# Th. M. NieuwenhuizenUniversity of Amsterdam | UVA · Institute for Theoretical Physics

Th. M. Nieuwenhuizen

PhD

## About

277

Publications

16,832

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7,125

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Citations since 2017

Introduction

I have worked in many fields of science, including: disordered chains, disordered systems, statistical physics, multiple light scattering, spin glasses, thermodynamics of glasses, quantum physics, quantum thermodynamics, quantum measurement, biophysics, black holes, gravitation, cosmonomy, MACHO and neutrino dark matter, modified Newtonian gravity, neutrino mass, neutrino sector of the standard model.
My recent fields are: quantum measurement; cored black holes and dark matter as vacuum energy

Additional affiliations

September 2014 - September 2017

**International Institute of Physics**

Position

- Professor (Full)

October 2009 - December 2009

## Publications

Publications (277)

The Curie-Weiss model for quantum measurement describes the dynamical measurement of a spin-$\frac{1}{2}$ by an apparatus consisting of an Ising magnet of many spins $\frac{1}{2}$ coupled to a thermal phonon bath. To measure the $z$-component $s=-l,-l+1,\cdots,l$ of a spin $l$, a class of models is designed along the same lines, which involve $2l$...

It is postulated that the zero point energy density of the quantum vacuum acts firstly as dark energy and secondly as a fluid that builds the dark matter. Assisted by a small fraction of net charges in a cosmic plasma, zero point energy can condense on mass concentrations. No longer participating in the cosmic expansion, they constitute ``electro-z...

The Curie–Weiss model for quantum measurement describes the dynamical measurement of a spin-12 by an apparatus consisting of an Ising magnet of many spins 12 coupled to a thermal phonon bath. To measure the z-component s=−l,−l+1,⋯,l of a spin l, a class of models is designed along the same lines, which involve 2l order parameters. As required for u...

A small object hidden in a multiple scattering medium is accurately located using a continuous light source. Good agreement between theory and experiment is found.

Presented is a brief overview of recent developments of topics addressed by the reviews and original papers of this volume related to non-equilibrium phenomena in various (especially mesoscopic) systems and the foundations of quantum physics.

An accurate, spherically symmetric description of the mass distribution is presented for two quite virialized galaxy clusters, Abell 1689 and Abell 1835. A suitable regularization of the small eigenvalues of the covariance matrices is introduced. A stretched exponential profile is assumed for the brightest cluster galaxy. A similar stretched expone...

The hydrogen ground-state problem is a touchstone for the theory of Stochastic Electrodynamics. Recently, we have shown numerically and theoretically that the H-atom self-ionizes after a characteristic time. In another approach, we reconsidered the harmonic oscillator and renormalized the stochastic force in order to suppress high-frequency tails s...

In this paper, the harmonic oscillator problem in Stochastic Electrodynamics is revisited. Using the exact shape of the Lorentz damping term prevents run-away effects. After introducing a cut-off in the stochastic power spectrum and regularizing the stochastic force, all relevant integrals are dominated by resonance effects only and results are der...

In an EPR setup, simultaneous measurement of two non-commuting observables is considered at station A and, possibly after a time delay, at station B. At each station one apparatus measures the z-component of a spin, while a second one measures the x-component of the same spin simultaneously. The dynamics of the measurements is solved explicitly. It...

This text presents a brief overview of the recent development of topics addressed by the original papers of this volume related to non-equilibrium phenomena in various (especially mesoscopic) systems and the foundations of quantum physics. A selection of relevant literature is included.

The minimally extended standard model contains three right handed or sterile neutrinos, coupled to the active ones by a Dirac mass matrix and mutually by a Majorana mass matrix. In a limit the physical masses are pairwise degenerate and the neutrinos attain Dirac signature. Hereby the maximal mixing for pseudo-Dirac neutrinos is impotent, so that t...

The MOdified Gravity (MOG) theory of J. Moffat assumes a massive vector particle which causes a repulsive contribution to the tensor gravitation. For the galaxy cluster A1689 new data for the X-ray gas and the strong lensing properties are presented. Fits to MOG are possible by adjusting the galaxy density profile. However, this appears to work as...

Two types of quantum measurements, measuring the spins of an entangled pair and attempting to measure a spin at either of two positions, are analysed dynamically by apparatuses of the Curie–Weiss type. The outcomes comply with the standard postulates.
This article is part of the themed issue ‘Second quantum revolution: foundational questions’.

Galaxy clusters, employed by Zwicky to demonstrate the existence of dark matter, pose new stringent tests. If merging clusters demonstrate that dark matter is self-interacting with cross section $\sigma/m\sim 2$ cm$^2$/gr, MACHOs, primordial black holes and light axions that build MACHOs are ruled out as cluster dark matter. Recent strong lensing a...

A doubly-peaked quasar microlensing event in the lensed Twin Quasar Q0957+561 A,B (Colley and Schild 2003) is analysed within several lensing models. In the most realistic model a lens resolves in image B the ellipse shaped, bright inner rim of the quasar's accretion disk, intersecting it twice. This lens weighs 0.5 Earth mass and is located inside...

The possibility of performing simultaneous measurements in quantum mechanics is investigated in the context of the Curie-Weiss model for a projective measurement. Concretely, we consider a spin-$\frac{1}{2}$ system simultaneously interacting with two magnets, which act as measuring apparatuses of two different spin components. We work out the dynam...

Ilya Schmelzer wrote recently: {\it Nieuwenhuizen argued that there exists some "contextuality loophole" in Bell's theorem. This claim in unjustified}. It is made clear that this arose from attaching a meaning to the title and the content of the paper different from the one intended by Nieuwenhuizen. "Contextual loophole" means only that if the sup...

In order to elucidate the properties currently attributed to ideal measurements, one must explain how the concept of an individual event with a well-defined outcome may emerge from quantum theory which deals with statistical ensembles, and how different runs issued from the same initial state may end up with different final states. This so-called “...

Various theories, such as MOND, MOG, Emergent Gravity and $f(R)$ theories avoid dark matter by assuming a change in General Relativity and/or in Newton's law. Galactic rotation curves are typically described well. Here the application to galaxy clusters is considered, focussed on the good lensing and X-ray data for A1689. As a start, the no-dark-ma...

De la Peña 1980 and Puthoff 1987 show that circular orbits in the hydrogen problem of Stochastic Electrodynamics connect to a stable situation, where the electron neither collapses onto the nucleus nor gets expelled from the atom. Although the Cole-Zou 2003 simulations support the stability, our recent numerics always lead to self-ionisation. Here...

The dark matter in the galaxy cluster Abell 1689 is modelled as an isothermal sphere of neutrinos. New data on the 2d mass density allow an accurate description of its core and halo. The model has no "missing baryon problem" and beyond 2.1 Mpc the baryons have the cosmic mass abundance. Combination of cluster data with the cosmic dark matter fracti...

The dark matter in the galaxy cluster Abell 1689 is modelled by isothermal
neutrinos. New data on the $2d$ mass density allow an accurate description of
its core and halo. There is no "missing baryon problem" and the baryons occur
at the cosmic mass fraction beyond $2.1$ Mpc. Combining cluster and cosmic data
leads to a solution of the dark matter...

Stochastic electrodynamics is a classical theory which assumes that the
physical vacuum consists of classical stochastic fields with average energy
$\frac{1}{2}\hbar \omega$ in each mode, i.e., the zero-point Planck spectrum.
While this classical theory explains many quantum phenomena related to harmonic
oscillator problems, hard results on nonline...

In a recent paper [arXiv:1502.06856] the authors studied numerically the
hydrogen ground state in stochastic electrodynamics (SED) within the the
non-relativistic approximation. In quantum theory the leading non-relativistic
corrections to the ground state energy dominate the Lamb shift related to the
photon cloud that should cause the quantum-like...

In a recent paper the authors studied numerically the hydrogen ground state in stochastic electrodynamics (SED) within the the non-relativistic approximation. In quantum theory the leading non-relativistic corrections to the ground state energy dominate the Lamb shift related to the photon cloud that should cause the quantum-like behaviour of SED....

The Advanced School on Quantum Foundations and Open Quantum Systems was an exceptional combination of lectures. These comprise lectures in standard physics and investigations on the foundations of quantum physics.
On the one hand it included lectures on quantum information, quantum open systems, quantum transport and quantum solid state. On the oth...

The outcome of a single quantum experiment is unpredictable, except in a
pure-state limit. The definite process that takes place in the apparatus may
either be intrinsically random or be explainable from a deeper theory. While
the first scenario is the standard lore, the latter implies that quantum
mechanics is emergent. In that case, it is likely...

In textbooks, ideal quantum measurements are described in terms of the tested
system only by the collapse postulate and Born's rule. This level of
description offers a rather flexible position for the interpretation of quantum
mechanics. Here we analyse an ideal measurement as a process of interaction
between the tested system S and an apparatus A,...

The Advanced School on Quantum Foundations and Open Quantum Systems was an exceptional combination of lectures. These comprise lectures in standard physics and investigations on the foundations of quantum physics. On the one hand it included lectures on quantum information, quantum open systems, quantum transport and quantum solid state. On the oth...

In textbooks, ideal quantum measurements are described in terms of the tested system only by the collapse postulate and Born’s rule. This level of description offers a rather flexible position for the interpretation of quantum mechanics. Here we analyse an ideal measurement as a process of interaction between the tested system S and an apparatus A,...

Recent weak and strong lensing data of the galaxy cluster A1689 are modelled
by dark fermions that are quantum degenerate within some core. The gas density,
deduced from X-ray observations up to 1 Mpc and obeying a cored power law, is
taken as input, while the galaxy mass density is modelled. An additional dark
matter tail may arise from cold or wa...

To study ideal measurement processes involving a tested system S coupled
to an apparatus A, we rely on a minimalist, statistical formulation of
quantum mechanics, where states encode properties of ensembles. The
required final state of S+A is shown to have a Gibbsian thermodynamic
equilibrium form, not only for a large ensemble of runs, but also fo...

Recent Herschel/SPIRE maps of the Small and Large Magellanic Clouds (SMC,
LMC) exhibit in each thousands of clouds. Observed at 250 microns, they must be
cold, T ~ 15 K, hence the name "Herschel cold clouds" (HCCs). From the observed
rotational velocity profile and the assumption of spherical symmetry, the
Galactic mass density is modeled in a form...

We consider the Herschel–Planck infrared observations of presumed condensations of interstellar material at a measured temperature of approximately 14 K (Juvela et al 2012 Astron. Astrophys.
541 A12), the triple point temperature of hydrogen. The standard picture is challenged that the material is cirrus-like clouds of ceramic dust responsible for...

The recent Sumi et al (2010, 2011) detection of free roaming planet mass
MACHOs in cosmologically significant numbers recalls their original detection
in quasar microlening studies (Schild 1996, Colley and Schild 2003). We
consider the microlensing signature of such a population, and find that the
nano-lensing (microlensing) would be well character...

The full text of this article is available in the PDF provided.

This paper deals with the recent state of the art of the following topics presented at the FQMT'11 conference: foundations of quantum physics, quantum measurement; nonequilibrium quantum statistical physics; quantum thermodynamics; quantum measurement, entanglement and coherence; dissipation, dephasing, noise, and decoherence; quantum optics; macro...

Small values of lithium observed in a small, primitive, Galaxy-Halo star SDSS
J102915 + 172927 cannot be explained using the standard cold dark matter CDM
theory of star formation, but are easily understood using the Gibson/Schild
1996 hydrogravitationaldynamics (HGD) theory. From HGD, primordial H-4He gas
fragments into Earth-mass planets in trill...

With general arguments it is motivated that we are still in search of a hidden-variables theory or sub-quantum mechanics. Aspects of a solvable model for quantum measurements are discussed, and a solution of the quantum measurement problem within ordinary quantum theory. The related statistical interpretation of quantum mechanics is advocated. Soli...

Textbooks on cosmology exhibit a thermodynamic inconsistency for free
streaming, decoupled matter. It is connected here to the chemical potential,
which deviates from its equilibrium value $\mu=\alpha k_BT$, where $\alpha$ is
the usual parameter of the Fermi-Dirac or Bose-Einstein distribution function.

The workshop "New directions in modern cosmology", organized by Theo
Nieuwenhuizen, Rudy Schild, Francesco Sylos Labini and Ruth Durrer, was held
from September 27 until October 1, 2010, in the Lorentz Center in Leiden, the
Netherlands. A transcript of the final round table discussion, chaired by Theo
Nieuwenhuizen and Rudy Schild, is presented. Th...

It is assumed that a galaxy starts as a dark halo of a few million Jeans
clusters (JCs), each of which consists of nearly a trillion micro brown dwarfs,
MACHOs of Earth mass. JCs in the galaxy center heat up their MACHOs by tidal
forces, which makes them expand, so that coagulation and star formation occurs.
Being continuously fed by matter from by...

The quantum measurement problem, understanding why a unique outcome is
obtained in each individual experiment, is tackled by solving models. After an
introduction we review the many dynamical models proposed over the years. A
flexible and rather realistic model is introduced, describing the measurement
of the $z$-component of a spin through interac...

The KATRIN experiment in Karlsruhe Germany will monitor the decay of tritium,
which produces an electron-antineutrino. While the present upper bound for its
mass is 2 eV/$c^2$, KATRIN will search down to 0.2 eV$/c^2$. If the dark matter
of the galaxy cluster Abell 1689 is modeled as degenerate isothermal fermions,
the strong and weak lensing data m...

One of the tests of nucleosynthesis theory is the $^3$He abundance in the
Galaxy. $^3$He$^+$ is observed through its 3.46 cm hyperfine level in Hii
regions and the $^3$He/H ratio compares well with theory. Since $^3$He can be
created or destroyed in nuclear reactions, one would expect that its abundance
shows a trend with the amount of such reactio...

The Schwarzschild\char21{}de Sitter and Reissner-Nordstr\"om\char21{}de Sitter black hole metrics appear as exact solutions in the recently formulated massive gravity of de Rham, Gabadadze and Tolley, where the mass term sets the curvature scale. They occur within a two-parameter family of de Rham, Gabadadze and Tolley mass terms. They show no trac...

Recent observations put forward that quasars are black holes with a magnetic dipole moment and no event horizon. To model hairy black holes a quantum field for hydrogen is considered in curved space, coupled to the scalar curvature. An exact, regular solution for the interior metric occurs for supermassive black holes. The equation of state is
p...

It is explained on a physical basis how absence of contextuality allows Bell inequalities to be violated, without bringing
an implication on locality or realism. Hereto we connect first to the local realistic theory Stochastic Electrodynamics, and
then put the argument more broadly. Thus even if Bell Inequality Violation is demonstrated beyond reas...

Recent observations put forward that quasars are black holes with a magnetic dipole moment and no event horizon. To model hairy black holes a quantum field for hydrogen is considered in curved space, coupled to the scalar curvature. An exact, regular solution for the interior metric occurs for supermassive black holes. The equation of state is p =...

Context: The baryonic dark matter dominating the structures of galaxies is widely considered as mysterious, but hints for it have been in fact detected in several astronomical observations at optical, infrared, and radio wavelengths. We call attention to the nature of galaxy merging, the observed rapid microlensing of a quasar, the detection of "co...

Given the state of a quantum system, one can calculate the expectation value
of any observable of the system. However, the inverse problem of determining
the state by performing different measurements is not a trivial task. In
various experimental setups it is reasonably straightforward to reconstruct the
state of a quantum system employing linear...

The dark matter of a spherical, relaxed galaxy cluster is modeled by isothermal, non‐interacting fermions; the galaxies and X‐ray gas by isothermal classical distributions. A fit to lensing data of the cluster Abell 1689 works well and yields a mass of a few eV. This low value casts doubt on the existence of a Cold Dark Matter particle.

Gravitational hydrodynamics acknowledges that hydrodynamics is essentially nonlinear and viscous. In the plasma, at $z=5100$, the viscous length enters the horizon and causes fragmentation into plasma clumps surrounded by voids. The latter have expanded to 38 Mpc now, explaining the cosmic void scale $30/h=42$ Mpc. After the decoupling the Jeans me...

The lensing data of the galaxy cluster Abell 1689 can be explained by an isothermal fermion model with a mass of 1-2 eV. The best candidate is the 1.5 eV neutrino; its mass will be searched down to 0.2 eV in KATRIN 2015. If its righthanded (sterile) modes were created too, there is 20% neutrino hot dark matter. Their condensation on clusters explai...

This paper summarizes the recent state of the art of the following topics presented at the FQMT’08 conference: Foundations of quantum physics, Quantum measurement; Quantum noise, decoherence and dephasing; Cold atoms and Bose–Einstein condensation; Physics of quantum computing and information; Nonequilibrium quantum statistical mechanics; Quantum,...

A dynamical model of a quantum measurement process is introduced, where the tested system S, a spin 1 2 , is simultaneously coupled with two apparatuses A and A ′ . Alone, A would measure the componen sz whereas A ′ alone would measurê sx. The apparatus A simulates an Ising magnetic dot involving N spins weakly coupled to a bath of phonons at a tem...

Confinement-induced orientational alignment of quasi-2D fluids
The first-mover advantage in scientific publication
Surprisingly similar scaling in and out of equilibrium
Do non-relativistic neutrinos constitute the dark matter?

The gravitational hydrodynamics of the primordial plasma with neutrino hot dark matter is considered as a challenge to the bottom-up cold-dark-matter paradigm. Viscosity and turbulence induce a top-down fragmentation scenario before and at decoupling. The first step is the creation of voids in the plasma, which expand to 37 Mpc on the average now....

This paper investigates the question whether a realistic black hole can be in principal similar to a star, having a large but finite redshift at its horizon. If matter spreads throughout the interior of a supermassive black hole with mass $M\sim10^9M_\odot$, it has an average density comparable to air and it may arise from a Bose-Einstein condensat...

The thermally induced denaturation of DNA in the presence of attractive solid
surface is studied. The two strands of DNA are modeled via two coupled flexible
chains without volume interactions. If the two strands are adsorbed on the
surface, the denaturation phase-transition disappears. Instead, there is a
smooth crossover to a weakly naturated sta...

The dark matter of the Abell 1689 galaxy cluster is modeled by thermal, non-relativistic gravitating fermions and its galaxies and X-ray gas by isothermal distributions. A fit yields a mass of $h_{70}^{1/2}(12/{\overline g})^{1/4}$1.445 $(30)$ eV. A dark matter fraction $\Omega_\nu=h_{70}^{-3/2}0.1893$ $(39)$ occurs for ${\overline g}=12$ degrees o...

It is explained on a physical basis how absence of contextuality allows Bell inequalities to be violated, without bringing an implication on locality or realism. The point is that the initial values of the hidden variables of the detectors are mutually exclusive for different detector settings. Therefore they have no reason to possess a common prob...

Theory and observations reveal fatal flaws in the standard LambdaCDM model. The cold dark matter hierarchical clustering paradigm predicts a gradual bottom-up growth of gravitational structures assuming linear, collisionless, ideal flows and unrealistic CDM condensations and mergers. Collisional fluid mechanics with viscosity, turbulence, and diffu...

Maxwell started to describe gravitation as a field in Minkowski space. Such an approach brought Babak and Grishchuk in 1999 the gravitational energy-momentum tensor. Simple manipulations allow the Einstein equations to take the form Amunu = (8piG/c4)Thetamunu, where A is the acceleration tensor and Theta, the total energy momentum tensor, is conser...

This article reports an open discussion that took place during the Keenan Symposium “Meeting the Entropy Challenge” (held in Cambridge, Massachusetts, on October 5, 2007) following the short presentations—each reported as a separate article in the present volume—by Joseph Smith Jr., Howard Butler, Andrew Foley, Kimberly Hamad‐Schifferli, Bernhardt...

This article reports an open discussion that took place during the Keenan Symposium “Meeting the Entropy Challenge” (held in Cambridge, Massachusetts, on October 4, 2007) following the short presentations—each reported as a separate article in the present volume—by Seth Lloyd, Owen Maroney, Silviu Guiasu, Ping Ao, Jochen Gemmer, Bernard Guy, Gian P...

We study an ensemble of two-level systems interacting with a thermal bath. This is a well-known model for glasses. The origin of memory effects in this model is a quasistationary but nonequilibrium state of a single two-level system, which is realized due to a finite-rate cooling and slow thermally activated relaxation. We show that single-particle...

Within the Relativistic Theory of Gravitation it is shown that the equation of state $p=\rho$ holds near the center of a black hole. For the stiff equation of state $p=\rho-\rho_c$ the interior metric is solved exactly. It is matched with the Schwarzschild metric, which is deformed in a narrow range beyond the horizon. The solution is regular every...

The Schwarzschild metric has a divergent energy density at the horizon, which motivates a new approach to black holes. If matter is spread uniformly throughout the interior of a supermassive black hole, with mass M~M=2.34 108M, it may arise from a Bose-Einstein condensate of densely packed H atoms. Within the relativistic theory of gravitation with...

This article reports an open discussion that took place during the Keenan Symposium ``Meeting the Entropy Challenge'' (held in Cambridge, Massachusetts, on October 5, 2007) following the short presentations-each reported as a separate article in the present volume-by Thomas Widmer, Ernest Geskin, James Keck, Noam Lior, Debjyoti Banerjee, Richard Pe...

In the relativistic theory of gravitation, space-time is Minkowskian, and gravitation is a physical field, next to electromagnetism. The bimetric coupling of Riemann and Minkowski metrics allows to define a unique, local gravitational energy density. The case of a positiv cosmological constant is considered. For cosmology, the ΛCDM model is covered...

An argument is given why the classical theory called Stochastic Electrodynamics may reproduce scattering and ionization experiments of electrons on atomic hydrogen.

In classical electrodynamics, extended with gradients of the electric and magnetic fields, a linear soliton is presented which bears features of the Kerr-Newman electron of electro-gravity. This is considered as a model for the electron, having a ring shape, with diameter equal to the Compton length h/mc and thickness smaller by the fine structure...

This is a transcript of the round table discussion, moderated by G. 't
Hooft, that took place at the end of the workshop "Beyond The Quantum"
in the Lorentz Center of the University of Leiden, the Netherlands, 29
May - 2 June 2006.
It displays current views on foundations of quantum mechanics.

pt. A. Introductions. The mathematical basis for deterministic quantum
mechanics / G.'t Hooft. What did we learn from quantum gravity? / A.
Ashtekar. Bose-Einstein condensates and EPR quantum non-locality / F.
Laloe. The quantum measurement process: lessons from an exactly solvable
model / A.E. Allahverdyan, R. Balian and Th. M. Nieuwenhuizen -- pt...

The density matrix of a two-level system (spin, atom) is usually determined
by measuring the three non-commuting components of the Pauli vector. This
density matrix can also be obtained via the measurement data of two commuting
variables, using a single apparatus. This is done by coupling the two-level
system to a mode of radiation field, where the...

Models of a directed polymer chain are studied in the presence of disorder in two and three dimensions, which describe adsorption-desorption transitions due to an attracting substrate. In particular, the free energy and the scaling behavior of the monomer concentration profile in the vicinity of the transition are calculated using a grand canonical...

A model is presented which describes magnetic properties of high-Tc superconductors when flux creep is the leading mechanism for dissipation. This model reduces the behaviour of a complex current pattern to the behaviour of essentially one single current loop which contains a fluctuating number of flux quanta. It is shown that the dynamics of such...

We consider the quantum XY spin chain with quasi-periodic two-valued exchange couplings and a uniform transverse field. The equivalence of the system with a free fermionic model permits a detailed analysis of its thermodynamics. The zero-temperature magnetization is a Cantor function of the applied field. The zero-field specific heat and susceptibi...

The spectra of random systems usually have an exponential singularity (Lifshitz tail) in the density of states at band edges: this singularity is a pure exponential for, e.g., the Anderson model with a binary potential distribution. It has been shown recently, at least in one dimension, that the Lifshitz singularity is affected by a universal logar...

In realistic spin glasses a fraction c of spins is located at random positions. Their couplings are determined by the relative spin positions. For such systems a field theory is formulated. In a certain mean-field limit it generalizes the Sherrington-Kirkpatrick free energy of a random bond spin glass. In general, an infinity of multistate overlaps...

We consider one-dimensional disordered systems (e.g., harmonic, tight-binding, Ising,...) where the value of the random variable (e.g., mass, site energy, magnetic field,...) at a given site is correlated with the value at the previous site. For a certain class of transition probabilities we present exact solutions of the integrated density of stat...

Semi-ballistic transport occurs when cavities have a moderate amount of elastic scattering, so that transport in the long direction(s) become diffusive. Transmission patterns are studied in this regime for disordered waveguides and for Fabry-Pérot interferometers with "dirty" mirrors. The results have implications for mesoscopic conductors at zero...

The minimal-work principle asserts that work done on a thermally isolated equilibrium system is minimal for the slowest (adiabatic) realization of a given process. This principle, one of the formulations of the second law, is operationally well defined for any finite (few particle) Hamiltonian system. Within classical Hamiltonian mechanics, we show...

The glass transition is considered within two toys models, a mean field spin glass and a directed polymer in a correlated
random potential.
In the spin glass model there occurs a dynamical transition, where the the system condenses in a state of lower entropy. The
extensive entropy loss, called complexity or information entropy, is calculated by a...

Starting with a field theoretic approach in Minkowski space, the gravitational energy momentum tensor is derived from the Einstein equations in a straightforward manner. This allows to present them as acceleration tensor = const. × total energy momentum tensor. For flat space cosmology the gravitational energy cancels the material energy. In the re...

The measurement of a spin-$\half$ is modeled by coupling it to an apparatus, that consists of an Ising magnetic dot coupled to a phonon bath. Features of quantum measurements are derived from the dynamical solution of the measurement, regarded as a process of quantum statistical mechanics. Schr\"odinger cat terms involving both the system and the a...

For the Kerr-Newman black hole, it is pointed out that the active gravitational mass equals twice the inertial mass. This remains valid when the solution is applied as a model for the electron. The factor 2 also occurs in a classical electrodynamics model for the electron proposed recently, where gravity is negligible. On the basis of this, one may...

A Hamiltonian model is solved, which satisfies all requirements for a realistic ideal quantum measurement. The system S is a spin-½, whose z-component is measured through coupling with an apparatus A = M + B, consisting of a magnet M formed by a set of N >> 1 spins with quartic infinite-range Ising interactions, and a phonon bath B at temperature T...

Already Einstein could never see quantum mechanics as a complete theory. Nowadays, many researchers, including ‘t Hooft, view quantum mechanics as a statistical description of some underlying reality. The workshop Beyond the Quantum, organized in Spring 2006 at the Lorentz Center in Leiden, The Netherlands, was one of the first meetings completely...

In the past thirty years, the area of spin glasses has experienced rapid growth, including the development of solvable models for glassy systems. Yet these developments have only been recorded in the original research papers, rather than in a single source. Thermodynamics of the Glassy State presents a comprehensive account of the modern theory of...

This is a transcript of the round table that took place during the conference Quantum Theory: Reconsideration of Foundations - 3, June 2005, Vaxjo, Sweden. There are presented opinions of leading experts in quantum foundations on such fundamental problems as the origin of quantum fluctuations and completeness of quantum mechanics.