SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 68: Quantum Gases: Bosons V
Q 68.5: Vortrag
Freitag, 10. März 2023, 15:30–15:45, B305
Wilsonian Renormalization in the Symmetry-Broken Polar Phase of a Spin-1 Bose Gas — •Niklas Rasch1, Aleksandr N. Mikheev1,2, and Thomas Gasenzer1,2 — 1Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, Germany — 2Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, Germany
Wilsonian renormalization group theory is applied in a 1-loop perturbative expansion to the spin-1 Bose gas both in the thermal and in the symmetry-broken polar phase. For the latter, the symmetry is broken explicitly and flow equations including the renormalization of the condensate density are computed. A scheme is established for investigating the flow equations in a cut-off independent manner at fixed particle density. We observe the emergence of anomalous scaling in the chemical potential which relates to a flow towards the quasi-relativistic phononic regime. To restore convergent flow equations, we explicitly include wave-function renormalization of the first order time derivative and adapt the rescaling scheme. This yields convergent, cut-off independent predictions for all couplings. We are able to qualitatively describe the gas close to criticality, e.g. the shift of the critical temperature, and quantitatively predict low-temperature observables, e.g. condensate depletion.