Time dependent Schrödinger equation for black hole evaporation: No information loss

In 1976 S. Hawking claimed that “Because part of the information about the state of the system is lost down the hole, the final situation is represented by a density matrix rather than a pure quantum state”. ¹ This was the starting point of the popular “black hole (BH) information paradox”.     

The generalized uncertainty principle in (A)dS space and the modification of Hawking temperature from the minimal length

Recently, the Heisenberg's uncertainty principle has been extended to incorporate the existence of a large (cut-off) length scale in de Sitter or anti-de Sitter space, and the Hawking temperatures of the Schwarzshild–(anti) de Sitter black holes have been reproduced by using the extended uncertainty principle. I generalize the extended uncertainty to the case with an absolute minimum length and compute its modification to the Hawking temperature. I obtain a general trend that the generalized uncertainty principle due to the absolute minimum length “always” increases the Hawking temperature, implying “faster” decay, which is in conformity with the result in the asymptotically flat space. I also revisit the black hole-string phase transition, in the context of the generalized uncertainty principle.     

Wavepacket dynamics, quantum reversibility, and random matrix theory

We introduce and analyze the physics of “driving reversal” experiments. These are prototype wavepacket dynamics scenarios probing quantum irreversibility. Unlike the mostly hypothetical “time reversal” concept, a “driving reversal” scenario can be realized in a laboratory experiment, and is relevant to the theory of quantum dissipation. We study both the energy spreading and the survival probability in such experiments. We also introduce and study the “compensation time” (time of maximum return) in such a scenario. Extensive effort is devoted to figuring out the capability of either linear response theory or random matrix theory (RMT) to describe specific features of the time evolution. We explain that RMT modeling leads to a strong non-perturbative response effect that differs from the semiclassical behavior.     

Statistical dynamics of religion evolutions

A religion affiliation can be considered as a “degree of freedom” of an agent on the human genre network. A brief review is given on the state of the art in data analysis and modelization of religious “questions” in order to suggest and if possible initiate further research, after using a “statistical physics filter”. We present a discussion of the evolution of 18 so-called religions, as measured through their number of adherents between 1900 and 2000. Some emphasis is made on a few cases presenting a minimum or a maximum in the investigated time range—thereby suggesting a competitive ingredient to be considered, besides the well accepted “at birth” attachment effect. The importance of the “external field” is still stressed through an Avrami late stage crystal growth-like parameter. The observed features and some intuitive interpretations point to opinion based models with vector, rather than scalar, like agents.     

Weak measurement and Bohmian conditional wave functions

It was recently pointed out and demonstrated experimentally by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be “directly measured” using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a perhaps entangled multi-particle system, the result is precisely the so-called “conditional wave function” of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave function which Bohmian mechanics uniquely makes possible. Similarly, a weak-measurement-based procedure for directly measuring a sub-system’s density matrix should yield, under appropriate circumstances, the Bohmian “conditional density matrix” as opposed to the standard reduced density matrix. Experimental arrangements to demonstrate this behavior–and also thereby reveal the non-local dependence of sub-system state functions on distant interventions–are suggested and discussed.     

An optical study of the correlation between growth kinetics and microstructure of μc-Si grown by SiH4-H2 PECVD

Fully microcrystalline silicon, μc-Si, thin films have been deposited on corning glass by plasma enhanced chemical vapor deposition (PECVD) using SiH₄-H₂. The effects of the surface treatment and of the deposition temperature on microstructure of μc-Si films are investigated by “in situ” laser reflectance interferometry (LRI), “ex situ” spectroscopic ellipsometry (SE) and Raman spectroscopy. LRI indicated the existence of a “crystalline seeding time”, which is indicative of the crystallite nucleation, and depends on substrate treatments. Longer “crystalline seeding time” results in a lower density of crystalline nuclei, which grow laterally, yielding to complete suppression of the amorphous incubation layer and to growth of very dense, fully crystalline layer at a growth temperature as low as 120 °C.     

Negative probabilities and information gain in weak measurements

We study the outcomes in a general measurement with postselection, and derive upper bounds for the pointer readings in weak measurement. The probabilities inferred from weak measurements change along with the coupling strength; and the true probabilities can be obtained when the coupling is strong enough. By calculating the information gain of the measuring device about which path the particles pass through, we show that the “negative probabilities” only emerge for cases when the information gain is little due to very weak coupling between the measuring device and the particles. When the coupling strength increases, we can unambiguously determine whether a particle passes through a given path every time, hence the average shifts always represent true probabilities, and the strange “negatives probabilities” disappear.     

Two mechanisms of spiral-pair-source creation in excitable media

Two new modes of generating spiral pairs in an excitable medium have been found. They depend on a geometrical structure (GS) inside the medium. This may be formed e.g. as a result of scars or fibrosis in the heart tissue, or artificially built in a chemical reaction substrate. Both sources involve a GS composed of a circular “convergent lens” bounded by two opaque “walls”. One mode can be induced by a single wave and behaves as a “flip-flop” type of a limit cycle. The other mode is generated by a train of plane waves impinging on the GS, and is created at the focus of the converging wave-fragments.     

Dixon's extended bodies and impulsive gravitational waves

The “reaction” of an extended body to the passage of an exact plane gravitational wave is discussed following Dixon's model. The analysis performed shows several general features, e.g. even if initially absent, the body acquires a spin induced by the quadrupole structure, the center of mass moves from its initial position, as well as certain “spin-flip” or “spin-glitch” effects which are being observed.     

Reproducible resistive switching effect for memory applications in heterocontacts based on strongly correlated electron systems

The transitional processes in heterocontacts based on strongly correlated electron systems (SCES) are studied for analyzing of the effect of resistive switching (ERS). It has been shown that the process is asymmetric with respect to switching into “on” and “off” states, the switching time is controlled by a voltage level, this time can be less than microseconds, on the other hand, relaxation processes can reach tens seconds. The switching is controlled by two processes: a change in the resistance state of the normal metal/SCES interface under effect of electric current field and by electrodiffusion of oxygen to vacancies, at that the doping level of the contact area and resistive properties of the heterocontact change. In particular, electrodiffusion of mobile oxygen induced by the electric field makes it possible to use a device with ERS as a memristor. On the other hand, a possibility to control the switching time and ON and OFF parameters show the possibilities to use these devices as memory elements “RAM”.     

A minimal mechanical device displaying bona fide stochastic resonance

A sphere in a shaken box with two connected compartments was monitored experimentally. The peaks of the residence time distribution appear at integer multiples of the driving period. The area below the first peak, the signal-to-noise ratio and the output signal power have maxima at a common value of the driving period Td. These maxima occur at the mimimum of TK/Td (TK: “Kramer's time”).     

Dependence of adenine isolation efficiency on the chain length evidenced using paramagnetic particles and voltammetry measurements

The main aim of this work was to study the dependence of oligoadenine isolation efficiency on the chain length by using paramagnetic particles covered by homo-deoxythymidines ((dT)25) with subsequent detection by adsorptive transfer technique coupled with square wave voltammetry. For this purpose, the oligonucleotides of the length A5, A10, A15, A20, A25, A30, A35, A40 and poly(A) in various concentrations were chosen. We determined that the isolation efficiency defined as “isolated oligonucleotide concentration”/“given oligonucleotide concentration” was about 55% on average. Sequence A25 demonstrated the best binding onto microparticles surface.     

Morphological and dynamical aspects of the room evacuation process

We study the evacuation of a set of 200 pedestrians from a room under a state of panic. The dynamics of the pedestrians is given by the Social Force Model. The degree of panic is controlled by a parameter v_d which represents the velocity at which pedestrians wish to move. We show that the “faster is slower effect” can be understood in terms of the works performed by the different forces present in the system and the role played by dissipative terms in the model. Beyond the maximum flow rate the “granular cluster” mass distribution displays a transition from exponentially decaying to “U-shaped” as this value of v_d evacuation efficiency begins to decrease rapidly.     

Particle creation by a black hole as a consequence of the Casimir effect

Particle creation by a black hole is investigated in terms of temperature corrections to the Casimir effect. The reduction of the Hawking effect to more familiar effects observed in the laboratory enables us to reveal the mechanism of particle creation. The blackbody nature of the Hawking radiation is due to the interaction of virtual particles with the surface of a cavity formed by the Schwarzschild gravitational field potential barrier. These particles are squeezed out by the contraction of the potential barrier and appear to an observer atJ ⁺ as the real blackbody ones.     

Modulation instability: The beginning

We discuss the early history of an important field of “sturm and drang” in modern theory of nonlinear waves. It is demonstrated how scientific demand resulted in independent and almost simultaneous publications by many different authors on modulation instability, a phenomenon resulting in a variety of nonlinear processes such as envelope solitons, envelope shocks, freak waves, etc. Examples from water wave hydrodynamics, electrodynamics, nonlinear optics, and convection theory are given.     

Noncollinear wave mixing for measurement of dynamic processes in polymers: Physical ageing in thermoplastics and epoxy cure

Elastic wave mixing using an immersion method has shown effective monitoring and scanning capabilities when applied to thermoplastic ageing, epoxy curing, and non-destructive testing. In water, excitation and reception of waves do not require physical contact between the tools and the specimen, making the acquisition of high-resolution C-scans possible. The nonlinear material parameters exhibit a much higher sensitivity to the specimen state compared to linear ones. Thus, the nonlinear data for polymethyl methacrylate (PMMA) have a 40% difference between zones of “young” and “aged” material, while the linear data show no difference at all. Methodology and logistics of the immersion wave-mixing method are discussed in detail. Monitoring of epoxy curing has also revealed a good sensitivity of the method to this complex process including several characteristic stages, such as the time of maximal viscosity, the gel time, and the vitrification time. These stages are independently verified in separate rheometry measurements. The presented method allows for a number of possibilities: wave-mode and frequency separations, elimination of surrounding medium influence, “steering” (scanning) a scattered wave, controlling the location of the intersection volume, single-sided or double-sided measurements, and operation in detector mode.     

Information erasure in quantum systems

The physical cost of information erasure is considered within a new approach that regards erasure as loss of correlation between the state of an erasable quantum system and that of an enduring “referent” system holding classical information. A physical model of information erasure built on this referential picture is described in detail, and lower bounds on entropic and energetic costs are obtained from quantum dynamics and entropic inequalities alone.     

Fullerenes in molecular liquids. Solutions in “good” solvents: Another view

Brief review and update information concerning the state of “bare” (unmodified) fullerenes in different solvents, including organosols and hydrosols, is given. The hydrophobic nature of fullerene dispersions in aqueous media is discussed. The possibility of the existence of thermodynamic equilibrium in (fullerene + non-polar solvent) system is questioned. The modern data allow returning to the consideration of C₆₀ (C₇₀, etc.) molecules as colloidal (or sub-colloidal) species, inclined to aggregation. Recent publications support the idea of the solvophobic solvation of fullerene molecules even in “good” solvents. Hence, the solvophobic effect, in concert with the van-der-Waals attraction, seems to be driving forces of permanent (though sometimes very slow) aggregate formation, analogous to coagulation of nano-sized particles of common solvophobic colloidal systems.