在所有情况下,crossover 是通过改变配对关联的长度尺度(即费米子对的“大小”)相对于粒子间距来实现的,如下图所示。 图1 双组分费米气体中的BCS-BEC crossover 需要注意的是,对于非零角动量的配对,如 p-波配对,在零温度下,BCS和BEC区域之间实际上存在相变,而不是 crossover。因此,本文将仅限于讨论各向同性...
我们现在转向有限温度TT对BCS-BEC crossover 的影响。在这里,对于足够大的热涨落,对的凝聚态最终会被破坏,因此系统会经历一个连续相变,转变为正常费米(玻色)气体,分别在BCS(BEC)极限中。此外,相变温度由凝聚态的低能激发决定。在BCS区域 \frac1{k_Fa_s}\ll-1 中,配对能隙较小,配对凝聚基本上与配对形成一...
详细介绍了BCS-BEC Crossover(怎么翻译比较好?常见的翻译为“渡越”,大家把crossover和“相变”区分开即可,热力学相变是伴随对称性破缺的,且存在可观测量的不连续性,而crossover是一个连续的过程)。另外,BCS-BEC crossover也被认为可能与高温超导体的赝能隙现象有关。 全文依然采用路径积分量子场论的框架,且额外...
不是相变... 序参量本质上是一样的, 而且在整个 crossover 的过程中连续变化. 先说实验. 因为在 BCS-BEC crossover 中间的 unitary region 是强相互作用的, 因此我们其实没有特别好的理论去描述它. 在这个 region 里有没有发生相变, 最终是实验说了算. 在 拓扑学在物理研究中有哪些具体应用？
The crossover between Bose–Einstein condensation of diquark bound states and condensation of diquark resonances (Cooper pairs) in the continuum is discussed as a Mott effect. This effect consists in the transition of bound states into the continuum of scattering states under the influence of ...
s pixel area and the imaging system’s magnification, we obtain the number of atoms. We include additional laser-intensity-dependent corrections51. The imaging system has a resolution of 2.2 μm. The optical absorption cross-section changes its value throughout the BEC–BCS crossover, ...
相对论系统中的BCS-BEC越渡相变热力学
Zhao, "BEC-BCS crossover in a (p + ip)-wave pairing Hamiltonian coupled to bosonic molecular pairs," Nuclear Physics B, vol. 848, pp. 372-397, July 2011.C. Dunning, P.S. Isaac, J. Links, and S.-Y. Zhao, BEC-BCS crossover in a (p+ip)- wave pairing Hamiltonian coupled to ...
The BCS-BEC Crossover and the Unitary Fermi Gas is a collaborative effort by leading international experts to provide an up-to-date introduction and a comprehensive overview of current research in this fast-moving field. It is now understood that the unitary regime that lies right in the midd...