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J. W. van Holten

Publications and source records attributed to J. W. van Holten.

At least 19 recordsLinked to original sources

A Huygens-Leibniz-Lange framework for classical mechanics

I discuss the physical basis of classical mechanics, such as expressed commonly using the framework of Newton's Principia. Newton's formulation of the laws of motion is seen to have quite a few ambiguities and shortcomings. Therefore I offer an alternative set of laws, based in particular on ideas of his contemporaries Huygens and Leibniz with a crucial addition by Ludwig Lange, which avoids the problems with Newton's formulation. It is shown that from these laws of motion all the usual results of classical mechanics, as it concerns the motion of idealized point masses, can be rederived. The application of these principles to relativistic point particles is discussed.

physics.hist-ph↗

Signature of Majorana neutrinos in equal-sign W-production by lepton scattering

The question whether standard-model neutrinos are Dirac or Majorana particles is presently undecided. In principle it could be decided in favor of a Majorana signature if same-sign charged lepton scattering would be observed to produce $W$-boson pairs, which is a lepton-number violating process. The cross section of this scattering process is computed; depending on the initial state the result gives access to different components of the mass matrix. It could also shed light on physics beyond the standard model.

hep-ph↗

Dynamics of cosmological scalar fields

This paper reviews the dynamics of an isotropic and homogeneous cosmological scalar field. A general approach to the solution of the Einstein-Klein-Gordon equations is developed, which does not require slow-roll or other approximations. General conclusions about the qualitative behaviour of the solutions can be drawn, and examples of explicit solutions for some interesting cases are given. It is also shown how to find scalar potentials giving rise to a predetermined scalar field behaviour and associated evolution of the scale factor.

gr-qc↗

Conformal symmetry and supersymmetry in Rindler space

This paper addresses the fate of extended space-time symmetries, in particular conformal symmetry and supersymmetry, in two-dimensional Rindler space-time appropriate to a uniformly accelerated non-inertial frame in flat 1+1-dimensional space-time. Generically, in addition to a conformal co-ordinate transformation, the transformation of fields from Minkowski to Rindler space is accompanied by local conformal and Lorentz transformations of the components, which also affect the Bogoliubov transformations between the associated Fock spaces. I construct these transformations for massless scalars and spinors, as well as for the ghost and super-ghost fields necessary in theories with local conformal and supersymmetries, as arising from coupling to 2-D gravity or supergravity. Cancellation of the anomalies in Minkowski and in Rindler space requires theories with the well-known critical spectrum of particles arising in string theory in the limit of infinite strings, and is relevant for the equivalence of Minkowski and Rindler frame theories.

hep-th↗

The HiSPARC Experiment

The High School Project on Astrophysics Research with Cosmics (HiSPARC) is a large extensive air shower (EAS) array with detection stations throughout the Netherlands, United Kingdom, Denmark and Namibia. HiSPARC is a collaboration of universities, scientific institutes and high schools. The majority of detection stations is hosted by high schools. A HiSPARC station consists of two or four scintillators placed inside roof boxes on top of a building. The measured response of a detector to single incoming muons agrees well with GEANT4 simulations. The response of a station to EASs agrees with simulations as well. A four-scintillator station was integrated in the KASCADE experiment and was used to determine the accuracy of the shower direction reconstruction. Using simulations, the trigger efficiency of a station to detect a shower as function of both distance to the shower core and zenith angle was determined. The HiSPARC experiment is taking data since 2003. The number of stations (~140 in 2019) still increases. The project demonstrates that its approach is viable for educational purposes and that scientific data can be obtained in a collaboration with high school students and teachers.

astro-ph.IM↗

Gravitational waves from generalized newtonian sources

I review the elementary theory of gravitational waves on a Minkowski background and the quadrupole approximation. The modified conservation laws for energy and momentum keeping track of the gravitational-wave flux are presented. The theory is applied to two-body systems in bound and scattering states subject to newtonian gravity generalized to include a 1/r3 force allowing for orbital precession. The evolution of the orbits is studied in the adiabatic approximation. From these results I derive the conditions for capture of two bodies to form a bound state by the emission of gravitational radiation.

gr-qc↗

Chaplygin gas halos

Unification of dark matter and dark energy as short- and long-range manifestations of a single cosmological substance is possible in models described by the generalized Chaplygin gas equation of state. We show it admits halo-like structures and discuss their density profiles, the resulting space-time geometry and the rotational velocity profiles expected in these models.

gr-qc↗

D = 1 supergravity and quantum cosmology

Using a D = 1 supergravity framework I construct a super-Friedmann equation for an isotropic and homogenous universe including dynamical scalar fields. In the context of quantum theory this becomes an equation for a wave-function of the universe of spinorial type, the Wheeler-DeWitt- Dirac equation. It is argued that a cosmological constant breaks a certain chiral symmetry of this equation, a symmetry in the Hilbert space of universe states, which could protect a small cosmological constant from being affected by large quantum corrections.

gr-qc↗

Field theoretical approach to gravitational waves

The aim of these notes is to give an accessible and self-contained introduction to the theory of gravitational waves as the theory of a relativistic symmetric tensor field in a Minkowski background spacetime. This is the approach of a particle physicist: the graviton is identified with a particular irreducible representation of the Poincaré group, corresponding to vanishing mass and spin two. It is shown how to construct an action functional giving the linear dynamics of gravitons, and how General Relativity can be obtained from it. The Hamiltonian formulation of the linear theory is examined in detail. We study the emission of gravitational waves and apply the results to the simplest case of a binary Newtonian system.

gr-qc↗

Dynamical Space-Time and Gravitational Waves

According to General Relativity gravity is the result of the interaction between matter and space-time geometry. In this interaction space-time geometry itself is dynamical: it can store and transport energy and momentum in the form of gravitational waves. We give an introductory account of this phenomenon and discuss how the observation of gravitational waves may open up a fundamentally new window on the universe.

gr-qc↗

Spinning bodies in curved space-time

We study the motion of neutral and charged spinning bodies in curved space-time in the test-particle limit. We construct equations of motion using a closed covariant Poisson-Dirac bracket formulation which allows for different choices of the hamiltonian. We derive conditions for the existence of constants of motion and apply the formalism to the case of spherically symmetric space-times. We show that the periastron of a spinning body in a stable orbit in a Schwarzschild or Reissner-Nordstrøm background not only precesses, but also varies radially. By analysing the stability conditions for circular motion we find the innermost stable circular orbit (ISCO) as a function of spin. It turns out that there is an absolute lower limit on the ISCOs for increasing prograde spin. Finally we establish that the equations of motion can also be derived from the Einstein equations using an appropriate energy-momentum tensor for spinning particles.

gr-qc↗

Spinning bodies in General Relativity

A covariant hamiltonian formalism for the dynamics of compact spinning bodies in curved space-time in the test-particle limit is described. The construction allows a large class of hamiltonians accounting for specific properties and interactions of spinning bodies. The dynamics for a minimal and a specific non-minimal hamiltonian is discussed. An independent derivation of the equations of motion from an appropriate energy-momentum tensor is provided. It is shown how to derive constants of motion, both background-independent and background-dependent ones.

gr-qc↗

Canonical D = 1 supergravity framework for FLRW cosmology

We construct an extension of standard flat FLRW cosmology with matter, possessing local D = 1, N = 1 proper-time supersymmetry. The fundamental equation for the resulting mini-superspace models of quantum universes is a Dirac-like analogue of the Friedmann and Wheeler-DeWitt equations. We provide solutions of this equation for specific matter configurations based on the supersymmetric O(3) and O(2, 1) sigma-models. It turns out that in the compact model the volume rate of growth of the universe is quantized and non-vanishing due to the zero-point energy of the scalar fields. In the non-compact model the spectrum of the growth rates is continuous but subject to an uncertainty relation involving the scale and the growth factor.

gr-qc↗

Covariant hamiltonian spin dynamics in curved space-time

The dynamics of spinning particles in curved space-time is discussed, emphasizing the hamiltonian formulation. Different choices of hamiltonians allow for the description of different gravitating systems. We give full results for the simplest case with minimal hamiltonian, constructing constants of motion including spin. The analysis is illustrated by the example of motion in Schwarzschild space-time. We also discuss a non-minimal extension of the hamiltonian giving rise to a gravitational equivalent of the Stern-Gerlach force. We show that this extension respects a large class of known constants of motion for the minimal case.

gr-qc↗

Neutrinos, a window on new physics

This paper reviews some aspects of the physics of neutrinos, in particular neutrino masses and the issue of Dirac versus Majorana neutrinos. The see-saw mechanism is described and it is argued that the Majorana nature of neutrinos can be tested by measuring the invisible decays of the Higgs particle, as its decay into neutrinos is determined by their Yukawa couplings, i.e. the Dirac masses, rather than the physical Majorana masses. The measurement would allow us to probe the scale M of the large Majorana masses for right-handed singlet neutrinos. The optimal machine for performing such a measurement would be a future electron-positron collider.

hep-ph↗

Ballistic orbits in Schwarzschild space-time and gravitational waves from EMR binary mergers

We describe a special class of ballistic geodesics in Schwarzschild space-time, extending to the horizon in the infinite past and future of observer time, which are characterized by the property that they are in 1-1 correspondence, and completely degenerate in energy and angular momentum, with stable circular orbits. We derive analytic expressions for the source terms in the Regge-Wheeler and Zerilli-Moncrief equations for a point-particle moving on such a ballistic orbit, and compute the gravitational waves emitted during the infall in an Extreme Mass Ratio black-hole binary coalescence. In this way a geodesic description for the plunge phase of compact binaries is obtained.

gr-qc↗

Gauge-covariant extensions of Killing tensors and conservation laws

In classical and quantum mechanical systems on manifolds with gauge-field fluxes, constants of motion are constructed from gauge-covariant extensions of Killing vectors and tensors. This construction can be carried out using a manifestly covariant procedure, in terms of covariant phase space with a covariant generalization of the Poisson brackets, c.q. quantum commutators. Some examples of this construction are presented.

math-ph↗