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Wyszukujesz frazę "03.75.Nt" wg kryterium: Temat


Tytuł:
Determinants of Mass Poverty in the Contemporary Global Economy
Autorzy:
Jakimowicz, A.
Baklarz, A.
Tematy:
89.65.Gh
03.75.Nt
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1029499.pdf  Link otwiera się w nowym oknie
Opis:
The concept of mass poverty was defined by Galbraith in late 1970s and it applies to societies with agriculture as the dominant branch of the economy. This paper examines the importance of this phenomenon and factors affecting it in the contemporary world. There are a growing number of studies supporting the claim that the method of electricity consumption is a key factor of economic growth which makes it possible to escape mass poverty. Moreover, in order to solve the problem, it is necessary to determine access to capital in such countries and societies, understood as M2 aggregate. In this manner, the problem at hand is reduced to determination of the relationships between the following variables: percentage of rural population, rules of managing electrical energy and M2 aggregate. These findings were used to formulate three study hypotheses. According to the first hypothesis, the effect of the electricity use method on M2 varies from one country to another, with several identifiable patterns. According to the second hypothesis, the process of leaving the mass poverty sphere follows either the Bose-Einstein distribution or the Boltzmann distribution. The third hypothesis indicates that effects of efforts aimed at eliminating mass poverty in certain conditions are not permanent. Verification of these three hypotheses indicates the adequacy of the theory of mass poverty in the contemporary world.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fermionic Mediated Effective Interaction for the Two-Dimensional Bose-Fermi Mixtures under Artificial Magnetic Field
Autorzy:
Polak, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1429103.pdf  Link otwiera się w nowym oknie
Opis:
The strongly interacting bosonic and non-interacting fermionic mixtures of diluted gases are studied. An artificial magnetic field is introduced in theory by imposing a Peierls phase shift on the wave functions of the constituents. A highly nontrivial limit of the quantum-Hall limit is achieved which provides oscillations effects of the fermion mediated interaction between bosons. In consequence the effective interaction between bosons can change the magnitude and sign. This provides possible explanations of the bosonic coherence loss observed experimentally in the "time of flight" and "peak width" experiments.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conductivity of Strongly Correlated Bosons in the Simple Cubic Lattice - Magnetic Field and Hopping Anisotropy Effects
Autorzy:
Sajna, A.
Polak, T.
Micnas, R.
Tematy:
03.75.Lm
05.30.Jp
03.75.Nt
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1386533.pdf  Link otwiera się w nowym oknie
Opis:
We investigate optical conductivity in three dimensional system of bosons under strong magnetic field. In particular, we consider Bose Hubbard model in the strongly correlated limit, where Mott insulator phase emerges. For chosen rational number of magnetic flux per cell we show that response of the system gains complex peaks behavior on the order of frequency corresponding to on-site boson repulsive interaction. Moreover, when anisotropy in hopping energy for the direction parallel to magnetic field is tuned up, the non-monotonous behavior of the optical conductivity could appear. The obtained results can be experimentally probed in the system of ultracold atoms loaded on an optical lattice.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Rotor Approach to the Mott-Insulator Transition in the Bose-Hubbard Model
Autorzy:
Polak, T.
Kopeć, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1812265.pdf  Link otwiera się w nowym oknie
Opis:
We present the novel approach to the Bose-Hubbard model using the U(1) quantum rotor description. We formulate a problem in the phase only action using an effective action formalism and obtain analytical formulae for the critical lines. We show that the nontrivial U(1) phase field configurations have an impact on the phase diagrams. The topological character of the quantum field is governed by terms of the integer charges -- winding numbers n. The comparison of the presented results with recently obtained quantum Monte Carlo numerical calculations suggests that the competition between quantum effects in strongly interacting boson systems is correctly captured by our model.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Maintaining Defect/Energetic Droplets from Two Interacting Bose-Einstein Condensates
Autorzy:
Dzhunushaliev, V.
Tematy:
03.75.Lm
03.75.Nt
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1399170.pdf  Link otwiera się w nowym oknie
Opis:
We consider two interacting Bose-Einstein condensates with different kinds of the potential energy of interaction of the condensates: (a) the standard potential, (b) the potential has a positive three-body and a negative two-body scattering terms, and (c) the potential has a positive four-body and a negative three-body scattering terms for the first Bose-Einstein condensate and a positive three-body and a negative two-body scattering terms for the second Bose-Einstein condensate. It is shown that in these cases there exist stationary regular spherically symmetric solutions. Physically such solution is either a defect or an energetic droplet created by the condensates. The defect is a cavity filled with one Bose-Einstein condensate on the background of another Bose-Einstein condensate. The droplet is an object with zero energy density at the infinity. For (a) and (b) cases the obtained objects are supported by a constant external trapping potential and for (c) case the droplet is a self-maintaining object without any external potential. The possibility of construction of an elementary logic qubit device on the basis of this droplet is discussed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dimensional Reduction and Localization of a Bose-Einstein Condensate in a Quasi-1D Bichromatic Optical Lattice
Autorzy:
Salasnich, L.
Adhikari, S.
Tematy:
03.75.Nt
03.75.Lm
64.60.Cn
67.85.Hj
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1190087.pdf  Link otwiera się w nowym oknie
Opis:
We analyze the localization of a Bose-Einstein condensate in a one-dimensional bichromatic quasi-periodic optical-lattice potential by numerically solving the 1D Gross-Pitaevskii equation (1D GPE). We first derive the 1D Gross-Pitaevskii equation from the dimensional reduction of the 3D quantum field theory of interacting bosons obtaining two coupled differential equations (for axial wave fuction and space-time dependent transverse width) which reduce to the 1D Gross-Pitaevskii equation under strict conditions. Then, by using the 1D Gross-Pitaevskii equation we report the suppression of localization in the interacting Bose-Einstein condensate when the repulsive scattering length between bosonic atoms is sufficiently large.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transitions in Optical Lattices at Finite Temperatures
Autorzy:
Polak, T.
Kopeć, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
67.40.Kh
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1810621.pdf  Link otwiera się w nowym oknie
Opis:
We discuss the finite-temperature phase diagram in three-dimensional Bose-Hubbard model relevant for the Bose-Einstein condensates in optical lattices, by employing U(1) quantum rotor approach and the topologically constrained path integral, that includes a summation over U(1) topological charge. The effective action formalism allows us to formulate a problem in the phase only action and obtain analytical formulae for the critical lines beyond mean-field theory.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bose-Hubbard Model in the Rotating Frame of Reference
Autorzy:
Polak, T.
Kopeć, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1536643.pdf  Link otwiera się w nowym oknie
Opis:
Following a novel experimental arrangement which can rotate a two-dimensional optical lattice at frequencies up to several kilohertz we discuss the ground state of the two-dimensional Bose-Hubbard Hamiltonian, relevant for rotating gaseous Bose-Einstein condensates, by employing U(1) quantum rotor approach and the topologically constrained path integral. Ultracold atoms in such a rotating lattice can be used for the direct quantum simulation of strongly correlated systems under large effective magnetic fields. We derive an effective quantum action for the Bose-Hubbard model, which enables a non-perturbative treatment of the zero-temperature phase transition in the rotating frame. We calculate the ground-state phase diagram, analytically deriving maximum repulsive energy for several rational values of the frustration rotation parameter f = 0, 1/2, 1/3, 1/4, and 1/6 for the square and triangular lattice. Performed calculations revealed strong non-monotonical dependence of the critical ratio of the kinetic energy to the repulsive on-site energy, that separates the global coherent from the insulating state, on topology of the lattice.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutral Bosonic Condensates in Layered 2D Structures under Artificial Magnetic Field
Autorzy:
Polak, T.
Zaleski, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1429105.pdf  Link otwiera się w nowym oknie
Opis:
We show that the properties of the ideal Bose gas in three-dimensional optical lattice can be closely mimicked by finite two dimensional systems with only ten of layers. The match between critical properties strongly depends on the anisotropy of the hopping amplitudes in and between layers which we fully control. The theory we provided can be directly used in the experiments and results in less challenging requirements of the setups. We also present the phase diagram with its non-monotonic dependence of the ratio of tunneling to on-site repulsion when artificial magnetic field is applied to the system.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lost of Bosonic Coherence Due to the Fermionic Presence Under the Synthetic Magnetic Field
Autorzy:
Polak, T.
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1431224.pdf  Link otwiera się w nowym oknie
Opis:
We have studied effects of inter-species interaction of the bosons in a Bose-Fermi mixture over a large regime of particle numbers under the synthetic magnetic field. Analytically derived formulas for the density of states for several values of the magnetic fields f=1/2,1/3,1/4,1/6,1/8 and 3/8 allows us to calculate, with a very good accuracy, the effective interaction between bosons. The presence of the Hofstadter butterfly spectrum and fermionic species induces alternating sign potential between neutral bosonic atoms. Consequently bosons can attract or repulse each other whether sign of it strongly depends on the strength of the magnetic field applied to the sample.
Dostawca treści:
Biblioteka Nauki
Artykuł

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