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1.
Bose--Einstein Condensates with Two- and Three-Body Interactions in an Anharmonic Trap at Finite Temperature
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The transition temperature, the depletion of the condensate atoms and the collective excitations of a Bose-Einstein condensation (BEC) with two- and three-body interactions in an anharmonic trap at finite temperature are studied in detail. By using the Popov version of the Hartree-Fock-Bogoliubov (HFB) approximation, an extended self-consistent model describing BEC with both two- and three-body interactions in a distorted harmonic potential at finite temperature is obtained and solved numerically. The results show that the transition temperature, the condensed atom number and the collective excitations are modified dramatically by the atomic three-body interactions and the distortion of the harmonic trap. 相似文献
2.
We consider rotational motion of an interacting atomic
Bose-Einstein condensate (BEC) with both two- and three-body
interactions in a quadratic-plus-quartic and harmonic-plus-Gaussian
trap. By using the variational method, the influence of the
three-body interaction and the anharmonicity of the trap on the
lowest energy surface mode excitation and the spontaneous shape
deformation (responsible for the vortex formation) in a rotating BEC
is discussed in detail. It is found that the repulsive three-body
interaction helps the formation of the vortex and reduces the lowest
energy surface mode frequency and the critical rotational frequency
of the system. Moreover, the critical rotational frequency for the
vortex formation in the harmonic-plus-Gaussian potential is lower
than that in the quadratic-plus-quartic potential. 相似文献
3.
V. G. Zelevinsky 《Physics of Atomic Nuclei》2009,72(7):1107-1115
Conventional many-body quantum theory considers, as a rule, a system of particles in the mean field interacting through two-body
forces. Recently it was suggested that in nuclear physics many-body forces, first of all three-body ones, are important for
saturation of nuclear matter and for many details of nuclear structure. We consider possible influence of three-body forces,
regardless of their origin (bare nucleon interactions or effective medium phenomena), on many-body dynamics. The new effects
include, but are not limited to, renormalization of pairing and other two-body forces, enhancement of anharmonicity for collective
modes, and special features of shell model calculations.
The text was submitted by the author in English. 相似文献
4.
Using variational method, the wave function of a quasi two-dimensionalBose-Einstein Condensate in an anharmonic trap is analyzed and the influence of gravity on the collective excitations is studied. It is found that the effect of gravity on the condensate has got crucial dependence on the anharmonicity of the trap. 相似文献
5.
M. M. A. Ahmed M. Sebawe Abdalla E. M. Khalil A. -S. F. Obada 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2013,67(9):1-10
We study the stability of attractive atomic Bose-Einstein condensate and the macroscopic quantum many-body tunneling (MQT) in the anharmonic trap. We utilize correlated two-body basis function which keeps all possible two-body correlations. The anharmonic parameter (λ) is slowly tuned from harmonic to anharmonic. For each choice of λ the many-body equation is solved adiabatically. The use of the van der Waals interaction gives realistic picture which substantially differs from the mean-field results. For weak anharmonicity, we observe that the attractive condensate gains stability with larger number of bosons compared to that in the pure harmonic trap. The transition from resonances to bound states with weak anharmonicity also differs significantly from the earlier study of [N. Moiseyev, L.D. Carr, B.A. Malomed, Y.B. Band, J. Phys. B 37, L193 (2004)]. We also study the tunneling of the metastable condensate very close to the critical number N cr of collapse and observe that near collapse the MQT is the dominant decay mechanism compared to the two-body and three-body loss rate. We also observe the power law behavior in MQT near the critical point. The results for pure harmonic trap are in agreement with mean-field results. However, we fail to retrieve the power law behavior in anharmonic trap although MQT is still the dominant decay mechanism. 相似文献
6.
G. Morigi H. Walther 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):261-269
We study from the point of view of quantum information the properties of the collective oscillations of a linear chain of
ions trapped in a linear Paul trap and composed of two ion species. We discuss extensively sympathetic cooling of the chain
and the effect of anharmonicity on laser-cooling and quantum-information processing.
Received 19 May 2000 相似文献
7.
The collective excitations of low-dimensional Bose-Einstein
condensates with two- and three-body interactions in anharmonic
potentials are investigated. Using the standard variational approach, the governing equations of motions for the low-energy excitations are obtained by solving time-dependent
Gross-Pitaevskii-Ginzburg equation, and the excitation spectrums are calculated in small amplitude limit. The frequency shift and nonlinear mode coupling induced by the anharmonic distortion
(adding cubic, quartic, or quintic term to a harmonic trap) are studied. 相似文献
8.
Effects of three-body interaction on collective excitation and stability of Bose--Einstein condensate
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This paper investigates the collective excitation and stability of
low-dimensional Bose--Einstein condensates with two- and three-body
interactions by the variational analysis of the time-dependent
Gross--Pitaevskii--Ginzburg equation. The spectrum of the low-energy
excitation and the effective potential for the width of the
condensate are obtained. The results show that: (i) the repulsive
two-body interaction among atoms makes the frequency red-shifted for
the internal excitation and the repulsive or attractive three-body
interaction always makes it blue-shifted; (ii) the region for the
existence of the stable bound states is obtained by identifying the
critical value of the two- and three-body interactions. 相似文献
9.
E. Fersino B. A. Malomed G. Mussardo A. Trombettoni 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(3):417-426
We study the effect of an optical lattice (OL) on the ground-state properties of one-dimensional ultracold bosons with three-body
attractive interactions and two-body repulsive interactions, which are described by a cubic-quintic Gross-Pitaevskii equation
with a periodic potential. Without the optical lattice and with a vanishing two-body interaction term, normalizable soliton
solutions of the Townes type are possible only at a critical value of the interaction strength, at which an infinite degeneracy of the ground state
occurs; a repulsive two-body interaction makes such localized solutions unstable. We show that the OL opens a stability window
around the critical point when the strength of the periodic potential is above a critical threshold. We also consider the
effect of an external parabolic trap, studying how the stability properties depend on the matching between minima of the periodic
potential and the minimum of the parabolic trap. 相似文献
10.
D. A. Tabor V. Rajagopal Y.-W. Lin B. Odom 《Applied physics. B, Lasers and optics》2012,107(4):1097-1104
Growing and studying large Coulomb crystals, composed of tens to hundreds of thousands of ions, in linear quadrupole ion traps presents new challenges for trap implementation. We consider several trap designs, first comparing the total driven micromotion amplitude as a function of location within the trapping volume; total micromotion is an important point of comparison since it can limit crystal size by transfer of radiofrequency drive energy into thermal energy. We also compare the axial component of micromotion, which leads to first-order Doppler shifts along the preferred spectroscopy axis in precision measurements on large Coulomb crystals. Finally, we compare trapping potential anharmonicity, which can induce nonlinear resonance heating by shifting normal mode frequencies onto resonance as a crystal grows. We apply a non-deforming crystal approximation for simple calculation of these anharmonicity-induced shifts, allowing a straightforward estimation of when crystal growth can lead to excitation of different nonlinear heating resonances. In the anharmonicity point of comparison, we find significant differences between the trap designs, with an original rotated-endcap trap performing better than the conventional in-line endcap trap. 相似文献
11.
A. V. Meremianin 《Few-Body Systems》2009,45(1):11-23
The perturbation theory with respect to the potential energy of three particles is considered. The first-order correction
to the continuum wave function of three free particles is derived. It is shown that the use of the collective multipole expansion
of the free three-body Green function over the set of Wigner D-functions can reduce the dimensionality of perturbative matrix elements from twelve to six. The explicit expressions for
the coefficients of the collective multipole expansion of the free Green function are derived. It is found that the S-wave multipole coefficient depends only upon three variables instead of six as higher multipoles do. The possible applications
of the developed theory to the three-body molecular break-up processes are discussed. 相似文献
12.
A density-matrix formalism which includes the effects of three-body ground-state correlations is applied to the standard Lipkin
model. The reason to consider the complicated three-body correlations is that the truncation scheme of reduced density matrices
up to the two-body level does not give satisfactory results to the standard Lipkin model. It is shown that the inclusion of
the three-body correlations drastically improves the properties of the ground states and excited states. It is pointed out
that lack of mean-field effects in the standard Lipkin model enhances the relative importance of the three-body ground-state
correlations. Formal aspects of the density-matrix formalism such as a relation to the variational principle and the stability
condition of the ground state are also discussed. It is pointed out that the three-body ground-state correlations are necessary
to satisfy the stability condition. 相似文献
13.
B. Pozzi L. Salasnich A. Parola L. Reatto 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(3):367-370
We study the thermodynamics of the Bose-condensed atomic hydrogen confined in the Ioffe-Pritchard potential. Such a trapping
potential, that models the magnetic trap used in recent experiments with hydrogen, is anharmonic and strongly anisotropic.
We calculate the ground-state properties, the condensed and non-condensed fraction and the Bose-Einstein transition temperature.
The thermodynamics of the system is strongly affected by the anharmonicity of this external trap. Finally, we consider the
possibility to detect Josephson-like currents by creating a double-well barrier with a laser beam.
Received 15 February 2000 相似文献
14.
W. Zuo A. Lejeune U. Lombardo J.F. Mathiot 《The European Physical Journal A - Hadrons and Nuclei》2002,14(4):469-475
Brueckner calculations including a microscopic three-body force have been extended to isospin-asymmetric nuclear matter. The
effects of the three-body force on the equation of state and on the single-particle properties of nuclear matter are discussed
with a view to possible applications in nuclear physics and astrophysics. It is shown that, even in the presence of the three-body
force, the empirical parabolic law of the energy per nucleon vs. isospin asymmetry β = (N - Z)/A is fulfilled in the whole asymmetry range 0≤β≤1 up to high densities. The three-body force provides a strong enhancement
of the symmetry energy which increases with density in good agreement with the predictions of relativistic approaches. The
Lane's assumption that proton and neutron mean fields linearly vary vs. the isospin parameter is violated at high density due to the three-body force, while the momentum dependence of the mean
fields turns out to be only weakly affected. Consequently, a linear isospin split of the neutron and proton effective masses
is found for both cases with and without the three-body force. The isospin effects on multifragmentation events and collective
flows in heavy-ion collisions are briefly discussed along with the conditions for direct URCA processes to occur in the neutron
star cooling.
Received: 18 February 2002 / Accepted: 16 May 2002 相似文献
15.
16.
We study the collective field formulation of a restricted form of the multi-species Calogero model, in which the three-body interactions are set to zero. We show that the resulting collective field theory is invariant under certain duality transformations, which interchange, among other things, particles and antiparticles, and thus generalize the well known strong-weak coupling duality symmetry of the ordinary Calogero model. We identify all these dualities, which form an Abelian group, and study their consequences. We also study the ground state and small fluctuations around it in detail, starting with the two-species model, and then generalizing to an arbitrary number of species. 相似文献
17.
Z. Ke W. Shi G. Gwinner K. Sharma S. Toews J. Dilling V. L. Ryjkov 《Hyperfine Interactions》2006,173(1-3):103-111
We present simulations of electron and proton cooling of highly charged ions in a Penning trap, including the potentially
detrimental effects of radiative, dielectronic, and three-body recombination in electron cooling. We show a preliminary design
for a cooler trap accommodating both electron and proton cooling, which will be a component of the TITAN ion-trap facility
under construction at TRIUMF for precision mass measurements of short-lived radioactive nuclei.
相似文献
18.
We investigate the stability and phase transition of localized modes in Bose–Einstein Condensates (BECs) in an optical lattice with the discrete nonlinear Schrödinger model by considering both two- and three-body interactions. We find that there are three types of localized modes, bright discrete breather (DB), discrete kink (DK), and multi-breather (MUB). Moreover, both two- and three-body on-site repulsive interactions can stabilize DB, while on-site attractive three-body interactions destabilize it. There is a critical value for the three-body interaction with which both DK and MUB become the most stable ones. We give analytically the energy thresholds for the destabilization of localized states and find that they are unstable (stable) when the total energy of the system is higher (lower) than the thresholds. The stability and dynamics characters of DB and MUB are general for extended lattice systems. Our result is useful for the blocking, filtering, and transfer of the norm in nonlinear lattices for BECs with both two- and three-body interactions. 相似文献
19.
Jack MW 《Physical review letters》2002,89(14):140402
A Born-Markov master equation is used to investigate the decoherence of the state of a macroscopically occupied mode of a cold atom trap due to three-body loss. In the large-number limit only coherent states remain pure for times longer than the decoherence time: the time it takes for just three atoms to be lost from the trap. For large numbers of atoms (N>10(4)) the decoherence time is found to be much faster than the phase-collapse time caused by intratrap atomic collisions. 相似文献
20.
By making use of two different modes, we made further investigation of how the competition between internal vibration energy and collective rotation energy affects the geometric structures and internal motions of three-body systems. 相似文献