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Wyszukujesz frazę "Bułka, B." wg kryterium: Autor


Tytuł:
Dynamics of a Charge Qubit Encoded in a Double Quantum Dot
Autorzy:
Łuczak, J.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1030456.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.67.Lx
73.63.Kv
73.23.Ra
Opis:
We study the short time dynamics of a charge qubit encoded in two coherently coupled quantum dots connected to external electrodes. In the regime of sequential tunneling the waiting time distribution is used to investigate in details statistics of the tunneling events and their correlations. We show that the coherent rotation of the qubit state on the Bloch sphere can be seen in tunneling events when an electron is injected and leave the system. Decoherence, relaxation of the qubit state as well as leakage processes are studied by means of transient currents.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 748-750
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Logic operations of charge qubit in a triple quantum dot
Autorzy:
Ptaszyński, K.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1157205.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
03.67.Lx
Opis:
Studies for a single charge qubit and two capacitively coupled qubits built on triple quantum dots are presented. We show feasibility of implementing two-qubit gate operations, e.g. the CPHASE gate can be implemented with the fidelity higher than 99% for strong couplings.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-30-A-32
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dark States and Transport through Quantum Dots
Autorzy:
Tooski, S.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1428598.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.-w
33.57.+c
73.23.-b
73.63.Kv
Opis:
We consider current through triple and quadruple quantum dot systems in an in-plane electric field and in the sequential tunneling regime. The electric field breaks symmetry of the system and can trap electron in a dark state in which current flow can completely be blocked. Consequently rotating the electric field, one can observe current oscillations and blockades due to dark state.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1231-1233
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cross-Correlations and Charge Pumping in Shot Noise οf Coupled Quantum Dot System
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1791333.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
73.50.Td
Opis:
We analyze current auto- and cross-correlations in the system of two capacitively coupled large quantum dots. Our attention is focused on the strong inter-dot coupling when an electron transfer through one of the quantum dots induces charge pumping through the second quantum dot. We show individual contributions to shot noise from various tunneling processes in the charge space.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 879-881
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of Current Auto- and Cross-Correlations in Double Quantum Dots
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1810396.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.63.Kv
73.50.Td
Opis:
Studies of an enhancement of current shot noises are presented for a device of two large quantum dots coupled capacitively. We analyze current-current correlation functions, and show that a dynamical Coulomb blockade is responsible for an enhancement of the Fano factors. This process can lead also to an electron bunching and positive current cross-correlations. Our theoretical results are discussed in light of recent shot noise experiments.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 117-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oscillations in Magnetoresistance and Interlayer coupling in Magnetic Sandwich Structures
Autorzy:
Barnaś, J.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1955443.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Jn
72.15.Gd
Opis:
Kubo formalism is used to calculate the magnetoresistance due to magnetization rotation in a structure consisting of two magnetic films separated by a nonmagnetic layer. In the approximation of a uniform relaxation time for each layer, the oscillatory term in magnetoresistance corresponds to the oscillation period which depends on the potential barriers at the interfaces. This period is longer than the oscillation period observed in the coupling parameter.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 253-256
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Transport in Thin-Film Structures
Autorzy:
Bułka, B.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930612.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.-h
73.61.At
Opis:
General quantum-mechanical description of electronic transport in thin-film structures, which is based on the Kubo approach, is presented and applied to a single film with ideal surfaces. The cases of a constant chemical potential and a constant particle number are considered and analysed numerically.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 465-468
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Singlet-Triplet Switching Induced by Electric Field in Triple Quantum Dots
Autorzy:
Łuczak, J.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1427582.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.-w
33.57.+c
73.23.-b
73.63.Kv
Opis:
We analyze influence of an external electric field on magnetic properties of a triple quantum dot system in a triangular and linear geometry. The system contains four electrons and is described by an extended Hubbard model which includes electron correlations and exchange processes. The electric field leads to splitting of energy levels (the Stark effect) and to transition between the singlet and triplet states.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1195-1197
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interference Effects in Three-Terminal Hybrid Systems with Quantum Dots
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1403609.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
74.45.+c
73.23.-b
Opis:
Conductance in a three-terminal hybrid system with two quantum dots is analyzed. Our attention is focused on an influence of decoherence on interference effects in the Andreev transport. In particular, we have found that a change of coupling to the third electrode can strongly modify a shape of the Fano-type resonances. This effect is due to activation of nonlocal Andreev reflection (CAR) processes.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 981-983
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Current Shot Noise and Bunching of Electrons in Multilevel Quantum Dots
Autorzy:
Michałek, G.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813512.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
72.70.+m
Opis:
Currents and their fluctuations in multilevel quantum dots are studied theoretically in the limit of sequential tunneling. The spin degrees of freedom, many-body electronic states (singlet and triplet) as well as relaxation processes between the levels of the quantum dots are considered. In general, due to the rapid relaxation processes the shot noise is sub-Poissonian, however for a large polarization of the outgoing currents from the singlet and triplet states one gets the super-Poissonian type of the shot noise due to the bunching of tunneling events.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 27-30
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superconductivity in Hubbard Model with Correlated Hopping
Autorzy:
Bułka, B. R.
Robaszewska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1955520.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
71.30.+h
74.20.Mn
Opis:
Using the slave-boson method in its spin- and charge-rotational invariant representation we determine stability of the superconducting state in the Hubbard model with correlated hopping. In general the term with correlated hopping violates electron-hole symmetry, however, in the special case when the correlated hopping integral X is equal to the uncorrelated hopping integral t the electron-hole symmetry remains. We investigate this case and show that correlations induced by onsite Coulomb interactions U yield to the normal state with exactly single occupied sites (corresponding to |U=∞⟩). The phase diagram of the superconducting state is determined for the different electron concentration n. At the half-filled band (n=1) a direct transition from the Mott insulator to the superconducting state occurs.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 363-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Negative Differential Resistance and Super-Poissonian Shot Noise in a System of Single Electron Transistors
Autorzy:
Michałek, G.
Bułka, B. R.
Powiązania:
https://bibliotekanauki.pl/articles/2028848.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.Hk
73.40.Gk
73.50.Td
Opis:
Currents and their fluctuations in two capacitively coupled single electron transistors were studied within the sequential tunneling approach. A special attention was focused on the effect of the negative differential resistance, which appears due to the Coulomb interactions of accumulated charges on both the single electron transistors. In this case large polarization fluctuations are activated, which results in a significant enhancement of the current shot noise.
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 431-436
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linear and Non-Linear Response in T-Shaped Electron Waveguides
Autorzy:
Bek, M.
Bułka, B.
Wróbel, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791289.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.63.Rt
85.35.Ds
85.35.Be
Opis:
We present theoretical studies of three-terminal ballistic junction in linear and non-linear regime. Various conductance and voltage dips and peaks are observed and their origin is explained as influence of the bend resistance and the threshold effect.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 829-831
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of Quantum Interference in Electronic Transport through Carbon Nanotubes
Autorzy:
Babiaczyk, W. I.
Bułka, B. R.
Powiązania:
https://bibliotekanauki.pl/articles/2035583.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.-b
73.23.-b
73.63.Fg
Opis:
We performed studies of coherent electronic transport through a single walled carbon nanotube. In the calculations multiple scattering on the contacts and interference processes were taken into account. Conductance is a composition of contributions from different channels. We studied also spin-dependent transport in the system with ferromagnetic electrodes. The magnetoresistance is large and shows large oscillations, it can be even negative in some cases.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 597-602
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interplay of Kondo and Fano Resonance in Electronic Transport in Nanostructures
Autorzy:
Bułka, B. R.
Stefański, P.
Tagliacozzo, A.
Powiązania:
https://bibliotekanauki.pl/articles/2043700.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.-b
72.15.Qm
75.20.Hr
Opis:
Quantum interference and electronic correlations are processes relevant for electronic transport in nanostructures. We present theoretical studies of transport for various models, which take into account these processes and describe the Fano resonance as well as many-body effects like the Kondo resonance. The results are compared with transport measurements performed on a small quantum dot strongly coupled to electrodes, a large semi-open quantum dot, a side-attached quantum dot to a quantum wire systems and a quantum dot embedded in the metallic ring. We show how conductance characteristics of the Kondo and the Fano resonance are modified in different situations.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 555-569
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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