Comment on `Strong Vortex Liquid Correlation' from Multiterminal Measurements on Untwinned YBa${}_2$Cu${}_3$O${}_{7-\delta }$ Single Crystals'

A.Rydh and "O.Rapp [Phys. Rev. Lett. {\bf 86}, 1873 (2001).] claim that the vortex liquid in untwinned YBa${}_2$Cu${}_3$O${}_{7-\delta }$ crystals is correlated above the melting transition, in striking contrast to previous work [D.L'opez {\it et al.}, Phys. Rev. Lett. {\bf 76}, 4034 (1996).]. In this Comment we present new measurements using the same experimental technique on twinned and untwinned YBa${}_2$Cu${}_3$O${}_{7-\delta }$ crystals with similar overall characteristics as those reported by Rydh and Rapp . The comparison of the vortex correlation response in both cases indicates that the central conclusion of their work is not correct. Our results reconfirm the work by L'opez {\it et al.} and points on the origin of the misinterpretation in the work of Rydh and Rapp.