Localization of a two-component Bose–Einstein condensate in a two-dimensional bichromatic optical lattice

Xi, Kui-Tian; Li, Jinbin; Shi, Dan

doi:10.1016/j.physb.2013.12.010

Cited by 8 publications

(4 citation statements)

References 41 publications

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“…On the other hand, the effect of contact interactions, dipole-dipole interactions and disorder on the diffusion properties of 1D dipolar two-component condensates were studied in [42], identifying again the conditions for subdiffusion. The study of the diffusive behavior of a 2D two-component BEC in a disordered potential was undertaken in [43]. Finally, an important study on an impurity immersed in a two-component BEC was reported in [44].…”

Section: Introductionmentioning

confidence: 99%

Control of anomalous diffusion of a Bose polaron

Charalambous

García-March

Muñoz-Gil

et al. 2020

Quantum

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We study the diffusive behavior of a Bose polaron immersed in a coherently coupled two-component Bose-Einstein Condensate (BEC). Polaron superdiffuses if it couples in the same manner to both components, i.e. either attractively or repulsively to both of them. This is the same behavior as that of an impurity immersed in a single BEC. Conversely, the polaron exhibits a transient nontrivial subdiffusive behavior if it couples attractively to one of the components and repulsively to the other. The anomalous diffusion exponent and the duration of the subdiffusive interval can be controlled with the Rabi frequency of the coherent coupling between the two components, and with the coupling strength of the impurity to the BEC.

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Section: Introductionmentioning

confidence: 99%

Control of anomalous diffusion of a Bose polaron

Charalambous

García-March

Muñoz-Gil

et al. 2020

Quantum

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“…There have also been studies of dynamical effects including those associated with ramping up the optical lattice [22][23][24]. Recent studies show theories about, for example, phase diagram and stability [25,26], evolution of coherence or number-squeezing during ramp-up [27][28][29]. Other works have investigated other equilibrium or nonequilibrium properties via various stochastic theories including a truncated Wigner method applied to singlecomponent BECs [30,31], which will also be interesting once extended to multi-component BECs.…”

Section: Introductionmentioning

confidence: 99%

Phase coherence and fragmentation of two-component Bose-Einstein condensates loaded in state-dependent optical lattices

Shim

Bergeman

2016

Phys. Rev. A

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A binary mixture of interacting Bose-Einstein Condensates (BEC) in the presence of fragmentation-driving external lattice potentials forms two interdependent mean-field lattices made of each component. These effective mean-field lattices, like ordinary optical lattices, can induce additional fragmentation and phase coherence loss of BECs between lattice sites. In this study, we consider the nonequilibrium dynamics of two hyperfine states of 1D Bose-Einstein condensates, subjected to state-dependent optical lattices. Our numerical calculations using the truncated Wigner approximation (TWA) show that phase coherence in a mixture of two-component BECs can be lost not just by optical lattices, but by mean-field lattices gradually formed by other components, and we reveal that such an effect of internal mean-field lattices, however, is limited, contrary to external optical lattices, in regard to phase decoherence.

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“…On the other hand, the effect of contact interactions, dipole-dipole interactions and disorder on the diffusion properties of 1D dipolar two-component condensates were studied in (Bai and Xue, 2015), identifying again the conditions for subdiffusion. The study of the diffusive behaviour of a 2D two-component BEC in a disordered potential was undertaken in (Xi et al, 2014). Finally, an important study on an impurity immersed in a two-component BEC was reported in (Ashida et al, 2018).…”

Section: Control Of Anomalous Diffusion Of a Bose Polaron In A Cohere...mentioning

confidence: 99%

“…The open quantum system approach has been used recently in the context of ultracold quantum gases to study the diffusion of an impurity and two impurities in a BEC (Lampo et al, 2017a, for the movement of a bright soliton in a superfluid in one dimension (Efimkin et al, 2016a), among other examples (Hurst et al, 2017b, Keser and Galitski, 2018, Bonart and Cugliandolo, 2012a). On the other hand, the effect of contact interactions, dipoledipole interactions and disorder on the diffusion properties of 1D dipolar two-component condensates were studied in (Bai and Xue, 2015), identifying again the conditions for subdiffusion, while the study for the diffusive behaviour of a 2D two-component BEC in a disordered potential was undertaken in (Xi et al, 2014). Finally, an important study 6.…”

Section: Control Of Anomalous Diffusion Of a Bose Polaron In A Cohere...mentioning

confidence: 99%

Quantum Brownian motion in Bose-Einstein condensates

Charalambous

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Quantum Brownian motion is one of the most prominent examples of an open quantum system, a system which cannot be treated in isolation from its environment. The simplest method to study the dynamics of a system undergoing such a type of motion, that satisfies Heisenberg Uncertainty principle is the approach of Quantum Generalized Langevin Equations (QGLE), which was used throughout this thesis. A Quantum Brownian motion approach is used in this work to study the Bose polaron problem. In this case, one transforms the original problem into one where the impurities are treated as quantum Brownian particles interacting with a bath composed of the Bogoliubov modes of the condensate. Then by deriving the relevant QGLE, it was shown that the dynamics of the Bose polaron exhibit memory effects. This was studied for both a free Bose-Einstein condensate (BEC) and a harmonically trapped one, in both cases for experimentally relevant parameters. Taking advantage of this recent theoretical development, we study a number of phenomena that can be examined under this prism and show how various microdevices can be constructed and controlled. In the first project, we study the creation of entanglement and squeezing of two uncoupled impurities that are immersed in a single common (BEC) bath. We treat these impurities as two quantum Brownian particles. We study two scenarios:(i) In the absence of an external potential, we observe sudden death of entanglement;(ii) In the presence of an external harmonic potential, where entanglement survives even at the asymptotic time limit. In our second work, we studied the diffusive behavior of a Bose Polaron immersed in a coherently coupled two-component BEC. The particle superdiffuses if it couples in the same manner to both components, i.e. if it couples either attractively or repulsively to both of them. This is the same behavior of an impurity immersed in a single BEC. Conversely, we find that it exhibits a transient nontrivial subdiffusive behavior if it couples attractively to one of the components and repulsively with the other. We show how the magnitude of the anomalous exponent reached and the duration of the subdiffusive interval can be controlled with the Rabi frequency of the coherent coupling between the two components and the coupling strength of the impurity to the BEC. Then we proceeded with the construction of two microdevices, a quantum sub-nk thermometer and a heat diode. In the first project, we introduced a novel minimally disturbing method for sub-nK thermometry in a BEC. In this case, the impurity acted as a thermometer, where one detects temperature fluctuations from measurements of the position and momentum of the impurity. Crucially, these cause minimal backaction on the BEC and hence, realize a nondemolition temperature measurement. Following the paradigm of the emerging field of quantum thermometry, we combine tools from quantum parameter estimation and the theory of open quantum systems to solve the problem in full generality. We thus avoid any simplification, such as demanding thermalization of the impurity atoms. In our final work, we investigated the heat transport and the control of heat current among two spatially separated trapped BECs, each of them at a different temperature. To allow for heat transport among the two independent BECs we consider a link made of two dipole-dipole interacting harmonically trapped impurities, each of them interacting with one of the BECs. We address the dependence of heat current and current-current correlations on the physical parameters of the system. Interestingly, we show that heat rectification, can occur in our system, when a periodic driving on the trapping frequencies of the impurities is considered. Therefore, our system is a possible setup for the implementation of a phononic circuit, and hence contributes in the general framework of using BECs as platforms for quantum information processing. El movimiento Browniano, es un ejemplo de un sistema abierto, es decir un sistema que no se puede tratar en aislamiento. El método más simple para estudiar la dinámica de dicho sistema, que cumple el principio de la incertidumbre de Heisenberg es el de Quantum Generalized Langevin Equations (QGLE), que es el método que se usa en esta tesis. La perspectiva de Quantum Brownian motion se ha usado para estudiar muchos sistemas, entre ellos el problema de Bose polaron. En este caso, uno pasa el problema original a uno donde las impurezas se tratan como partículas Brownianas quanticas interactuando con un baño compuesto de modos de Bogoliubov del condensado. Después de derivar la QGLE relevante, se puede demostrar que la dinámica del Bose polaron muestra efectos de memoria. Esto se ha estudiado tanto en un Bose Einstein Condensate (BEC) libre como en uno atrapado en un trapo harmónico, para parámetros relevantes en experimentos. Aprovechando de este reciente desarrollo, estudiamos muchos fenómenos que se pueden investigar bajo este prisma y mostramos cómo se pueden construir y controlar varios microdispositivos. En el primer proyecto, estudiamos la creación de enlazamiento y squeezing de dos impurezas no acopladas, inmersas en un único BEC baño común. Estudiamos dos senarios: (i) en la ausencia de un potencial externo, donde observamos la muerte repentina del enlazamiento (ii) en la presencia de un trapo externo harmónico, donde el enlazamiento sobrevive incluso en el límite asintótico de largos tiempos. En nuestro segundo trabajo, estudiamos el comportamiento difusivo de un Bose polaron inmerso en un BEC de dos componentes que están acopladas coherentemente. La partícula es superdffusa si se acopla en la misma manera a los dos componentes, i.e. atractivamente o repulsivamente, como en el caso de un unico BEC. En el caso contrario, encontramos que la partícula muestra un comportamiento transitorio non-trivial. Mostramos como la magnitud del exponente anómalo y la duración del periodo transitorio se pueden controlar a través de la frecuencia Rabi del acoplamiento coherente entre los dos componentes y la fuerza del acoplamiento de la impureza a los dos componentes del BEC. En seguida, procedemos con la construcción de dos microdispositivos, un termómetro quántico y un diodo térmico. En el primer proyecto, hemos introducido un nuevo método de mínimo disturbio, que sirve para termometría en temperaturas sub-nK en un BEC. Nuestra técnica está basada otra vez en el modelo de Bose polaron, donde esta vez la impureza inmersa en un BEC sirve como un termómetro. La propuesta es detectar fluctuaciones de la temperatura de las medidas de la posición y el impulso de la impureza. Crucialmente, estas causan una reacción mínima en el BEC y, por lo tanto, realizan una medida de la temperatura no demoledora. En nuestro trabajo, evitamos cualquiera simplificación, como la imposición de la termalización de la impureza, o del acoplamiento débil de la impureza con el BEC. En el último trabajo, investigamos el transporte de calor y el control de corrientes de calor entre dos BECs espacialmente separados y atrapados harmónicamente, en temperaturas distintas. El flujo de calor entre los dos BECs, esta facilitado a través de dos impurezas harmónicamente atrapadas, cada una interactuando con su propio BEC. Las impurezas estan acopladas a traves de interacciones de dipolo-dipolo. Examinamos la dependencia del corriente de calor y sus correlaciones en los parámetros físicos del sistema. Mostramos que la rectificación del corriente del calor, i.e. el flujo de calor unidireccional puede ocurrir en el sistema, cuando aplicamos una conducción periódica en las frecuencias de los trapos de las impurezas. Por lo tanto, nuestro sistema es una posible configuración para la implementación de un circuito fononico.

show abstract

Localization of a two-component Bose–Einstein condensate in a two-dimensional bichromatic optical lattice

Cited by 8 publications

References 41 publications

Control of anomalous diffusion of a Bose polaron

Control of anomalous diffusion of a Bose polaron

Phase coherence and fragmentation of two-component Bose-Einstein condensates loaded in state-dependent optical lattices

Quantum Brownian motion in Bose-Einstein condensates

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