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1.
Tunneling dynamics of Bose-Einstein condensates with higher-order interactions in optical lattice
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The nonlinear Landau-Zener tunneling and nonlinear Rabi oscillations of Bose-Einstein condensate (BEC) with higher-order atomic interaction between the Bloch bands in an accelerating optical lattice are discussed. Within the two-level model, the tunneling probability of BEC with higher-order atomic interaction between Bloch bands is obtained. We finds that the tunneling rate is closely related to the higher-order atomic interaction. Furthermore, the nonlinear Rabi oscillations of BEC with higher-order atomic interaction between the bands are discussed by imposing a periodic modulation on the level bias. Analytical expressions of the critical higher-order atomic interaction for suppressing/enhancing the Rabi oscillations are obtained. It is shown that the critical value strongly depends on the modulation parameters (i.e., the modulation amplitude and frequency) and the strength of periodic potential. 相似文献
2.
Carusotto I Pitaevskii L Stringari S Modugno G Inguscio M 《Physical review letters》2005,95(9):093202
We show that Bloch oscillations of ultracold fermionic atoms in the periodic potential of an optical lattice can be used for a sensitive measurement of forces at the micrometer length scale, e.g., in the vicinity of a dielectric surface. In particular, the proposed approach allows us to perform a local and direct measurement of the Casimir-Polder force which is, for realistic experimental parameters, as large as 10(-4) gravity. 相似文献
3.
The paper studies the dynamics of a Bose-Einstein condensate loaded in a 1D parabolic optical lattice and excited by a sudden shifting of the lattice center. Depending on the initial shift, this dynamics is either the dipole or Bloch oscillations of the atoms. The effects of the dephasing and atom-atom interactions on the above atomic oscillations are discussed. 相似文献
4.
J. Brand A. R. Kolovsky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):331-336
The dynamics of a Bose-Einstein condensate is studied theoretically in a combined periodic plus harmonic external potential.
Different dynamical regimes of stable and unstable collective dipole and Bloch
oscillations are analysed in terms of a quantum mechanical pendulum
model. Nonlinear interactions are shown to counteract quantum-mechanical dephasing and lead to phase-coherent, superfluid
transport. 相似文献
5.
The higher-order interactions of Bose-Einstein condensate in multi-dimensional optical lattices are discussed both analytically and numerically.It is demonstrated that the effects of the higher-order atomic interactions on the sound speed and the stabilities of Bloch waves strongly depend on the lattice strength.In the presence of higher-order effects,tighter and high-dimensional lattices are confirmed to be two positive factors for maintaining the system's energetic stability,and the dynamical instability of Bloch waves can take place simultaneously with the energetic instability.In addition,we find that the higher-order interactions exhibit a long-range behavior and the long-lived coherent Bloch oscillations in a tilted optical lattice exist.Our results provide an effective way to probe the higher-order interactions in optical lattices. 相似文献
6.
The periodic spin domains of spinor Bose-Einstein condensates confined in a one-dimensional optical lattice are studied in terms of the equation of motion of the spinor which is reduced to the nonlinear Schrödinger equation with the help of Holstein-Primakoff transformation. It is shown that the spin domains obtained analytically can be easily controlled by adjusting the light-induced dipole-dipole interaction, which is realizable in optical lattice created by red-detuned laser beams with modulating intensity. The dynamical stability of the spin domains is also demonstrated. 相似文献
7.
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
8.
9.
Poli N Wang FY Tarallo MG Alberti A Prevedelli M Tino GM 《Physical review letters》2011,106(3):038501
We report on a precision measurement of gravitational acceleration using ultracold strontium atoms confined in an amplitude-modulated vertical optical lattice. An uncertainty Δg/g ≈ 10(-7) is reached by measuring at the 5th harmonic of the Bloch frequency. The value obtained with this microscopic quantum system is consistent with the one measured with a classical gravimeter. Using lattice modulation to prepare the atomic sample, we also achieve high visibility of Bloch oscillations for ~ 20 s. These results can be of relevance for testing gravitational redshift and Newtonian law at micrometer scale. 相似文献
10.
We study the dynamics of a Bose-Einstein condensate subject to a particular Penrose tiling lattice. In such a lattice, the potential energy at each site depends on the neighbour sites, accordingly to the model introduced by Sutherland [16]. The Bose-Einstein wavepacket, initially at rest at the lattice symmetry center, is released. We observe a very complex time-evolution that strongly depends on the symmetry center (two choices are possible), on the potential energy landscape dispersion, and on the interaction strength. The condensate-width oscillates at different frequencies and we can identify large-frequency reshaping oscillations and low-frequency rescaling oscillations. We discuss in which conditions these oscillations are spatially bounded, denoting a self-trapping dynamics. 相似文献
11.
A. R. Kolovsky 《The European physical journal. Special topics》2007,151(1):103-112
The work discusses transport of cold atoms in optical
lattices. Two related but different problems are considered: interacting Bose
atoms subject to a static field (i.e., the atoms in a tilted lattice);
and non-interacting atoms in a tilted lattice in the presence of
a buffer gas. For these two systems we found, respectively:
periodic, quasiperiodic, or decaying Bloch oscillations, as it depends on
the strength of atom-atom interactions and the magnitude of the static field;
diffusive directed current of atoms, similar to the
electron current in ordinary conductors. 相似文献
12.
We study the energy spectrum of ultracold fermionic atoms on the two-dimensional triangular optical lattice subjected to a perpendicular effective magnetic field, which can be realized with laser beams. We derive the generalized Harper's equations and numerically solve them, then we obtain the Hofstadter's butterfly-like energy spectrum, which has a novel fractal structure. The observability of the Hofstadter's butterfly spectrum is also discussed. 相似文献
13.
We demonstrate the phenomenon of directed diffusion in a symmetric periodic potential. This has been realized with cold atoms in a one-dimensional dissipative optical lattice. The stochastic process of optical pumping leads to a diffusive dynamics of the atoms through the periodic structure, while a zero-mean force which breaks the temporal symmetry of the system is applied by phase modulating one of the lattice beams. The atoms are set into directed motion as a result of the breaking of the temporal symmetry of the system. 相似文献
14.
We investigate the Bloch and dipole oscillations of a Bose Einstein condensate (BEC) in an optical superlattice. We show that,
as the effective mass increases in an optical superlattice, the BEC is localized in accordance with recent experimental observations
[J.E. Lye et. al. Phys. Rev. A 75, 061603 (2007)]. In addition, we find that the secondary optical lattice is a useful additional tool to manipulate
the dynamics of the atoms.
相似文献
15.
G. Roux S. Capponi P. Lecheminant P. Azaria 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(3):293-308
We study spin 3/2 fermionic cold atoms with attractive interactions confined in a one-dimensional optical lattice. Using numerical
techniques, we determine the phase diagram for a generic density. For the chosen parameters, one-particle excitations are
gapped and the phase diagram is separated into two regions: one where the two-particle excitation gap is zero, and one where
it is finite. In the first region, the two-body pairing fluctuations (BCS) compete with the density ones. In the other one,
a molecular superfluid (MS) phase, in which bound-states of four particles form, competes with the density fluctuations. The
properties of the transition line between these two regions is studied through the behavior of the entanglement entropy. The
physical features of the various phases, comprising leading correlations, Friedel oscillations, and excitation spectra, are
presented. To make the connection with experiments, the effect of a harmonic trap is taken into account. In particular, we
emphasize the conditions under which the appealing MS phase can be realized, and how the phases could be probed by using the
density profiles and the associated structure factor. Lastly, the consequences on the flux quantization of the different nature
of the pairing in the BCS and MS phases are studied in a situation where the condensate is in a ring geometry. 相似文献
16.
Bloch oscillations are a powerful tool to investigate spectra with Dirac points. By varying band parameters, Dirac points can be manipulated and merged at a topological transition toward a gapped phase. Under a constant force, a Fermi sea initially in the lower band performs Bloch oscillations and may Zener tunnel to the upper band mostly at the location of the Dirac points. The tunneling probability is computed from the low-energy universal Hamiltonian describing the vicinity of the merging. The agreement with a recent experiment on cold atoms in an optical lattice is very good. 相似文献
17.
Andrey R. Kolovsky 《Frontiers of Physics》2012,7(1):3-7
Quantum dynamics of a charged particle in a two-dimensional (2D) lattice subject to magnetic and electric fields is a rather complicated interplay between cyclotron oscillations (the case of vanishing electric field) and Bloch oscillations (zero magnetic field), details of which has not yet been completely understood. In the present work we suggest to study this problem by using cold atoms in optical lattices. We introduce a one-dimensional (1D) model which can be easily realized in laboratory experiments with quasi-1D optical lattices and show that this model captures many features of the cyclotron-Bloch dynamics of the quantum particle in 2D square lattices. 相似文献
18.
Kolovsky AR 《Physical review letters》2003,90(21):213002
This paper studies Bloch oscillations of ultracold atoms in an optical lattice, in the presence of atom-atom interactions. A new, interaction-induced Bloch period is identified. Analytical results are corroborated by realistic numerical calculations. 相似文献
19.
We make use of a coordinate-free approach to implement Vakhitov-Kolokolov criterion for stability analysis in order to study
the effects of three-body atomic recombination and lattice potential on the matter-wave bright solitons formed in Bose-Einstein
condensates. We analytically demonstrate that (i) the critical number of atoms in a stable BEC soliton is just half the number
of atoms in a marginally stable Townes-like soliton and (ii) an additive optical lattice potential further reduces this number
by a factor of √1 − bg
3 with g
3 the coupling constant of the lattice potential and b = 0.7301.
相似文献
20.
Sk. Golam Ali B. Talukdar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):315-322
We consider matter-wave bright solitons in the presence of three-body atomic recombination, an axial periodic modulation and
a feeding term, and use a variational method to derive conditions to have dynamically stabilized solitons due to compensation
between the dissipation and alimentation of atoms from external sources. We critically examine how the BEC soliton is affected
by the imbalance between the internal atom loss and external feeding. We pay special attention
to study the influence of these terms on the soliton dynamics in optical lattice potentials that cause periodic modulation. 相似文献