Showing papers in "Annalen der Physik in 2011"
TL;DR: In this paper, the authors present the application of thermal modeling to the Rosetta flyby anomaly as well as to the Pioneer anomaly, and show that thermal recoil pressure is not the cause of the ROSET flyby, but likely resolves the anomalous acceleration observed for Pioneer 10.
Abstract: Thermal modeling of complex systems faces the problems of an effective digitalization of the detailed geometry and properties of the system, calculation of the thermal flows and temperature maps, treatment of the thermal radiation including possible multiple reflections, inclusion of additional external influences, extraction of the radiation pressure from calculated surface data as well as computational effectiveness. In previous publications [1, 2] the solution to these problems have been outlined and a first application to the Pioneer spacecraft have been shown. Here we like to present the application of our thermal modeling to the Rosetta flyby anomaly as well as to the Pioneer anomaly. The analysis outlines that thermal recoil pressure is not the cause of the Rosetta flyby anomaly but likely resolves the anomalous acceleration observed for Pioneer 10.
99 citations
TL;DR: In this article, the spin-orbit Hamiltonian for two self-gravitating spinning compact objects up to and including 3.5PN was shown to be equivalent in strength to a three-5PN effect.
Abstract: We present the next-to-next-to-leading order post-Newtonian (PN) spin-orbit Hamiltonian for two self-gravitating spinning compact objects. If at least one of the objects is rapidly rotating, then the corresponding interaction is comparable in strength to a 3.5PN effect. The result in the present paper in fact completes the knowledge of the post-Newtonian Hamiltonian for binary spinning black holes up to and including 3.5PN. The Hamiltonian is checked via known results for the test-spin case and via the global Poincare algebra with the center-of-mass vector uniquely determined by an ansatz.
86 citations
TL;DR: In this article, an extension of the canonical formalism of Arnowitt, Deser, and Misner from self-gravitating point-masses to objects with spin was proposed.
Abstract: The present article aims at an extension of the canonical formalism of Arnowitt, Deser, and Misner from self-gravitating point-masses to objects with spin. This would allow interesting applications, e.g., within the post-Newtonian (PN) approximation. The extension succeeded via an action approach to linear order in the single spins of the objects without restriction to any further approximation. An order-by-order construction within the PN approximation is possible and performed to the formal 3.5PN order as a verification. In principle both approaches are applicable to higher orders in spin. The PN next-to-leading order spin(1)-spin(1) level was tackled, modeling the spin-induced quadrupole deformation by a single parameter. All spin-dependent Hamiltonians for rapidly rotating bodies up to and including 3PN are calculated.
84 citations
Abstract: This paper explains the multi-orbital band structures and itinerant magnetism of the iron-pnictide and chalcogenide superconductors. We first describe the generic band structure of a single, isolated FeAs layer. Use of its Abelian glide-mirror group allows us to reduce the primitive cell to one FeAs unit. For the lines and points of high symmetry in the corresponding large, square Brillouin zone, we specify how the one-electron Hamiltonian factorizes. From density-functional theory, and for the observed structure of LaOFeAs, we generate the set of eight Fe d and As p localized Wannier functions and their tight-binding (TB) Hamiltonian, h (k) . For comparison, we generate the set of five Fe d Wannier orbitals. The topology of the bands, i. e. allowed and avoided crossings, specifically the origin of the d6 pseudogap, is discussed, and the role of the As p orbitals and the elongation of the FeAs4 tetrahedron emphasized. We then couple the layers, mainly via interlayer hopping between As pz orbitals, and give the formalism for simple tetragonal and body-centered tetragonal (bct) stackings. This allows us to explain the material-specific 3D band structures, in particular the complicated ones of bct BaFe2As2 and CaFe2As2 whose interlayer hoppings are large. Due to the high symmetry, several level inversions take place as functions of kz or pressure, and linear band dispersions (Dirac cones) are found at many places. The underlying symmetry elements are, however, easily broken by phonons or impurities, for instance, so that the Dirac points are not protected. Nor are they pinned to the Fermi level because the Fermi surface has several sheets. From the paramagnetic TB Hamiltonian, we form the band structures for spin spirals with wavevector q by coupling h (k) and h (k + q). The band structure for stripe order is studied in detail as a function of the exchange potential, Δ, or moment, m, using Stoner theory. Gapping of the Fermi surface (FS) for small Δ requires matching of FS dimensions (nesting) and d-orbital characters. The interplay between pd hybridization and magnetism is discussed using simple 4 × 4 Hamiltonians. The origin of the propeller-shaped Fermi surface is explained in detail. Finally, we express the magnetic energy as the sum over band-structure energies and this enables us to understand to what extent the magnetic energies might be described by a Heisenberg Hamiltonian, and to address the much discussed interplay between the magnetic moment and the elongation of the FeAs4 tetrahedron.
82 citations
TL;DR: In this article, the effect of electron-phonon interactions on the electronic band structure of solids has been investigated from both the experimental and theoretical side, with a special emphasis on the Allen-Heine-Cardona approach.
Abstract: The modifications of the electronic band structure of solids due to electron-phonon interactions (temperature and zero-point motion effects) have been explored by Manuel Cardona from both the experimental and theoretical sides. In the present contribution, we focus on the theoretical approaches to such effects. Although the situation has improved since the seventies, the wish for a fully developed theory (and associated efficient implementations) is not yet fulfilled. We review noticeable semi-empirical and first-principle studies, with a special emphasis on the Allen-Heine-Cardona (AHC) approach. We then focus on the non-diagonal Debye-Waller contribution, appearing beyond the rigid-ion approximation, in a Density-Functional Theory (DFT) approach. A numerical study shows that they can be sizeable (10%-50%) for diatomic molecules. We also present the basic idea of a new formalism, based on Density-Functional Perturbation Theory, that allows one to avoid the sums over a large number of empty states, and speed up the calculation by one order of magnitude, compared to the straightforward implementation of the AHC approach within DFT. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
81 citations
TL;DR: In this article, the authors have demonstrated potentials of this technique in CeO2 and TiO2 nanocrystalline systems analyzing their optical phonon properties, and demonstrated the potential of the technique in this system in terms of optical mode shift and broadening.
Abstract: The conventional Raman scattering spectroscopy is one of the most used and powerful techniques for characterization of nano-sized materials and structures. By proper analysis of optical mode shift and broadening in nanomaterials based on phonon confinement model, it is possible to deduce about the influence of various effects like particle size and size distribution, strain, change of phonon dispersion, substitutional effects, defect states and nonstoichiometry, electron-phonon coupling. We have demonstrated potentials of this technique in CeO2 and TiO2 nanocrystalline systems analyzing their optical phonon properties.
73 citations
TL;DR: In this article, the influence of a classical background based on the violation of the Lorentz symmetry on the relativistic Anandan quantum phase was studied and it was shown that the choice of the LRS violation background provided an abelian contribution for the AAN phase.
Abstract: We study the influence of a classical background based on the violation of the Lorentz symmetry on the relativistic Anandan quantum phase. We show that the choice of the Lorentz symmetry violation background provides an abelian contribution for the relativistic Anandan quantum phase.
66 citations
TL;DR: In this article, a new methodology is formulated for solving the reduced Fokker-Planck (FP) equations in high dimensions based on the idea that the state space of large-scale nonlinear stochastic dynamic system is split into two subspaces.
Abstract: In this paper, a new methodology is formulated for solving the reduced Fokker-Planck (FP) equations in high dimensions based on the idea that the state space of large-scale nonlinear stochastic dynamic system is split into two subspaces. The FP equation relevant to the nonlinear stochastic dynamic system is then integrated over one of the subspaces. The FP equation for the joint probability density function of the state variables in another subspace is formulated with some techniques. Therefore, the FP equation in high-dimensional state space is reduced to some FP equations in low-dimensional state spaces, which are solvable with exponential polynomial closure method. Numerical results are presented and compared with the results from Monte Carlo simulation and those from equivalent linearization to show the effectiveness of the presented solution procedure. It attempts to provide an analytical tool for the probabilistic solutions of the nonlinear stochastic dynamics systems arising from statistical mechanics and other areas of science and engineering.
65 citations
TL;DR: In this article, a simple and natural way to derive the observed small, positive cosmological constant from the gravitational interaction of condensing fermions was presented, where the axial-axial vector four-fermion interaction term in the Dirac Lagrangian for spinor fields was derived.
Abstract: We present a simple and natural way to derive the observed small, positive cosmological constant from the gravitational interaction of condensing fermions. In the Riemann-Cartan spacetime, torsion gives rise to the axial–axial vector four-fermion interaction term in the Dirac Lagrangian for spinor fields. We show that this nonlinear term acts like a cosmological constant if these fields have a nonzero vacuum expectation value. For quark fields in QCD, such a torsion-induced cosmological constant is positive and its energy scale is only about 8 times larger than the observed value. Adding leptons to this picture could lower this scale to the observed value.
58 citations
TL;DR: In this paper, the D-dimensional Klein-Gordon equation in the presence of both Coulomb and Cornell potentials was investigated by quasi-exact methodology and closed form of eigenfunctions was reported and the energy behavior for different states was numerically discussed.
Abstract: We investigate the D-dimensional Klein-Gordon equation in the presence of both Coulomb and Cornell potentials by quasi-exact methodology. The Coulomb potential yields a degenerate result as the dimension increases, i.e. the quantum number l plays no role in the energy relation. For the Cornell potential, however, the behavior is different and no degeneracy exists. Closed form of eigenfunctions is reported and the energy behavior for different states is numerically discussed.
47 citations
TL;DR: In this paper, the vibrational properties of ZnAl 2O4 and ZnGa2O4 under pressure were investigated and a first-principles density functional study was presented.
Abstract: In this work we present a first-principles density functional study of the vibrational properties of ZnAl2O4 and ZnGa2O4 as function of hydrostatic pressure. Based on our previous structural characterization of these two compounds under pressure, herewith, we report the pressure dependence on both systems of the vibrational modes for the cubic spinel structure, for the CaFe2O4-type structure (Pnma )i n ZnAl2O4 and for marokite (Pbcm )Z nGa2O4. Additionally we report a second order phase transition in ZnGa2O4 from the marokite towards the CaTi2O4-type structure (Cmcm), for which we also calculate the pressure dependence of the vibrational modes at the Γ point. Our calculations are complemented with Raman scattering measurements up to 12 GPa that show a good overall agreement between our calculated and measured mode frequencies. c
TL;DR: In this article, a geometric representation of all non-birefringent linear media is derived based on Schuller et al.'s representation of the optical metric up to a constant.
Abstract: Based on a recent work by Schuller et al., a geometric representation of all skewonless, non-birefringent linear media is obtained. The derived constitutive law is based on a “core”, encoding the optical metric up to a constant. All further corrections are provided by two (anti-)selfdual bivectors, and an “axion”. The bivectors are found to vanish if the optical metric has signature (3,1) – that is, if the Fresnel equation is hyperbolic. We propose applications of this result in the context of transformation optics and premetric electrodynamics.
TL;DR: In this article, an analytical model is introduced to compute the Raman spectrum of Si-Ge core shell nanowires, where the materials are assumed to be elastically isotropic and the largest components of the strain tensor are not significantly affected by this approximation.
Abstract: An analytical model is introduced to compute the Raman spectrum of Si-Ge core shell nanowires. For the calculation of the strain, the materials are assumed to be elastically isotropic. It is argued that the largest components of the strain tensor are not significantly affected by this approximation. The phonon modes in the presence of strain are calculated using the known deformation potential tensors for Si and Ge. Predictions are made for Si-Ge and Ge-Si core-shell nanowires with axes along the 〈 011 〉 and 〈 111 〉 crystallographic directions. The results are presented in a way that makes it very simple to compare with experimental data and to extend the calculation to cases in which the shell consists of a Si1-xGex alloy.
TL;DR: In this paper, a study is given for the evolution of a flat, isotropic and homogeneous universe, which is filled with a causal bulk viscous cosmological fluid, described by an ultrarelativistic equation of state, and bulk viscosity coefficient obtained from recent lattice QCD calculations.
Abstract: In the present work a study is given for the evolution of a flat, isotropic and homogeneous Universe, which is filled with a causal bulk viscous cosmological fluid. We describe the viscous properties by an ultra-relativistic equation of state, and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived by using the energy equation obtained from the assumption of the covariant conservation of the energy-momentum tensor of the matter in the Universe. By assuming a power law dependence of the bulk viscosity coefficient, temperature and relaxation time on the energy density, we derive the evolution equation for the Hubble function. By using the equations of state from recent lattice QCD simulations and heavy-ion collisions we obtain an approximate solution of the field equations. In this treatment for the viscous cosmology, no evidence for singularity is observed. For example, both the Hubble parameter and the scale factor are finite at t = 0, where t is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non-viscous and ideal gas. Also it is noticed that the thermodynamic quantities, like temperature, energy density and bulk pressure remain finite. Particular solutions are also considered in order to prove that the free parameter in this model does qualitatively influence the final results.
TL;DR: In this paper, the authors calculate energy and momentum of a spherically symmetric dilaton frame using the gravitational energy-momentum 3-form within the tetrad formulation of general relativity (GR).
Abstract: We calculate energy and momentum of a spherically symmetric dilaton frame using the gravitational energy-momentum 3-form within the tetrad formulation of general relativity (GR). The frame we use is characterized by an arbitrary function ϒ with the help of which all the previously found solutions can be reproduced. We show how the effect of inertia (which is mainly reproduced from ϒ) makes the total energy and momentum always different from the well known result when we use the Riemannian connection
. On the other hand, when use is made of the covariant formulation of teleparallel gravity, which implies to take into account the pure gauge connection, teleparallel gravity always yields the physically relevant result for the energy and momentum.
TL;DR: In this paper, an extension of relativistic dynamics for which all admissible solutions will have have a speed bounded by the speed of light c and the acceleration bounded by am is presented.
Abstract: Based on the generalized principle of relativity and the ensuing symmetry, we have shown that there are only two possible types of transformations between uniformly accelerated systems. The rst allowable type of transformation holds if and only if the Clock Hypothesis is true. If the Clock Hypothesis is not true, the transformation is of Lorentz-type and implies the existence of a universal maximal acceleration am. We present an extension of relativistic dynamics for which all admissible solutions will have have a speed bounded by the speed of light c and the acceleration bounded by am. An additional Doppler type shift for an accelerated source is predicted. The formulas for such shift are the same as for the usual Doppler shift with v=c replaced by a=am. The W. Kundig experiment of measurement of the transverse Doppler shift in an accelerated system was also exposed to a longtitudal shift due to the acceleration. This experiment, as reanalyzed by Kholmetskii et al, shows that the Clock Hypothesis is not valid. Based on the results of this experiment, we predict that the value of the maximal acceleration am is of the order 10 19 m=s 2 . Moreover, our analysis provides a way to measure experimentally the maximal acceleration with existing technology.
TL;DR: In this paper, the issue of half-filling vs. away from half filling of the donor band (i.e., uncompensated vs. compensated semiconductors) is discussed in detail.
Abstract: The metal-insulator (MI) transition in Si:P can be tuned by varying the P concentration or – for barely insulating samples – by application of uniaxial stress S. On-site Coulomb interactions lead to the formation of localized magnetic moments and the Kondo effect on the metallic side, and to a Hubbard splitting of the donor band on the insulating side. Continuous stress tuning allows the observation of finite-temperature dynamic scaling of σ (T,S) and hence a reliable determination of the critical exponent μ of the extrapolated zero-temperature conductivity σ (0) ∼ | S - Sc |μ, i.e., μ = 1, and of the dynamical exponent z = 3. The issue of half-filling vs. away from half-filling of the donor band (i.e., uncompensated vs. compensated semiconductors) is discussed in detail.
TL;DR: In this article, the relativistic analogue of the Landau-He-McKellar-Wilkens quantization can be achieved through the noninertial effects of the Fermi-Walker reference frame without assuming the existence of a magnetic charge density.
Abstract: We show that the relativistic analogue of the Landau-He-McKellar-Wilkens quantization can be achieved through the noninertial effects of the Fermi-Walker reference frame without assuming the existence of a magnetic charge density and discuss the nonrelativistic limit of the energy levels. We also obtain the Dirac spinors for positive-energy values parallel and antiparallel to the z axis of the spacetime and obtain the Gordon decomposition of the Dirac probability current Jμ.
TL;DR: In this article, the authors studied the conditions under which a change of the Dirac matrices leads to an equivalent Hamiltonian operator H or an equivalent energy operator E in a curved spacetime.
Abstract: The Dirac equation in a curved spacetime depends on a field of coefficients (essentially the Dirac matrices), for which a continuum of different choices are possible. We study the conditions under which a change of the coefficient fields leads to an equivalent Hamiltonian operator H, or to an equivalent energy operator E. We do that for the standard version of the gravitational Dirac equation, and for two alternative equations based on the tensor representation of the Dirac fields. The latter equations may be defined when the spacetime is four-dimensional, noncompact, and admits a spinor structure. We find that, for each among the three versions of the equation, the vast majority of the possible coefficient changes do not lead to an equivalent operator H, nor to an equivalent operator E, whence a lack of uniqueness. In particular, we prove that the Dirac energy spectrum is not unique. This non-uniqueness of the energy spectrum comes from an effect of the choice of coefficients, and applies in any given coordinates.
TL;DR: In this paper, the evolution of a flat, isotropic and homogeneous universe is studied and the background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous fluid and dark energy.
Abstract: The evolution of a flat, isotropic and homogeneous universe is studied. The background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous fluid and dark energy. The energy density relations obtained from the assumption of covariant conservation of energy-momentum tensor of the background matter in the early universe are used to derive the basic equation for the Hubble parameter H. The viscous properties described by ultra-relativistic equations of state and bulk viscosity taken from recent heavy-ion collisions and lattice QCD calculations have been utilized to give an approximate solution of the field equations. The cosmological constant is conjectured to be related to the energy density of the vacuum. In this treatment, there is a clear evidence for singularity at vanishing cosmic time t indicating the dominant contribution from the dark energy. The time evolution of H seems to last for much longer time than the ideal case, where both cosmological constant and viscosity coefficient are entirely vanishing.
TL;DR: In this article, the electronic and vibrational properties of uniaxially strained graphene and graphene nanoribbons were investigated under different configurations of strain in directions other than the zigzag or armchair direction.
Abstract: We report first-principles studies on the electronic and vibrational properties of uniaxially strained graphene and graphene nanoribbons The band structure of extended graphene shows an interesting behavior under uniaxial strain in directions other than the zigzag or armchair direction While strained graphene remains semi-metallic, one-dimensional graphene nanoribbons allow band-gap tuning via strain The shift of the strain-induced band-gap in armachair nanoribbons depends on their family At small strain the band-gap of all AGNRs depends linearly on the amount of strain Concerning the vibrational spectra, we compare strain-induced shift rates of the G modes in two-dimensional graphene and AGNRs The shift rates of the G- and G+ modes in AGNRs strongly reflect the common classification into three families For large ribbon widths all shift rates converge to their counterparts in graphene
TL;DR: Tessmer and Schafer as discussed by the authors provided full-analytical GW forms for eccentric nonspinning compact binaries of arbitrary mass ratio in the time Fourier domain. And they avoided, for the first time, the semi analytic property of recent descriptions, i.e., the demand of inverting the higher-order Kepler equation numerically but keeping all other computations analytic.
Abstract: The article provides full-analytical gravitational wave (GW) forms for eccentric nonspinning compact binaries of arbitrary mass ratio in the time Fourier domain. We avoid, for the first time, the semi-analytical property of recent descriptions, i.e. the demand of inverting the higher-order Kepler equation numerically but keeping all other computations analytic. The article is a completion of a previous article (Tessmer and Schafer, 2010. arXiv:1006.3714) to second post-Newtonian (2PN) order in the harmonic GW amplitude and conservative orbital dynamics. The GW amplitudes are given in spherical tensor components. A fully analytical inversion formula of the Kepler equation in harmonic coordinates is provided, as well as the analytic time Fourier expansion of trigonometric functions of the eccentric anomaly in terms of sines and cosines of the mean anomaly. Copyright line will be provided by the publisher
TL;DR: A Weyl geometric scale covariant approach to gravity due to Omote, Dirac, and Utiyama (1971ff) is reconsidered in this paper, which can be extended to the electroweak sector of elementary particle fields, taking into account their basic scaling freedom.
Abstract: A Weyl geometric scale covariant approach to gravity due to Omote, Dirac, and Utiyama (1971ff) is reconsidered. It can be extended to the electroweak sector of elementary particle fields, taking into account their basic scaling freedom. Already Cheng (1988) indicated that electroweak symmetry breaking, usually attributed to the Higgs field with a boson expected at 0.1− 0.3TeV , may be due to a coupling between Weyl geometric gravity and electroweak interactions. Weyl geometry seems to be well suited for treating questions of elementary particle physics, which relate to scale invariance and its “breaking”. This setting suggests the existence of a scalar field boson at the surprisingly low energy of ∼ 1eV . That may appear unlikely; but, as a payoff, the acquirement of mass arises as a result of coupling to gravity in agreement with the understanding of mass as the gravitational charge of fields.
TL;DR: In this paper, a proper quantization rule was proposed to calculate the energy spectra of solvable quantum systems using the Sturm-Liouville theorem, where the number of the nodes of the logarithmic derivative of the wave function increases by one, the momentum integral will increase by π.
Abstract: In this article, we present proper quantization rule, ∫k(x) dx - ∫k0(x) dx = nπ, where
and study solvable potentials. We find that the energy spectra of solvable systems can be calculated only from its ground state obtained by the Sturm-Liouville theorem. The previous complicated and tedious integral calculations involved in exact quantization rule are greatly simplified. The beauty and simplicity of proper quantization rule come from its meaning – whenever the number of the nodes of the logarithmic derivative ϕ(x) = ψ(x)-1dψ(x) /dx or the number of the nodes of the wave function ψ(x) increases by one, the momentum integral will increase by π. We apply two different quantization rules to carry out a few typically solvable quantum systems such as the one-dimensional harmonic oscillator, the Morse potential and its generalization as well as the asymmetrical trigonometric Scarf potential and show a great advantage of the proper quantization rule over the original exact quantization rule.
TL;DR: In this paper, an approach for the ab initio calculation of materials with strong electronic correlations is proposed, which is based on all local vertex corrections beyond the bare Coulomb interaction.
Abstract: We propose an approach for the ab initio calculation of materials with strong electronic correlations which is based on all local (fully irreducible) vertex corrections beyond the bare Coulomb interaction. It includes the so-called GW and dynamical mean field theory and important non-local correlations beyond, with a computational effort estimated to be still manageable.
TL;DR: In this paper, the spectrum of thermal radiation in every direction is described and a sound basis for the self-consistent analysis of radiative heat transport across interfaces, gaps, layered and other important structures.
Abstract: Planck's law of thermal radiation is limited to equilibrium systems that have a definite temperature and do not carry any heat flux. Here we extend it to steady-state systems with a constant heat flux. The obtained formulas explicitly describe the spectrum of thermal radiation in every direction and provide a sound basis for the self-consistent analysis of radiative heat transport across interfaces, gaps, layered and other important structures.
TL;DR: In this article, the authors review the work and life of Otto Stern who developed the molecular beam technique and with its aid laid the foundations of experimental atomic physics, including the experimental test of the Maxwell-Boltzmann distribution of molecular velocities (1920), experimental demonstration of space quantization of angular momentum (1922), diffraction of matter waves comprised of atoms and molecules by crystals (1931), and the determination of the magnetic dipole moments of the proton and deuteron (1933).
Abstract: We review the work and life of Otto Stern who developed the molecular beam technique and with its aid laid the foundations of experimental atomic physics. Among the key results of his research are: the experimental test of the Maxwell-Boltzmann distribution of molecular velocities (1920), experimental demonstration of space quantization of angular momentum (1922), diffraction of matter waves comprised of atoms and molecules by crystals (1931) and the determination of the magnetic dipole moments of the proton and deuteron (1933).
TL;DR: The quantum Boltzmann equation has been used to explain a number of experiments in semiconductor optics in the past two decades, including models of excitons in bulk materials, electron-hole plasmas, and polariton gases as discussed by the authors.
Abstract: The quantum Boltzmann equation, or Fokker-Planck equation, has been used to successfully explain a number of experiments in semiconductor optics in the past two decades. This paper reviews some of the developments of this work, including models of excitons in bulk materials, electron-hole plasmas, and polariton gases. Copyright line will be provided by the publisher odinger equation for many-particle systems. The equation for the time evolution of the distribution function of a quantum many-body system is variously called a quantum Boltzmann equation (after the collision term in the classical Boltzmann equation, discussed in Ref. (1), Section 5.9), a master equation (when the states are discrete), or a Fokker- Planck equation. While the formalism of time-dependent quantum mechanics of many-particle systems was well de- veloped in the mid-twentieth century, two developments occurred in the 1980's that allowed much more quantitative application to experiments on nonequilibrium systems. The first was the arrival of cheap, fast computers that allowed numerical solution of the quantum Boltzmann equation using iterative meth- ods. The second was the development of ultrafast optics methods which allowed direct observation of the distribution function of carriers in semiconductors (and in some metals) out of equilibrium. A related development, in the 1990's, was the accomplishment of trapped cold atom gases, which also allowed direct measurement of the distribution function of a gas. The results of quantum Boltzmann equations could thus be directly compared to experimental measurements of particle distribution functions instead of only average properties. In the limit of low particle density, the quantum Boltzmann equation has the form of simply adding all the rates determined by Fermi's golden rule for all possible scattering processes. For evolution due to single-particle transitions, this is given by @ni @t = X
TL;DR: The suggested link between human consciousness and collapse of wave function does not seem viable and several predictions that follow from this hypothetical relationship are formulated and that can be empirically tested.
Abstract: It has been suggested that consciousness plays an important role in quantum mechanics as it is necessary for the collapse of wave function during the measurement. Here we formulated several predictions that follow from this hypothetical relationship and that can be empirically tested. Experimental results that are already available suggest falsification of these predictions. Thus, the suggested link between human consciousness and collapse of wave function does not seem viable. We discuss the implications of these conclusions on the role of the human observer for quantum mechanics and on the role of quantum mechanics for the observer's consciousness.
TL;DR: In this paper, the cofermion-quasiparticle hybridization gap was proposed as a generalization of exciton in the slave-boson framework to explain the origin of the zero surface formation.
Abstract: Underdoped Mott insulators provide us with a challenge of many-body physics. Recent renewed understanding is discussed in terms of the evolution of pole and zero structure of the single-particle Green's function. Pseudogap as well as Fermi arc/pocket structure in the underdoped cuprates is well reproduced from the recent cluster extension of the dynamical mean-field theory. Emergent coexisting zeros and poles set the underdoped Mott insulator apart from the Fermi liquid, separated by topological transitions. The cofermion proposed as a generalization of exciton in the slave-boson framework accounts for the origin of the zero surface formation. The cofermion-quasiparticle hybridization gap offers a natural understanding of the pseudogap and various unusual Mottness. Furthermore the cofermion offers a novel pairing mechanism, where the cofermion has two roles: It reinforces the Cooper pair as a pair partner of the quasiparticle and acts as a glue as well. It provides a strong insight for solving the puzzle found in the dichotomy of the gap structure.