论文标题
原子和分子bose-Einstein冷凝物中激发的寿命
Lifetime of Excitations in Atomic and Molecular Bose-Einstein Condensates
论文作者
论文摘要
最近的实验进步在热平衡中产生了分子超流体（MSF）。这为研究相关的热力学和动态反应的新一类实验打开了大门。我们回顾了原子超氟（ASF）和MSF阶段中相图和准粒子谱的理论图。我们进一步计算出单环阶的准颗粒寿命的参数依赖性。在MSF阶段，$ u（1）$粒子数对称分解为$ \ MATHBB {z} _2 $，并且Spectrum除了Gaped $ \ Mathbb {Z} _2 _2 _2 $ - protepted Atoteptyateyation-preteptyateation-pretected attyatomlike模式外，还表现出无间隙的金石模式。在ASF阶段，$ u（1）$对称性完全断裂，留下戈德石模式和未保护的间隙模式。在这两个阶段中，戈德石模式都以著名的Belyaev结果给出的速率衰减，如单个组件冷凝物。在MSF阶段，间隙模式锐利到临界的Cherenkov动量，超出了声子。在ASF阶段，即使在小动量处，间隙模式也以恒定的速率衰减。这些衰减速率控制了微饰面隧道实验中的光谱响应，并在通过分子云发射的原子的传输光谱中导致了鲜明的特征。
Recent experimental progress has produced Molecular Superfluids (MSF) in thermal equilibrium; this opens the door to a new class of experiments investigating the associated thermodynamic and dynamical responses. We review the theoretical picture of the phase diagram and quasiparticle spectrum in the Atomic Superfluid (ASF) and MSF phases. We further compute the parametric dependence of the quasiparticle lifetimes at one-loop order. In the MSF phase, the $U(1)$ particle number symmetry breaks to $\mathbb{Z}_2$ and the spectrum exhibits a gapless Goldstone mode in addition to a gapped $\mathbb{Z}_2$-protected atom-like mode. In the ASF phase, the $U(1)$ symmetry breaks completely, leaving behind a Goldstone mode and an unprotected gapped mode. In both phases, the Goldstone mode decays with a rate given by the celebrated Belyaev result, as in a single component condensate. In the MSF phase, the gapped mode is sharp up to a critical Cherenkov momentum beyond which it emits phonons. In the ASF phase, the gapped mode decays with a constant rate even at small momenta. These decay rates govern the spectral response in microtrap tunneling experiments and lead to sharp features in the transmission spectrum of atoms fired through molecular clouds.
