Fernández-Nieves, AlbertoMolina Ruiz, Fernando2026-02-132026-02-132026-01https://hdl.handle.net/2445/226869Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2026, Tutor: Alberto Fernández-NievesLiquid 4He presents a continuous phase transition at Tλ ≈ 2.17 K from a normal fluid (He I) to a superfluid (He II). This work explores the theoretical framework explaining He II’s unique behavior. We will focus on Landau’s two-fluid model, which treats He II as a mixture of a superfluid component with zero entropy that remains in the ground state, and a normal fluid component associated to the excitations of Helium. The model successfully explains key experimental phenomena and predicts the existence of second sound, a temperature wave unique to quantum fluids.8 p.application/pdfengcc-by-nc-nd (c) Molina, 2026http://creativecommons.org/licenses/by-nc-nd/4.0/SuperfluïdesaCondensació de Bose-EinsteinTreballs de fi de grauSuperfluidityBose-Einstein condensationBachelor's thesesinfo:eu-repo/semantics/bachelorThesisinfo:eu-repo/semantics/openAccess