ترغب بنشر مسار تعليمي؟ اضغط هنا

Assessment of interspecies scattering lengths $a_{12}$ from stability of two-component Bose-Einstein condensates

322   0   0.0 ( 0 )
 نشر من قبل Daniel Schumayer
 تاريخ النشر 2004
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

A stability method is used to assess possible values of interspecies scattering lengths a_12 in two-component Bose-Einstein condensates described within the Gross-Pitaevskii approximation. The technique, based on a recent stability analysis of solitonic excitations in two-component Bose-Einstein condensates, is applied to ninety combinations of atomic alkali pairs with given singlet and triplet intraspecies scattering lengths as input parameters. Results obtained for values of a_12 are in a reasonable agreement with the few ones available in the literature and with those obtained from a Painleve analysis of the coupled Gross-Pitaevskii equations.



قيم البحث

اقرأ أيضاً

We propose and analyze a general mechanism of disorder-induced order in two-component Bose-Einstein condensates, analogous to corresponding effects established for XY spin models. We show that a random Raman coupling induces a relative phase of pi/2 between two BECs and that the effect is robust. We demonstrate it in 1D, 2D and 3D at T=0 and present evidence that it persists at small T>0. Applications to phase control in ultracold spinor condensates are discussed.
We examine the effect of the intra- and interspecies scattering lengths on the dynamics of a two-component Bose-Einstein condensate, particularly focusing on the existence and stability of solitonic excitations. For each type of possible soliton pair s stability ranges are presented in tabulated form. We also compare the numerically established stability of bright-bright, bright-dark and dark-dark solitons with our analytical prediction and with that of Painleve-analysis of the dynamical equation. We demonstrate that tuning the inter-species scattering length away from the predicted value (keeping the intra-species coupling fixed) breaks the stability of the soliton pairs.
We use collective oscillations of a two-component Bose-Einstein condensate (2CBEC) of Rb atoms prepared in the internal states $ket{1}equivket{F=1, m_F=-1}$ and $ket{2}equivket{F=2, m_F=1}$ for the precision measurement of the interspecies scattering length $a_{12}$ with a relative uncertainty of $1.6times 10^{-4}$. We show that in a cigar-shaped trap the three-dimensional (3D) dynamics of a component with a small relative population can be conveniently described by a one-dimensional (1D) Schr{o}dinger equation for an effective harmonic oscillator. The frequency of the collective oscillations is defined by the axial trap frequency and the ratio $a_{12}/a_{11}$, where $a_{11}$ is the intra-species scattering length of a highly populated component 1, and is largely decoupled from the scattering length $a_{22}$, the total atom number and loss terms. By fitting numerical simulations of the coupled Gross-Pitaevskii equations to the recorded temporal evolution of the axial width we obtain the value $a_{12}=98.006(16),a_0$, where $a_0$ is the Bohr radius. Our reported value is in a reasonable agreement with the theoretical prediction $a_{12}=98.13(10),a_0$ but deviates significantly from the previously measured value $a_{12}=97.66,a_0$ cite{Mertes07} which is commonly used in the characterisation of spin dynamics in degenerate Rb atoms. Using Ramsey interferometry of the 2CBEC we measure the scattering length $a_{22}=95.44(7),a_0$ which also deviates from the previously reported value $a_{22}=95.0,a_0$ cite{Mertes07}. We characterise two-body losses for the component 2 and obtain the loss coefficients ${gamma_{12}=1.51(18)times10^{-14} textrm{cm}^3/textrm{s}}$ and ${gamma_{22}=8.1(3)times10^{-14} textrm{cm}^3/textrm{s}}$.
Gaseous Bose-Einstein condensates (BECs) have become an important test bed for studying the dynamics of quantized vortices. In this work we use two-photon Doppler sensitive Bragg scattering to study the rotation of sodium BECs. We analyze the microsc opic flow field and present laboratory measurements of the coarse-grained velocity profile. Unlike time-of-flight imaging, Bragg scattering is sensitive to the direction of rotation and therefore to the phase of the condensate. In addition, we have non-destructively probed the vortex flow field using a sequence of two Bragg pulses.
313 - M. Abad , A. Recati 2013
We present a self-consistent study of coherently coupled two-component Bose-Einstein condensates. Finite spin-flipping coupling changes the first order demixing phase transition for Bose-Bose mixtures to a second order phase transition between an unp olarized and a polarized state. We analise the excitation spectrum and the structure factor along the transition for a homogeneous system. We discuss the main differences at the transition between a coherent coupled gas and a two-component mixture. We finally study the ground state when spin-(in)dependent trapping potentials are added to the system, focusing on optical lattices, which give rise to interesting new configurations.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا