One model of these substances consists of two independent phases, one condensed state and one normal state, and was formulated by Tizsa. The mixing of a working liquid and one of these substances allows cooling down to 2 millikelvins in a dilution refrigerator. One of these substances can be created using isentropic compression in a Pomeranchuk cell. These substances display quantized (10[1])vortices called rotons that can form in these substances as predicted by Landau. (10[1]-5[2])These substances (-5[1])have high thermal conductivity (10[1])due to propagating temperature waves called second sound. (10[1])Below the lambda point, (-5[1])helium-4 transitions (-5[1])to one of these (10[1])substances. (10[2])These substances can form Rollin films that enable them to creep up walls. (-5[1])For 10 points, name these substances that have zero viscosity (10[1]-5[1])and flow without friction. ■END■ (10[5])