Are Quasiparticles and Phonons Identical in Bose–Einstein Condensates?
Are Quasiparticles and Phonons Identical in Bose–Einstein Condensates?
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玻色-爱因斯坦凝聚中的准粒子和声子相同吗？
DOI：
10.7566/jpsj.85.124004
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发表时间：
2016
影响因子：
1.7
通讯作者：
T. Kita
中科院分区：
文献类型：
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作者：
K. Tsutsui;Y. Kato;T. Kita
我们研究了一个相互作用的无自旋玻色-爱因斯坦凝聚体，以从理论上阐明它的准粒子(单粒子激发)和集体模(两粒子激发)的光谱是否相同，正如Gavoret和Nozieres[Ann]所得出的结论。太棒了。(纽约)28,349(1964)]。我们推导了它们的一阶矩和二阶矩的解析表达式，从而将集体模谱峰的Bijl-Feynman公式推广到它的宽度(反寿命)，并推广到单粒子通道。所得到的公式表明，在长波长范围内，集体模谱的宽度明显为零，而准粒子谱的宽度明显保持有限。我们还利用变分优化的Jastrow波函数对模型相互作用势的两个光谱的峰和宽度进行了数值计算。由此发现，准粒子谱的宽度随着波数的减小而趋于恒定。这个标记为d..。
We study an interacting spinless Bose–Einstein condensate to clarify theoretically whether the spectra of its quasiparticles (one-particle excitations) and collective modes (two-particle excitations) are identical, as concluded by Gavoret and Nozieres [Ann. Phys. (N.Y.) 28, 349 (1964)]. We derive analytic expressions for their first and second moments so as to extend the Bijl–Feynman formula for the peak of the collective-mode spectrum to its width (inverse lifetime) and also to the one-particle channel. The obtained formulas indicate that the width of the collective-mode spectrum manifestly vanishes in the long-wavelength limit, whereas that of the quasiparticle spectrum apparently remains finite. We also evaluate the peaks and widths of the two spectra numerically for a model interaction potential in terms of the Jastrow wave function optimized by a variational method. It is thereby found that the width of the quasiparticle spectrum increases towards a constant as the wavenumber decreases. This marked d...
影响因子：
19.6
作者：
S. Utsunomiya;L. Tian;G. Roumpos;C. Lai;N. Kumada;T. Fujisawa;M. Kuwata-Gonokami;A. Löffler;S. Höfling;A. Forchel;Y. Yamamoto
通讯作者：
S. Utsunomiya;L. Tian;G. Roumpos;C. Lai;N. Kumada;T. Fujisawa;M. Kuwata-Gonokami;A. Löffler;S. Höfling;A. Forchel;Y. Yamamoto