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A. M. Lisewski

Publications and source records attributed to A. M. Lisewski.

10 recordsLinked to original sources
arXiv2012

Earth's extensive entropy bound

The possibility of planetary mass black hole production by crossing entropy limits is addressed. Such a possibility is given by pointing out that two geophysical quantities have comparable values: first, Earth's total negative entropy flux integrated over geological time and, second, its extensive entropy bound, which follows as a tighter bound to the Bekenstein limit when entropy is an extensive function. The similarity between both numbers suggests that the formation of black holes from planets may be possible through a strong fluctuation toward thermodynamic equilibrium which results in gravothermal instability and final collapse. Briefly discussed are implications for the astronomical observation of low mass black holes and for Fermi's paradox.

gr-qc↗
arXiv2006

Modal logic approach to preferred bases in the quantum universe

We present a modal logic based approach to the so-called endophysical quantum universe. In particular, we treat the problem of preferred bases and that of state reduction by employing an eclectic collection of methods including Baltag's analytic non-wellfounded set theory, a modal logic interpretation of Dempster-Shafer theory, and results from the theory of isometric embeddings of discrete metrics. Two basic principles, the bisimulation principle and the principle of imperfection, are derived that permit us to conduct an inductive proof showing that a preferred basis emerges at each evolutionary stage of the quantum universe. These principles are understood as theoretical realizations of the paradigm according to which the physical universe is a simulation on a quantum computer and a second paradigm saying that physical degrees of freedom are a model of Poincare's physical continuum. Several comments are given related to communication theory, to evolutionary biology, and to quantum gravity.

quant-ph↗
arXiv2006

The concept of strong and weak virtual reality

We approach the virtual reality phenomenon by studying its relationship to set theory, and we investigate the case where this is done using the wellfoundedness property of sets. Our hypothesis is that non-wellfounded sets (hypersets) give rise to a different quality of virtual reality than do familiar wellfounded sets. We initially provide an alternative approach to virtual reality based on Sommerhoff's idea of first and second order self-awareness; both categories of self-awareness are considered as necessary conditions for consciousness in terms of higher cognitive functions. We then introduce a representation of first and second order self-awareness through sets, and assume that these sets, which we call events, originally form a collection of wellfounded sets. Strong virtual reality characterizes virtual reality environments which have the limited capacity to create only events associated with wellfounded sets. In contrast, the more general concept of weak virtual reality characterizes collections of virtual reality mediated events altogether forming an entirety larger than any collection of wellfounded sets. By giving reference to Aczel's hyperset theory we indicate that this definition is not empty, because hypersets encompass wellfounded sets already. Moreover, we argue that weak virtual reality could be realized in human history through continued progress in computer technology. Finally, we reformulate our characterization into a more general framework, and use Baltag's Structural Theory of Sets (STS) to show that within this general hyperset theory Sommerhoff's first and second order self-awareness as well as both concepts of virtual reality admit a consistent mathematical representation.

cs.LO↗
arXiv2005

Representation of protein structure based on frequency distributions of oriented cycles in contact graphs

We present a statistical approach to protein structure by introducing a representation of protein folds based on simple observables defined as frequencies of oriented cycles in contact graphs. Motivated by the idea that these cycles may form a code of the entire protein structure we investigate its Shannon entropy. The latter shows a characteristic transitory behavior when traced over different values of the geometric threshold $t$ which defines protein residues in contact. To account for this observation, we propose a non-linear mechanical model-- formulated as a Hamiltonian system in which $t$ is regarded as a continuous parameter-- that allows to identify the behavior of the Shannon entropy as a first-order phase transition between a disordered and an ordered phase of the proposed mechanical system. The transition itself reflects the formation of protein structure when represented in terms of contact graph cycles, and it is identified as an example of a fragmentation transition known from several other statistical systems without a proper thermodynamic limit. Some interesting implications follow from our model including chirality, broken $t$-symmetry and one-dimensionality. Although defined from purely structural considerations, we further show that for native protein structures these observables follow some of the quantitative rules that are typically valid for amino acid types in protein sequences. Moreover, this relation between polypeptide structures and their amino acid sequences suggests a specific protein design alphabet.

q-bio.BM↗
arXiv2002

A Fixed Point Result for Environment-Induced Semigroups

Based on the environment induced semigroup approach to the quantum measurement process, we show that a certain class of these semigroups, referred to as contractive uniformly $k$-Lipschitzian semigroups, exhibit a fixed point property. With regard to the quantum measurement problem, semigroups of this kind ensure decoherence and the selection of a single state from the familiy of pointer states. In fact, the common fixed point is the selected state.

quant-ph↗
arXiv2000

Distributed Burning in Type Ia Supernovae: A Statistical Approach

We present a statistical model which shows the influence of turbulence on a thermonuclear flame propagating in C+O white dwarf matter. Based on a Monte Carlo description of turbulence, it provides a method for investigating the physics in the so-called distributed burning regime. Using this method we perform numerical simulations of turbulent flames and show that in this particular regime the flamelet model for the turbulent flame velocity loses its validity. In fact, at high turbulent intensities burning in the distributed regime can lead to a deceleration of the turbulent flame and thus induces a competing process to turbulent effects that cause a higher flame speed. It is also shown that in dense C+O matter turbulent heat transport is described adequately by the Peclet number, Pe, rather than by the Reynolds number, which means that flame propagation is decoupled from small-scale turbulence. Finally, at the onset of our results we argue that the available turbulent energy in an exploding C+O white dwarf is probably too low in order to make a deflagration to detonation transition possible.

astro-ph↗
arXiv2000

Constraints On The Delayed Transition to Detonation in Type Ia Supernovae

We investigate the possibility of a delayed detonation in a type Ia supernova under the assumption that the transition to detonation is triggered by turbulence only. Our discussion is based on the Zeldovich mechanism and suggests that typical turbulent velocities present during the explosion are not strong enough to allow this transition to occur. Although we are able to show that in carbon-rich matter (e.g., $X(^{12}$C$) = 0.75$) the possibility of a deflagration to detonation transition (DDT) is enhanced, even in this case the turbulent velocities needed are larger than the expected value of $u'(L) \approx 10^7 {cm s}^{-1}$ on a length-scale of $L \approx 10^6$ cm. Thus we conclude that a DDT may not be a common event during a thermonuclear explosion of a Chandrasekhar-mass white dwarf.

astro-ph↗
arXiv1999

Can all neurobiological processes be described by classical physics?

We discuss results recently given in an article by M. Tegmark (quant-ph/9907009) where he argues that neurons can be described appropriately by pure classical physics. This letter is dedicated to the question if this is really the case when the role of dissipation and noise -- the two concurrent phenomena present in these biological structures -- is taken into account. We argue that dissipation and noise might well be of quantum origin and give also a possible reason why neural dynamics is not classical.

quant-ph↗
arXiv1999

On the classical hydrodynamic limit of quantum field theories

We discuss the transition from a quantum to a classical domain for a model where a separation into environment and system is explicitely not given. Utilizing the coarse graining procedure for free quantum fields we also apply the projection method and the Hamiltonian principle to study possible cases of emergent classicality. General conditions for classical dynamics are given. Eventually, they lead to the equations of motion for a perfect classical fluid.

quant-ph↗