Quantum droplets in two-dimensional optical lattices
- PDF / 1,457,103 Bytes
- 10 Pages / 595.28 x 785.2 pts Page_size
- 68 Downloads / 193 Views
Front. Phys. 16(2), 22501 (2021)
Research article Quantum droplets in two-dimensional optical lattices Yi-Yin Zheng∗ , Shan-Tong Chen∗ , Zhi-Peng Huang, Shi-Xuan Dai, Bin Liu, Yong-Yao Li† , Shu-Rong Wang School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China Corresponding author. E-mail: † [email protected] Received July 19, 2020; accepted September 22, 2020
We study the stability of zero-vorticity and vortex lattice quantum droplets (LQDs), which are described by a two-dimensional (2D) Gross–Pitaevskii (GP) equation with a periodic potential and Lee– Huang–Yang (LHY) term. The LQDs are divided in two types: onsite-centered and offsite-centered LQDs, the centers of which are located at the minimum and the maximum of the potential, respectively. The stability areas of these two types of LQDs with different number of sites for zero-vorticity and vorticity with S = 1 are given. We found that the µ–N relationship of the stable LQDs with a fixed number of sites can violate the Vakhitov–Kolokolov (VK) criterion, which is a necessary stability condition for nonlinear modes with an attractive interaction. Moreover, the µ–N relationship shows that two types of vortex LQDs with the same number of sites are degenerated, while the zero-vorticity LQDs are not degenerated. It is worth mentioning that the offsite-centered LQDs with zero-vorticity and vortex LQDs with S = 1 are heterogeneous. Keywords lattice quantum droplets, optical lattices, vortex
1 Introduction In Bose–Einstein condensates (BECs), it is well known that free-space nonlinear modes may collapse in twodimensional (2D) and three-dimensional (3D) geometries via the action of the usual attractive cubic nonlinearity [1]. Hence, how to acquire stabilize nonlinear modes in multidimensional systems remains an important research topic. Generally, the simplest way is to modify the attractive cubic nonlinearity, which includes reducing the cubic nonlinearity to quadratic nonlinearity [2, 3], adding competitive nonlinearities, such as the competing cubicquintic nonlinearity [4–10], changing cubic nonlinearity to saturable nonlinearity [11] or nonlocal nonlinearity [12–16]. Subsequently, one can introduce spin–orbit coupling to stabilize self-trapped modes, i.e., matter-wave solitons [17–26] and quantum droplets (QDs) [27]. QDs, a new type of self-bound quantum liquid state, were created experimentally in dipolar bosonic gases of dysprosium [28] and erbium [29], as well as in mixtures of two atomic states of 39 K [30] with contact interactions. QDs have attracted much attention in the field of ultracold atoms ∗ These
authors contributed equally to this work. arXiv: 2009.06804. This article can also be found at http:// journal.hep.com.cn/fop/EN/10.1007/s11467-020-1011-3.
[31–61], which predicate a possibility in the framework of the 3D [31], 2D [32–38] and 1D [39–42] Gross–Pitaevskii (GP) equations. Research has shown that QDs have been formed with the help of zero-point quantum fluctuations, which can arrest the collapse of at
Data Loading...
