Complex-valued in-medium potential between heavy impurities in ultracold atoms
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| Format: | Preprint |
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2023
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| _version_ | 1866911448673812480 |
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| author | Akamatsu, Yukinao Endo, Shimpei Fujii, Keisuke Hongo, Masaru |
| author_facet | Akamatsu, Yukinao Endo, Shimpei Fujii, Keisuke Hongo, Masaru |
| contents | We formulate the induced potential in a finite temperature cold atomic medium between two heavy impurities, or polarons, which is shown to be \textit{complex-valued} in general. The imaginary part of the complex-valued potential describes a decoherence effect, and thus, the resulting Schrödinger equation for the two polarons acquires a non-Hermitian term. We apply the developed formulation to two representative cases of polarons interacting with medium particles through the $s$-wave contact interaction: (i) the normal phase of single-component (i.e., spin-polarized) fermions using the fermionic field theory, and (ii) a superfluid phase using the superfluid effective field theory, which is valid either for a Bose-Einstein condensate (BEC) of a single-component Bose gas or for the BEC-BCS crossover in two-component fermions at a low-energy regime. Computing the leading-order term, the imaginary part of the potential in both cases is found to show a universal $r^{-2}$ behavior at long distance. We propose three experimental ways to observe the effects of the universal imaginary potential in cold atoms. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2312_08241 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Complex-valued in-medium potential between heavy impurities in ultracold atoms Akamatsu, Yukinao Endo, Shimpei Fujii, Keisuke Hongo, Masaru Quantum Gases High Energy Physics - Theory Nuclear Theory We formulate the induced potential in a finite temperature cold atomic medium between two heavy impurities, or polarons, which is shown to be \textit{complex-valued} in general. The imaginary part of the complex-valued potential describes a decoherence effect, and thus, the resulting Schrödinger equation for the two polarons acquires a non-Hermitian term. We apply the developed formulation to two representative cases of polarons interacting with medium particles through the $s$-wave contact interaction: (i) the normal phase of single-component (i.e., spin-polarized) fermions using the fermionic field theory, and (ii) a superfluid phase using the superfluid effective field theory, which is valid either for a Bose-Einstein condensate (BEC) of a single-component Bose gas or for the BEC-BCS crossover in two-component fermions at a low-energy regime. Computing the leading-order term, the imaginary part of the potential in both cases is found to show a universal $r^{-2}$ behavior at long distance. We propose three experimental ways to observe the effects of the universal imaginary potential in cold atoms. |
| title | Complex-valued in-medium potential between heavy impurities in ultracold atoms |
| topic | Quantum Gases High Energy Physics - Theory Nuclear Theory |
| url | https://arxiv.org/abs/2312.08241 |