论文标题
二进制玻色混合物与种间景点的微观配对理论：玻色症BEC-BCS交叉和超稀释型低维量子液滴
Microscopic pairing theory of a binary Bose mixture with interspecies attractions: bosonic BEC-BCS crossover and ultradilute low-dimensional quantum droplets
论文作者
论文摘要
超大量子液滴正在吸引新的物质状态，其中有吸引力的平均场力可以通过量子波动中的排斥力平衡，以避免崩溃。在这里，我们通过概括传统的bogoliubov理论来包括三维的两大成分玻色 - 玻璃混合物中的超稀释量子液滴的显微镜理论，它通过概括了常规的bogoliubov理论来包括由种间吸引力引起的骨配对。我们的配对理论完全等同于各种方法，因此为量子液滴的能量提供了上限。在三个维度中，我们预测了从Bose-Einstein冷凝物（BEC）到Bardeen-cooper--cooper--schrieffer（BCS）超级流体的跨界存在强烈相互作用的玻色液滴的存在，并映射了波斯尼克BEC-BEC-BCS交叉相图。在一个维度中，我们发现由配对理论计算得出的一维玻色液滴的能量与最新的扩散蒙特卡洛模拟{[} phys都非常吻合。莱特牧师。 \ textbf {122}，105302（2019）{]}，几乎所有相互作用的强度都存在。在两个维度中，我们表明，当种间吸引力超过临界值时，玻色液滴消失了，可能会变成类似孤子的多体结合状态。在阈值以下，配对理论或多或少地预测了与Petrov和Astrakharchik {[} Phys得出的Bogoliubov理论相同的结果。莱特牧师。 \ textbf {117}，100401（2016）{]}。这两种理论的预测能量高于扩散的蒙特卡洛结果，这是由于种间吸引力较弱，并且在二维中越来越重要的作用越来越重要。
Ultradilute quantum droplets are intriguing new state of matter, in which the attractive mean-field force can be balanced by the repulsive force from quantum fluctuations to avoid collapse. Here, we present a microscopic theory of ultradilute quantum droplets in three-, one- and two-dimensional two-component Bose-Bose mixtures, by generalizing the conventional Bogoliubov theory to include the bosonic pairing arising from the interspecies attraction. Our pairing theory is fully equivalent to a variational approach and hence gives an upper bound for the energy of quantum droplets. In three dimensions, we predict the existence of a strongly interacting Bose droplet at the crossover from Bose-Einstein condensates (BEC) to Bardeen--Cooper--Schrieffer (BCS) superfluids and map out the bosonic BEC-BCS crossover phase diagram. In one dimension, we find that the energy of the one-dimensional Bose droplet calculated by the pairing theory is in an excellent agreement with the latest diffusion Monte Carlo simulation {[}Phys. Rev. Lett. \textbf{122}, 105302 (2019){]}, for nearly all the interaction strengths at which quantum droplets exist. In two dimensions, we show that Bose droplets disappear and may turn into a soliton-like many-body bound state, when the interspecies attraction exceeds a critical value. Below the threshold, the pairing theory predicts more or less the same results as the Bogoliubov theory derived by Petrov and Astrakharchik {[}Phys. Rev. Lett. \textbf{117}, 100401 (2016){]}. The predicted energies from both theories are higher than the diffusion Monte Carlo results, due to the weak interspecies attraction and the increasingly important role played by the beyond-Bogoliubov-approximation effect in two dimensions.
