Landau-Zener tunneling in a nonlinear three-level system

Wang, Guanfang; Ye, Difa; Fu, Libin; Chen, Xuzong; Liu, Jie

doi:10.1103/physreva.74.033414

Cited by 83 publications

(60 citation statements)

References 31 publications

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“…Therefore, H[k x , k y , ψ(k x , k y )] is a representative and natural choice to accommodate bosonic mean-field interactions and to motivate experimental investigations. As expected from previous theoretical and experimental studies of nonlinear Bloch bands in zero or one dimensional systems [47,[54][55][56][57][58][59][60][61], a self-crossing loop structure emerges as g increases beyond a critical value g c . Specifically, for g = g c , the bottom band starts to develop a cusp [see the red circle in Fig.…”

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confidence: 49%

Nonlinear Dirac cones

et al. 2017

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Physics arising from two-dimensional (2D) Dirac cones has been a topic of great theoretical and experimental interest to studies of gapless topological phases and to simulations of relativistic systems. Such 2D Dirac cones are often characterized by a π Berry phase and are destroyed by a perturbative mass term. By considering mean-field nonlinearity in a minimal two-band Chern insulator model, we obtain a novel type of Dirac cones that are robust to local perturbations without symmetry restrictions. Due to a different pseudo-spin texture, the Berry phase of the Dirac cone is no longer quantized in π, and can be continuously tuned as an order parameter. Furthermore, in an Aharonov-Bohm (AB) interference setup to detect such Dirac cones, the adiabatic AB phase is found to be π both theoretically and computationally, offering an observable topological invariant and a fascinating example where the Berry phase and AB phase are fundamentally different.We hence discover a nonlinearity-induced quantum phase transition from a known topological insulating phase to an unusual gapless topological phase. *

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confidence: 49%

Nonlinear Dirac cones

et al. 2017

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“…Recently this protocol has been proposed to transport single atoms [11,12], Cooper pairs [13] and electrons [14,15,16,17]. Here we extend these ideas to the transport of dilute gas BECs containing thousands of atoms.In this article we elucidate the properties of the threewell system by first considering a three-mode approximation [18,19,20], where the form of the potential is arXiv:0709.0985v1 [cond-mat.other] …”

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confidence: 99%

Spatial coherent transport of interacting dilute Bose gases

et al. 2008

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Classically it is impossible to have transport without transit, i.e., if the points one, two and three lie sequentially along a path then an object moving from one to three must, at some point in time, be located at two. However, for a quantum particle in a three-well system it is possible to transport the particle between wells one and three such that the probability of finding it at any time in the classically accessible state in well two is negligible. We consider theoretically the analogous scenario for a Bose-Einstein condensate confined within a three well system. In particular, we predict the adiabatic transportation of an interacting Bose-Einstein condensate of 2000 7 Li atoms from well one to well three without transiting the allowed intermediate region. To an observer of this macroscopic quantum effect it would appear that, over a timescale of the order of 1s, the condensate had transported, but not transited, a macroscopic distance of ∼ 20µm between wells one and three.The system under consideration is schematically shown in Fig. 1(a), where a three-dimensional harmonic trap is split into three regions via the addition of two parallel repulsive Gaussian potentials. With the Bose-Einstein condensate (BEC) [blue object in Fig. 1(a)], initially in well 1, we show how it is possible, through adiabatic changes to the tunneling rates between the wells, to transport it into well 3 with minimal (ideally zero) occupation of the intervening well. This effect as a function of time is shown in Fig. 1(b), where an interacting BEC of 2000 7 Li atoms is transported from well 1 to well 3 over a timescale of ∼ 1s, with less than 1% atoms occupying well 2 at any particular time. As such it appears that the BEC is transported from well 1 to well 3 without transiting through well 2.This effect of transport without transit (TWT) can be likened to the lay concept of teleportation. However, although TWT relies on quantum control of the global BEC state and associated tunneling matrix elements, it is quite distinct from the quantum definition of teleportation [1]. In the TWT of a BEC we describe the many body system in a time dependent mean-field approximation. As such the wavefunction used to describe the condensed state is a classical field and can not describe such properties as entanglement and hence quantum teleportation.The ideas underpinning the protocol for TWT stem from Stimulated Raman Adiabatic Passage (STIRAP) [2,3,4,5]. STIRAP is a robust optical technique for transferring population between two atomic states, |1 and |3 , via an intermediate excited state, |2 . Using off-resonant pulses to couple states |1 to |2 and |2 to |3 , characterised by coupling parameters K 12 and K 23 , and such that K 23 precedes and overlaps K 12 , the population can be adiabatically transferred from state |1 to |3 . Population transfer is achieved via a superposition of states |1 and |3 with the occupation of state |2 strongly suppressed. These techniques are used in quantum optics for coherent internal state transfer [5,6,7,8] and h...

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“…In the three-level approximation the Hamiltonian can therefore be written as with the individual traps. Note that this Hamiltonian has been extensively investigated for constant couplings between the traps [25,26]. As the particle number in each individual trap is a function of time, the chemical potentials µ i will change and destroy the resonances between the traps.…”

Section: Nonlinear Systemsmentioning

confidence: 99%

Coherent adiabatic transport of atoms in radio-frequency traps

Morgan

O’Sullivan²,

Busch³

2011

Phys. Rev. A

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Coherent transport by adiabatic passage has recently been suggested as a high-fidelity technique to engineer the center-of-mass state of single atoms in inhomogeneous environments. While the basic theory behind this process is well understood, several conceptual challenges for its experimental observation have still to be addressed. One of these is the difficulty that currently available optical or magnetic micro-trap systems have in adjusting the tunneling rate time dependently while keeping resonance between the asymptotic trapping states at all times. Here we suggest that both requirements can be fulfilled to a very high degree in an experimentally realistic setup based on radio-frequency traps on atom chips. We show that operations with close to 100% fidelity can be achieved and that these systems also allow significant improvements for performing adiabatic passage with interacting atomic clouds

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Landau-Zener tunneling in a nonlinear three-level system

Cited by 83 publications

References 31 publications

Nonlinear Dirac cones

Nonlinear Dirac cones

Spatial coherent transport of interacting dilute Bose gases

Coherent adiabatic transport of atoms in radio-frequency traps

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