Gawryluk Krzysztof, Brewczyk Mirosław
Wydział Fizyki, Uniwersytet w Białymstoku, ul. K. Ciołkowskiego 1L, 15245, Białystok, Poland.
Sci Rep. 2024 May 11;14(1):10815. doi: 10.1038/s41598-024-61521-5.
We numerically study the transport properties of a two-dimensional Fermi gas in a weakly and strongly interacting regimes, in the range of temperatures close to the transition to a superfluid phase. For that we excite sound waves in a fermionic mixture by using the phase imprinting technique, follow their evolution, and finally determine both their speed and attenuation. Our formalism, originated from a density-functional theory, incorporates thermal fluctuations via the grand canonical ensemble description and with the help of Metropolis algoritm. From numerical simulations we extract temperature dependence of the sound velocity and diffusivity as well as the dependence on the interaction strength. We emphasize the role of virtual vortex-antivortex pairs creation in the process of sound dissipation.
我们对二维费米气体在弱相互作用和强相互作用区域、接近超流相转变温度范围内的输运性质进行了数值研究。为此，我们通过相位印记技术在费米子混合物中激发声波，跟踪其演化，最终确定其速度和衰减。我们的形式体系源自密度泛函理论，通过巨正则系综描述并借助 metropolis 算法纳入热涨落。从数值模拟中，我们提取了声速和扩散率的温度依赖性以及对相互作用强度的依赖性。我们强调了虚涡旋 - 反涡旋对的产生在声耗散过程中的作用。
