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    Tytuł:
    Decoherence and Noise in Loschmidt Echo Experiments
    Autorzy:
    Alicki, R.
    Miklaszewski, W.
    Pogorzelska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/2044622.pdf
    Data publikacji:
    2006-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    Opis:
    We discuss some recent results concerning the decoherence in controlled quantum open systems within the mathematical setting corresponding to motion reversal experiments (the Loschmidt echo). We compare the case of randomly chosen sequence of unitary dynamical maps with the case of a constant dynamics corresponding to a classically chaotic evolution. The interplay between chaos and decoherence is illustrated by the new numerical results on the quantum Arnold cat map perturbed by a measurement process. Open problems related to the simple operational characterization of the decoherence strength are discussed.
    Źródło:
    Acta Physica Polonica A; 2006, 109, 1; 121-129
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Carrier Spin Dephasing during Spin-Preserving Tunneling in Coupled Quantum Dots
    Autorzy:
    Krzykowski, M.
    Gawełczyk, M.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1185791.pdf
    Data publikacji:
    2016-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    85.75.-d
    03.65.Yz
    Opis:
    In this contribution we study carrier tunneling in a system consisting of a pair of coupled quantum dots. We predict the presence of a spin dephasing channel in such a system, which is associated with a "welcher-weg" type of decoherence process occurring during carrier tunneling. In our model such a process is caused by a mismatch of g-factor values in two quantum dots in the presence of external magnetic field. This leads to a mismatch in spin Zeeman splitting between the dots and, in consequence, to the distinguishability of phonons emitted during the tunneling of carriers with opposite spins. Thus we demonstrate a process of spin dephasing without any direct spin-environment coupling present in the model.
    Źródło:
    Acta Physica Polonica A; 2016, 130, 5; 1165-1168
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Accuracy of Effective Mass Equation for a Single and Double Cylindrical Quantum Dot
    Autorzy:
    Mielnik-Pyszczorski, A.
    Gawarecki, K.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033130.pdf
    Data publikacji:
    2017-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    85.75.-d
    03.65.Yz
    Opis:
    In this contribution we study the accuracy of various forms of electron effective mass equation in reproducing spectral and spin-related features of quantum dot systems. We compare the results of the standard 8 band k·p model to those obtained from effective mass equations obtained by perturbative elimination procedures in various approximtions for a cylindrical quantum dot or a system of two such dots. We calculate the splitting of electronic shells, the electron g-factor and spin-orbit induced spin mixing and show that for a cylindrical dot the g-factor is reproduced very exactly, while for the two other quantities the effective mass equation is much less accurate.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 2; 376-379
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Behavior of Quantum Fisher Information of Bell Pairs under Decoherence Channels
    Autorzy:
    Ozaydin, F.
    Altintas, A.
    Bugu, S.
    Yesilyurt, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/1194957.pdf
    Data publikacji:
    2014-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.67.-a
    03.65.Ud
    03.65.Yz
    Opis:
    Quantum Fisher information has recently been an essential tool for analyzing the phase sensitivity of the quantum states in various quantum tasks, requiring high precision, such as quantum clock synchronization, positioning and many applications which include quantum interferometers. Due to the interactions with the environment, all quantum systems are subject to various decoherence effects. Therefore the research on quantum Fisher information under decoherence has been recently attracting more attention. In this work, analyzing the quantum Fisher information, we study the phase sensitivity of bipartite quantum correlations, in particular four Bell pairs amplitude damping channels. For a specific Bell state we arrive at similar results of Greenberger-Horne-Zeilinger (GHZ) states (as expected). For the other three Bell states, we present our results which point the interesting behavior of quantum Fisher information with respect to the decoherence rate. We also find the regions where the quantum Fisher information exhibits discontinuities.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 2; 606-607
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quantum Fisher Information of Bipartitions of W States
    Autorzy:
    Ozaydin, F.
    Altintas, A.
    Yesilyurt, C.
    Bugu, S.
    Erol, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/1192332.pdf
    Data publikacji:
    2015-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.67.-a
    03.65.Ud
    03.65.Yz
    Opis:
    We study the quantum Fisher information (QFI) of W states and W-like states under decoherence. In particular, we find that on the contrary to amplitude damping and depolarizing decoherence, a W-like state of 3 qubits obtained by discarding 1 qubit of a genuine W state of 4 qubits is more robust than a genuine W state of 3 qubits under amplitude amplifying and phase damping decoherence.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 4; 1233-1235
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Optical Setup for Deterministic Creation of Four Partite W state
    Autorzy:
    Yesilyurt, C.
    Bugu, S.
    Diker, F.
    Altintas, A.
    Ozaydin, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/1401331.pdf
    Data publikacji:
    2015-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.67.-a
    03.65.Ud
    03.65.Yz
    Opis:
    In order to create polarization based entanglement networks of W₄ state, we propose an optical setup, which uses only four horizontally polarized photons as resource which implies no entanglement requirement as a resource. This setup can generate target state deterministically, by operating several quantum optical gates, which can be realized with current photonics technology. The setup we propose is composed of one Not, two Hadamard, five Controlled Not (CNot) and one Toffoli gate.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 4; 1230-1232
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of a Two-Qubit Decoherence by Using Bloch Vectors
    Autorzy:
    Ahmadi, F.
    Jami, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1364150.pdf
    Data publikacji:
    2014-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    03.67.Pp
    03.65.-w
    Opis:
    The loss of the coherence happens due to the interaction between the desired system and its surroundings. Addressing decoherence is one of the main concepts in the study of quantum channels to access their potential for various scale. In this process the information of the system is penetrated into the environment. Therefore, the measurement of the environment could be used as the error correction method. Phase damping channels principally belong to random unitary channels and can be corrected by classical information. This paper presents a method to generate non-random unitary phase damping channels based on the Bloch vectors in two qubits systems. A phase damping channel which consisted of a two qubits system and a single qubit environment was investigated. The results demonstrated that the phase damping channels belong to random unitary dynamics if the three-dimensional tetrahedron volume spanned by the Bloch vectors in $ℝ^3$ is not zero, or, the same hyperplane in $ℝ^3$ was not pointed by the Bloch vectors. It is found that the Bell state belongs to random unitary class and can be corrected based on classical information obtained from environmental measurements.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 5; 1088-1092
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonexistence of the Classical Trajectories in the Stern-Gerlach Experiment
    Autorzy:
    Arsenijević, M.
    Dugić, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1537871.pdf
    Data publikacji:
    2010-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Ta
    03.65.Yz
    81.16.Ta
    Opis:
    The Stern-Gerlach experiment is a paradigm of the quantum measurement of spin. Its physical interpretation is in intimate relation with the physical basis of the current research in the atomic (molecular) nanofabrication procedures. Nevertheless, interpretation of the experiment is an open issue yet. Here, we give the arguments for the physical nonexistence of the so-called classical trajectories of the atoms (molecules) in front of the screen. Some nanotech-related consequences are distinguished.
    Źródło:
    Acta Physica Polonica A; 2010, 117, 5; 760-763
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Control of Entanglement in a Damped Jaynes-Cummings Model by Transient Effects
    Autorzy:
    Kayhan, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1401862.pdf
    Data publikacji:
    2015-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Ud
    42.50.Ct
    03.65.Yz
    Opis:
    In this work, we study the entanglement dynamics of the damped Jaynes-Cummings model with the transient effects modeled as the linear sweep of the coupling coefficient between the atom and the field. We show that the decoherence of the entanglement can be controlled by the transient effects under the influence of damping. These effects can accelerate and can decelerate the decoherence of the entanglement during the time-evolution of the system, by adjusting the frequency of the Rabi oscillations.
    Źródło:
    Acta Physica Polonica A; 2015, 128, 3; 256-258
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Complete and Partial Loss of Entanglement Due to a Phonon-Assisted Dephasing Process
    Autorzy:
    Roszak, K.
    Machnikowski, P.
    Jacak, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046996.pdf
    Data publikacji:
    2006-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.67.Lx
    03.65.Yz
    63.20.Kr
    Opis:
    We study the evolution of entanglement between two excitons in a double quantum dot system coupled to a super-Ohmic reservoir. As expected entanglement is more fragile than local coherence, but, surprisingly, for a set of pure states disentanglement can be complete in a finite time under conditions that lead to the usual partial pure-dephasing.
    Źródło:
    Acta Physica Polonica A; 2006, 110, 3; 331-336
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-Markovian Dynamic of Gaussian Quantum Discord in Continuous-Variable Systems
    Autorzy:
    Liu, X.
    Wu, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1203878.pdf
    Data publikacji:
    2014-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    03.65.Ta
    03.65.Ud
    03.67.Mn
    Opis:
    We show the special dynamic characteristic of Gaussian quantum discord, exhibited by two-mode Gaussian symmetric squeezed thermal states (STS) in continuous-variable (CV) systems with a common non-Markovian environment, is definitely different from Markov processes. We demonstrate that Gaussian quantum discord can be created whenever the information flow from environment back to the system. We also show that the rate of decrease for Gaussian quantum discord is related to the coupling constant. We discover that the initial value of Gaussian quantum discord is determined by the average number of thermal photons of the system.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 3; 652-655
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Phonon-Induced Dephasing of Optically Driven Exciton States in Quantum Dots: Spectral Interpretation
    Autorzy:
    Machnikowski, P.
    Jacak, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/2044498.pdf
    Data publikacji:
    2005-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    63.20.Kr
    03.65.Yz
    Opis:
    We discuss phonon-induced perturbation of optically driven coherent dynamics of a confined exciton in a quantum dot in terms of nonlinear spectra of the driving pulse. Damping of pulse-area-dependent Rabi oscillations and phonon-assisted pumping of optically inactive states are analyzed.
    Źródło:
    Acta Physica Polonica A; 2005, 108, 5; 761-767
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Entanglement in Open Quantum Systems
    Autorzy:
    Buchleitner, A.
    Carvalho, A. R. R.
    Mintert, F.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047819.pdf
    Data publikacji:
    2007-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.67.Mn
    03.65.Ud
    03.65.Yz
    42.50.Lc
    Opis:
    We give a compact review of some of our recent results on the quantification, the measurement, and the time evolution of entanglement in open quantum systems of variable structure and dimension. Also a first experimental implementation is briefly discussed.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 4; 575-588
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Collective Spontaneous Emission from a System of Quantum Dots
    Autorzy:
    Abdussalam, W.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1403617.pdf
    Data publikacji:
    2012-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    42.50.Ct
    03.65.Yz
    Opis:
    We study the spontaneous emission from a regular lateral array or a randomly distributed ensemble of quantum dots under strong excitation (full inversion) conditions. We focus on the similarities and differences between the cases of random and regular arrangement of the dots and show that there is very little difference between the evolution of luminescence in these two cases, both for identical dots and for a realistically inhomogeneously broadened ensemble. This means that the enhanced emission or superradiance effect is not due to accidental clustering of pairs of dots. Moreover, we point out that observation of an enhanced emission under weak excitation does not prove that true superradiance will develop in a fully inverted system.
    Źródło:
    Acta Physica Polonica A; 2012, 122, 6; 994-996
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Collective Spontaneous Emission from Pairs of Quantum Dots: Long-Range vs. Short-Range Couplings
    Autorzy:
    Abdussalam, W.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492857.pdf
    Data publikacji:
    2011-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    42.50.Ct
    03.65.Yz
    Opis:
    We study the spontaneous emission from a coherently delocalized exciton state in a double quantum dot as a function of the distance between the dots, focusing on the similarities and differences between the cases of radiative (long-range, dipole) and tunnel coupling between the excitons in the dots. We show that there may be no qualitative difference between the collective emission induced by these two coupling types in spite of their essentially different physical properties.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 5; 865-867
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fidelity in Quasi-1D Systems as a Probe for Anderson Localization
    Autorzy:
    Bodyfelt, J.
    Zheng, M.
    Kottos, T.
    Kuhl, U.
    Stöckmann, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1585120.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.25.Dd
    72.15.Rn
    03.65.Nk
    03.65.Yz
    Opis:
    We analyze the echo dynamics in quasi-one-dimensional random media to investigate how the transition from localization to delocalization is encoded in its temporal decay properties. Our analysis extends from the standard perturbative regime corresponding to small perturbations (with respect to the mean level spacing) in the echo dynamics, out to the Wigner decay regime. On the theoretical side, our results rely on a banded random matrix modeling, and show in the localized regime under small perturbations a novel decay of the fidelity (Loschmidt echo), differing from the typical Gaussian decay seen within both diffusive and chaotic systems. For larger perturbation strengths, typical Wigner exponential decays are observed. Scattering echo measurements are performed experimentally within a quasi-1D microwave cavity randomly populated with point-like scatterers. Agreements are observed between experiments, numerics, and theoretical predictions.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 756-764
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Disorder-Assisted Exciton Transport
    Autorzy:
    Scholak, T.
    Zech, T.
    Wellens, T.
    Buchleitner, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492761.pdf
    Data publikacji:
    2011-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    87.15.hj
    05.60.Gg
    03.65.Ud
    03.65.Yz
    Opis:
    We discuss the possibly constructive role of disorder for the optimization of exciton transport in the FMO (Fenna-Matthews-Olson) light harvesting complex. Our analysis, which models the FMO as a 3D random graph, demonstrates the existence of a small fraction of optimal, though highly asymmetric, non-periodic conformations, which yield near-to-optimal coherent excitation transport. We argue that, on transient time scales, such quantum interference enhanced transport does always better than stochastic activation.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 6A; A-089-A-094
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Entanglement and Statistical Properties of a System Consisting of Three-Level Atom Interacting with a Nonlinear Kerr Medium Field
    Autorzy:
    Abdel-Khalek, S.
    Al-Rajhi, M.
    Berrada, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398909.pdf
    Data publikacji:
    2016-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    03.67.-a
    42.50.Dv
    42.50.Gy
    Opis:
    In this paper, we present a proper quantum system to perform different tasks of quantum information processing with optimal conditions. We study the populations, entanglement, and nonclassical properties of a system consisting of three level atom interacting with a nonlinear Kerr medium field constructed in the framework of generalized Heisenberg algebra. We quantify these quantities in terms of different parameters involved in the whole system considering the case of moving and stationary atom in the real experimental meaning of the coupling constant. The nonlinearity introduced by these kinds of fields play a useful role to create high amount of entanglement during the time evolution. Interestingly, the relationship between the degree of nonlinearity and robust of entanglement is explored in this present model.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 6; 1083-1088
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Singlet-Triplet Dephasing in Asymmetric Quantum Dot Molecules
    Autorzy:
    Marcinowski, Ł.
    Roszak, K.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791331.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.21.La
    03.65.Yz
    72.10.Di
    03.67.Lx
    Opis:
    We discuss pure dephasing of singlet-triplet superpositions in two-electron double quantum dots due to elastic phonon scattering. We generalize our previous results to a system built of two non-identical dots. We show that the asymmetry must be very strong in order to considerably affect the dephasing rate.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 874-876
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Phonon-Induced Pure Dephasing of Two-Electron Spin States in Vertical Quantum Dot Molecules
    Autorzy:
    Roszak, K.
    Machnikowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791332.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.21.La
    03.65.Yz
    72.10.Di
    03.67.Lx
    Opis:
    Phonon-induced dephasing of two-electron spin states in two vertically stacked self-assembled GaAs/InGaAs quantum dots is studied. A pure dephasing process due to elastic phonon scattering is found to dominate at low temperatures. This process is independent of the spin-orbit coupling and does not require the presence of a magnetic field. It relies on interdot tunneling and the Pauli principle, which make the double quantum dot gate for spin based quantum computing possible, and therefore cannot be avoided.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 877-878
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Asymmetry Induced Localization
    Autorzy:
    Kohler, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399044.pdf
    Data publikacji:
    2013-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    05.30.-d
    03.65.Yz
    05.45.Mt
    73.23.-b
    Opis:
    We consider a two-level system, which couples via non-commuting operators to two independent oscillator baths. When the coupling is symmetric, the renormalized hopping matrix element is finite even for infinitely strong coupling strength. The two-level system is in a delocalized phase. For finite coupling strength a localization transition occurs for a critical asymmetry angle, which separates the localized from the delocalized phase. Using the method of flow equations we are able to monitor real time dynamics.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 6; 1053-1059
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fidelity Decay in Chaotical and Random Systems
    Autorzy:
    Kohler, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492437.pdf
    Data publikacji:
    2011-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    05.30.-d
    03.65.Yz
    05.45.Mt
    73.23.-b
    Opis:
    Fidelity is the overlap of wave functions with the same initial state propagated in time by slightly different Hamiltonians. Its behavior depends crucially on the choice of the initial wave function state. We review two cases: first, the initial state is random. In this case a simple analytic relation with parametric spectral correlations can be established. The latter quantity is completely determined by the spectral data and can therefore be measured, without knowledge about the wave function. Second, the initial state is an eigenstate of the unperturbed system. In this case fidelity is identical to the survival probability. We find unexpected features like revival and non-ergodicity. In this case fluctuations around the mean are large and the full fidelity distribution becomes a non-trivial function. The full fidelity distribution can be calculated in the long time limit and for small perturbations.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 6A; A-119-A-126
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Scanning-Gate Microscopy of Semiconductor Nanostructures: An Overview
    Autorzy:
    Martins, F.
    Hackens, B.
    Sellier, H.
    Liu, P.
    Pala, M. G.
    Baltazar, S.
    Desplanque, L.
    Wallart, X.
    Bayot, V.
    Huant, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047914.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.21.La
    73.23.Ad
    03.65.Yz
    85.35.Ds
    Opis:
    This paper presents an overview of scanning-gate microscopy applied to the imaging of electron transport through buried semiconductor nanostructures. After a brief description of the technique and of its possible artifacts, we give a summary of some of its most instructive achievements found in the literature and we present an updated review of our own research. It focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. In all of the given examples, we emphasize how a local-probe approach is able to shed new, or complementary, light on transport phenomena which are usually studied by means of macroscopic conductance measurements.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 569-575
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dephasing of Electron Spin Qubits due to their Interaction with Nuclei in Quantum Dots
    Autorzy:
    Cywiński, Ł.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047915.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    76.30.-v
    76.60.Lz
    02.60.Cb
    Opis:
    Coherence of spins of electrons confined in III-V quantum dots is strongly affected by their hyperfine interaction with the nuclei. In this paper an introduction to this subject is presented. Some theoretical approaches to the problem will be outlined. Most attention will be given to the quasi-static bath approximation, to the cluster expansion theories of dephasing due to the nuclear dynamics induced by the dipolar interactions (spectral diffusion), and to the effective Hamiltonian based theory of dephasing due to hyperfine-mediated interactions. The connections between the theoretical results and various experiments will be emphasized.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 576-587
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Collective Luminescence and Phonon-Induced Processes in Double Quantum Dots
    Autorzy:
    Machnikowski, P.
    Roszak, K.
    Sitek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791287.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    03.65.Yz
    78.67.Hc
    03.67.Lx
    71.38.-k
    73.63.Kv
    Opis:
    We study the evolution of a quantum state of a double quantum dot system interacting with the electromagnetic environment and with the lattice modes, in the presence of a coupling between the two dots. We propose a unified approach to the simulation of the system evolution under joint impact of the two reservoirs. We discuss the sub- and superradiant radiative decay of the system, the phonon-induced decay of entanglement between the dots, and the transfer of excitation between them.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 818-825
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-25 z 25

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