Cosmological applications of the Brown-York quasilocal mass

The Brown-York quasilocal energy is applied to three cosmological problems which have previously been studied with the Hawking-Hayward quasilocal energy (Newtonian simulations of large scale structure formation, turnaround radius in the present accelerating universe, and lensing by the cosmological constant). It is found that, in an appropriate gauge and to first order in the amplitude of the cosmological perturbations describing local structures, the Hawking-Hayward and the Brown-York quasilocal masses predict the same results.