We recalculate the two loop corrections in the background heat bath using real time formalism. The procedure of the integrations of loop momenta with dependence on finite temperature before the momenta without it has ...We recalculate the two loop corrections in the background heat bath using real time formalism. The procedure of the integrations of loop momenta with dependence on finite temperature before the momenta without it has been followed. We determine the mass and wavefunction renormalization constants in the low temperature limit of QED, for the first time with this preferred order of integrations. The correction to electron mass and spinors in this limit is important in the early universe at the time of primordial nucleosynthesis as well as in astrophysics.展开更多
We study the relation between chiral and UA(1)symmetries in the quark-meson model.Although quarks and mesons are described in mean field approximation,the topological susceptibility characterizing the UA(1)breaking co...We study the relation between chiral and UA(1)symmetries in the quark-meson model.Although quarks and mesons are described in mean field approximation,the topological susceptibility characterizing the UA(1)breaking comprises two components:one controlled by the condensate and the other by the meson fluctuation.The UA(1)restoration is governed by the competition of these components.In a hot medium,the condensates melt.However,the fluctuation is enhanced.Therefore,the UA(1)symmetry cannot be solely restored via the temperature effect.Nevertheless,the baryon density reduces the condensates and fluctuation,and thereby,the UA(1)symmetry can only be restored in a dense or dense and hot medium.The strange condensate plays a weak role in the susceptibility,and the chiral and UA(1)symmetry restorations occur almost at the same critical point.展开更多
文摘We recalculate the two loop corrections in the background heat bath using real time formalism. The procedure of the integrations of loop momenta with dependence on finite temperature before the momenta without it has been followed. We determine the mass and wavefunction renormalization constants in the low temperature limit of QED, for the first time with this preferred order of integrations. The correction to electron mass and spinors in this limit is important in the early universe at the time of primordial nucleosynthesis as well as in astrophysics.
基金the National Natural Science Foundation of China(11890712,12075129,2018YFA0306503,2020B0301030008)。
文摘We study the relation between chiral and UA(1)symmetries in the quark-meson model.Although quarks and mesons are described in mean field approximation,the topological susceptibility characterizing the UA(1)breaking comprises two components:one controlled by the condensate and the other by the meson fluctuation.The UA(1)restoration is governed by the competition of these components.In a hot medium,the condensates melt.However,the fluctuation is enhanced.Therefore,the UA(1)symmetry cannot be solely restored via the temperature effect.Nevertheless,the baryon density reduces the condensates and fluctuation,and thereby,the UA(1)symmetry can only be restored in a dense or dense and hot medium.The strange condensate plays a weak role in the susceptibility,and the chiral and UA(1)symmetry restorations occur almost at the same critical point.
