| Abstract: Current and future surveys aim to map the large scale structure with unprecedented accuracy. Predicting the nonlinear matter distribution in large-scale structure surveys requires balancing theoretical accuracy against computational feasibility. While Numerical Simulations are fairly accurate, they are slow and shot noise limited.
Lagrangian Perturbation Theory (LPT) provides an alternative perturbative description which involves expanding the particle displacement in powers of the initial density field. The late-time
density and velocity are calculated from the evolved displacement. Usually, LPT is applied at first order (Zeldovich approximation) or at second order (2LPT) to set up N-body initial conditions [1]. However, LPT is known to have a finite time of validity for spherically expanding voids [2]; a multi-step re-expansion scheme has been proposed to overcome this limitation [3,4]. In this work, we validate this scheme by comparing with N-body simulations and show that when compared to a single step LPT scheme, the LPT re-expansion scheme gives a more accurate reproduction of the matter power spectrum on quasi-linear scales at early epoch.
References:
[1] Crocce, Pueblas and Scoccimarro
https://ui.adsabs.harvard.edu/abs/2012ascl.soft01005C/abstract
[2] Sahni & Coles - MNRAS , 1996, Vol. 282, p. 641
[3] Nadkarni-Ghosh & Chernoff - MNRAS ,2011, Vol. 410, p. 1454
[4] Nadkarni-Ghosh & Chernoff - MNRAS , 2013, Vol. 431, p. 799 |
