Miroslaw Kozlowski

Picosecond thermal pulses in thin gold films

In this paper it has been shown that, with the advent of lasers with a very short pulse duration, the effect of thermal wave propagation becomes important. To consider this effect, hyperbolic heat conduction in thin gold films was studied. It was shown that for heat fluxes of the order 108 W·cm−2, a thermal wave is generated in thin gold films. The consideration of the hyperbolicity of heat transfer enables one to describe the temperature profile with one value of fluence.

“Order-order” relaxations in intermetallics

Abstract “Order-order” relaxation processes in high-temperature intermetallics occur after an abrupt change of temperature and are controlled by atomic migration in the almost perfect superstructure. The related experiments were carried out using systems being of technological interest and representing three common types of superstructures: L12 (Ni3Al-based quasi-binaries), L10 (FePd, FePt) and B2 (NiAl, FeAl). The corresponding Monte Carlo (MC) simulations of “order-order” kinetics involving the Glauber dynamics implemented with vacancy mechanism for atomic jumps were performed. The studies indicate a crucial role of anti-site-easy-diffusion channels offered by particular superstructures in determining the character of “order-order” processes and their relationship to steady-state self-diffusion. Specific mechanisms of the relaxations in triple-defect B2-ordered binaries are discussed.

Causal heat transport induced by zeptosecond laser pulses

The thermal phenomena induced by zeptosecond (10 m 21 s) laser pulses are discussed in this article. Considering the theoretical proposal of the lasetron , the Heaviside equation for heat transport on zeptosecond time scale is formulated. In the article, the modified Schrodinger equation (Janina Marciak-koz ^ owska and Miros ^ aw Koz ^ owski (2002). Lasers in Engineering , 12 , 53) for quantum phenomena on the zeptosecond time scale was also discussed.

Modified schrödinger equation for attosecond laser pulse interaction with matter

Recently the measurement of X-ray pulses approaching the attosecond frontier was published (M. Drescher et al ., Science 291 (2001) p. 1923). The attosecond laser pulse enables the study and control of the motion of electrons inside atoms. In this paper we develop and solve the modified Schrodinger equation (MSE) which describes the interaction of electrons with its surroundings in an atom. This interaction can be detected only using an attosecond laser pulse within the relaxation time of the interaction which is of the order of 10 attoseconds.

The thermal inertia of materials heated with a laser pulse faster than relaxation time

The nonlocal hyperbolic heat conduction equation is used to describe the thermal inertia of thin metal films (TMF) heated with femtosecond laser pulses. It is shown that for TMF the signatures of thermal inertia are (i) the delay of the heating process and (ii) the strong localization of the thermal energy in TMF.

The time arrow in a Planck gas

In this paper the quantum heat transport equation (QHT) is applied to the study of thermal properties of Planck gas, i.e., a gas of massive particles with mass equal to the Planck massMP = (łc/G)1/2 and whose relaxation time equals the Planck timeτp = (łG/c5)1/2. The quantum of thermal energy for a Planck gas,EPlanck = 1019GeV, and the quantum thermal diffusion coefficientDPlanck = (ħG/c)1/2 are calculated. Within the framework of QHT the thermal phenomena in a Planck gas can be divided into two classes: for a time period shorter thanτp, the time reversal symmetry holds and for a time period longer thanτp, time symmetry is broken, i.e., a time arrow is created.

Atomic migration and ordering phenomena in bulk and thin films of FePd and FePt

Abstract “Order–order” kinetics was studied by means of “in situ” and quasi-residual (REST) resistometry in bulk and thin films of L10-ordered FePd and FePt intermetallics. Substantial effect of magnetic ordering on the activation energy for chemical ordering was revealed in FePd. A discontinuous change of ordering dynamics was detected in FePt between 800 and 830 K. The results are consistent with the data of Fe* diffusion in FePt multilayer examined by means of nuclear resonant scattering in grazing-incidence geometry (GINRS). Monte Carlo (MC) simulations of “order–order” processes in L10-ordered bulk FePd and FePt and nano-layered FePt have been carried out using Glauber dynamics with vacancy mechanism of atomic jumps. Multi-time-scale “order–order” relaxations observed in the bulk were predominated in nanolayers by a reorientation of the initial z-variant L10 superstructure into a mixture of x- and y-variants.

KLEIN-GORDON THERMAL EQUATION FOR A PLANCK GAS

In this paper the quantum hyperbolic equation formulated in our earlier paper [Found. Phys. Lett.10, 599 (1997)] is applied to the study of the propagation of the initial thermal state of the universe. It is shown that the propagation depends on the barrier height. The Planck wall potential is introduced,VP = ħ/8tP= 1.125 1018 GeV, wheretP is a Planck time. For the barrier heightV <VP, the master thermal equation isthe modified telegrapher’sequation, and for barrier heightV >VP the master equation is theKlein- Gordon equation. The solutions of both type equations for Cauchy boundary conditions are discussed.

The Smearing Out of the Thermal Initial Conditions Created in a Planck Era

In this paper the quantum heat transport in a Planck gas in the presence of the potential (other than the thermal one) is investigated. The new quantum heat transport equation which generalizes our potential-free QHT is developed. The thermal wave solution of QHT for a Planck gas is obtained and a condition for distortionless propagation of thermal wave is formulated. It is argued that the initial conditions of the Beginning (i.e., at t=0) are smeared in the time scale of the Planck time.

Discretization of the thermal excitation in highly excited matter

In this paper the thermal energy diffusion for quantum particles is described. The quantum heat transport equation is obtained. It is shown that, for a short-time thermal excitation (of the order of the relaxation time), the excited matter response is quantized on the different levels (atomic, nuclear, quark) with quantum thermal energy equalEatomic ∼9 eV,Enuclear ∼7 MeV, andEquark ∼139 MeV.