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Lech S Borkowski

Lech S Borkowski
Emanuel School

PhD
Twitter @LechSBorkowski

About

57
Publications
10,221
Reads
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385
Citations
Additional affiliations
February 2011 - February 2016
Adam Mickiewicz University
Position
  • Professor (Associate)
October 1998 - January 2011
Adam Mickiewicz University
Position
  • Professor (Assistant)
September 1997 - September 1998
Georgia Institute of Technology
Position
  • Researcher
Education
August 1989 - August 1995
University of Florida
Field of study
  • Physics
September 1987 - August 1989
February 1983 - July 1987
Wrocław University of Technology
Field of study
  • Physics

Publications

Publications (57)
Data
Ministry of Foreign Affairs of Belarus note in response to my father's inquiry, delivered via the Polish Embassy in Minsk, concerning information related to the imprisonment of Bolesław Borkowski by the Soviet NKVD in 1945 and the following years.
Data
Document issued by the concentration camp authority in the Soviet Union to my father Bolesław Borkowski on 20 September 1954. He was convicted to ten years imprisonment by the Soviet War Tribunal of the NKVD (The People's Commissariat for Internal Affairs) in Brześć on the Bug river during the 7-9 June 1945 session. Bolesław deserted from the comm...
Data
This is an opinion issued by a psychologist on request of the Regional Center of Occupational Medicine in Zielona Góra, Poland. The psychologist was asked to conduct an evaluation of the mental state of Małgorzata Głuchowska (MG). While psychological testing is used sometimes in some highly specialized areas related to professional duties, there ex...
Data
This text file contains transcripts of psychologist's Sarbina Sobkowska speech during Małgorzata Głuchowska's visit on 13 November 2015. Polish text is followed by English translation. MG, who was a certified piano teacher at the State School of Music in Zielona Góra (Państwowa Szkoła Muzyczna) at the time, was obliged to visit the psychologist on...
Data
This is a text file containing transcripts of psychologist's Sarbina Sobkowska speech during Małgorzata Głuchowska's visit on 4 November 2015. The Polish text is followed by English translation. MG, who was a certified piano teacher at the State School of Music in Zielona Góra (Państwowa Szkoła Muzyczna) at the time, was obliged to visit the psycho...
Article
We consider a two-band superconductor (SC) whose order parameter (OP) components in each band are constants of opposite sign. Conduction electrons interact with impurities described by the Anderson model. We calculate the density of states (DOS) of this system within a mean-field slave-boson approximation. The position of impurity-induced states in...
Article
Full-text available
We analyze the response of the Morris-Lecar model to a periodic train of short current pulses in the period-amplitude plane. For a wide parameter range encompassing both class 2 and class 3 behavior in Hodgkin's classification there is a multimodal transition between the set of odd modes and the set of all modes. It is located between the 2:1 and 3...
Article
Full-text available
We study the response of the Hodgkin-Huxley neuron stimulated periodically by biphasic rectangular current pulses. The optimal response for charge-balanced input is obtained for cathodic-first pulses with an inter-phase gap (IPG) approximately equal 5 ms. For short pulses the topology of the global bifurcation diagram in the period-amplitude plane...
Article
Full-text available
We describe general characteristics of the Hodgkin-Huxley neuron's response to a periodic train of short current pulses with Gaussian noise. The deterministic neuron is bistable for antiresonant frequencies. When the stimuli arrive at the resonant frequency the firing rate is a continuous function of the current amplitude I(0) and scales as (I(0)-I...
Article
The experimental data of Takahashi [Physica D 43, 318 (1990)], on the response of squid giant axons stimulated by periodic sequence of short current pulses is interpreted within the Hodgkin-Huxley model. The minimum of the firing rate as a function of the stimulus amplitude I0 in the high-frequency regime is due to the multimodal transition. Below...
Article
We consider the superconducting state of $d+s$ symmetry with finite concentration of Anderson impurities in the limit $\Delta_s/\Delta_d \ll 1$. The model consists of a BCS-like term in the Hamiltonian and the Anderson impurity treated in the self-consistent large-$N$ mean field approximation. Increasing impurity concentration or lowering the ratio...
Book
Full-text available
This book describes the dynamics of the Hodgkin-Huxley neuron stimulated by periodic and stochastic stimuli. In the high frequency regime there is a multi-modal transition between odd-only modes and the state with both odd and even modes. This singularity appears in the presence of noise as a stochastic anti-resonance. The competition of different...
Article
We study the response of a Hodgkin-Huxley neuron stimulated by a periodic sequence of conductance pulses arriving through the synapse in the high-frequency regime. In addition to the usual excitation threshold there is a smooth crossover from the firing to the silent regime for increasing pulse amplitude gsyn. The amplitude of the voltage spikes de...
Article
We study thermodynamic properties of an Ising model of a ferromagnetic nanoscopic pyramid deposited onto a ferromagnetic bulk substrate. The influence of the interaction between the pyramid and the substrate is calculated in terms of the equilibrium reduced-state (density) operator used for description of thermodynamic properties of nanoscopic syst...
Article
We study the Ising model of a ferromagnetic nanopyramid deposited on a ferromagnetic substrate. The interaction between the pyramid and the substrate is calculated in terms of the reduced-state (density) operator. The spatial distribution of fluctuations of the molecular field and magnetization is obtained within the Gaussian approximation.
Article
We present results for the density of states of a s+d-wave superconductor containing finite concentration of Anderson impurities within the self-consistent slave boson approximation. There may be zero, one or two peaks in the energy gap at low energies. The height of the peaks is controlled by the impurity concentration whereas their position depen...
Article
We study thermodynamic properties of an Ising model of a ferromagnetic nanoscopic pyramid deposited on a ferromagnetic bulk substrate. The influence of the interaction between the pyramid and the substrate is calculated in terms of the reduced-state (density) operator used for description of thermodynamic properties of nanoscopic systems. The spati...
Article
Full-text available
We study the evolution from BCS to Bose limit in a two-dimensional d-wave superconductor at zero temperature and low density of charge carriers within the mean-field theory. We examine single quasiparticle properties when particle density and attraction strength are varied. For sufficiently high interaction strength there is a critical density belo...
Preprint
Full-text available
The evolution from BCS to BEC superconductivity in the s-wave and d-wave channels is analyzed at zero temperature for a two-dimensional superconductor. Spectroscopic quantities for s-wave and d-wave systems present fundamental differences when particle density and attraction strength are varied. A detailed analysis of single quasiparticle propertie...
Article
Full-text available
In ordinary metals, antiferromagnetic exchange between conduction electrons and a magnetic impurity leads to screening of the impurity spin below the Kondo temperature, $T_K$. In systems such as semimetals, small-gap semiconductors and unconventional superconductors, a reduction in available conduction states near the chemical potential can greatly...
Article
Superconducting states with "extended s-wave" symmetry have been suggested in connection with recent ARPES experiments on BSCCO. In the presence of impurities, thermodynamic properties of such states reflect a residual density of states $N(0)$ for a range of concentrations. While properties reflecting $N(\omega)$ alone will be similar to those of d...
Thesis
Typescript. Thesis (Ph. D.)--University of Florida, 1995. Vita. Includes bibliographical references (leaves 84-89).
Article
Systematic impurity doping in the Cu-O plane of the hole-doped cuprate superconductors may allow one to decide between unconvention al ("d-wave") and anisotropic conventional ("s-wave") states as possible candidates for the order parameter in these materials. We show that potential scattering of any strength always increases the gap minima of such...
Article
Full-text available
We discuss the effect of multichannel Kondo impurities on superconductivity. In the strong coupling regime such impurities are pairbreakers, in contrast to the ordinary Kondo effect. Measurements of $T_c$-suppression may help in identifying impurities displaying this more exotic exchange coupling to the conduction band. Comment: 3 pages, 4 figures,...
Article
Full-text available
We present a self-consistent theory of superconductors in the presence of Kondo impurities, using large-$N$ slave-boson methods to treat the impurity dynamics. The technique is tested on the s-wave case and shown to give good results compared to other methods for $T_K > T_c$. We calculate low temperature thermodynamic and transport properties for v...
Article
We present a self-consistent theory of Kondo impurities in gapless unconventional superconductors valid in the Fermi-liquid regime T≲TK. The impurity degrees of freedom are treated using the large-N slave-boson technique, leading to tractable equations describing the interplay between the Kondo effect and superconductivity. We show that for a singl...
Article
The superfluid A phase of 3He in thin films is studied at temperature T = 0. A simple model of the van der Waals interaction between the superfluid and the substrate is proposed. The influence of this interaction on the critical superflow for film thicknesses d
Article
The superflow of 3He in thin films on rough surfaces is studied using the formalism of microscopic theory. The gap equation is solved and the free energy and the superflow are calculated for three two-dimensional states that may exist in films with thickness d approximately xi 0. In the absence of flow the two-dimensional B state and the two-dimens...
Article
Recently it has been reported that the transition temperature to superfluid state of He3 in thin film is highly affected by various types of substratum. In this note we try to elucidate this effect by the inclusion of the Van der Waals forces into consideration. Though the model used is very simplified the proper behaviour is found.
Article
The transition from the superfluid to the gapless superfluid state in 3He films is studied. The equations for the energy gap are derived and solved numerically. The influence of surface roughness and film thickness on this transition is discussed. Phase transition curves are found.

Projects

Projects (2)
Project
Analysis of topics stated in the project's title. Project's web page: https://lsborkowski.com/pol/