game theory relies on the unrealistic assumption of (commonly known) perfect rationality, participants in game playing experiments are at best boundedly rational. This makes it necessary to supplement orthodox game theory by a behavioral theory of game playing. We first point out that this applies also to (one person-) decision theory. After reviewing the influential experiments based on repeated games and the ultimatum game the typical reactions to the striking experimental ...
Linker, Patrick
2016-01-01
A couple of quantum gravity theories were proposed to make theoretical predictions about the behavior of gravity. The most recent approach to quantum gravity, called E-theory, is proposed mathematical, but there is not formulated much about what dynamics of gravity this theory proposes. This research paper treats the main results of the application of E-theory to General relativity involving conservation laws and scattering of particles in presence of gravity. Also the low-energy limit of thi...
Areas of emphasis include acceleration algorithms for the Monte Carlo analysis of lattice field and gauge theories, quaternionic generalizations of complex quantum mechanics and field theory, application of the renormalization group to the QCD phase transition, the quantum Hall effect, and black holes. Other work involved string theory, statistical properties of energy levels in integrable quantum systems, baryon asymmetry and the electroweak phase transition, anisotropies of the cosmic microwave background, and theory of superconductors
Vygotsky theories & meaningful relationships
Robert, Michelle Suzanne
2005-01-01
This Project contains two main topics: "The Vygotsky Theories" and "Meaningful Relationships". Both were selected to be taught to teachers, principals, managing officials and supervisors in Mexico's context, all of which will be done in workshops under my supervision and care. The first theme: "The Vygotsky's Theories" explains his Theories and Notions on "Early Childhood Education", "Social Development Theory"; "Learning and Development of Preschool Children" and "The Zone of Proximal Develo...
Combustion theory and modeling
Buckmaster, J; Clavin, Paul; Liñán Martínez, Amable; Matalon, M.; Peters, N; Sivashinsky, G.; Williams, F. A.
2005-01-01
In honor of the fiftieth anniversary of the Combustion Institute, we are asked to assess accomplishments of theory in combustion over the past fifty years and prospects for the future. The title of our article is chosen to emphasize that development of theory necessarily goes hand-in-hand with specification of a model. Good conceptual models underlie successful mathematical theories. Models and theories are discussed here for deflagrations, detonations, diffusion flames, ignition, propellant ...
Thulasiraman, K
2011-01-01
This adaptation of an earlier work by the authors is a graduate text and professional reference on the fundamentals of graph theory. It covers the theory of graphs, its applications to computer networks and the theory of graph algorithms. Also includes exercises and an updated bibliography.
Comparing Measurement Theories.
Schumacker, Randall E.
In comparing measurement theories, it is evident that the awareness of the concept of measurement error during the time of Galileo has lead to the formulation of observed scores comprising a true score and error (classical theory), universe score and various random error components (generalizability theory), or individual latent ability and error…
Positioning Theory in Paradigms
FU Xiao-qiu
2015-01-01
This article discusses the importance of theory and paradigm to a researcher. It starts from introducing and analyzing the definition of the two terms, by using the theories in the field of intercultural communication as examples. To a good researcher, he needs not only clarifying the paradigm his research is positioned, but also integrating the theories in his paradigm.
Reflections on Activity Theory
Bakhurst, David
2009-01-01
It is sometimes suggested that activity theory represents the most important legacy of Soviet philosophy and psychology. But what exactly "is" activity theory? The canonical account in the West is given by Engestrom, who identifies three stages in the theory's development: from Vygotsky's insights, through Leontiev's articulation of the…
Battenfeld, Ingo
2008-01-01
This thesis presents Topological Domain Theory as a powerful and flexible framework for denotational semantics. Topological Domain Theory models a wide range of type constructions and can interpret many computational features. Furthermore, it has close connections to established frameworks for denotational semantics, as well as to well-studied mathematical theories, such as topology and computable analysis.
Andersen, Jack
2015-01-01
Purpose To provide a small overview of genre theory and its associated concepts and to show how genre theory has had its antecedents in certain parts of the social sciences and not in the humanities. Findings The chapter argues that the explanatory force of genre theory may be explained with its ...
Constructivist Grounded Theory?
Barney G. Glaser, PhD, Hon. PhD
2012-06-01
Full Text Available AbstractI refer to and use as scholarly inspiration Charmaz’s excellent article on constructivist grounded theory as a tool of getting to the fundamental issues on why grounded theory is not constructivist. I show that constructivist data, if it exists at all, is a very, very small part of the data that grounded theory uses.
Sobreiro, R. F.; Tomaz, A. A.; Otoya, V. J. Vasquez
2012-01-01
Pure gauge theories for de Sitter, anti de Sitter and orthogonal groups, in four-dimensional Euclidean spacetime, are studied. It is shown that, if the theory is asymptotically free and a dynamical mass is generated, then an effective geometry may be induced and a gravity theory emerges.
Renormalizable Tensor Field Theories
Geloun, Joseph Ben
2016-01-01
Extending tensor models at the field theoretical level, tensor field theories are nonlocal quantum field theories with Feynman graphs identified with simplicial complexes. They become relevant for addressing quantum topology and geometry in any dimension and therefore form an interesting class of models for studying quantum gravity. We review the class of perturbatively renormalizable tensor field theories and some of their features.
Missinne, Leo E.; Wilcox, Victoria
This paper discusses the life, theories, and therapeutic techniques of psychotherapist, Viktor E. Frankl. A brief biography of Frankl is included discussing the relationship of his early experiences as a physician to his theory of personality. Frankl's theory focusing on man's need for meaning and emphasizing the spiritual dimension in each human…
Superspace conformal field theory
Quella, Thomas [Koeln Univ. (Germany). Inst. fuer Theoretische Physik; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-07-15
Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.
Vazzana, Anthony; Garth, David
2007-01-01
One of the oldest branches of mathematics, number theory is a vast field devoted to studying the properties of whole numbers. Offering a flexible format for a one- or two-semester course, Introduction to Number Theory uses worked examples, numerous exercises, and two popular software packages to describe a diverse array of number theory topics.
Matsumoto, Kohji
2002-01-01
The book includes several survey articles on prime numbers, divisor problems, and Diophantine equations, as well as research papers on various aspects of analytic number theory such as additive problems, Diophantine approximations and the theory of zeta and L-function Audience Researchers and graduate students interested in recent development of number theory
Peim, Nick
2009-01-01
This paper seeks to re-examine Yrio Engestrom's activity theory as a technology of knowledge designed to enable positive transformations of specific practices. The paper focuses on a key paper where Engestrom defines the nature and present state of activity theory. Beginning with a brief account of the relations between activity theory and…
Superspace conformal field theory
Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.
Davis, Philip W.
This volume explores objectively the essential characteristic of nine twentieth-century linguistic theories with the theoretical variant for discussion based on one closely representative of work within a given approach or usually associated with the name of the theory. First, the theory of Ferdinand de Saussure is discussed based on his book,…
La theorie autrement (Theory in Another Light).
Bertocchini, Paola; Costanzo, Edwige
1985-01-01
Outlines a technique using articles from "Le Francais dans le Monde" to teach reading comprehension and theory simultaneously to teachers of French as a second language. Describes a program in Italy using this approach. (MSE)
Prest, M
1988-01-01
In recent years the interplay between model theory and other branches of mathematics has led to many deep and intriguing results. In this, the first book on the topic, the theme is the interplay between model theory and the theory of modules. The book is intended to be a self-contained introduction to the subject and introduces the requisite model theory and module theory as it is needed. Dr Prest develops the basic ideas concerning what can be said about modules using the information which may be expressed in a first-order language. Later chapters discuss stability-theoretic aspects of module
Kilmister, Clive William
1970-01-01
Special Theory of Relativity provides a discussion of the special theory of relativity. Special relativity is not, like other scientific theories, a statement about the matter that forms the physical world, but has the form of a condition that the explicit physical theories must satisfy. It is thus a form of description, playing to some extent the role of the grammar of physics, prescribing which combinations of theoretical statements are admissible as descriptions of the physical world. Thus, to describe it, one needs also to describe those specific theories and to say how much they are limit
Barron, E N
2013-01-01
An exciting new edition of the popular introduction to game theory and its applications The thoroughly expanded Second Edition presents a unique, hands-on approach to game theory. While most books on the subject are too abstract or too basic for mathematicians, Game Theory: An Introduction, Second Edition offers a blend of theory and applications, allowing readers to use theory and software to create and analyze real-world decision-making models. With a rigorous, yet accessible, treatment of mathematics, the book focuses on results that can be used to
Bollobas, Bela
2004-01-01
The ever-expanding field of extremal graph theory encompasses a diverse array of problem-solving methods, including applications to economics, computer science, and optimization theory. This volume, based on a series of lectures delivered to graduate students at the University of Cambridge, presents a concise yet comprehensive treatment of extremal graph theory.Unlike most graph theory treatises, this text features complete proofs for almost all of its results. Further insights into theory are provided by the numerous exercises of varying degrees of difficulty that accompany each chapter. A
Antonio De Felice
2010-06-01
Full Text Available Over the past decade, f(R theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R theories to cosmology and gravity – such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans–Dicke theory and Gauss–Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.
Förste, S; Forste, Stefan; Louis, Jan
1996-01-01
In this lecture we review some of the recent developments in string theory on an introductory and qualitative level. In particular we focus on S-T-U dualities of toroidally compactified ten-dimensional string theories and outline the connection to M-theory. Dualities among string vacua with less supersymmetries in six and four space-time dimensions is discussed and the concept of F-theory is briefly presented. (Lecture given by J. Louis at the Workshop on Gauge Theories, Applied Supersymmetry and Quantum Gravity, Imperial College, London, UK, July 5--10, 1996.)
Gross, Jonathan L
2003-01-01
The Handbook of Graph Theory is the most comprehensive single-source guide to graph theory ever published. Best-selling authors Jonathan Gross and Jay Yellen assembled an outstanding team of experts to contribute overviews of more than 50 of the most significant topics in graph theory-including those related to algorithmic and optimization approaches as well as ""pure"" graph theory. They then carefully edited the compilation to produce a unified, authoritative work ideal for ready reference.Designed and edited with non-experts in mind, the Handbook of Graph Theory makes information easy to fi
Niederreiter, Harald
2015-01-01
This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas. Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc. Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...
Introduction to bifurcation theory
Bifurcation theory is a subject with classical mathematical origins. The modern development of the subject starts with Poincare and the qualitative theory of differential equations. In recent years, the theory has undergone a tremendous development with the infusion of new ideas and methods from dynamical systems theory, singularity theory, group theory, and computer-assisted studies of dynamics. As a result, it is difficult to draw the boundaries of the theory with any confidence. In this review, the objects in question will be parameterized families of dynamical systems (vector fields or maps). In the sciences these families commonly arise when one formulates equations of motion to model a physical system. We specifically analyze how the time evolution near an equilibrium can change as parameters are varied; for simplicity we consider the case of a single parameter only
Computational invariant theory
Derksen, Harm
2015-01-01
This book is about the computational aspects of invariant theory. Of central interest is the question how the invariant ring of a given group action can be calculated. Algorithms for this purpose form the main pillars around which the book is built. There are two introductory chapters, one on Gröbner basis methods and one on the basic concepts of invariant theory, which prepare the ground for the algorithms. Then algorithms for computing invariants of finite and reductive groups are discussed. Particular emphasis lies on interrelations between structural properties of invariant rings and computational methods. Finally, the book contains a chapter on applications of invariant theory, covering fields as disparate as graph theory, coding theory, dynamical systems, and computer vision. The book is intended for postgraduate students as well as researchers in geometry, computer algebra, and, of course, invariant theory. The text is enriched with numerous explicit examples which illustrate the theory and should be ...
Johnson, C V
2006-01-01
We present a class of solvable models that resemble string theories in many respects but have a strikingly different non-perturbative sector. In particular, there are no exponentially small contributions to perturbation theory in the string coupling, which normally are associated with branes and related objects. Perturbation theory is no longer an asymptotic expansion, and so can be completely re-summed to yield all the non-perturbative physics. We examine a number of other properties of the theories, for example constructing and examining the physics of loop operators, which can be computed exactly, and gain considerable understanding of the difference between these new theories and the more familiar ones, including the possibility of how to interpolate between the two types. Interestingly, the models we exhibit contain a family of zeros of the partition function which suggest a novel phase structure. The theories are defined naturally by starting with models that yield well-understood string theories and al...
A Reconciliation of Collision Theory and Transition State Theory
Yi, Y. G.
2001-01-01
A statistical-mechanical treatment of collision leads to a formal connection with transition-state theory, suggesting that collision theory and transition-state theory might be joined ultimately as a collision induced transition state theory.
Blagojević, Milutin
2012-01-01
During the last five decades, gravity, as one of the fundamental forces of nature, has been formulated as a gauge field theory of the Weyl-Cartan-Yang-Mills type. The resulting theory, the Poincar\\'e gauge theory of gravity, encompasses Einstein's gravitational theory as well as the teleparallel theory of gravity as subcases. In general, the spacetime structure is enriched by Cartan's torsion and the new theory can accommodate fermionic matter and its spin in a perfectly natural way. The present reprint volume contains articles from the most prominent proponents of the theory and is supplemented by detailed commentaries of the editors. This guided tour starts from special relativity and leads, in its first part, to general relativity and its gauge type extensions a la Weyl and Cartan. Subsequent stopping points are the theories of Yang-Mills and Utiyama and, as a particular vantage point, the theory of Sciama and Kibble. Later, the Poincar\\'e gauge theory and its generalizations are explored and specific topi...
Supersymmetry and String Theory
Dine, Michael
2016-01-01
Preface to the first edition; Preface to the second edition; A note on choice of metric; Text website; Part I. Effective Field Theory: The Standard Model, Supersymmetry, Unification: 1. Before the Standard Model; 2. The Standard Model; 3. Phenomenology of the Standard Model; 4. The Standard Model as an effective field theory; 5. Anomalies, instantons and the strong CP problem; 6. Grand unification; 7. Magnetic monopoles and solitons; 8. Technicolor: a first attempt to explain hierarchies; Part II. Supersymmetry: 9. Supersymmetry; 10. A first look at supersymmetry breaking; 11. The Minimal Supersymmetric Standard Model; 12. Supersymmetric grand unification; 13. Supersymmetric dynamics; 14. Dynamical supersymmetry breaking; 15. Theories with more than four conserved supercharges; 16. More supersymmetric dynamics; 17. An introduction to general relativity; 18. Cosmology; 19. Astroparticle physics and inflation; Part III. String Theory: 20. Introduction; 21. The bosonic string; 22. The superstring; 23. The heterotic string; 24. Effective actions in ten dimensions; 25. Compactification of string theory I. Tori and orbifolds; 26. Compactification of string theory II. Calabi–Yau compactifications; 27. Dynamics of string theory at weak coupling; 28. Beyond weak coupling: non-perturbative string theory; 29. Large and warped extra dimensions; 30. The landscape: a challenge to the naturalness principle; 31. Coda: where are we headed?; Part IV. The Appendices: Appendix A. Two-component spinors; Appendix B. Goldstone's theorem and the pi mesons; Appendix C. Some practice with the path integral in field theory; Appendix D. The beta function in supersymmetric Yang–Mills theory; References; Index.
Matrix String Theory As A Generalized Quantum Theory
Minic, Djordje
1997-01-01
Matrix String Theory of Banks, Fischler, Shenker and Susskind can be understood as a generalized quantum theory (provisionally named "quansical" theory) which differs from Adler's generalized trace quantum dynamics. The effective Matrix String Theory Hamiltonian is constructed in a particular fermionic realization of Matrix String Theory treated as an example of "quansical" theory.
Class field theory from theory to practice
Gras, Georges
2003-01-01
Global class field theory is a major achievement of algebraic number theory, based on the functorial properties of the reciprocity map and the existence theorem. The author works out the consequences and the practical use of these results by giving detailed studies and illustrations of classical subjects (classes, idèles, ray class fields, symbols, reciprocity laws, Hasse's principles, the Grunwald-Wang theorem, Hilbert's towers,...). He also proves some new or less-known results (reflection theorem, structure of the abelian closure of a number field) and lays emphasis on the invariant (/cal T) p, of abelian p-ramification, which is related to important Galois cohomology properties and p-adic conjectures. This book, intermediary between the classical literature published in the sixties and the recent computational literature, gives much material in an elementary way, and is suitable for students, researchers, and all who are fascinated by this theory. In the corrected 2nd printing 2005, the author improves s...
The theories on inequality: class theory
Ali Arslan
2006-11-01
Full Text Available This stduy aims to analyse class theory and its major expansions. In addition, the problems and dilemmas of class theory are discussed. Social inequality, either socially or economically, is one of the most common features of capitalist societies. Some people or some social groups have more money, more prestige, more privilege and more influence on the decision making process. Two main strategies have been used for analysing and explaining inequalities. The first and most popular strategy is “class theory” which stresses ownership and control to explain class differentiation. It concentrates on the inequalities based mainly on the ownership or non-ownership of economic resources. Class theory was fathered by Karl Marx and especially developed by Marxist writers. Class analysts focus on identification of classes as the major social forces of society. There are two main schools of thought in class theory with their variations within each school: a Marxist Class Theory, b Weberian Class Theory If the Marxist class analysis and Weberian class analysis are examined it will be seen that, two approaches are incompatible and it is impossible to synthesise them. Nevertheless, Hindess sees Weber’s view as the correction of and supplement to Marx’s ideas rather than an alternative. When the ideas of Marx and Weber are compared, it will be clearly seen that both Marx and Weber explain classes in relation to the economy. Nevertheless, while Marx defines classes in terms of the relations of production, Weber defines them in relation to the market.
In the last few years lattice gauge theory has become the primary tool for the study of nonperturbative phenomena in gauge theories. The lattice serves as an ultraviolet cutoff, rendering the theory well defined and amenable to numerical and analytical work. Of course, as with any cutoff, at the end of a calculation one must consider the limit of vanishing lattice spacing in order to draw conclusions on the physical continuum limit theory. The lattice has the advantage over other regulators that it is not tied to the Feynman expansion. This opens the possibility of other approximation schemes than conventional perturbation theory. Thus Wilson used a high temperature expansion to demonstrate confinement in the strong coupling limit. Monte Carlo simulations have dominated the research in lattice gauge theory for the last four years, giving first principle calculations of nonperturbative parameters characterizing the continuum limit. Some of the recent results with lattice calculations are reviewed
Petrov, Alexey A
2016-01-01
This book is a broad-based text intended to help the growing student body interested in topics such as gravitational effective theories, supersymmetric effective theories, applications of effective theory techniques to problems in condensed matter physics (superconductivity) and quantum chromodynamics (such as soft-collinear effective theory). It begins with a review of the use of symmetries to identify the relevant degrees of freedom in a problem, and then presents a variety of methods that can be used to solve physical problems. A detailed discussion of canonical examples of effective field theories with increasing complexity is then conducted. Special cases such as supersymmetry and lattice EFT are discussed, as well as recently-found applications to problems in gravitation and cosmology. An appendix includes various factoids from group theory and other topics that are used throughout the text, in an attempt to make the book self-contained.
Algebraic quantum field theory
The basic assumption that the complete information relevant for a relativistic, local quantum theory is contained in the net structure of the local observables of this theory results first of all in a concise formulation of the algebraic structure of the superselection theory and an intrinsic formulation of charge composition, charge conjugation and the statistics of an algebraic quantum field theory. In a next step, the locality of massive particles together with their spectral properties are wed for the formulation of a selection criterion which opens the access to the massive, non-abelian quantum gauge theories. The role of the electric charge as a superselection rule results in the introduction of charge classes which in term lead to a set of quantum states with optimum localization properties. Finally, the asymptotic observables of quantum electrodynamics are investigated within the framework of algebraic quantum field theory. (author)
Chung, Daniel J H
2016-01-01
We reformulate gauge theories in analogy with the vierbein formalism of general relativity. More specifically, we reformulate gauge theories such that their gauge dynamical degrees of freedom are local fields that transform linearly under the dual representation of the charged matter field. These local fields, which naively have the interpretation of non-local operators similar to Wilson lines, satisfy constraint equations. A set of basis tensor fields are used to solve these constraint equations, and their field theory is constructed. A new local symmetry in terms of the basis tensor fields is used to make this field theory local and maintain a Hamiltonian that is bounded from below. The field theory of the basis tensor fields is what we call the basis tensor gauge theory.
Rotor theories by Professor Joukowsky: Momentum theories
van Kuik, G. A. M.; Sørensen, Jens Nørkær; Okulov, V. L.
2015-01-01
This paper is the first of two papers on the history of rotor aerodynamics with special emphasis on the role of Joukowsky. The present one focuses on the development of the momentum theory while the second one surveys the development of vortex theory for rotors. Joukowsky has played a major role in...... Momentum still is the basis of current rotor design codes. He applied some assumptions limiting the validity to moderate and high tip speed ratios. Sorensen and van Kuik published a solution for wind turbines with very low tip speed ratios, which is now expanded to propellers as well, with one remaining...
Theory and context / Theory in context
Glaveanu, Vlad Petre
2014-01-01
trans-disciplinary manner. Consideration needs to be given as well to connected scholarship focusing on imagination, innova-tion, and improvisation. Last but not least, an expanded the-ory of context cannot ignore the institutional context of doing research on creativity. Creativity scholars are facing......It is debatable whether the psychology of creativity is a field in crisis or not. There are clear signs of increased fragmenta-tion and a scarcity of integrative efforts, but is this necessari-ly bad? Do we need more comprehensive theories of creativ-ity and a return to old epistemological...
Schumacher, Benjamin; Westmoreland, Michael D.
2012-01-01
Modal quantum theory (MQT) is a "toy model" of quantum theory in which amplitudes are elements of a general field. The theory predicts, not the probabilities of a measurement result, but only whether or not a result is possible. In this paper we review MQT and extend it to include mixed states, generalized measurements and open system dynamics. Even though MQT does not have density operators, superoperators or any concept of "positivity", we can nevertheless establish a precise analogue to th...
Vinokurov, Evgeny
2007-01-01
The manuscript represents a comprehensive theory of enclaves and exclaves. The theory comprises both political and economic aspects. It is the first general book on the world’s enclaves and exclaves. Due to its comprehensive and pioneer character, it has a potential to become a book of reference for the nascent and promising research field. In its attempt to provide a fully-fledged theory of enclaves and exclaves, it covers a wide scope of regions and territories throughout the world. Basical...
Theory Modeling and Simulation
Shlachter, Jack [Los Alamos National Laboratory
2012-08-23
Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.
Supergravity for Effective Theories
Daniel Baumann; Daniel Green(Stanford Institute for Theoretical Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, U.S.A.)
2011-01-01
Higher-derivative operators are central elements of any effective field theory. In supersymmetric theories, these operators include terms with derivatives in the K\\"ahler potential. We develop a toolkit for coupling such supersymmetric effective field theories to supergravity. We explain how to write the action for minimal supergravity coupled to chiral superfields with arbitrary numbers of derivatives and curvature couplings. We discuss two examples in detail, showing how the component actio...
stakeholder theory in perspective
Damak-Ayadi, Salma; Pesqueux, Yvon
2005-01-01
Those who use stakeholder theory as a reference are both underlining the correlation between facts and a certain conceptualisation thereof (Section 1) and trying to make the necessary shift from a “panoptic” analysis akin to a panoramic vision of texts and positions (Section 2) to an “in-depth” one geared towards an understanding of their foundations (Section 3). As a “theory of organisations”, stakeholder theory helps to nourish a relational model of organisations by revisiting questions abo...
Thorbj, rn Knudsen
2002-01-01
The present article provides a minimal description of the causal structure of economic selection theory and outlines how the internal selection dynamics of business organisations can be reconciled with selection in competitive markets. In addition to generic similarity in terms of the Darwinian principles of variation, continuity and selection, it is argued that economic selection theory should mimic the causal structure of neo-Darwinian theory. Two of the most influential explanations of eco...
Relevance Theory in Translation
Shao Jun; Jiang Min
2008-01-01
In perspective of relevance theory, translation is regarded as communication. According to relevance theory, communication not only requires encoding, transfer and decoding processes, but also involves inference in addition. As communication, translation decision-making is also based on the human beings' inferential mental faculty. Concentrating on relevance theory, this paper tries to analyze and explain some translation phenomena in two English versions of Cai Gen Tan-My Crude Philosophy of Life.
Accounting and Economic Theory
Martin Shubik
2003-01-01
This paper deals with the changing relationship between economic theory and accounting practice and theory. It argues that many of the basic problems encountered in practice cannot be avoided in any attempt to construct an economic theory adequate to handle dynamics. In particular problems of timing become critical. furthermore, there are several critical problems concerning profit maximization, the nature of the rate of interest, agency problems within the firm and the payment of dividends w...
Marx Boopathi
2012-01-01
The game theory techniques are used to find the equilibrium of a market. Game theory refers to the ways in which strategic interactions among economic agents produce outcomes with respect to the preferences (or utilities) of those agents, where the outcomes in question might have been intended by none of the agents. The oligopolistic market structures are taken and how game theory applies to them is explained.
Supergravity from Gauge Theory
Berkowitz, Evan
2016-01-01
Gauge/gravity duality is the conjecture that string theories have dual descriptions as gauge theories. Weakly-coupled gravity is dual to strongly-coupled gauge theories, ideal for lattice calculations. I will show precision lattice calculations that confirm large-N continuum D0-brane quantum mechanics correctly reproduces the leading-order supergravity prediction for a black hole's internal energy---the first leading-order test of the duality---and constrains stringy corrections.
Introduction to superstring theory
This is a very basic introduction to the AdS/CFT correspondence. The first lecture motivates the duality between gauge theories and gravity/string theories. The next two lectures introduce the bosonic and supersymmetric string theories. The fourth lecture is devoted to study Dp-branes and finally, in the fifth lecture I discuss the two worlds: N=4 SYM in 3+1 flat dimensions and type IIB superstrings in AdS5 x S5. (author)
Botond Koszegi
2014-01-01
This review provides a critical survey of psychology-and-economics ("behavioral-economics") research in contract theory. First, I introduce the theories of individual decision making most frequently used in behavioral contract theory, and formally illustrate some of their implications in contracting settings. Second, I provide a more comprehensive (but informal) survey of the psychology-and-economics work on classical contract-theoretic topics: moral hazard, screening, mechanism design, and i...
Ed Nosal; Peter Rupert
2002-01-01
It wasn’t A Beautiful Mind—the book or the movie—that made John Forbes Nash, Jr., famous. It was his work in game theory, a theory that models strategic interactions between people as games. Before Nash, the only games theorists could get a handle on were artificial ones with no real-world applications. Nash’s insights enabled economists to expand the use of game theory to interesting practical problems.
Ostwald, Wolfgang
1988-01-01
A brief summary of the fundamentals of the Linear theory of flotation is given. The theory by no means contradicts the previous Laminar theory or even the thermodynamics (Wark-Siedler), rather it is a refinement of the known Hardy-Langmuir-Harkin conceptions for the case when there are not two phases and phase boundaries, but rather three phases and corresponding phase boundary edges. The appearance of such three-phase boundaries (ore, water, air) is characteristic for modern flotation methods.
Automated Lattice Perturbation Theory
Monahan, Christopher
2014-11-01
I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.
Chartrand, Gary
1984-01-01
Graph theory is used today in the physical sciences, social sciences, computer science, and other areas. Introductory Graph Theory presents a nontechnical introduction to this exciting field in a clear, lively, and informative style. Author Gary Chartrand covers the important elementary topics of graph theory and its applications. In addition, he presents a large variety of proofs designed to strengthen mathematical techniques and offers challenging opportunities to have fun with mathematics. Ten major topics - profusely illustrated - include: Mathematical Models, Elementary Concepts of Grap
Tong, David
2009-01-01
This is a one semester course on bosonic string theory aimed at beginning graduate students. The lectures assume a working knowledge of quantum field theory and general relativity. Contents: 1. The Classical String 2. The Quantum String 3. Open Strings and D-Branes 4. Introducing Conformal Field Theory 5. The Polyakov Path Integral and Ghosts 6. String Interactions 7. The Low-Energy Effective Action 8. Compactification and T-Duality
Introduction to superstring theory
Nunez, Carmen [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina)], e-mail: carmen@iafe.uba.ar
2009-07-01
This is a very basic introduction to the AdS/CFT correspondence. The first lecture motivates the duality between gauge theories and gravity/string theories. The next two lectures introduce the bosonic and supersymmetric string theories. The fourth lecture is devoted to study Dp-branes and finally, in the fifth lecture I discuss the two worlds: N=4 SYM in 3+1 flat dimensions and type IIB superstrings in AdS{sub 5} x S5. (author)
Griselda Deelstra; Guillaume Plantin
2014-01-01
Reinsurance is an important production factor of non-life insurance. The efficiency and the capacity of the reinsurance market directly regulate those of insurance markets. The purpose of this book is to provide a concise introduction to risk theory, as well as to its main application procedures to reinsurance. The first part of the book covers risk theory. It presents the most prevalent model of ruin theory, as well as a discussion on insurance premium calculation principles and the mathemat...
Deelstra, Griselda; Plantin, Guillaume
2014-01-01
Reinsurance is an important production factor of non-life insurance. The efficiency and the capacity of the reinsurance market directly regulate those of insurance markets. The purpose of this book is to provide a concise introduction to risk theory, as well as to its main application procedures to reinsurance. The first part of the book covers risk theory. It presents the most prevalent model of ruin theory, as well as a discussion on insurance premium calculation principles and the math...
Hypergraph theory an introduction
Bretto, Alain
2013-01-01
This authored monograph presents hypergraph theory and covers both traditional elements of the theory as well as more original concepts such as entropy of hypergraph, similarities and kernels. Moreover, the author gives a detailed account to applications of the theory, including, but not limited to, applications for telecommunications and modeling of parallel data structures. The target audience primarily comprises researchers and practitioners in applied sciences but the book may also be beneficial for graduate students.
Extended Theories of Gravitation
Fatibene, Lorenzo
2016-01-01
In this paper we shall review the equivalence between Palatini$-f(\\mathcal R)$ theories and Brans- Dicke (BD) theories at the level of action principles. We shall define the Helmholtz Lagrangian associated to Palatini$-f(\\mathcal R)$ theory and we will define some transformations which will be useful to recover Einstein frame and Brans-Dicke frame. We shall see an explicit example of matter field and we will discuss how the conformal factor affects the physical quantities.
Some of the difficulties and limitations encountered when teaching neutron slowing down theory to nuclear engineering students, are examined. Specific problems in teaching the kinetics of the slowing down of neutrons, the neutron balance equation, resonance escape probabilities, and the continuous slowing down theory, are considered and it is suggested that, as far as possible, use should be made, by analogy, of the work already done with the students in deriving diffusion theory and its one group equation. (U.K.)