Finite-size test for the finite-temperature chiral phase transition in lattice QCD

A finite-size test was carried out for the finite-temperature chiral phase transition in QCD for flavor number ${\mathit{N}}_{\mathit{f}}$=4 and 2 on a lattice with four time slices using the Kogut-Susskind quark action at quark mass of 0.025 in lattice units. All the evidence supports a first-order transition for ${\mathit{N}}_{\mathit{f}}$=4. For ${\mathit{N}}_{\mathit{f}}$=2, however, the data on spatial lattice up to ${12}^3$ fail to yield convincing finite-size signatures for a first-order transition at this quark mass.