Bosonic Functional Determinant Approach and its Application to Polaron Spectra
arXiv:2403.13582 · doi:10.1103/PhysRevA.110.063303
Abstract
The functional determinant approach (FDA) is a simple method to compute exactly certain observables for ideal quantum systems and has been successfully applied to the Fermi polaron problem to obtain the dynamical overlap and spectral function. Unfortunately, its application to Bosonic ultracold gases is prohibited by the failure of the grand canonical ensemble for these systems. In this paper, we show how to circumvent this problem and develop a Bosonic FDA. This yields exact injection and ejection spectra for ideal Bose polarons at arbitrary temperatures. While coherent features visible at absolute zero quickly smear out with rising temperature as expected, the line width of the main peak is, counterintuitively, found to decrease near unitarity. Furthermore, we provide explicit formulas for the overlap operator, which allow to compute the necessary determinants for both Bose and Fermi polarons more efficiently than previously possible.
10 pages, 3 figures
References in corpus (28)
- Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate
- Bose polarons in the strongly interacting regime
- Universal phase diagram of a strongly interacting Fermi gas with unbalanced spin populations
- Ultrafast many-body interferometry of impurities coupled to a Fermi sea
- Field-theoretical study of the Bose polaron
- Feynman path-integral treatment of the BEC-impurity polaron
- Time dependent impurity in ultracold fermions: orthogonality catastrophe and beyond
- Bose polarons near quantum criticality
- Quantum dynamics of ultracold Bose polarons
- Condensate fluctuations of a trapped, ideal Bose gas
- Non-equilibrium quantum dynamics and formation of the Bose polaron
- A mesoscopic Rydberg impurity in an atomic quantum gas
- Bose polarons at finite temperature and strong coupling
- Real-space dynamics of attractive and repulsive polarons in Bose-Einstein condensates
- Theory of excitation of Rydberg polarons in an atomic quantum gas
- Mobile impurity in a Bose-Einstein condensate and the orthogonality catastrophe
- Observation of the phononic Lamb shift with a synthetic vacuum
- Fate of the Bose polaron at finite temperature
- Observation of Atom Number Fluctuations in a Bose-Einstein Condensate
- Theory of a resonantly interacting impurity in a Bose-Einstein condensate
- Quantum behavior of a heavy impurity strongly coupled to a Bose gas
- Dynamical variational approach to Bose polarons at finite temperatures
- Theory of radio-frequency spectroscopy of impurities in quantum gases
- From Efimov Physics to the Bose Polaron using Gaussian States
- Quench Dynamics of the Ideal Bose Polaron at Zero and Nonzero Temperatures
- Observation of Microcanonical Atom Number Fluctuations in a Bose-Einstein Condensate
- Observation of -tails after expansion of Bose-Einstein Condensates with impurities
- Disorder in order: Localization without randomness in a cold atom system