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Wyszukujesz frazę "Domanski, T." wg kryterium: Autor


Tytuł:
On Realization of the Bose-Einstein Condensates and Quantum Superfluids
Autorzy:
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1536541.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.-z
74.20.Mn
74.40.-n
Opis:
The purpose of this work is twofold. In the first part we describe superfluidity/superconductivity as an emergent phenomenon resulting from two-body correlations in presence of the Bose-Einstein condensation of particles. We briefly discuss the underlying mechanism for bosons as well as fermion pairs and illustrate various realizations of superfluidity emphasizing the recent examples. In the second part we study the glassy liquid of incoherent pairs which might exist above the transition temperature $T_{c}$ in the underdoped regime of cuprate superconductors. In particular, we explore the angular variation of pseudogap within two-dimensional version of the boson-fermion model using for a quantitative analysis the projective method. We find that above $T_{c}$ the pseudogap closes first near the nodal areas restoring there pieces (arcs) of the Fermi surface whereas remaining parts of the large Fermi surface around the antinodal points are still absent due to incoherent pairs. Upon increasing temperature the length of the Fermi arcs enlarges because the superconducting correlations are gradually suppressed. An intriguing death of Fermi surface can thus be closely related to the Bogoliubov quasiparticles whose existence in the pseudogap state has been predicted by us and confirmed recently by the angle resolved photoemission spectroscopy measurements on $Bi_2Sr_2CaCu_2O_8$ and $La_{1.895}Sr_{0.105}CuO_4$ compounds.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 204-211
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudogap and Other Precursor Signatures in the Systems with Local Fermion Pairs
Autorzy:
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038382.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Mn
71.10.Li
03.75.Kk
Opis:
We consider precursor effects of the superconducting order which possibly show up in the normal state of high temperature superconducting materials. The local pairs of electrons or holes are formed there well above the transition temperature T$\text{}_{c}$. Due to strong quantum fluctuations the single particle density of states can be partly depleted near the Fermi energy leading to the pseudogap. We claim that this feature should go hand in hand with emergence of the Bogoliubov-type quasiparticles. In the normal state they are expected to be damped and acquire the long lifetime upon passing T$\text{}_{c}$. These Bogoliubov-type quasiparticles may nevertheless become correlated on a finite spatial and temporal scale. We discuss how such short-range pair correlations can be detected experimentally.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 553-560
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Renormalization Group Approach for the Double Exchange Ferromagnets
Autorzy:
Zapalska, M.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1409624.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.10.Cc
75.47.Gk
75.30.Et
75.30.Ds
Opis:
The discovery of the colossal magnetoresistance (CMR) in the manganese oxides with perovskite structures $T_1 - x DMnO_3$ (T = La, Pr, Nd; D=Sr, Ca, Ba, Pb) and its potential technological application motivated theoretical and experimental researchers to study the itinerant ferromagnetism. A first theoretical description of this phenomenon in terms of the double-exchange mechanism was given a long time ago by Zener. In this model, the spin orientation of adjacent Mn-moments is associated with kinetic exchange of conduction $e_g$ electrons. Consequently, alignment of the core Mn-spins by an external magnetic field causes higher conductivity. The Mn ions are considered as localized forming a spin of S = 3/2 and they are coupled to the itinerant electrons by a strong ferromagnetic Hund coupling, $J_H$ > 0. We apply the flow equation technique (nonperturbative method, based on continuous canonical transformation) to the double-exchange model for ferromagnetism described by the Kondo type Hamiltonian. We want to eliminate the interaction term responsible for non-conservation of magnon number and to take into account fermion and magnon degrees of freedom. We express the spin operators of Mn ions via the magnon operators (the Holstein-Primakoff transformation) and investigate the magnon excitation spectrum determined by Green's function.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1099-1101
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interplay between the Correlations and Superconductivity in Electron Transport through the Double Quantum Dots
Autorzy:
Barański, J.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1428494.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
74.50.+r
Opis:
We study the influence of electron correlations on nonequilibrium transport through the quantum dots coupled between one metallic and one superconducting electrode. Such type of nanodevices are characterized by the induced on-dot pairing spread from the superconducting lead (proximity effect) and effectively responsible for mixing the particle with hole excitations. On the other hand, strong Coulomb repulsion between the opposite spin electrons tends to suppress a double occupancy of the quantum dots competing with the on-dot superconducting order. The Coulomb interactions can also cause a screening of the quantum dot spin by itinerant electrons of the metallic lead giving rise to formation of the Kondo resonance. We analyze interplay of such phenomena for the setup of double quantum dots where the quantum interference (such as Fano) effects influence the subgap electron transport through the Andreev scattering.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1213-1215
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single Particle Excitation Spectrum of a Proximized Quantum Dot: The Flow Equation Study
Autorzy:
Zapalska, M.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1374179.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.10.Cc
71.27.+a
72.15.Qm
74.45.+c
Opis:
We study the in-gap states of a quantum dot hybridized with the metallic and superconducting reservoirs applying the continuous unitary transformation to the Anderson-type Hamiltonian. We derive the set of flow equations and analyse the effective single particle excitation spectrum of the correlated quantum dot in presence of the induced electron pairing.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-137-A-140
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The In-Gap Charge Current through the Correlated Quantum Dot Hybridized with Superconductor
Autorzy:
Donabidowicz, A.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1812275.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We explore the Andreev tunnelling through the strongly correlated quantum dot embedded between the normal and superconducting electrodes. For a small external voltage |eV| <$∆_s$ the electron arriving from the normal lead can be converted into a pair on the quantum dot and further propagates in the superconducting lead while simultaneously the hole is reflected back to the normal electrode. Conductance of such anomalous current is very sensitive to the particle-hole mixing of the quantum dot spectrum. We analyze the influence of the proximity effect and the Coulomb interactions on the differential Andreev conductance focusing on the extreme limit $∆_s$ → ∞.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 75-82
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluctuations between the BCS and BEC Limits in the System of Ultracold Alkali Atoms
Autorzy:
Domański, T.
Donabidowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046728.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Mn
03.75.Kk
03.75.Ss
Opis:
We investigate the fluctuations induced by time-dependent interchange between the Bardeen-Cooper-Schrieffer and Bose-Einstein condensation regimes in the ultracold gas of fermion atoms. Such crossover can be triggered by varying the external magnetic field across the Feshbach resonance. Experimental realization is usually done via very fast switching which leads to the nonequilibrium effects. In this paper we focus on the ground state properties. In particular, we analyze time dependence of the wave function and consider fluctuations of the order parameters.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 471-476
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tunneling through the Quantum Dot Coupled to Incoherent Superconductor
Autorzy:
Donabidowicz, A.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/2047329.pdf
Data publikacji:
2007-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We study the equilibrium and non-equilibrium properties of the strongly correlated quantum dot coupled between normal and superconducting leads. The effect of electron pair coherence, Coulomb interactions, and d-wave anisotropy of the order parameter are discussed with a particular account of their influence on a charge tunneling through the quantum dot.
Źródło:
Acta Physica Polonica A; 2007, 111, 5; 671-682
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interference Effects on Double Quantum Dots Coupled Between Metallic and Superconducting Leads
Autorzy:
Barański, J.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1431289.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
74.50.+r
Opis:
We describe the quantum interference effects in the nanodevice consisting of the double quantum dot coupled to the metallic and superconducting electrodes. In such heterostructures the superconducting properties are spread to the quantum dot due to the proximity effect. We investigate the density of states and anomalous Andreev conductance of the interfacial quantum dot exploring the conditions necessary for appearance of the Fano-type lineshapes. We also consider the electron correlations and discuss an interplay between the Coulomb blockade and the Fano-type interference.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 812-815
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic Response of the BCS Superconductor: Flow Equation Approach
Autorzy:
Zapalska, M.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1431495.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.Fg
71.10.Li
05.10.Cc
Opis:
We address the linear response for superconductors using the non-perturbative technique based on the continuous unitary transformation. We discuss how this method rigorously reproduces the standard BCS solution and point out how such result can be generalized to the case of electron systems with strong pairing fluctuations and in presence of the nonequilibrium phenomena.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 854-857
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon Signatures of a Quantum Impurity with Induced Electron Pairing
Autorzy:
Barański, J.
Domański, T.
Powiązania:
https://bibliotekanauki.pl/articles/1374760.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
73.23.Hk
74.45.+c
74.50.+r
63.22.-m
Opis:
We analyze the effective spectrum of a vibrating molecule coupled between one conducting and another superconducting electrode. The proximity effect induces electron pairing which is manifested by the subgap quasiparticle peaks (the Andreev states) whose broadening depends on a hybridization with the conducting electrode. On the other hand, the electron-phonon interaction leads to a multilevel structure with the polaronic states separated by the phonon energy. We inspect a combined effect of both these (polaronic and induced pairing) phenomena.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-73-A-76
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subgap Current through the Strongly Correlated Quantum Dot Hybridized with the Normal and Superconducting Leads
Autorzy:
Domański, T.
Donabidowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1810301.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
74.20.Fg
74.45.+c
Opis:
We investigate charge tunneling through the strongly correlated quantum dot placed between the metallic and superconducting leads. For small voltages |V| ≤ Δ/e applied across the junction the current is transmitted by the anomalous mechanism of the Andreev reflections. Such transport is sensitive to the strong Coulomb interactions which can be responsible for the charging effect and, at low temperatures, for appearance of the Kondo resonance. We analyze their signatures in the differential Andreev conductance.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 86-88
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhomogeneities in Superconductors Described by the Two-Component Model
Autorzy:
Krzyszczak, J.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1537060.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
74.20.-z
74.81.-g
Opis:
We study fluctuations of the superconducting order parameter of s-wave symmetry caused by nonmagnetic disorder present both in the boson and fermion subsystems using the Bogoliubov-de Gennes equations. In particular, we are interested if some features of the d-wave model persist for s-wave symmetry as well. These are: positive correlations between positions of impurities and the magnitude of energy gap, the homogeneity of the local density of states at low energies, nanoscale inhomogeneity of the coherence peak positions and their non-uniform height. We have found that spatial variations of s-wave order parameter are positively correlated with the positions of impurities. Such behavior has been observed in scanning tunneling measurements on d-wave symmetry BSCCO-2122 superconductors.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 360-363
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Real Space Bogoliubov-de Gennes Equations Study of the Boson-Fermion Model
Autorzy:
Krzyszczak, J.
Domański, T.
Wysokiński, K.
Powiązania:
https://bibliotekanauki.pl/articles/1812295.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
74.20.-z
74.81.-g
Opis:
The boson-fermion model was proposed to describe superconductivity in short coherence length superconductors. In this work we use it to study impurity induced inhomogeneities in high temperature superconductors as found in numerous scanning tunnelling measurements. The model was formulated in real space and solved with help of Bogoliubov-de Gennes approach. Disorder in the boson or fermion subsystem is directly coupled to the superconducting order parameter and leads to severe changes of superconducting properties like local order parameter and density of states. We present the results for many impurities randomly distributed over otherwise clean and periodic two-dimensional square lattice.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 165-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Do Van Hove Singularities in Leads Influence Tunneling Current through Quantum Dot?
Autorzy:
Krawiec, M.
Domański, T.
Wysokiński, K. I.
Powiązania:
https://bibliotekanauki.pl/articles/1991636.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
72.15.Qm
71.27.+a
Opis:
Using the Landauer type formula for the current through quantum dot we have studied the influence of the singularities in the density of states in leads on the differential conductance of the system and answered affirmatively the above question. The presence of Van Hove singularities in the leads may induce an additional structure on the conductance vs. voltage curve. The dot itself has been described by the single impurity Anderson model with a very strong "on-dot" Coulomb repulsion. We also simulate the effect of electron-phonon interaction in the dot by allowing for the fluctuations of the "impurity" energy level.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 411-414
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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