论文标题
大规模不变超流体的散布
Gapped dilatons in scale invariant superfluids
论文作者
论文摘要
我们研究了一个范式的范式模型，其中全局$ u（1）$和比例对称性被共同且自发损坏。在零密度下，该模型具有非压缩平坦方向，在有限密度下，必须稍微提起。所得的低能频谱由标准的无间隙$ U（1）$ NAMBU-GOLDSTONE模式和光diLATON组成，其间隙由化学电位确定并由耦合校正。即使$ u（1）$和比例对称性通勤，但$ u（1）$ nambu-goldstone与Dilaton之间存在混合，这对于恢复了保形流体的预期动态至关重要，并导致声子以声音速度传播。结果仅依赖于对病房 - 塔卡哈西身份的准确研究，并根据标准波动计算进行检查。我们将结果扩展到增强的超流体，并评论我们的发现与凝结物质应用的相关性。
We study a paradigmatic model in field theory where a global $U(1)$ and scale symmetries are jointly and spontaneously broken. At zero density the model has a non-compact flat direction, which at finite density needs to be slightly lifted. The resulting low-energy spectrum is composed by a standard gapless $U(1)$ Nambu-Goldstone mode and a light dilaton whose gap is determined by the chemical potential and corrected by the couplings. Even though $U(1)$ and scale symmetries commute, there is a mixing between the $U(1)$ Nambu-Goldstone and the dilaton that is crucial to recover the expected dynamics of a conformal fluid and leads to a phonon propagating at the speed of sound. The results rely solely on an accurate study of the Ward-Takahashi identities and are checked against standard fluctuation computations. We extend our results to a boosted superfluid, and comment the relevance of our findings to condensed matter applications.
